Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block

Pull cgroup writeback support from Jens Axboe:
 "This is the big pull request for adding cgroup writeback support.

  This code has been in development for a long time, and it has been
  simmering in for-next for a good chunk of this cycle too.  This is one
  of those problems that has been talked about for at least half a
  decade, finally there's a solution and code to go with it.

  Also see last weeks writeup on LWN:

        http://lwn.net/Articles/648292/"

* 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits)
  writeback, blkio: add documentation for cgroup writeback support
  vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB
  writeback: do foreign inode detection iff cgroup writeback is enabled
  v9fs: fix error handling in v9fs_session_init()
  bdi: fix wrong error return value in cgwb_create()
  buffer: remove unusued 'ret' variable
  writeback: disassociate inodes from dying bdi_writebacks
  writeback: implement foreign cgroup inode bdi_writeback switching
  writeback: add lockdep annotation to inode_to_wb()
  writeback: use unlocked_inode_to_wb transaction in inode_congested()
  writeback: implement unlocked_inode_to_wb transaction and use it for stat updates
  writeback: implement [locked_]inode_to_wb_and_lock_list()
  writeback: implement foreign cgroup inode detection
  writeback: make writeback_control track the inode being written back
  writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
  mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use
  writeback: implement memcg writeback domain based throttling
  writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes
  writeback: implement memcg wb_domain
  writeback: update wb_over_bg_thresh() to use wb_domain aware operations
  ...

Documentation/cgroups/blkio-controller.txt

@@ -387,8 +387,81 @@ groups and put applications in that group which are not driving enough
 IO to keep disk busy. In that case set group_idle=0, and CFQ will not idle
 on individual groups and throughput should improve.
 
-What works
+Writeback
-==========
+=========
-- Currently only sync IO queues are support. All the buffered writes are
+
-  still system wide and not per group. Hence we will not see service
+Page cache is dirtied through buffered writes and shared mmaps and
-  differentiation between buffered writes between groups.
+written asynchronously to the backing filesystem by the writeback
+mechanism.  Writeback sits between the memory and IO domains and
+regulates the proportion of dirty memory by balancing dirtying and
+write IOs.
+
+On traditional cgroup hierarchies, relationships between different
+controllers cannot be established making it impossible for writeback
+to operate accounting for cgroup resource restrictions and all
+writeback IOs are attributed to the root cgroup.
+
+If both the blkio and memory controllers are used on the v2 hierarchy
+and the filesystem supports cgroup writeback, writeback operations
+correctly follow the resource restrictions imposed by both memory and
+blkio controllers.
+
+Writeback examines both system-wide and per-cgroup dirty memory status
+and enforces the more restrictive of the two.  Also, writeback control
+parameters which are absolute values - vm.dirty_bytes and
+vm.dirty_background_bytes - are distributed across cgroups according
+to their current writeback bandwidth.
+
+There's a peculiarity stemming from the discrepancy in ownership
+granularity between memory controller and writeback.  While memory
+controller tracks ownership per page, writeback operates on inode
+basis.  cgroup writeback bridges the gap by tracking ownership by
+inode but migrating ownership if too many foreign pages, pages which
+don't match the current inode ownership, have been encountered while
+writing back the inode.
+
+This is a conscious design choice as writeback operations are
+inherently tied to inodes making strictly following page ownership
+complicated and inefficient.  The only use case which suffers from
+this compromise is multiple cgroups concurrently dirtying disjoint
+regions of the same inode, which is an unlikely use case and decided
+to be unsupported.  Note that as memory controller assigns page
+ownership on the first use and doesn't update it until the page is
+released, even if cgroup writeback strictly follows page ownership,
+multiple cgroups dirtying overlapping areas wouldn't work as expected.
+In general, write-sharing an inode across multiple cgroups is not well
+supported.
+
+Filesystem support for cgroup writeback
+---------------------------------------
+
+A filesystem can make writeback IOs cgroup-aware by updating
+address_space_operations->writepage[s]() to annotate bio's using the
+following two functions.
+
+* wbc_init_bio(@wbc, @bio)
+
+  Should be called for each bio carrying writeback data and associates
+  the bio with the inode's owner cgroup.  Can be called anytime
+  between bio allocation and submission.
+
+* wbc_account_io(@wbc, @page, @bytes)
+
+  Should be called for each data segment being written out.  While
+  this function doesn't care exactly when it's called during the
+  writeback session, it's the easiest and most natural to call it as
+  data segments are added to a bio.
+
+With writeback bio's annotated, cgroup support can be enabled per
+super_block by setting MS_CGROUPWB in ->s_flags.  This allows for
+selective disabling of cgroup writeback support which is helpful when
+certain filesystem features, e.g. journaled data mode, are
+incompatible.
+
+wbc_init_bio() binds the specified bio to its cgroup.  Depending on
+the configuration, the bio may be executed at a lower priority and if
+the writeback session is holding shared resources, e.g. a journal
+entry, may lead to priority inversion.  There is no one easy solution
+for the problem.  Filesystems can try to work around specific problem
+cases by skipping wbc_init_bio() or using bio_associate_blkcg()
+directly.

Documentation/cgroups/memory.txt

@@ -493,6 +493,7 @@ pgpgin		- # of charging events to the memory cgroup. The charging
 pgpgout		- # of uncharging events to the memory cgroup. The uncharging
 		event happens each time a page is unaccounted from the cgroup.
 swap		- # of bytes of swap usage
+dirty		- # of bytes that are waiting to get written back to the disk.
 writeback	- # of bytes of file/anon cache that are queued for syncing to
 		disk.
 inactive_anon	- # of bytes of anonymous and swap cache memory on inactive

block/bio.c

@@ -1988,6 +1988,28 @@ struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_
 EXPORT_SYMBOL(bioset_create_nobvec);
 
 #ifdef CONFIG_BLK_CGROUP
+
+/**
+ * bio_associate_blkcg - associate a bio with the specified blkcg
+ * @bio: target bio
+ * @blkcg_css: css of the blkcg to associate
+ *
+ * Associate @bio with the blkcg specified by @blkcg_css.  Block layer will
+ * treat @bio as if it were issued by a task which belongs to the blkcg.
+ *
+ * This function takes an extra reference of @blkcg_css which will be put
+ * when @bio is released.  The caller must own @bio and is responsible for
+ * synchronizing calls to this function.
+ */
+int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
+{
+	if (unlikely(bio->bi_css))
+		return -EBUSY;
+	css_get(blkcg_css);
+	bio->bi_css = blkcg_css;
+	return 0;
+}
+
 /**
  * bio_associate_current - associate a bio with %current
  * @bio: target bio
@@ -2004,26 +2026,17 @@ EXPORT_SYMBOL(bioset_create_nobvec);
 int bio_associate_current(struct bio *bio)
 {
 	struct io_context *ioc;
-	struct cgroup_subsys_state *css;
 
-	if (bio->bi_ioc)
+	if (bio->bi_css)
 		return -EBUSY;
 
 	ioc = current->io_context;
 	if (!ioc)
 		return -ENOENT;
 
-	/* acquire active ref on @ioc and associate */
 	get_io_context_active(ioc);
 	bio->bi_ioc = ioc;
-
+	bio->bi_css = task_get_css(current, blkio_cgrp_id);
-	/* associate blkcg if exists */
-	rcu_read_lock();
-	css = task_css(current, blkio_cgrp_id);
-	if (css && css_tryget_online(css))
-		bio->bi_css = css;
-	rcu_read_unlock();
-
 	return 0;
 }
 

block/blk-cgroup.c

@@ -19,11 +19,12 @@
 #include <linux/module.h>
 #include <linux/err.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/slab.h>
 #include <linux/genhd.h>
 #include <linux/delay.h>
 #include <linux/atomic.h>
-#include "blk-cgroup.h"
+#include <linux/blk-cgroup.h>
 #include "blk.h"
 
 #define MAX_KEY_LEN 100
@@ -33,6 +34,8 @@ static DEFINE_MUTEX(blkcg_pol_mutex);
 struct blkcg blkcg_root;
 EXPORT_SYMBOL_GPL(blkcg_root);
 
+struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css;
+
 static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
 
 static bool blkcg_policy_enabled(struct request_queue *q,
@@ -182,6 +185,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
 				    struct blkcg_gq *new_blkg)
 {
 	struct blkcg_gq *blkg;
+	struct bdi_writeback_congested *wb_congested;
 	int i, ret;
 
 	WARN_ON_ONCE(!rcu_read_lock_held());
@@ -193,22 +197,30 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
 		goto err_free_blkg;
 	}
 
+	wb_congested = wb_congested_get_create(&q->backing_dev_info,
+					       blkcg->css.id, GFP_ATOMIC);
+	if (!wb_congested) {
+		ret = -ENOMEM;
+		goto err_put_css;
+	}
+
 	/* allocate */
 	if (!new_blkg) {
 		new_blkg = blkg_alloc(blkcg, q, GFP_ATOMIC);
 		if (unlikely(!new_blkg)) {
 			ret = -ENOMEM;
-			goto err_put_css;
+			goto err_put_congested;
 		}
 	}
 	blkg = new_blkg;
+	blkg->wb_congested = wb_congested;
 
 	/* link parent */
 	if (blkcg_parent(blkcg)) {
 		blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false);
 		if (WARN_ON_ONCE(!blkg->parent)) {
 			ret = -EINVAL;
-			goto err_put_css;
+			goto err_put_congested;
 		}
 		blkg_get(blkg->parent);
 	}
@@ -238,18 +250,15 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
 	blkg->online = true;
 	spin_unlock(&blkcg->lock);
 
-	if (!ret) {
+	if (!ret)
-		if (blkcg == &blkcg_root) {
-			q->root_blkg = blkg;
-			q->root_rl.blkg = blkg;
-		}
 		return blkg;
-	}
 
 	/* @blkg failed fully initialized, use the usual release path */
 	blkg_put(blkg);
 	return ERR_PTR(ret);
 
+err_put_congested:
+	wb_congested_put(wb_congested);
 err_put_css:
 	css_put(&blkcg->css);
 err_free_blkg:
@@ -342,15 +351,6 @@ static void blkg_destroy(struct blkcg_gq *blkg)
 	if (rcu_access_pointer(blkcg->blkg_hint) == blkg)
 		rcu_assign_pointer(blkcg->blkg_hint, NULL);
 
-	/*
-	 * If root blkg is destroyed.  Just clear the pointer since root_rl
-	 * does not take reference on root blkg.
-	 */
-	if (blkcg == &blkcg_root) {
-		blkg->q->root_blkg = NULL;
-		blkg->q->root_rl.blkg = NULL;
-	}
-
 	/*
 	 * Put the reference taken at the time of creation so that when all
 	 * queues are gone, group can be destroyed.
@@ -405,6 +405,8 @@ void __blkg_release_rcu(struct rcu_head *rcu_head)
 	if (blkg->parent)
 		blkg_put(blkg->parent);
 
+	wb_congested_put(blkg->wb_congested);
+
 	blkg_free(blkg);
 }
 EXPORT_SYMBOL_GPL(__blkg_release_rcu);
@@ -812,6 +814,8 @@ static void blkcg_css_offline(struct cgroup_subsys_state *css)
 	}
 
 	spin_unlock_irq(&blkcg->lock);
+
+	wb_blkcg_offline(blkcg);
 }
 
 static void blkcg_css_free(struct cgroup_subsys_state *css)
@@ -868,7 +872,9 @@ done:
 	spin_lock_init(&blkcg->lock);
 	INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);
 	INIT_HLIST_HEAD(&blkcg->blkg_list);
-
+#ifdef CONFIG_CGROUP_WRITEBACK
+	INIT_LIST_HEAD(&blkcg->cgwb_list);
+#endif
 	return &blkcg->css;
 
 free_pd_blkcg:
@@ -892,9 +898,45 @@ free_blkcg:
  */
 int blkcg_init_queue(struct request_queue *q)
 {
-	might_sleep();
+	struct blkcg_gq *new_blkg, *blkg;
+	bool preloaded;
+	int ret;
 
-	return blk_throtl_init(q);
+	new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
+	if (!new_blkg)
+		return -ENOMEM;
+
+	preloaded = !radix_tree_preload(GFP_KERNEL);
+
+	/*
+	 * Make sure the root blkg exists and count the existing blkgs.  As
+	 * @q is bypassing at this point, blkg_lookup_create() can't be
+	 * used.  Open code insertion.
+	 */
+	rcu_read_lock();
+	spin_lock_irq(q->queue_lock);
+	blkg = blkg_create(&blkcg_root, q, new_blkg);
+	spin_unlock_irq(q->queue_lock);
+	rcu_read_unlock();
+
+	if (preloaded)
+		radix_tree_preload_end();
+
+	if (IS_ERR(blkg)) {
+		kfree(new_blkg);
+		return PTR_ERR(blkg);
+	}
+
+	q->root_blkg = blkg;
+	q->root_rl.blkg = blkg;
+
+	ret = blk_throtl_init(q);
+	if (ret) {
+		spin_lock_irq(q->queue_lock);
+		blkg_destroy_all(q);
+		spin_unlock_irq(q->queue_lock);
+	}
+	return ret;
 }
 
 /**
@@ -996,50 +1038,19 @@ int blkcg_activate_policy(struct request_queue *q,
 {
 	LIST_HEAD(pds);
 	LIST_HEAD(cpds);
-	struct blkcg_gq *blkg, *new_blkg;
+	struct blkcg_gq *blkg;
 	struct blkg_policy_data *pd, *nd;
 	struct blkcg_policy_data *cpd, *cnd;
 	int cnt = 0, ret;
-	bool preloaded;
 
 	if (blkcg_policy_enabled(q, pol))
 		return 0;
 
-	/* preallocations for root blkg */
+	/* count and allocate policy_data for all existing blkgs */
-	new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
-	if (!new_blkg)
-		return -ENOMEM;
-
 	blk_queue_bypass_start(q);
-
-	preloaded = !radix_tree_preload(GFP_KERNEL);
-
-	/*
-	 * Make sure the root blkg exists and count the existing blkgs.  As
-	 * @q is bypassing at this point, blkg_lookup_create() can't be
-	 * used.  Open code it.
-	 */
 	spin_lock_irq(q->queue_lock);
-
-	rcu_read_lock();
-	blkg = __blkg_lookup(&blkcg_root, q, false);
-	if (blkg)
-		blkg_free(new_blkg);
-	else
-		blkg = blkg_create(&blkcg_root, q, new_blkg);
-	rcu_read_unlock();
-
-	if (preloaded)
-		radix_tree_preload_end();
-
-	if (IS_ERR(blkg)) {
-		ret = PTR_ERR(blkg);
-		goto out_unlock;
-	}
-
 	list_for_each_entry(blkg, &q->blkg_list, q_node)
 		cnt++;
-
 	spin_unlock_irq(q->queue_lock);
 
 	/*
@@ -1140,10 +1151,6 @@ void blkcg_deactivate_policy(struct request_queue *q,
 
 	__clear_bit(pol->plid, q->blkcg_pols);
 
-	/* if no policy is left, no need for blkgs - shoot them down */
-	if (bitmap_empty(q->blkcg_pols, BLKCG_MAX_POLS))
-		blkg_destroy_all(q);
-
 	list_for_each_entry(blkg, &q->blkg_list, q_node) {
 		/* grab blkcg lock too while removing @pd from @blkg */
 		spin_lock(&blkg->blkcg->lock);

block/blk-core.c

@@ -32,12 +32,12 @@
 #include <linux/delay.h>
 #include <linux/ratelimit.h>
 #include <linux/pm_runtime.h>
+#include <linux/blk-cgroup.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/block.h>
 
 #include "blk.h"
-#include "blk-cgroup.h"
 #include "blk-mq.h"
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
@@ -63,6 +63,31 @@ struct kmem_cache *blk_requestq_cachep;
  */
 static struct workqueue_struct *kblockd_workqueue;
 
+static void blk_clear_congested(struct request_list *rl, int sync)
+{
+#ifdef CONFIG_CGROUP_WRITEBACK
+	clear_wb_congested(rl->blkg->wb_congested, sync);
+#else
+	/*
+	 * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't
+	 * flip its congestion state for events on other blkcgs.
+	 */
+	if (rl == &rl->q->root_rl)
+		clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+#endif
+}
+
+static void blk_set_congested(struct request_list *rl, int sync)
+{
+#ifdef CONFIG_CGROUP_WRITEBACK
+	set_wb_congested(rl->blkg->wb_congested, sync);
+#else
+	/* see blk_clear_congested() */
+	if (rl == &rl->q->root_rl)
+		set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+#endif
+}
+
 void blk_queue_congestion_threshold(struct request_queue *q)
 {
 	int nr;
@@ -623,8 +648,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 
 	q->backing_dev_info.ra_pages =
 			(VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
-	q->backing_dev_info.state = 0;
+	q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;
-	q->backing_dev_info.capabilities = 0;
 	q->backing_dev_info.name = "block";
 	q->node = node_id;
 
@@ -847,13 +871,8 @@ static void __freed_request(struct request_list *rl, int sync)
 {
 	struct request_queue *q = rl->q;
 
-	/*
+	if (rl->count[sync] < queue_congestion_off_threshold(q))
-	 * bdi isn't aware of blkcg yet.  As all async IOs end up root
+		blk_clear_congested(rl, sync);
-	 * blkcg anyway, just use root blkcg state.
-	 */
-	if (rl == &q->root_rl &&
-	    rl->count[sync] < queue_congestion_off_threshold(q))
-		blk_clear_queue_congested(q, sync);
 
 	if (rl->count[sync] + 1 <= q->nr_requests) {
 		if (waitqueue_active(&rl->wait[sync]))
@@ -886,25 +905,25 @@ static void freed_request(struct request_list *rl, unsigned int flags)
 int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
 {
 	struct request_list *rl;
+	int on_thresh, off_thresh;
 
 	spin_lock_irq(q->queue_lock);
 	q->nr_requests = nr;
 	blk_queue_congestion_threshold(q);
-
+	on_thresh = queue_congestion_on_threshold(q);
-	/* congestion isn't cgroup aware and follows root blkcg for now */
+	off_thresh = queue_congestion_off_threshold(q);
-	rl = &q->root_rl;
-
-	if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
-		blk_set_queue_congested(q, BLK_RW_SYNC);
-	else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
-		blk_clear_queue_congested(q, BLK_RW_SYNC);
-
-	if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
-		blk_set_queue_congested(q, BLK_RW_ASYNC);
-	else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
-		blk_clear_queue_congested(q, BLK_RW_ASYNC);
 
 	blk_queue_for_each_rl(rl, q) {
+		if (rl->count[BLK_RW_SYNC] >= on_thresh)
+			blk_set_congested(rl, BLK_RW_SYNC);
+		else if (rl->count[BLK_RW_SYNC] < off_thresh)
+			blk_clear_congested(rl, BLK_RW_SYNC);
+
+		if (rl->count[BLK_RW_ASYNC] >= on_thresh)
+			blk_set_congested(rl, BLK_RW_ASYNC);
+		else if (rl->count[BLK_RW_ASYNC] < off_thresh)
+			blk_clear_congested(rl, BLK_RW_ASYNC);
+
 		if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
 			blk_set_rl_full(rl, BLK_RW_SYNC);
 		} else {
@@ -1014,12 +1033,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags,
 				}
 			}
 		}
-		/*
+		blk_set_congested(rl, is_sync);
-		 * bdi isn't aware of blkcg yet.  As all async IOs end up
-		 * root blkcg anyway, just use root blkcg state.
-		 */
-		if (rl == &q->root_rl)
-			blk_set_queue_congested(q, is_sync);
 	}
 
 	/*

block/blk-integrity.c

@@ -21,6 +21,7 @@
  */
 
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/mempool.h>
 #include <linux/bio.h>
 #include <linux/scatterlist.h>

block/blk-sysfs.c

@@ -6,11 +6,12 @@
 #include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/blktrace_api.h>
 #include <linux/blk-mq.h>
+#include <linux/blk-cgroup.h>
 
 #include "blk.h"
-#include "blk-cgroup.h"
 #include "blk-mq.h"
 
 struct queue_sysfs_entry {

block/blk-throttle.c

@@ -9,7 +9,7 @@
 #include <linux/blkdev.h>
 #include <linux/bio.h>
 #include <linux/blktrace_api.h>
-#include "blk-cgroup.h"
+#include <linux/blk-cgroup.h>
 #include "blk.h"
 
 /* Max dispatch from a group in 1 round */

block/bounce.c

@@ -13,6 +13,7 @@
 #include <linux/pagemap.h>
 #include <linux/mempool.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/init.h>
 #include <linux/hash.h>
 #include <linux/highmem.h>

block/cfq-iosched.c

@@ -14,8 +14,8 @@
 #include <linux/rbtree.h>
 #include <linux/ioprio.h>
 #include <linux/blktrace_api.h>
+#include <linux/blk-cgroup.h>
 #include "blk.h"
-#include "blk-cgroup.h"
 
 /*
  * tunables

block/elevator.c

@@ -35,11 +35,11 @@
 #include <linux/hash.h>
 #include <linux/uaccess.h>
 #include <linux/pm_runtime.h>
+#include <linux/blk-cgroup.h>
 
 #include <trace/events/block.h>
 
 #include "blk.h"
-#include "blk-cgroup.h"
 
 static DEFINE_SPINLOCK(elv_list_lock);
 static LIST_HEAD(elv_list);

block/genhd.c

@@ -8,6 +8,7 @@
 #include <linux/kdev_t.h>
 #include <linux/kernel.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/init.h>
 #include <linux/spinlock.h>
 #include <linux/proc_fs.h>

drivers/block/drbd/drbd_int.h

@@ -38,6 +38,7 @@
 #include <linux/mutex.h>
 #include <linux/major.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/genhd.h>
 #include <linux/idr.h>
 #include <net/tcp.h>

drivers/block/drbd/drbd_main.c

@@ -2359,7 +2359,7 @@ static void drbd_cleanup(void)
  * @congested_data:	User data
  * @bdi_bits:		Bits the BDI flusher thread is currently interested in
  *
- * Returns 1<<BDI_async_congested and/or 1<<BDI_sync_congested if we are congested.
+ * Returns 1<<WB_async_congested and/or 1<<WB_sync_congested if we are congested.
  */
 static int drbd_congested(void *congested_data, int bdi_bits)
 {
@@ -2376,14 +2376,14 @@ static int drbd_congested(void *congested_data, int bdi_bits)
 	}
 
 	if (test_bit(CALLBACK_PENDING, &first_peer_device(device)->connection->flags)) {
-		r |= (1 << BDI_async_congested);
+		r |= (1 << WB_async_congested);
 		/* Without good local data, we would need to read from remote,
 		 * and that would need the worker thread as well, which is
 		 * currently blocked waiting for that usermode helper to
 		 * finish.
 		 */
 		if (!get_ldev_if_state(device, D_UP_TO_DATE))
-			r |= (1 << BDI_sync_congested);
+			r |= (1 << WB_sync_congested);
 		else
 			put_ldev(device);
 		r &= bdi_bits;
@@ -2399,9 +2399,9 @@ static int drbd_congested(void *congested_data, int bdi_bits)
 			reason = 'b';
 	}
 
-	if (bdi_bits & (1 << BDI_async_congested) &&
+	if (bdi_bits & (1 << WB_async_congested) &&
 	    test_bit(NET_CONGESTED, &first_peer_device(device)->connection->flags)) {
-		r |= (1 << BDI_async_congested);
+		r |= (1 << WB_async_congested);
 		reason = reason == 'b' ? 'a' : 'n';
 	}
 

drivers/block/pktcdvd.c

@@ -61,6 +61,7 @@
 #include <linux/freezer.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/backing-dev.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_ioctl.h>
 #include <scsi/scsi.h>

drivers/char/raw.c

@@ -12,6 +12,7 @@
 #include <linux/fs.h>
 #include <linux/major.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/module.h>
 #include <linux/raw.h>
 #include <linux/capability.h>

drivers/md/bcache/request.c

@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/hash.h>
 #include <linux/random.h>
+#include <linux/backing-dev.h>
 
 #include <trace/events/bcache.h>
 

drivers/md/dm.c

@@ -2080,7 +2080,7 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
 			 * the query about congestion status of request_queue
 			 */
 			if (dm_request_based(md))
-				r = md->queue->backing_dev_info.state &
+				r = md->queue->backing_dev_info.wb.state &
 				    bdi_bits;
 			else
 				r = dm_table_any_congested(map, bdi_bits);

drivers/md/dm.h

@@ -14,6 +14,7 @@
 #include <linux/device-mapper.h>
 #include <linux/list.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/hdreg.h>
 #include <linux/completion.h>
 #include <linux/kobject.h>

drivers/md/md.h

@@ -16,6 +16,7 @@
 #define _MD_MD_H
 
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/kobject.h>
 #include <linux/list.h>
 #include <linux/mm.h>

drivers/md/raid1.c

@@ -745,7 +745,7 @@ static int raid1_congested(struct mddev *mddev, int bits)
 	struct r1conf *conf = mddev->private;
 	int i, ret = 0;
 
-	if ((bits & (1 << BDI_async_congested)) &&
+	if ((bits & (1 << WB_async_congested)) &&
 	    conf->pending_count >= max_queued_requests)
 		return 1;
 
@@ -760,7 +760,7 @@ static int raid1_congested(struct mddev *mddev, int bits)
 			/* Note the '|| 1' - when read_balance prefers
 			 * non-congested targets, it can be removed
 			 */
-			if ((bits & (1<<BDI_async_congested)) || 1)
+			if ((bits & (1 << WB_async_congested)) || 1)
 				ret |= bdi_congested(&q->backing_dev_info, bits);
 			else
 				ret &= bdi_congested(&q->backing_dev_info, bits);

drivers/md/raid10.c

@@ -914,7 +914,7 @@ static int raid10_congested(struct mddev *mddev, int bits)
 	struct r10conf *conf = mddev->private;
 	int i, ret = 0;
 
-	if ((bits & (1 << BDI_async_congested)) &&
+	if ((bits & (1 << WB_async_congested)) &&
 	    conf->pending_count >= max_queued_requests)
 		return 1;
 

drivers/mtd/devices/block2mtd.c

@@ -20,6 +20,7 @@
 #include <linux/delay.h>
 #include <linux/fs.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/bio.h>
 #include <linux/pagemap.h>
 #include <linux/list.h>

drivers/staging/lustre/lustre/include/linux/lustre_patchless_compat.h

@@ -55,9 +55,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
 	if (PagePrivate(page))
 		page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
 
-	if (TestClearPageDirty(page))
+	cancel_dirty_page(page);
-		account_page_cleaned(page, mapping);
-
 	ClearPageMappedToDisk(page);
 	ll_delete_from_page_cache(page);
 }

fs/9p/v9fs.c

@@ -320,31 +320,21 @@ fail_option_alloc:
 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 		  const char *dev_name, char *data)
 {
-	int retval = -EINVAL;
 	struct p9_fid *fid;
-	int rc;
+	int rc = -ENOMEM;
 
 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 	if (!v9ses->uname)
-		return ERR_PTR(-ENOMEM);
+		goto err_names;
 
 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
-	if (!v9ses->aname) {
+	if (!v9ses->aname)
-		kfree(v9ses->uname);
+		goto err_names;
-		return ERR_PTR(-ENOMEM);
-	}
 	init_rwsem(&v9ses->rename_sem);
 
 	rc = bdi_setup_and_register(&v9ses->bdi, "9p");
-	if (rc) {
+	if (rc)
-		kfree(v9ses->aname);
+		goto err_names;
-		kfree(v9ses->uname);
-		return ERR_PTR(rc);
-	}
-
-	spin_lock(&v9fs_sessionlist_lock);
-	list_add(&v9ses->slist, &v9fs_sessionlist);
-	spin_unlock(&v9fs_sessionlist_lock);
 
 	v9ses->uid = INVALID_UID;
 	v9ses->dfltuid = V9FS_DEFUID;
@@ -352,10 +342,9 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 
 	v9ses->clnt = p9_client_create(dev_name, data);
 	if (IS_ERR(v9ses->clnt)) {
-		retval = PTR_ERR(v9ses->clnt);
+		rc = PTR_ERR(v9ses->clnt);
-		v9ses->clnt = NULL;
 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
-		goto error;
+		goto err_bdi;
 	}
 
 	v9ses->flags = V9FS_ACCESS_USER;
@@ -368,10 +357,8 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	}
 
 	rc = v9fs_parse_options(v9ses, data);
-	if (rc < 0) {
+	if (rc < 0)
-		retval = rc;
+		goto err_clnt;
-		goto error;
-	}
 
 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 
@@ -405,10 +392,9 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
 							v9ses->aname);
 	if (IS_ERR(fid)) {
-		retval = PTR_ERR(fid);
+		rc = PTR_ERR(fid);
-		fid = NULL;
 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
-		goto error;
+		goto err_clnt;
 	}
 
 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
@@ -420,12 +406,20 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	/* register the session for caching */
 	v9fs_cache_session_get_cookie(v9ses);
 #endif
+	spin_lock(&v9fs_sessionlist_lock);
+	list_add(&v9ses->slist, &v9fs_sessionlist);
+	spin_unlock(&v9fs_sessionlist_lock);
 
 	return fid;
 
-error:
+err_clnt:
+	p9_client_destroy(v9ses->clnt);
+err_bdi:
 	bdi_destroy(&v9ses->bdi);
-	return ERR_PTR(retval);
+err_names:
+	kfree(v9ses->uname);
+	kfree(v9ses->aname);
+	return ERR_PTR(rc);
 }
 
 /**

fs/9p/vfs_super.c

@@ -130,11 +130,7 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 	fid = v9fs_session_init(v9ses, dev_name, data);
 	if (IS_ERR(fid)) {
 		retval = PTR_ERR(fid);
-		/*
+		goto free_session;
-		 * we need to call session_close to tear down some
-		 * of the data structure setup by session_init
-		 */
-		goto close_session;
 	}
 
 	sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
@@ -195,8 +191,8 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 
 clunk_fid:
 	p9_client_clunk(fid);
-close_session:
 	v9fs_session_close(v9ses);
+free_session:
 	kfree(v9ses);
 	return ERR_PTR(retval);
 

fs/block_dev.c

@@ -14,6 +14,7 @@
 #include <linux/device_cgroup.h>
 #include <linux/highmem.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/module.h>
 #include <linux/blkpg.h>
 #include <linux/magic.h>
@@ -546,7 +547,8 @@ static struct file_system_type bd_type = {
 	.kill_sb	= kill_anon_super,
 };
 
-static struct super_block *blockdev_superblock __read_mostly;
+struct super_block *blockdev_superblock __read_mostly;
+EXPORT_SYMBOL_GPL(blockdev_superblock);
 
 void __init bdev_cache_init(void)
 {
@@ -687,11 +689,6 @@ static struct block_device *bd_acquire(struct inode *inode)
 	return bdev;
 }
 
-int sb_is_blkdev_sb(struct super_block *sb)
-{
-	return sb == blockdev_superblock;
-}
-
 /* Call when you free inode */
 
 void bd_forget(struct inode *inode)

fs/buffer.c

@@ -30,6 +30,7 @@
 #include <linux/quotaops.h>
 #include <linux/highmem.h>
 #include <linux/export.h>
+#include <linux/backing-dev.h>
 #include <linux/writeback.h>
 #include <linux/hash.h>
 #include <linux/suspend.h>
@@ -44,6 +45,9 @@
 #include <trace/events/block.h>
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
+static int submit_bh_wbc(int rw, struct buffer_head *bh,
+			 unsigned long bio_flags,
+			 struct writeback_control *wbc);
 
 #define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)
 
@@ -623,21 +627,22 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode);
  *
  * If warn is true, then emit a warning if the page is not uptodate and has
  * not been truncated.
+ *
+ * The caller must hold mem_cgroup_begin_page_stat() lock.
  */
-static void __set_page_dirty(struct page *page,
+static void __set_page_dirty(struct page *page, struct address_space *mapping,
-		struct address_space *mapping, int warn)
+			     struct mem_cgroup *memcg, int warn)
 {
 	unsigned long flags;
 
 	spin_lock_irqsave(&mapping->tree_lock, flags);
 	if (page->mapping) {	/* Race with truncate? */
 		WARN_ON_ONCE(warn && !PageUptodate(page));
-		account_page_dirtied(page, mapping);
+		account_page_dirtied(page, mapping, memcg);
 		radix_tree_tag_set(&mapping->page_tree,
 				page_index(page), PAGECACHE_TAG_DIRTY);
 	}
 	spin_unlock_irqrestore(&mapping->tree_lock, flags);
-	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 }
 
 /*
@@ -668,6 +673,7 @@ static void __set_page_dirty(struct page *page,
 int __set_page_dirty_buffers(struct page *page)
 {
 	int newly_dirty;
+	struct mem_cgroup *memcg;
 	struct address_space *mapping = page_mapping(page);
 
 	if (unlikely(!mapping))
@@ -683,11 +689,22 @@ int __set_page_dirty_buffers(struct page *page)
 			bh = bh->b_this_page;
 		} while (bh != head);
 	}
+	/*
+	 * Use mem_group_begin_page_stat() to keep PageDirty synchronized with
+	 * per-memcg dirty page counters.
+	 */
+	memcg = mem_cgroup_begin_page_stat(page);
 	newly_dirty = !TestSetPageDirty(page);
 	spin_unlock(&mapping->private_lock);
 
 	if (newly_dirty)
-		__set_page_dirty(page, mapping, 1);
+		__set_page_dirty(page, mapping, memcg, 1);
+
+	mem_cgroup_end_page_stat(memcg);
+
+	if (newly_dirty)
+		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+
 	return newly_dirty;
 }
 EXPORT_SYMBOL(__set_page_dirty_buffers);
@@ -1158,11 +1175,18 @@ void mark_buffer_dirty(struct buffer_head *bh)
 
 	if (!test_set_buffer_dirty(bh)) {
 		struct page *page = bh->b_page;
+		struct address_space *mapping = NULL;
+		struct mem_cgroup *memcg;
+
+		memcg = mem_cgroup_begin_page_stat(page);
 		if (!TestSetPageDirty(page)) {
-			struct address_space *mapping = page_mapping(page);
+			mapping = page_mapping(page);
 			if (mapping)
-				__set_page_dirty(page, mapping, 0);
+				__set_page_dirty(page, mapping, memcg, 0);
 		}
+		mem_cgroup_end_page_stat(memcg);
+		if (mapping)
+			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 	}
 }
 EXPORT_SYMBOL(mark_buffer_dirty);
@@ -1684,8 +1708,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
 	struct buffer_head *bh, *head;
 	unsigned int blocksize, bbits;
 	int nr_underway = 0;
-	int write_op = (wbc->sync_mode == WB_SYNC_ALL ?
+	int write_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
-			WRITE_SYNC : WRITE);
 
 	head = create_page_buffers(page, inode,
 					(1 << BH_Dirty)|(1 << BH_Uptodate));
@@ -1774,7 +1797,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
 	do {
 		struct buffer_head *next = bh->b_this_page;
 		if (buffer_async_write(bh)) {
-			submit_bh(write_op, bh);
+			submit_bh_wbc(write_op, bh, 0, wbc);
 			nr_underway++;
 		}
 		bh = next;
@@ -1828,7 +1851,7 @@ recover:
 		struct buffer_head *next = bh->b_this_page;
 		if (buffer_async_write(bh)) {
 			clear_buffer_dirty(bh);
-			submit_bh(write_op, bh);
+			submit_bh_wbc(write_op, bh, 0, wbc);
 			nr_underway++;
 		}
 		bh = next;
@@ -2993,7 +3016,8 @@ void guard_bio_eod(int rw, struct bio *bio)
 	}
 }
 
-int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
+static int submit_bh_wbc(int rw, struct buffer_head *bh,
+			 unsigned long bio_flags, struct writeback_control *wbc)
 {
 	struct bio *bio;
 
@@ -3015,6 +3039,11 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
 	 */
 	bio = bio_alloc(GFP_NOIO, 1);
 
+	if (wbc) {
+		wbc_init_bio(wbc, bio);
+		wbc_account_io(wbc, bh->b_page, bh->b_size);
+	}
+
 	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
 	bio->bi_bdev = bh->b_bdev;
 	bio->bi_io_vec[0].bv_page = bh->b_page;
@@ -3039,11 +3068,16 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
 	submit_bio(rw, bio);
 	return 0;
 }
+
+int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
+{
+	return submit_bh_wbc(rw, bh, bio_flags, NULL);
+}
 EXPORT_SYMBOL_GPL(_submit_bh);
 
 int submit_bh(int rw, struct buffer_head *bh)
 {
-	return _submit_bh(rw, bh, 0);
+	return submit_bh_wbc(rw, bh, 0, NULL);
 }
 EXPORT_SYMBOL(submit_bh);
 
@@ -3232,8 +3266,8 @@ int try_to_free_buffers(struct page *page)
 	 * to synchronise against __set_page_dirty_buffers and prevent the
 	 * dirty bit from being lost.
 	 */
-	if (ret && TestClearPageDirty(page))
+	if (ret)
-		account_page_cleaned(page, mapping);
+		cancel_dirty_page(page);
 	spin_unlock(&mapping->private_lock);
 out:
 	if (buffers_to_free) {

fs/ext2/super.c

@@ -882,6 +882,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 		((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 		 MS_POSIXACL : 0);
+	sb->s_iflags |= SB_I_CGROUPWB;
 
 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||

fs/ext4/extents.c

@@ -39,6 +39,7 @@
 #include <linux/slab.h>
 #include <asm/uaccess.h>
 #include <linux/fiemap.h>
+#include <linux/backing-dev.h>
 #include "ext4_jbd2.h"
 #include "ext4_extents.h"
 #include "xattr.h"

fs/ext4/mballoc.c

@@ -26,6 +26,7 @@
 #include <linux/log2.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/backing-dev.h>
 #include <trace/events/ext4.h>
 
 #ifdef CONFIG_EXT4_DEBUG

fs/ext4/super.c

@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/parser.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>

fs/f2fs/node.c

@@ -53,7 +53,7 @@ bool available_free_memory(struct f2fs_sb_info *sbi, int type)
 							PAGE_CACHE_SHIFT;
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 2);
 	} else if (type == DIRTY_DENTS) {
-		if (sbi->sb->s_bdi->dirty_exceeded)
+		if (sbi->sb->s_bdi->wb.dirty_exceeded)
 			return false;
 		mem_size = get_pages(sbi, F2FS_DIRTY_DENTS);
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
@@ -70,7 +70,7 @@ bool available_free_memory(struct f2fs_sb_info *sbi, int type)
 				sizeof(struct extent_node)) >> PAGE_CACHE_SHIFT;
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
 	} else {
-		if (sbi->sb->s_bdi->dirty_exceeded)
+		if (sbi->sb->s_bdi->wb.dirty_exceeded)
 			return false;
 	}
 	return res;

fs/f2fs/segment.h

@@ -9,6 +9,7 @@
  * published by the Free Software Foundation.
  */
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 
 /* constant macro */
 #define NULL_SEGNO			((unsigned int)(~0))
@@ -714,7 +715,7 @@ static inline unsigned int max_hw_blocks(struct f2fs_sb_info *sbi)
  */
 static inline int nr_pages_to_skip(struct f2fs_sb_info *sbi, int type)
 {
-	if (sbi->sb->s_bdi->dirty_exceeded)
+	if (sbi->sb->s_bdi->wb.dirty_exceeded)
 		return 0;
 
 	if (type == DATA)

fs/fat/file.c

@@ -11,6 +11,7 @@
 #include <linux/compat.h>
 #include <linux/mount.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/fsnotify.h>
 #include <linux/security.h>
 #include "fat.h"

fs/fat/inode.c

@@ -18,6 +18,7 @@
 #include <linux/parser.h>
 #include <linux/uio.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <asm/unaligned.h>
 #include "fat.h"
 

fs/fuse/file.c

@@ -1445,9 +1445,9 @@ static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
 
 	list_del(&req->writepages_entry);
 	for (i = 0; i < req->num_pages; i++) {
-		dec_bdi_stat(bdi, BDI_WRITEBACK);
+		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
 		dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP);
-		bdi_writeout_inc(bdi);
+		wb_writeout_inc(&bdi->wb);
 	}
 	wake_up(&fi->page_waitq);
 }
@@ -1634,7 +1634,7 @@ static int fuse_writepage_locked(struct page *page)
 	req->end = fuse_writepage_end;
 	req->inode = inode;
 
-	inc_bdi_stat(inode_to_bdi(inode), BDI_WRITEBACK);
+	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
 	inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
 
 	spin_lock(&fc->lock);
@@ -1749,9 +1749,9 @@ static bool fuse_writepage_in_flight(struct fuse_req *new_req,
 		copy_highpage(old_req->pages[0], page);
 		spin_unlock(&fc->lock);
 
-		dec_bdi_stat(bdi, BDI_WRITEBACK);
+		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
 		dec_zone_page_state(page, NR_WRITEBACK_TEMP);
-		bdi_writeout_inc(bdi);
+		wb_writeout_inc(&bdi->wb);
 		fuse_writepage_free(fc, new_req);
 		fuse_request_free(new_req);
 		goto out;
@@ -1848,7 +1848,7 @@ static int fuse_writepages_fill(struct page *page,
 	req->page_descs[req->num_pages].offset = 0;
 	req->page_descs[req->num_pages].length = PAGE_SIZE;
 
-	inc_bdi_stat(inode_to_bdi(inode), BDI_WRITEBACK);
+	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
 	inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
 
 	err = 0;

fs/gfs2/super.c

@@ -748,7 +748,7 @@ static int gfs2_write_inode(struct inode *inode, struct writeback_control *wbc)
 
 	if (wbc->sync_mode == WB_SYNC_ALL)
 		gfs2_log_flush(GFS2_SB(inode), ip->i_gl, NORMAL_FLUSH);
-	if (bdi->dirty_exceeded)
+	if (bdi->wb.dirty_exceeded)
 		gfs2_ail1_flush(sdp, wbc);
 	else
 		filemap_fdatawrite(metamapping);

fs/hfs/super.c

@@ -14,6 +14,7 @@
 
 #include <linux/module.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/mount.h>
 #include <linux/init.h>
 #include <linux/nls.h>

fs/hfsplus/super.c

@@ -11,6 +11,7 @@
 #include <linux/init.h>
 #include <linux/pagemap.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/vfs.h>

fs/inode.c

@@ -224,6 +224,7 @@ EXPORT_SYMBOL(free_inode_nonrcu);
 void __destroy_inode(struct inode *inode)
 {
 	BUG_ON(inode_has_buffers(inode));
+	inode_detach_wb(inode);
 	security_inode_free(inode);
 	fsnotify_inode_delete(inode);
 	locks_free_lock_context(inode->i_flctx);

fs/mpage.c

@@ -605,6 +605,8 @@ alloc_new:
 				bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH);
 		if (bio == NULL)
 			goto confused;
+
+		wbc_init_bio(wbc, bio);
 	}
 
 	/*
@@ -612,6 +614,7 @@ alloc_new:
 	 * the confused fail path above (OOM) will be very confused when
 	 * it finds all bh marked clean (i.e. it will not write anything)
 	 */
+	wbc_account_io(wbc, page, PAGE_SIZE);
 	length = first_unmapped << blkbits;
 	if (bio_add_page(bio, page, length, 0) < length) {
 		bio = mpage_bio_submit(WRITE, bio);

fs/nfs/filelayout/filelayout.c

@@ -32,6 +32,7 @@
 #include <linux/nfs_fs.h>
 #include <linux/nfs_page.h>
 #include <linux/module.h>
+#include <linux/backing-dev.h>
 
 #include <linux/sunrpc/metrics.h>
 

fs/nfs/internal.h

@@ -607,7 +607,7 @@ void nfs_mark_page_unstable(struct page *page)
 	struct inode *inode = page_file_mapping(page)->host;
 
 	inc_zone_page_state(page, NR_UNSTABLE_NFS);
-	inc_bdi_stat(inode_to_bdi(inode), BDI_RECLAIMABLE);
+	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_RECLAIMABLE);
 	 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 }
 

fs/nfs/write.c

@@ -853,7 +853,8 @@ static void
 nfs_clear_page_commit(struct page *page)
 {
 	dec_zone_page_state(page, NR_UNSTABLE_NFS);
-	dec_bdi_stat(inode_to_bdi(page_file_mapping(page)->host), BDI_RECLAIMABLE);
+	dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb,
+		    WB_RECLAIMABLE);
 }
 
 /* Called holding inode (/cinfo) lock */

fs/ocfs2/file.c

@@ -37,6 +37,7 @@
 #include <linux/falloc.h>
 #include <linux/quotaops.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 
 #include <cluster/masklog.h>
 

fs/reiserfs/super.c

@@ -21,6 +21,7 @@
 #include "xattr.h"
 #include <linux/init.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>
 #include <linux/quotaops.h>

fs/ufs/super.c

@@ -80,6 +80,7 @@
 #include <linux/stat.h>
 #include <linux/string.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/init.h>
 #include <linux/parser.h>
 #include <linux/buffer_head.h>

fs/xfs/xfs_aops.c

@@ -1873,6 +1873,7 @@ xfs_vm_set_page_dirty(
 	loff_t			end_offset;
 	loff_t			offset;
 	int			newly_dirty;
+	struct mem_cgroup	*memcg;
 
 	if (unlikely(!mapping))
 		return !TestSetPageDirty(page);
@@ -1892,6 +1893,11 @@ xfs_vm_set_page_dirty(
 			offset += 1 << inode->i_blkbits;
 		} while (bh != head);
 	}
+	/*
+	 * Use mem_group_begin_page_stat() to keep PageDirty synchronized with
+	 * per-memcg dirty page counters.
+	 */
+	memcg = mem_cgroup_begin_page_stat(page);
 	newly_dirty = !TestSetPageDirty(page);
 	spin_unlock(&mapping->private_lock);
 
@@ -1902,13 +1908,15 @@ xfs_vm_set_page_dirty(
 		spin_lock_irqsave(&mapping->tree_lock, flags);
 		if (page->mapping) {	/* Race with truncate? */
 			WARN_ON_ONCE(!PageUptodate(page));
-			account_page_dirtied(page, mapping);
+			account_page_dirtied(page, mapping, memcg);
 			radix_tree_tag_set(&mapping->page_tree,
 					page_index(page), PAGECACHE_TAG_DIRTY);
 		}
 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
-		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 	}
+	mem_cgroup_end_page_stat(memcg);
+	if (newly_dirty)
+		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 	return newly_dirty;
 }
 

fs/xfs/xfs_file.c

@@ -41,6 +41,7 @@
 #include <linux/dcache.h>
 #include <linux/falloc.h>
 #include <linux/pagevec.h>
+#include <linux/backing-dev.h>
 
 static const struct vm_operations_struct xfs_file_vm_ops;
 

include/linux/backing-dev-defs.h

@@ -0,0 +1,255 @@
+#ifndef __LINUX_BACKING_DEV_DEFS_H
+#define __LINUX_BACKING_DEV_DEFS_H
+
+#include <linux/list.h>
+#include <linux/radix-tree.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/percpu_counter.h>
+#include <linux/percpu-refcount.h>
+#include <linux/flex_proportions.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+
+struct page;
+struct device;
+struct dentry;
+
+/*
+ * Bits in bdi_writeback.state
+ */
+enum wb_state {
+	WB_registered,		/* bdi_register() was done */
+	WB_writeback_running,	/* Writeback is in progress */
+	WB_has_dirty_io,	/* Dirty inodes on ->b_{dirty|io|more_io} */
+};
+
+enum wb_congested_state {
+	WB_async_congested,	/* The async (write) queue is getting full */
+	WB_sync_congested,	/* The sync queue is getting full */
+};
+
+typedef int (congested_fn)(void *, int);
+
+enum wb_stat_item {
+	WB_RECLAIMABLE,
+	WB_WRITEBACK,
+	WB_DIRTIED,
+	WB_WRITTEN,
+	NR_WB_STAT_ITEMS
+};
+
+#define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
+
+/*
+ * For cgroup writeback, multiple wb's may map to the same blkcg.  Those
+ * wb's can operate mostly independently but should share the congested
+ * state.  To facilitate such sharing, the congested state is tracked using
+ * the following struct which is created on demand, indexed by blkcg ID on
+ * its bdi, and refcounted.
+ */
+struct bdi_writeback_congested {
+	unsigned long state;		/* WB_[a]sync_congested flags */
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct backing_dev_info *bdi;	/* the associated bdi */
+	atomic_t refcnt;		/* nr of attached wb's and blkg */
+	int blkcg_id;			/* ID of the associated blkcg */
+	struct rb_node rb_node;		/* on bdi->cgwb_congestion_tree */
+#endif
+};
+
+/*
+ * Each wb (bdi_writeback) can perform writeback operations, is measured
+ * and throttled, independently.  Without cgroup writeback, each bdi
+ * (bdi_writeback) is served by its embedded bdi->wb.
+ *
+ * On the default hierarchy, blkcg implicitly enables memcg.  This allows
+ * using memcg's page ownership for attributing writeback IOs, and every
+ * memcg - blkcg combination can be served by its own wb by assigning a
+ * dedicated wb to each memcg, which enables isolation across different
+ * cgroups and propagation of IO back pressure down from the IO layer upto
+ * the tasks which are generating the dirty pages to be written back.
+ *
+ * A cgroup wb is indexed on its bdi by the ID of the associated memcg,
+ * refcounted with the number of inodes attached to it, and pins the memcg
+ * and the corresponding blkcg.  As the corresponding blkcg for a memcg may
+ * change as blkcg is disabled and enabled higher up in the hierarchy, a wb
+ * is tested for blkcg after lookup and removed from index on mismatch so
+ * that a new wb for the combination can be created.
+ */
+struct bdi_writeback {
+	struct backing_dev_info *bdi;	/* our parent bdi */
+
+	unsigned long state;		/* Always use atomic bitops on this */
+	unsigned long last_old_flush;	/* last old data flush */
+
+	struct list_head b_dirty;	/* dirty inodes */
+	struct list_head b_io;		/* parked for writeback */
+	struct list_head b_more_io;	/* parked for more writeback */
+	struct list_head b_dirty_time;	/* time stamps are dirty */
+	spinlock_t list_lock;		/* protects the b_* lists */
+
+	struct percpu_counter stat[NR_WB_STAT_ITEMS];
+
+	struct bdi_writeback_congested *congested;
+
+	unsigned long bw_time_stamp;	/* last time write bw is updated */
+	unsigned long dirtied_stamp;
+	unsigned long written_stamp;	/* pages written at bw_time_stamp */
+	unsigned long write_bandwidth;	/* the estimated write bandwidth */
+	unsigned long avg_write_bandwidth; /* further smoothed write bw, > 0 */
+
+	/*
+	 * The base dirty throttle rate, re-calculated on every 200ms.
+	 * All the bdi tasks' dirty rate will be curbed under it.
+	 * @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
+	 * in small steps and is much more smooth/stable than the latter.
+	 */
+	unsigned long dirty_ratelimit;
+	unsigned long balanced_dirty_ratelimit;
+
+	struct fprop_local_percpu completions;
+	int dirty_exceeded;
+
+	spinlock_t work_lock;		/* protects work_list & dwork scheduling */
+	struct list_head work_list;
+	struct delayed_work dwork;	/* work item used for writeback */
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct percpu_ref refcnt;	/* used only for !root wb's */
+	struct fprop_local_percpu memcg_completions;
+	struct cgroup_subsys_state *memcg_css; /* the associated memcg */
+	struct cgroup_subsys_state *blkcg_css; /* and blkcg */
+	struct list_head memcg_node;	/* anchored at memcg->cgwb_list */
+	struct list_head blkcg_node;	/* anchored at blkcg->cgwb_list */
+
+	union {
+		struct work_struct release_work;
+		struct rcu_head rcu;
+	};
+#endif
+};
+
+struct backing_dev_info {
+	struct list_head bdi_list;
+	unsigned long ra_pages;	/* max readahead in PAGE_CACHE_SIZE units */
+	unsigned int capabilities; /* Device capabilities */
+	congested_fn *congested_fn; /* Function pointer if device is md/dm */
+	void *congested_data;	/* Pointer to aux data for congested func */
+
+	char *name;
+
+	unsigned int min_ratio;
+	unsigned int max_ratio, max_prop_frac;
+
+	/*
+	 * Sum of avg_write_bw of wbs with dirty inodes.  > 0 if there are
+	 * any dirty wbs, which is depended upon by bdi_has_dirty().
+	 */
+	atomic_long_t tot_write_bandwidth;
+
+	struct bdi_writeback wb;  /* the root writeback info for this bdi */
+	struct bdi_writeback_congested wb_congested; /* its congested state */
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */
+	struct rb_root cgwb_congested_tree; /* their congested states */
+	atomic_t usage_cnt; /* counts both cgwbs and cgwb_contested's */
+#endif
+	wait_queue_head_t wb_waitq;
+
+	struct device *dev;
+
+	struct timer_list laptop_mode_wb_timer;
+
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *debug_dir;
+	struct dentry *debug_stats;
+#endif
+};
+
+enum {
+	BLK_RW_ASYNC	= 0,
+	BLK_RW_SYNC	= 1,
+};
+
+void clear_wb_congested(struct bdi_writeback_congested *congested, int sync);
+void set_wb_congested(struct bdi_writeback_congested *congested, int sync);
+
+static inline void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
+{
+	clear_wb_congested(bdi->wb.congested, sync);
+}
+
+static inline void set_bdi_congested(struct backing_dev_info *bdi, int sync)
+{
+	set_wb_congested(bdi->wb.congested, sync);
+}
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+/**
+ * wb_tryget - try to increment a wb's refcount
+ * @wb: bdi_writeback to get
+ */
+static inline bool wb_tryget(struct bdi_writeback *wb)
+{
+	if (wb != &wb->bdi->wb)
+		return percpu_ref_tryget(&wb->refcnt);
+	return true;
+}
+
+/**
+ * wb_get - increment a wb's refcount
+ * @wb: bdi_writeback to get
+ */
+static inline void wb_get(struct bdi_writeback *wb)
+{
+	if (wb != &wb->bdi->wb)
+		percpu_ref_get(&wb->refcnt);
+}
+
+/**
+ * wb_put - decrement a wb's refcount
+ * @wb: bdi_writeback to put
+ */
+static inline void wb_put(struct bdi_writeback *wb)
+{
+	if (wb != &wb->bdi->wb)
+		percpu_ref_put(&wb->refcnt);
+}
+
+/**
+ * wb_dying - is a wb dying?
+ * @wb: bdi_writeback of interest
+ *
+ * Returns whether @wb is unlinked and being drained.
+ */
+static inline bool wb_dying(struct bdi_writeback *wb)
+{
+	return percpu_ref_is_dying(&wb->refcnt);
+}
+
+#else	/* CONFIG_CGROUP_WRITEBACK */
+
+static inline bool wb_tryget(struct bdi_writeback *wb)
+{
+	return true;
+}
+
+static inline void wb_get(struct bdi_writeback *wb)
+{
+}
+
+static inline void wb_put(struct bdi_writeback *wb)
+{
+}
+
+static inline bool wb_dying(struct bdi_writeback *wb)
+{
+	return false;
+}
+
+#endif	/* CONFIG_CGROUP_WRITEBACK */
+
+#endif	/* __LINUX_BACKING_DEV_DEFS_H */

include/linux/backing-dev.h

@@ -8,106 +8,13 @@
 #ifndef _LINUX_BACKING_DEV_H
 #define _LINUX_BACKING_DEV_H
 
-#include <linux/percpu_counter.h>
-#include <linux/log2.h>
-#include <linux/flex_proportions.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
-#include <linux/timer.h>
+#include <linux/blkdev.h>
 #include <linux/writeback.h>
-#include <linux/atomic.h>
+#include <linux/blk-cgroup.h>
-#include <linux/sysctl.h>
+#include <linux/backing-dev-defs.h>
-#include <linux/workqueue.h>
-
-struct page;
-struct device;
-struct dentry;
-
-/*
- * Bits in backing_dev_info.state
- */
-enum bdi_state {
-	BDI_async_congested,	/* The async (write) queue is getting full */
-	BDI_sync_congested,	/* The sync queue is getting full */
-	BDI_registered,		/* bdi_register() was done */
-	BDI_writeback_running,	/* Writeback is in progress */
-};
-
-typedef int (congested_fn)(void *, int);
-
-enum bdi_stat_item {
-	BDI_RECLAIMABLE,
-	BDI_WRITEBACK,
-	BDI_DIRTIED,
-	BDI_WRITTEN,
-	NR_BDI_STAT_ITEMS
-};
-
-#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
-
-struct bdi_writeback {
-	struct backing_dev_info *bdi;	/* our parent bdi */
-
-	unsigned long last_old_flush;	/* last old data flush */
-
-	struct delayed_work dwork;	/* work item used for writeback */
-	struct list_head b_dirty;	/* dirty inodes */
-	struct list_head b_io;		/* parked for writeback */
-	struct list_head b_more_io;	/* parked for more writeback */
-	struct list_head b_dirty_time;	/* time stamps are dirty */
-	spinlock_t list_lock;		/* protects the b_* lists */
-};
-
-struct backing_dev_info {
-	struct list_head bdi_list;
-	unsigned long ra_pages;	/* max readahead in PAGE_CACHE_SIZE units */
-	unsigned long state;	/* Always use atomic bitops on this */
-	unsigned int capabilities; /* Device capabilities */
-	congested_fn *congested_fn; /* Function pointer if device is md/dm */
-	void *congested_data;	/* Pointer to aux data for congested func */
-
-	char *name;
-
-	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
-
-	unsigned long bw_time_stamp;	/* last time write bw is updated */
-	unsigned long dirtied_stamp;
-	unsigned long written_stamp;	/* pages written at bw_time_stamp */
-	unsigned long write_bandwidth;	/* the estimated write bandwidth */
-	unsigned long avg_write_bandwidth; /* further smoothed write bw */
-
-	/*
-	 * The base dirty throttle rate, re-calculated on every 200ms.
-	 * All the bdi tasks' dirty rate will be curbed under it.
-	 * @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
-	 * in small steps and is much more smooth/stable than the latter.
-	 */
-	unsigned long dirty_ratelimit;
-	unsigned long balanced_dirty_ratelimit;
-
-	struct fprop_local_percpu completions;
-	int dirty_exceeded;
-
-	unsigned int min_ratio;
-	unsigned int max_ratio, max_prop_frac;
-
-	struct bdi_writeback wb;  /* default writeback info for this bdi */
-	spinlock_t wb_lock;	  /* protects work_list & wb.dwork scheduling */
-
-	struct list_head work_list;
-
-	struct device *dev;
-
-	struct timer_list laptop_mode_wb_timer;
-
-#ifdef CONFIG_DEBUG_FS
-	struct dentry *debug_dir;
-	struct dentry *debug_stats;
-#endif
-};
-
-struct backing_dev_info *inode_to_bdi(struct inode *inode);
 
 int __must_check bdi_init(struct backing_dev_info *bdi);
 void bdi_destroy(struct backing_dev_info *bdi);
@@ -117,97 +24,99 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 		const char *fmt, ...);
 int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
 int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);
-void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
+void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
-			enum wb_reason reason);
+			bool range_cyclic, enum wb_reason reason);
-void bdi_start_background_writeback(struct backing_dev_info *bdi);
+void wb_start_background_writeback(struct bdi_writeback *wb);
-void bdi_writeback_workfn(struct work_struct *work);
+void wb_workfn(struct work_struct *work);
-int bdi_has_dirty_io(struct backing_dev_info *bdi);
+void wb_wakeup_delayed(struct bdi_writeback *wb);
-void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
 
 extern spinlock_t bdi_lock;
 extern struct list_head bdi_list;
 
 extern struct workqueue_struct *bdi_wq;
 
-static inline int wb_has_dirty_io(struct bdi_writeback *wb)
+static inline bool wb_has_dirty_io(struct bdi_writeback *wb)
 {
-	return !list_empty(&wb->b_dirty) ||
+	return test_bit(WB_has_dirty_io, &wb->state);
-	       !list_empty(&wb->b_io) ||
-	       !list_empty(&wb->b_more_io);
 }
 
-static inline void __add_bdi_stat(struct backing_dev_info *bdi,
+static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi)
-		enum bdi_stat_item item, s64 amount)
 {
-	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
+	/*
+	 * @bdi->tot_write_bandwidth is guaranteed to be > 0 if there are
+	 * any dirty wbs.  See wb_update_write_bandwidth().
+	 */
+	return atomic_long_read(&bdi->tot_write_bandwidth);
 }
 
-static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
+static inline void __add_wb_stat(struct bdi_writeback *wb,
-		enum bdi_stat_item item)
+				 enum wb_stat_item item, s64 amount)
 {
-	__add_bdi_stat(bdi, item, 1);
+	__percpu_counter_add(&wb->stat[item], amount, WB_STAT_BATCH);
 }
 
-static inline void inc_bdi_stat(struct backing_dev_info *bdi,
+static inline void __inc_wb_stat(struct bdi_writeback *wb,
-		enum bdi_stat_item item)
+				 enum wb_stat_item item)
+{
+	__add_wb_stat(wb, item, 1);
+}
+
+static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 {
 	unsigned long flags;
 
 	local_irq_save(flags);
-	__inc_bdi_stat(bdi, item);
+	__inc_wb_stat(wb, item);
 	local_irq_restore(flags);
 }
 
-static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
+static inline void __dec_wb_stat(struct bdi_writeback *wb,
-		enum bdi_stat_item item)
+				 enum wb_stat_item item)
 {
-	__add_bdi_stat(bdi, item, -1);
+	__add_wb_stat(wb, item, -1);
 }
 
-static inline void dec_bdi_stat(struct backing_dev_info *bdi,
+static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
-		enum bdi_stat_item item)
 {
 	unsigned long flags;
 
 	local_irq_save(flags);
-	__dec_bdi_stat(bdi, item);
+	__dec_wb_stat(wb, item);
 	local_irq_restore(flags);
 }
 
-static inline s64 bdi_stat(struct backing_dev_info *bdi,
+static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
-		enum bdi_stat_item item)
 {
-	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
+	return percpu_counter_read_positive(&wb->stat[item]);
 }
 
-static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
+static inline s64 __wb_stat_sum(struct bdi_writeback *wb,
-		enum bdi_stat_item item)
+				enum wb_stat_item item)
 {
-	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
+	return percpu_counter_sum_positive(&wb->stat[item]);
 }
 
-static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
+static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item)
-		enum bdi_stat_item item)
 {
 	s64 sum;
 	unsigned long flags;
 
 	local_irq_save(flags);
-	sum = __bdi_stat_sum(bdi, item);
+	sum = __wb_stat_sum(wb, item);
 	local_irq_restore(flags);
 
 	return sum;
 }
 
-extern void bdi_writeout_inc(struct backing_dev_info *bdi);
+extern void wb_writeout_inc(struct bdi_writeback *wb);
 
 /*
  * maximal error of a stat counter.
  */
-static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
+static inline unsigned long wb_stat_error(struct bdi_writeback *wb)
 {
 #ifdef CONFIG_SMP
-	return nr_cpu_ids * BDI_STAT_BATCH;
+	return nr_cpu_ids * WB_STAT_BATCH;
 #else
 	return 1;
 #endif
@@ -231,50 +140,57 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
  * BDI_CAP_NO_WRITEBACK:   Don't write pages back
  * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages
  * BDI_CAP_STRICTLIMIT:    Keep number of dirty pages below bdi threshold.
+ *
+ * BDI_CAP_CGROUP_WRITEBACK: Supports cgroup-aware writeback.
  */
 #define BDI_CAP_NO_ACCT_DIRTY	0x00000001
 #define BDI_CAP_NO_WRITEBACK	0x00000002
 #define BDI_CAP_NO_ACCT_WB	0x00000004
 #define BDI_CAP_STABLE_WRITES	0x00000008
 #define BDI_CAP_STRICTLIMIT	0x00000010
+#define BDI_CAP_CGROUP_WRITEBACK 0x00000020
 
 #define BDI_CAP_NO_ACCT_AND_WRITEBACK \
 	(BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
 
 extern struct backing_dev_info noop_backing_dev_info;
 
-int writeback_in_progress(struct backing_dev_info *bdi);
+/**
-
+ * writeback_in_progress - determine whether there is writeback in progress
-static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
+ * @wb: bdi_writeback of interest
+ *
+ * Determine whether there is writeback waiting to be handled against a
+ * bdi_writeback.
+ */
+static inline bool writeback_in_progress(struct bdi_writeback *wb)
 {
+	return test_bit(WB_writeback_running, &wb->state);
+}
+
+static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
+{
+	struct super_block *sb;
+
+	if (!inode)
+		return &noop_backing_dev_info;
+
+	sb = inode->i_sb;
+#ifdef CONFIG_BLOCK
+	if (sb_is_blkdev_sb(sb))
+		return blk_get_backing_dev_info(I_BDEV(inode));
+#endif
+	return sb->s_bdi;
+}
+
+static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
+{
+	struct backing_dev_info *bdi = wb->bdi;
+
 	if (bdi->congested_fn)
-		return bdi->congested_fn(bdi->congested_data, bdi_bits);
+		return bdi->congested_fn(bdi->congested_data, cong_bits);
-	return (bdi->state & bdi_bits);
+	return wb->congested->state & cong_bits;
 }
 
-static inline int bdi_read_congested(struct backing_dev_info *bdi)
-{
-	return bdi_congested(bdi, 1 << BDI_sync_congested);
-}
-
-static inline int bdi_write_congested(struct backing_dev_info *bdi)
-{
-	return bdi_congested(bdi, 1 << BDI_async_congested);
-}
-
-static inline int bdi_rw_congested(struct backing_dev_info *bdi)
-{
-	return bdi_congested(bdi, (1 << BDI_sync_congested) |
-				  (1 << BDI_async_congested));
-}
-
-enum {
-	BLK_RW_ASYNC	= 0,
-	BLK_RW_SYNC	= 1,
-};
-
-void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
-void set_bdi_congested(struct backing_dev_info *bdi, int sync);
 long congestion_wait(int sync, long timeout);
 long wait_iff_congested(struct zone *zone, int sync, long timeout);
 int pdflush_proc_obsolete(struct ctl_table *table, int write,
@@ -318,4 +234,333 @@ static inline int bdi_sched_wait(void *word)
 	return 0;
 }
 
-#endif		/* _LINUX_BACKING_DEV_H */
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+struct bdi_writeback_congested *
+wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp);
+void wb_congested_put(struct bdi_writeback_congested *congested);
+struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
+				    struct cgroup_subsys_state *memcg_css,
+				    gfp_t gfp);
+void wb_memcg_offline(struct mem_cgroup *memcg);
+void wb_blkcg_offline(struct blkcg *blkcg);
+int inode_congested(struct inode *inode, int cong_bits);
+
+/**
+ * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode
+ * @inode: inode of interest
+ *
+ * cgroup writeback requires support from both the bdi and filesystem.
+ * Test whether @inode has both.
+ */
+static inline bool inode_cgwb_enabled(struct inode *inode)
+{
+	struct backing_dev_info *bdi = inode_to_bdi(inode);
+
+	return bdi_cap_account_dirty(bdi) &&
+		(bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) &&
+		(inode->i_sb->s_iflags & SB_I_CGROUPWB);
+}
+
+/**
+ * wb_find_current - find wb for %current on a bdi
+ * @bdi: bdi of interest
+ *
+ * Find the wb of @bdi which matches both the memcg and blkcg of %current.
+ * Must be called under rcu_read_lock() which protects the returend wb.
+ * NULL if not found.
+ */
+static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
+{
+	struct cgroup_subsys_state *memcg_css;
+	struct bdi_writeback *wb;
+
+	memcg_css = task_css(current, memory_cgrp_id);
+	if (!memcg_css->parent)
+		return &bdi->wb;
+
+	wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
+
+	/*
+	 * %current's blkcg equals the effective blkcg of its memcg.  No
+	 * need to use the relatively expensive cgroup_get_e_css().
+	 */
+	if (likely(wb && wb->blkcg_css == task_css(current, blkio_cgrp_id)))
+		return wb;
+	return NULL;
+}
+
+/**
+ * wb_get_create_current - get or create wb for %current on a bdi
+ * @bdi: bdi of interest
+ * @gfp: allocation mask
+ *
+ * Equivalent to wb_get_create() on %current's memcg.  This function is
+ * called from a relatively hot path and optimizes the common cases using
+ * wb_find_current().
+ */
+static inline struct bdi_writeback *
+wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
+{
+	struct bdi_writeback *wb;
+
+	rcu_read_lock();
+	wb = wb_find_current(bdi);
+	if (wb && unlikely(!wb_tryget(wb)))
+		wb = NULL;
+	rcu_read_unlock();
+
+	if (unlikely(!wb)) {
+		struct cgroup_subsys_state *memcg_css;
+
+		memcg_css = task_get_css(current, memory_cgrp_id);
+		wb = wb_get_create(bdi, memcg_css, gfp);
+		css_put(memcg_css);
+	}
+	return wb;
+}
+
+/**
+ * inode_to_wb_is_valid - test whether an inode has a wb associated
+ * @inode: inode of interest
+ *
+ * Returns %true if @inode has a wb associated.  May be called without any
+ * locking.
+ */
+static inline bool inode_to_wb_is_valid(struct inode *inode)
+{
+	return inode->i_wb;
+}
+
+/**
+ * inode_to_wb - determine the wb of an inode
+ * @inode: inode of interest
+ *
+ * Returns the wb @inode is currently associated with.  The caller must be
+ * holding either @inode->i_lock, @inode->i_mapping->tree_lock, or the
+ * associated wb's list_lock.
+ */
+static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
+{
+#ifdef CONFIG_LOCKDEP
+	WARN_ON_ONCE(debug_locks &&
+		     (!lockdep_is_held(&inode->i_lock) &&
+		      !lockdep_is_held(&inode->i_mapping->tree_lock) &&
+		      !lockdep_is_held(&inode->i_wb->list_lock)));
+#endif
+	return inode->i_wb;
+}
+
+/**
+ * unlocked_inode_to_wb_begin - begin unlocked inode wb access transaction
+ * @inode: target inode
+ * @lockedp: temp bool output param, to be passed to the end function
+ *
+ * The caller wants to access the wb associated with @inode but isn't
+ * holding inode->i_lock, mapping->tree_lock or wb->list_lock.  This
+ * function determines the wb associated with @inode and ensures that the
+ * association doesn't change until the transaction is finished with
+ * unlocked_inode_to_wb_end().
+ *
+ * The caller must call unlocked_inode_to_wb_end() with *@lockdep
+ * afterwards and can't sleep during transaction.  IRQ may or may not be
+ * disabled on return.
+ */
+static inline struct bdi_writeback *
+unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
+{
+	rcu_read_lock();
+
+	/*
+	 * Paired with store_release in inode_switch_wb_work_fn() and
+	 * ensures that we see the new wb if we see cleared I_WB_SWITCH.
+	 */
+	*lockedp = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
+
+	if (unlikely(*lockedp))
+		spin_lock_irq(&inode->i_mapping->tree_lock);
+
+	/*
+	 * Protected by either !I_WB_SWITCH + rcu_read_lock() or tree_lock.
+	 * inode_to_wb() will bark.  Deref directly.
+	 */
+	return inode->i_wb;
+}
+
+/**
+ * unlocked_inode_to_wb_end - end inode wb access transaction
+ * @inode: target inode
+ * @locked: *@lockedp from unlocked_inode_to_wb_begin()
+ */
+static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
+{
+	if (unlikely(locked))
+		spin_unlock_irq(&inode->i_mapping->tree_lock);
+
+	rcu_read_unlock();
+}
+
+struct wb_iter {
+	int			start_blkcg_id;
+	struct radix_tree_iter	tree_iter;
+	void			**slot;
+};
+
+static inline struct bdi_writeback *__wb_iter_next(struct wb_iter *iter,
+						   struct backing_dev_info *bdi)
+{
+	struct radix_tree_iter *titer = &iter->tree_iter;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	if (iter->start_blkcg_id >= 0) {
+		iter->slot = radix_tree_iter_init(titer, iter->start_blkcg_id);
+		iter->start_blkcg_id = -1;
+	} else {
+		iter->slot = radix_tree_next_slot(iter->slot, titer, 0);
+	}
+
+	if (!iter->slot)
+		iter->slot = radix_tree_next_chunk(&bdi->cgwb_tree, titer, 0);
+	if (iter->slot)
+		return *iter->slot;
+	return NULL;
+}
+
+static inline struct bdi_writeback *__wb_iter_init(struct wb_iter *iter,
+						   struct backing_dev_info *bdi,
+						   int start_blkcg_id)
+{
+	iter->start_blkcg_id = start_blkcg_id;
+
+	if (start_blkcg_id)
+		return __wb_iter_next(iter, bdi);
+	else
+		return &bdi->wb;
+}
+
+/**
+ * bdi_for_each_wb - walk all wb's of a bdi in ascending blkcg ID order
+ * @wb_cur: cursor struct bdi_writeback pointer
+ * @bdi: bdi to walk wb's of
+ * @iter: pointer to struct wb_iter to be used as iteration buffer
+ * @start_blkcg_id: blkcg ID to start iteration from
+ *
+ * Iterate @wb_cur through the wb's (bdi_writeback's) of @bdi in ascending
+ * blkcg ID order starting from @start_blkcg_id.  @iter is struct wb_iter
+ * to be used as temp storage during iteration.  rcu_read_lock() must be
+ * held throughout iteration.
+ */
+#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id)		\
+	for ((wb_cur) = __wb_iter_init(iter, bdi, start_blkcg_id);	\
+	     (wb_cur); (wb_cur) = __wb_iter_next(iter, bdi))
+
+#else	/* CONFIG_CGROUP_WRITEBACK */
+
+static inline bool inode_cgwb_enabled(struct inode *inode)
+{
+	return false;
+}
+
+static inline struct bdi_writeback_congested *
+wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
+{
+	return bdi->wb.congested;
+}
+
+static inline void wb_congested_put(struct bdi_writeback_congested *congested)
+{
+}
+
+static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
+{
+	return &bdi->wb;
+}
+
+static inline struct bdi_writeback *
+wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
+{
+	return &bdi->wb;
+}
+
+static inline bool inode_to_wb_is_valid(struct inode *inode)
+{
+	return true;
+}
+
+static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
+{
+	return &inode_to_bdi(inode)->wb;
+}
+
+static inline struct bdi_writeback *
+unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
+{
+	return inode_to_wb(inode);
+}
+
+static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
+{
+}
+
+static inline void wb_memcg_offline(struct mem_cgroup *memcg)
+{
+}
+
+static inline void wb_blkcg_offline(struct blkcg *blkcg)
+{
+}
+
+struct wb_iter {
+	int		next_id;
+};
+
+#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id)		\
+	for ((iter)->next_id = (start_blkcg_id);			\
+	     ({	(wb_cur) = !(iter)->next_id++ ? &(bdi)->wb : NULL; }); )
+
+static inline int inode_congested(struct inode *inode, int cong_bits)
+{
+	return wb_congested(&inode_to_bdi(inode)->wb, cong_bits);
+}
+
+#endif	/* CONFIG_CGROUP_WRITEBACK */
+
+static inline int inode_read_congested(struct inode *inode)
+{
+	return inode_congested(inode, 1 << WB_sync_congested);
+}
+
+static inline int inode_write_congested(struct inode *inode)
+{
+	return inode_congested(inode, 1 << WB_async_congested);
+}
+
+static inline int inode_rw_congested(struct inode *inode)
+{
+	return inode_congested(inode, (1 << WB_sync_congested) |
+				      (1 << WB_async_congested));
+}
+
+static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits)
+{
+	return wb_congested(&bdi->wb, cong_bits);
+}
+
+static inline int bdi_read_congested(struct backing_dev_info *bdi)
+{
+	return bdi_congested(bdi, 1 << WB_sync_congested);
+}
+
+static inline int bdi_write_congested(struct backing_dev_info *bdi)
+{
+	return bdi_congested(bdi, 1 << WB_async_congested);
+}
+
+static inline int bdi_rw_congested(struct backing_dev_info *bdi)
+{
+	return bdi_congested(bdi, (1 << WB_sync_congested) |
+				  (1 << WB_async_congested));
+}
+
+#endif	/* _LINUX_BACKING_DEV_H */

include/linux/bio.h

@@ -482,9 +482,12 @@ extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 extern unsigned int bvec_nr_vecs(unsigned short idx);
 
 #ifdef CONFIG_BLK_CGROUP
+int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 int bio_associate_current(struct bio *bio);
 void bio_disassociate_task(struct bio *bio);
 #else	/* CONFIG_BLK_CGROUP */
+static inline int bio_associate_blkcg(struct bio *bio,
+			struct cgroup_subsys_state *blkcg_css) { return 0; }
 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 static inline void bio_disassociate_task(struct bio *bio) { }
 #endif	/* CONFIG_BLK_CGROUP */

include/linux/blk-cgroup.h

@@ -46,6 +46,10 @@ struct blkcg {
 	struct hlist_head		blkg_list;
 
 	struct blkcg_policy_data	*pd[BLKCG_MAX_POLS];
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct list_head		cgwb_list;
+#endif
 };
 
 struct blkg_stat {
@@ -106,6 +110,12 @@ struct blkcg_gq {
 	struct hlist_node		blkcg_node;
 	struct blkcg			*blkcg;
 
+	/*
+	 * Each blkg gets congested separately and the congestion state is
+	 * propagated to the matching bdi_writeback_congested.
+	 */
+	struct bdi_writeback_congested	*wb_congested;
+
 	/* all non-root blkcg_gq's are guaranteed to have access to parent */
 	struct blkcg_gq			*parent;
 
@@ -149,6 +159,7 @@ struct blkcg_policy {
 };
 
 extern struct blkcg blkcg_root;
+extern struct cgroup_subsys_state * const blkcg_root_css;
 
 struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
 struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
@@ -209,6 +220,12 @@ static inline struct blkcg *bio_blkcg(struct bio *bio)
 	return task_blkcg(current);
 }
 
+static inline struct cgroup_subsys_state *
+task_get_blkcg_css(struct task_struct *task)
+{
+	return task_get_css(task, blkio_cgrp_id);
+}
+
 /**
  * blkcg_parent - get the parent of a blkcg
  * @blkcg: blkcg of interest
@@ -579,8 +596,8 @@ static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
 
 #else	/* CONFIG_BLK_CGROUP */
 
-struct cgroup;
+struct blkcg {
-struct blkcg;
+};
 
 struct blkg_policy_data {
 };
@@ -594,6 +611,16 @@ struct blkcg_gq {
 struct blkcg_policy {
 };
 
+#define blkcg_root_css	((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
+
+static inline struct cgroup_subsys_state *
+task_get_blkcg_css(struct task_struct *task)
+{
+	return NULL;
+}
+
+#ifdef CONFIG_BLOCK
+
 static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
 static inline void blkcg_drain_queue(struct request_queue *q) { }
@@ -623,5 +650,6 @@ static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q
 #define blk_queue_for_each_rl(rl, q)	\
 	for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
 
+#endif	/* CONFIG_BLOCK */
 #endif	/* CONFIG_BLK_CGROUP */
 #endif	/* _BLK_CGROUP_H */

include/linux/blkdev.h

@@ -12,7 +12,7 @@
 #include <linux/timer.h>
 #include <linux/workqueue.h>
 #include <linux/pagemap.h>
-#include <linux/backing-dev.h>
+#include <linux/backing-dev-defs.h>
 #include <linux/wait.h>
 #include <linux/mempool.h>
 #include <linux/bio.h>
@@ -787,25 +787,6 @@ extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 			 struct scsi_ioctl_command __user *);
 
-/*
- * A queue has just exitted congestion.  Note this in the global counter of
- * congested queues, and wake up anyone who was waiting for requests to be
- * put back.
- */
-static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
-{
-	clear_bdi_congested(&q->backing_dev_info, sync);
-}
-
-/*
- * A queue has just entered congestion.  Flag that in the queue's VM-visible
- * state flags and increment the global gounter of congested queues.
- */
-static inline void blk_set_queue_congested(struct request_queue *q, int sync)
-{
-	set_bdi_congested(&q->backing_dev_info, sync);
-}
-
 extern void blk_start_queue(struct request_queue *q);
 extern void blk_stop_queue(struct request_queue *q);
 extern void blk_sync_queue(struct request_queue *q);

include/linux/cgroup.h

@@ -773,6 +773,31 @@ static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
 	return task_css_check(task, subsys_id, false);
 }
 
+/**
+ * task_get_css - find and get the css for (task, subsys)
+ * @task: the target task
+ * @subsys_id: the target subsystem ID
+ *
+ * Find the css for the (@task, @subsys_id) combination, increment a
+ * reference on and return it.  This function is guaranteed to return a
+ * valid css.
+ */
+static inline struct cgroup_subsys_state *
+task_get_css(struct task_struct *task, int subsys_id)
+{
+	struct cgroup_subsys_state *css;
+
+	rcu_read_lock();
+	while (true) {
+		css = task_css(task, subsys_id);
+		if (likely(css_tryget_online(css)))
+			break;
+		cpu_relax();
+	}
+	rcu_read_unlock();
+	return css;
+}
+
 /**
  * task_css_is_root - test whether a task belongs to the root css
  * @task: the target task

include/linux/fs.h

@@ -35,6 +35,7 @@
 #include <uapi/linux/fs.h>
 
 struct backing_dev_info;
+struct bdi_writeback;
 struct export_operations;
 struct hd_geometry;
 struct iovec;
@@ -634,6 +635,14 @@ struct inode {
 
 	struct hlist_node	i_hash;
 	struct list_head	i_wb_list;	/* backing dev IO list */
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct bdi_writeback	*i_wb;		/* the associated cgroup wb */
+
+	/* foreign inode detection, see wbc_detach_inode() */
+	int			i_wb_frn_winner;
+	u16			i_wb_frn_avg_time;
+	u16			i_wb_frn_history;
+#endif
 	struct list_head	i_lru;		/* inode LRU list */
 	struct list_head	i_sb_list;
 	union {
@@ -1232,6 +1241,8 @@ struct mm_struct;
 #define UMOUNT_NOFOLLOW	0x00000008	/* Don't follow symlink on umount */
 #define UMOUNT_UNUSED	0x80000000	/* Flag guaranteed to be unused */
 
+/* sb->s_iflags */
+#define SB_I_CGROUPWB	0x00000001	/* cgroup-aware writeback enabled */
 
 /* Possible states of 'frozen' field */
 enum {
@@ -1270,6 +1281,7 @@ struct super_block {
 	const struct quotactl_ops	*s_qcop;
 	const struct export_operations *s_export_op;
 	unsigned long		s_flags;
+	unsigned long		s_iflags;	/* internal SB_I_* flags */
 	unsigned long		s_magic;
 	struct dentry		*s_root;
 	struct rw_semaphore	s_umount;
@@ -1806,6 +1818,11 @@ struct super_operations {
  *
  * I_DIO_WAKEUP		Never set.  Only used as a key for wait_on_bit().
  *
+ * I_WB_SWITCH		Cgroup bdi_writeback switching in progress.  Used to
+ *			synchronize competing switching instances and to tell
+ *			wb stat updates to grab mapping->tree_lock.  See
+ *			inode_switch_wb_work_fn() for details.
+ *
  * Q: What is the difference between I_WILL_FREE and I_FREEING?
  */
 #define I_DIRTY_SYNC		(1 << 0)
@@ -1825,6 +1842,7 @@ struct super_operations {
 #define I_DIRTY_TIME		(1 << 11)
 #define __I_DIRTY_TIME_EXPIRED	12
 #define I_DIRTY_TIME_EXPIRED	(1 << __I_DIRTY_TIME_EXPIRED)
+#define I_WB_SWITCH		(1 << 13)
 
 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
@@ -2241,7 +2259,13 @@ extern struct super_block *freeze_bdev(struct block_device *);
 extern void emergency_thaw_all(void);
 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
 extern int fsync_bdev(struct block_device *);
-extern int sb_is_blkdev_sb(struct super_block *sb);
+
+extern struct super_block *blockdev_superblock;
+
+static inline bool sb_is_blkdev_sb(struct super_block *sb)
+{
+	return sb == blockdev_superblock;
+}
 #else
 static inline void bd_forget(struct inode *inode) {}
 static inline int sync_blockdev(struct block_device *bdev) { return 0; }

include/linux/memcontrol.h

@@ -41,6 +41,7 @@ enum mem_cgroup_stat_index {
 	MEM_CGROUP_STAT_RSS,		/* # of pages charged as anon rss */
 	MEM_CGROUP_STAT_RSS_HUGE,	/* # of pages charged as anon huge */
 	MEM_CGROUP_STAT_FILE_MAPPED,	/* # of pages charged as file rss */
+	MEM_CGROUP_STAT_DIRTY,          /* # of dirty pages in page cache */
 	MEM_CGROUP_STAT_WRITEBACK,	/* # of pages under writeback */
 	MEM_CGROUP_STAT_SWAP,		/* # of pages, swapped out */
 	MEM_CGROUP_STAT_NSTATS,
@@ -67,6 +68,8 @@ enum mem_cgroup_events_index {
 };
 
 #ifdef CONFIG_MEMCG
+extern struct cgroup_subsys_state *mem_cgroup_root_css;
+
 void mem_cgroup_events(struct mem_cgroup *memcg,
 		       enum mem_cgroup_events_index idx,
 		       unsigned int nr);
@@ -112,6 +115,7 @@ static inline bool mm_match_cgroup(struct mm_struct *mm,
 }
 
 extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg);
+extern struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page);
 
 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
 				   struct mem_cgroup *,
@@ -195,6 +199,8 @@ void mem_cgroup_split_huge_fixup(struct page *head);
 #else /* CONFIG_MEMCG */
 struct mem_cgroup;
 
+#define mem_cgroup_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
+
 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
 				     enum mem_cgroup_events_index idx,
 				     unsigned int nr)
@@ -382,6 +388,29 @@ enum {
 	OVER_LIMIT,
 };
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg);
+struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
+void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pavail,
+			 unsigned long *pdirty, unsigned long *pwriteback);
+
+#else	/* CONFIG_CGROUP_WRITEBACK */
+
+static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
+{
+	return NULL;
+}
+
+static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,
+				       unsigned long *pavail,
+				       unsigned long *pdirty,
+				       unsigned long *pwriteback)
+{
+}
+
+#endif	/* CONFIG_CGROUP_WRITEBACK */
+
 struct sock;
 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
 void sock_update_memcg(struct sock *sk);

include/linux/mm.h

@@ -27,6 +27,7 @@ struct anon_vma_chain;
 struct file_ra_state;
 struct user_struct;
 struct writeback_control;
+struct bdi_writeback;
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES	/* Don't use mapnrs, do it properly */
 extern unsigned long max_mapnr;
@@ -1211,10 +1212,13 @@ int __set_page_dirty_nobuffers(struct page *page);
 int __set_page_dirty_no_writeback(struct page *page);
 int redirty_page_for_writepage(struct writeback_control *wbc,
 				struct page *page);
-void account_page_dirtied(struct page *page, struct address_space *mapping);
+void account_page_dirtied(struct page *page, struct address_space *mapping,
-void account_page_cleaned(struct page *page, struct address_space *mapping);
+			  struct mem_cgroup *memcg);
+void account_page_cleaned(struct page *page, struct address_space *mapping,
+			  struct mem_cgroup *memcg, struct bdi_writeback *wb);
 int set_page_dirty(struct page *page);
 int set_page_dirty_lock(struct page *page);
+void cancel_dirty_page(struct page *page);
 int clear_page_dirty_for_io(struct page *page);
 
 int get_cmdline(struct task_struct *task, char *buffer, int buflen);

include/linux/pagemap.h

@@ -651,7 +651,8 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
 int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
 				pgoff_t index, gfp_t gfp_mask);
 extern void delete_from_page_cache(struct page *page);
-extern void __delete_from_page_cache(struct page *page, void *shadow);
+extern void __delete_from_page_cache(struct page *page, void *shadow,
+				     struct mem_cgroup *memcg);
 int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
 
 /*

include/linux/writeback.h

@@ -7,6 +7,8 @@
 #include <linux/sched.h>
 #include <linux/workqueue.h>
 #include <linux/fs.h>
+#include <linux/flex_proportions.h>
+#include <linux/backing-dev-defs.h>
 
 DECLARE_PER_CPU(int, dirty_throttle_leaks);
 
@@ -84,8 +86,85 @@ struct writeback_control {
 	unsigned for_reclaim:1;		/* Invoked from the page allocator */
 	unsigned range_cyclic:1;	/* range_start is cyclic */
 	unsigned for_sync:1;		/* sync(2) WB_SYNC_ALL writeback */
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct bdi_writeback *wb;	/* wb this writeback is issued under */
+	struct inode *inode;		/* inode being written out */
+
+	/* foreign inode detection, see wbc_detach_inode() */
+	int wb_id;			/* current wb id */
+	int wb_lcand_id;		/* last foreign candidate wb id */
+	int wb_tcand_id;		/* this foreign candidate wb id */
+	size_t wb_bytes;		/* bytes written by current wb */
+	size_t wb_lcand_bytes;		/* bytes written by last candidate */
+	size_t wb_tcand_bytes;		/* bytes written by this candidate */
+#endif
 };
 
+/*
+ * A wb_domain represents a domain that wb's (bdi_writeback's) belong to
+ * and are measured against each other in.  There always is one global
+ * domain, global_wb_domain, that every wb in the system is a member of.
+ * This allows measuring the relative bandwidth of each wb to distribute
+ * dirtyable memory accordingly.
+ */
+struct wb_domain {
+	spinlock_t lock;
+
+	/*
+	 * Scale the writeback cache size proportional to the relative
+	 * writeout speed.
+	 *
+	 * We do this by keeping a floating proportion between BDIs, based
+	 * on page writeback completions [end_page_writeback()]. Those
+	 * devices that write out pages fastest will get the larger share,
+	 * while the slower will get a smaller share.
+	 *
+	 * We use page writeout completions because we are interested in
+	 * getting rid of dirty pages. Having them written out is the
+	 * primary goal.
+	 *
+	 * We introduce a concept of time, a period over which we measure
+	 * these events, because demand can/will vary over time. The length
+	 * of this period itself is measured in page writeback completions.
+	 */
+	struct fprop_global completions;
+	struct timer_list period_timer;	/* timer for aging of completions */
+	unsigned long period_time;
+
+	/*
+	 * The dirtyable memory and dirty threshold could be suddenly
+	 * knocked down by a large amount (eg. on the startup of KVM in a
+	 * swapless system). This may throw the system into deep dirty
+	 * exceeded state and throttle heavy/light dirtiers alike. To
+	 * retain good responsiveness, maintain global_dirty_limit for
+	 * tracking slowly down to the knocked down dirty threshold.
+	 *
+	 * Both fields are protected by ->lock.
+	 */
+	unsigned long dirty_limit_tstamp;
+	unsigned long dirty_limit;
+};
+
+/**
+ * wb_domain_size_changed - memory available to a wb_domain has changed
+ * @dom: wb_domain of interest
+ *
+ * This function should be called when the amount of memory available to
+ * @dom has changed.  It resets @dom's dirty limit parameters to prevent
+ * the past values which don't match the current configuration from skewing
+ * dirty throttling.  Without this, when memory size of a wb_domain is
+ * greatly reduced, the dirty throttling logic may allow too many pages to
+ * be dirtied leading to consecutive unnecessary OOMs and may get stuck in
+ * that situation.
+ */
+static inline void wb_domain_size_changed(struct wb_domain *dom)
+{
+	spin_lock(&dom->lock);
+	dom->dirty_limit_tstamp = jiffies;
+	dom->dirty_limit = 0;
+	spin_unlock(&dom->lock);
+}
+
 /*
  * fs/fs-writeback.c
  */	
@@ -93,9 +172,9 @@ struct bdi_writeback;
 void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
 void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
 							enum wb_reason reason);
-int try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
+bool try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
-int try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
+bool try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
-				  enum wb_reason reason);
+				   enum wb_reason reason);
 void sync_inodes_sb(struct super_block *);
 void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
 void inode_wait_for_writeback(struct inode *inode);
@@ -107,6 +186,123 @@ static inline void wait_on_inode(struct inode *inode)
 	wait_on_bit(&inode->i_state, __I_NEW, TASK_UNINTERRUPTIBLE);
 }
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+#include <linux/cgroup.h>
+#include <linux/bio.h>
+
+void __inode_attach_wb(struct inode *inode, struct page *page);
+void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
+				 struct inode *inode)
+	__releases(&inode->i_lock);
+void wbc_detach_inode(struct writeback_control *wbc);
+void wbc_account_io(struct writeback_control *wbc, struct page *page,
+		    size_t bytes);
+
+/**
+ * inode_attach_wb - associate an inode with its wb
+ * @inode: inode of interest
+ * @page: page being dirtied (may be NULL)
+ *
+ * If @inode doesn't have its wb, associate it with the wb matching the
+ * memcg of @page or, if @page is NULL, %current.  May be called w/ or w/o
+ * @inode->i_lock.
+ */
+static inline void inode_attach_wb(struct inode *inode, struct page *page)
+{
+	if (!inode->i_wb)
+		__inode_attach_wb(inode, page);
+}
+
+/**
+ * inode_detach_wb - disassociate an inode from its wb
+ * @inode: inode of interest
+ *
+ * @inode is being freed.  Detach from its wb.
+ */
+static inline void inode_detach_wb(struct inode *inode)
+{
+	if (inode->i_wb) {
+		wb_put(inode->i_wb);
+		inode->i_wb = NULL;
+	}
+}
+
+/**
+ * wbc_attach_fdatawrite_inode - associate wbc and inode for fdatawrite
+ * @wbc: writeback_control of interest
+ * @inode: target inode
+ *
+ * This function is to be used by __filemap_fdatawrite_range(), which is an
+ * alternative entry point into writeback code, and first ensures @inode is
+ * associated with a bdi_writeback and attaches it to @wbc.
+ */
+static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
+					       struct inode *inode)
+{
+	spin_lock(&inode->i_lock);
+	inode_attach_wb(inode, NULL);
+	wbc_attach_and_unlock_inode(wbc, inode);
+}
+
+/**
+ * wbc_init_bio - writeback specific initializtion of bio
+ * @wbc: writeback_control for the writeback in progress
+ * @bio: bio to be initialized
+ *
+ * @bio is a part of the writeback in progress controlled by @wbc.  Perform
+ * writeback specific initialization.  This is used to apply the cgroup
+ * writeback context.
+ */
+static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio)
+{
+	/*
+	 * pageout() path doesn't attach @wbc to the inode being written
+	 * out.  This is intentional as we don't want the function to block
+	 * behind a slow cgroup.  Ultimately, we want pageout() to kick off
+	 * regular writeback instead of writing things out itself.
+	 */
+	if (wbc->wb)
+		bio_associate_blkcg(bio, wbc->wb->blkcg_css);
+}
+
+#else	/* CONFIG_CGROUP_WRITEBACK */
+
+static inline void inode_attach_wb(struct inode *inode, struct page *page)
+{
+}
+
+static inline void inode_detach_wb(struct inode *inode)
+{
+}
+
+static inline void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
+					       struct inode *inode)
+	__releases(&inode->i_lock)
+{
+	spin_unlock(&inode->i_lock);
+}
+
+static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
+					       struct inode *inode)
+{
+}
+
+static inline void wbc_detach_inode(struct writeback_control *wbc)
+{
+}
+
+static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio)
+{
+}
+
+static inline void wbc_account_io(struct writeback_control *wbc,
+				  struct page *page, size_t bytes)
+{
+}
+
+#endif	/* CONFIG_CGROUP_WRITEBACK */
+
 /*
  * mm/page-writeback.c
  */
@@ -120,8 +316,12 @@ static inline void laptop_sync_completion(void) { }
 #endif
 void throttle_vm_writeout(gfp_t gfp_mask);
 bool zone_dirty_ok(struct zone *zone);
+int wb_domain_init(struct wb_domain *dom, gfp_t gfp);
+#ifdef CONFIG_CGROUP_WRITEBACK
+void wb_domain_exit(struct wb_domain *dom);
+#endif
 
-extern unsigned long global_dirty_limit;
+extern struct wb_domain global_wb_domain;
 
 /* These are exported to sysctl. */
 extern int dirty_background_ratio;
@@ -155,19 +355,12 @@ int dirty_writeback_centisecs_handler(struct ctl_table *, int,
 				      void __user *, size_t *, loff_t *);
 
 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
-unsigned long bdi_dirty_limit(struct backing_dev_info *bdi,
+unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh);
-			       unsigned long dirty);
-
-void __bdi_update_bandwidth(struct backing_dev_info *bdi,
-			    unsigned long thresh,
-			    unsigned long bg_thresh,
-			    unsigned long dirty,
-			    unsigned long bdi_thresh,
-			    unsigned long bdi_dirty,
-			    unsigned long start_time);
 
+void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time);
 void page_writeback_init(void);
 void balance_dirty_pages_ratelimited(struct address_space *mapping);
+bool wb_over_bg_thresh(struct bdi_writeback *wb);
 
 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
 				void *data);

include/trace/events/writeback.h

@@ -360,7 +360,7 @@ TRACE_EVENT(global_dirty_state,
 		__entry->nr_written	= global_page_state(NR_WRITTEN);
 		__entry->background_thresh = background_thresh;
 		__entry->dirty_thresh	= dirty_thresh;
-		__entry->dirty_limit = global_dirty_limit;
+		__entry->dirty_limit	= global_wb_domain.dirty_limit;
 	),
 
 	TP_printk("dirty=%lu writeback=%lu unstable=%lu "
@@ -399,13 +399,13 @@ TRACE_EVENT(bdi_dirty_ratelimit,
 
 	TP_fast_assign(
 		strlcpy(__entry->bdi, dev_name(bdi->dev), 32);
-		__entry->write_bw	= KBps(bdi->write_bandwidth);
+		__entry->write_bw	= KBps(bdi->wb.write_bandwidth);
-		__entry->avg_write_bw	= KBps(bdi->avg_write_bandwidth);
+		__entry->avg_write_bw	= KBps(bdi->wb.avg_write_bandwidth);
 		__entry->dirty_rate	= KBps(dirty_rate);
-		__entry->dirty_ratelimit = KBps(bdi->dirty_ratelimit);
+		__entry->dirty_ratelimit = KBps(bdi->wb.dirty_ratelimit);
 		__entry->task_ratelimit	= KBps(task_ratelimit);
 		__entry->balanced_dirty_ratelimit =
-					  KBps(bdi->balanced_dirty_ratelimit);
+					KBps(bdi->wb.balanced_dirty_ratelimit);
 	),
 
 	TP_printk("bdi %s: "
@@ -462,8 +462,9 @@ TRACE_EVENT(balance_dirty_pages,
 		unsigned long freerun = (thresh + bg_thresh) / 2;
 		strlcpy(__entry->bdi, dev_name(bdi->dev), 32);
 
-		__entry->limit		= global_dirty_limit;
+		__entry->limit		= global_wb_domain.dirty_limit;
-		__entry->setpoint	= (global_dirty_limit + freerun) / 2;
+		__entry->setpoint	= (global_wb_domain.dirty_limit +
+						freerun) / 2;
 		__entry->dirty		= dirty;
 		__entry->bdi_setpoint	= __entry->setpoint *
 						bdi_thresh / (thresh + 1);

init/Kconfig

@@ -1127,6 +1127,11 @@ config DEBUG_BLK_CGROUP
 	Enable some debugging help. Currently it exports additional stat
 	files in a cgroup which can be useful for debugging.
 
+config CGROUP_WRITEBACK
+	bool
+	depends on MEMCG && BLK_CGROUP
+	default y
+
 endif # CGROUPS
 
 config CHECKPOINT_RESTORE

mm/backing-dev.c

@@ -18,6 +18,7 @@ struct backing_dev_info noop_backing_dev_info = {
 	.name		= "noop",
 	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
+EXPORT_SYMBOL_GPL(noop_backing_dev_info);
 
 static struct class *bdi_class;
 
@@ -48,7 +49,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
 	struct bdi_writeback *wb = &bdi->wb;
 	unsigned long background_thresh;
 	unsigned long dirty_thresh;
-	unsigned long bdi_thresh;
+	unsigned long wb_thresh;
 	unsigned long nr_dirty, nr_io, nr_more_io, nr_dirty_time;
 	struct inode *inode;
 
@@ -66,7 +67,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
 	spin_unlock(&wb->list_lock);
 
 	global_dirty_limits(&background_thresh, &dirty_thresh);
-	bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh);
+	wb_thresh = wb_calc_thresh(wb, dirty_thresh);
 
 #define K(x) ((x) << (PAGE_SHIFT - 10))
 	seq_printf(m,
@@ -84,19 +85,19 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
 		   "b_dirty_time:       %10lu\n"
 		   "bdi_list:           %10u\n"
 		   "state:              %10lx\n",
-		   (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
+		   (unsigned long) K(wb_stat(wb, WB_WRITEBACK)),
-		   (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
+		   (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)),
-		   K(bdi_thresh),
+		   K(wb_thresh),
 		   K(dirty_thresh),
 		   K(background_thresh),
-		   (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)),
+		   (unsigned long) K(wb_stat(wb, WB_DIRTIED)),
-		   (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)),
+		   (unsigned long) K(wb_stat(wb, WB_WRITTEN)),
-		   (unsigned long) K(bdi->write_bandwidth),
+		   (unsigned long) K(wb->write_bandwidth),
 		   nr_dirty,
 		   nr_io,
 		   nr_more_io,
 		   nr_dirty_time,
-		   !list_empty(&bdi->bdi_list), bdi->state);
+		   !list_empty(&bdi->bdi_list), bdi->wb.state);
 #undef K
 
 	return 0;
@@ -255,13 +256,8 @@ static int __init default_bdi_init(void)
 }
 subsys_initcall(default_bdi_init);
 
-int bdi_has_dirty_io(struct backing_dev_info *bdi)
-{
-	return wb_has_dirty_io(&bdi->wb);
-}
-
 /*
- * This function is used when the first inode for this bdi is marked dirty. It
+ * This function is used when the first inode for this wb is marked dirty. It
  * wakes-up the corresponding bdi thread which should then take care of the
  * periodic background write-out of dirty inodes. Since the write-out would
  * starts only 'dirty_writeback_interval' centisecs from now anyway, we just
@@ -274,29 +270,497 @@ int bdi_has_dirty_io(struct backing_dev_info *bdi)
  * We have to be careful not to postpone flush work if it is scheduled for
  * earlier. Thus we use queue_delayed_work().
  */
-void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi)
+void wb_wakeup_delayed(struct bdi_writeback *wb)
 {
 	unsigned long timeout;
 
 	timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
-	spin_lock_bh(&bdi->wb_lock);
+	spin_lock_bh(&wb->work_lock);
-	if (test_bit(BDI_registered, &bdi->state))
+	if (test_bit(WB_registered, &wb->state))
-		queue_delayed_work(bdi_wq, &bdi->wb.dwork, timeout);
+		queue_delayed_work(bdi_wq, &wb->dwork, timeout);
-	spin_unlock_bh(&bdi->wb_lock);
+	spin_unlock_bh(&wb->work_lock);
 }
 
 /*
- * Remove bdi from bdi_list, and ensure that it is no longer visible
+ * Initial write bandwidth: 100 MB/s
  */
-static void bdi_remove_from_list(struct backing_dev_info *bdi)
+#define INIT_BW		(100 << (20 - PAGE_SHIFT))
-{
-	spin_lock_bh(&bdi_lock);
-	list_del_rcu(&bdi->bdi_list);
-	spin_unlock_bh(&bdi_lock);
 
-	synchronize_rcu_expedited();
+static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
+		   gfp_t gfp)
+{
+	int i, err;
+
+	memset(wb, 0, sizeof(*wb));
+
+	wb->bdi = bdi;
+	wb->last_old_flush = jiffies;
+	INIT_LIST_HEAD(&wb->b_dirty);
+	INIT_LIST_HEAD(&wb->b_io);
+	INIT_LIST_HEAD(&wb->b_more_io);
+	INIT_LIST_HEAD(&wb->b_dirty_time);
+	spin_lock_init(&wb->list_lock);
+
+	wb->bw_time_stamp = jiffies;
+	wb->balanced_dirty_ratelimit = INIT_BW;
+	wb->dirty_ratelimit = INIT_BW;
+	wb->write_bandwidth = INIT_BW;
+	wb->avg_write_bandwidth = INIT_BW;
+
+	spin_lock_init(&wb->work_lock);
+	INIT_LIST_HEAD(&wb->work_list);
+	INIT_DELAYED_WORK(&wb->dwork, wb_workfn);
+
+	err = fprop_local_init_percpu(&wb->completions, gfp);
+	if (err)
+		return err;
+
+	for (i = 0; i < NR_WB_STAT_ITEMS; i++) {
+		err = percpu_counter_init(&wb->stat[i], 0, gfp);
+		if (err) {
+			while (--i)
+				percpu_counter_destroy(&wb->stat[i]);
+			fprop_local_destroy_percpu(&wb->completions);
+			return err;
+		}
+	}
+
+	return 0;
 }
 
+/*
+ * Remove bdi from the global list and shutdown any threads we have running
+ */
+static void wb_shutdown(struct bdi_writeback *wb)
+{
+	/* Make sure nobody queues further work */
+	spin_lock_bh(&wb->work_lock);
+	if (!test_and_clear_bit(WB_registered, &wb->state)) {
+		spin_unlock_bh(&wb->work_lock);
+		return;
+	}
+	spin_unlock_bh(&wb->work_lock);
+
+	/*
+	 * Drain work list and shutdown the delayed_work.  !WB_registered
+	 * tells wb_workfn() that @wb is dying and its work_list needs to
+	 * be drained no matter what.
+	 */
+	mod_delayed_work(bdi_wq, &wb->dwork, 0);
+	flush_delayed_work(&wb->dwork);
+	WARN_ON(!list_empty(&wb->work_list));
+}
+
+static void wb_exit(struct bdi_writeback *wb)
+{
+	int i;
+
+	WARN_ON(delayed_work_pending(&wb->dwork));
+
+	for (i = 0; i < NR_WB_STAT_ITEMS; i++)
+		percpu_counter_destroy(&wb->stat[i]);
+
+	fprop_local_destroy_percpu(&wb->completions);
+}
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+#include <linux/memcontrol.h>
+
+/*
+ * cgwb_lock protects bdi->cgwb_tree, bdi->cgwb_congested_tree,
+ * blkcg->cgwb_list, and memcg->cgwb_list.  bdi->cgwb_tree is also RCU
+ * protected.  cgwb_release_wait is used to wait for the completion of cgwb
+ * releases from bdi destruction path.
+ */
+static DEFINE_SPINLOCK(cgwb_lock);
+static DECLARE_WAIT_QUEUE_HEAD(cgwb_release_wait);
+
+/**
+ * wb_congested_get_create - get or create a wb_congested
+ * @bdi: associated bdi
+ * @blkcg_id: ID of the associated blkcg
+ * @gfp: allocation mask
+ *
+ * Look up the wb_congested for @blkcg_id on @bdi.  If missing, create one.
+ * The returned wb_congested has its reference count incremented.  Returns
+ * NULL on failure.
+ */
+struct bdi_writeback_congested *
+wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
+{
+	struct bdi_writeback_congested *new_congested = NULL, *congested;
+	struct rb_node **node, *parent;
+	unsigned long flags;
+
+	if (blkcg_id == 1)
+		return &bdi->wb_congested;
+retry:
+	spin_lock_irqsave(&cgwb_lock, flags);
+
+	node = &bdi->cgwb_congested_tree.rb_node;
+	parent = NULL;
+
+	while (*node != NULL) {
+		parent = *node;
+		congested = container_of(parent, struct bdi_writeback_congested,
+					 rb_node);
+		if (congested->blkcg_id < blkcg_id)
+			node = &parent->rb_left;
+		else if (congested->blkcg_id > blkcg_id)
+			node = &parent->rb_right;
+		else
+			goto found;
+	}
+
+	if (new_congested) {
+		/* !found and storage for new one already allocated, insert */
+		congested = new_congested;
+		new_congested = NULL;
+		rb_link_node(&congested->rb_node, parent, node);
+		rb_insert_color(&congested->rb_node, &bdi->cgwb_congested_tree);
+		atomic_inc(&bdi->usage_cnt);
+		goto found;
+	}
+
+	spin_unlock_irqrestore(&cgwb_lock, flags);
+
+	/* allocate storage for new one and retry */
+	new_congested = kzalloc(sizeof(*new_congested), gfp);
+	if (!new_congested)
+		return NULL;
+
+	atomic_set(&new_congested->refcnt, 0);
+	new_congested->bdi = bdi;
+	new_congested->blkcg_id = blkcg_id;
+	goto retry;
+
+found:
+	atomic_inc(&congested->refcnt);
+	spin_unlock_irqrestore(&cgwb_lock, flags);
+	kfree(new_congested);
+	return congested;
+}
+
+/**
+ * wb_congested_put - put a wb_congested
+ * @congested: wb_congested to put
+ *
+ * Put @congested and destroy it if the refcnt reaches zero.
+ */
+void wb_congested_put(struct bdi_writeback_congested *congested)
+{
+	struct backing_dev_info *bdi = congested->bdi;
+	unsigned long flags;
+
+	if (congested->blkcg_id == 1)
+		return;
+
+	local_irq_save(flags);
+	if (!atomic_dec_and_lock(&congested->refcnt, &cgwb_lock)) {
+		local_irq_restore(flags);
+		return;
+	}
+
+	rb_erase(&congested->rb_node, &congested->bdi->cgwb_congested_tree);
+	spin_unlock_irqrestore(&cgwb_lock, flags);
+	kfree(congested);
+
+	if (atomic_dec_and_test(&bdi->usage_cnt))
+		wake_up_all(&cgwb_release_wait);
+}
+
+static void cgwb_release_workfn(struct work_struct *work)
+{
+	struct bdi_writeback *wb = container_of(work, struct bdi_writeback,
+						release_work);
+	struct backing_dev_info *bdi = wb->bdi;
+
+	wb_shutdown(wb);
+
+	css_put(wb->memcg_css);
+	css_put(wb->blkcg_css);
+	wb_congested_put(wb->congested);
+
+	fprop_local_destroy_percpu(&wb->memcg_completions);
+	percpu_ref_exit(&wb->refcnt);
+	wb_exit(wb);
+	kfree_rcu(wb, rcu);
+
+	if (atomic_dec_and_test(&bdi->usage_cnt))
+		wake_up_all(&cgwb_release_wait);
+}
+
+static void cgwb_release(struct percpu_ref *refcnt)
+{
+	struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback,
+						refcnt);
+	schedule_work(&wb->release_work);
+}
+
+static void cgwb_kill(struct bdi_writeback *wb)
+{
+	lockdep_assert_held(&cgwb_lock);
+
+	WARN_ON(!radix_tree_delete(&wb->bdi->cgwb_tree, wb->memcg_css->id));
+	list_del(&wb->memcg_node);
+	list_del(&wb->blkcg_node);
+	percpu_ref_kill(&wb->refcnt);
+}
+
+static int cgwb_create(struct backing_dev_info *bdi,
+		       struct cgroup_subsys_state *memcg_css, gfp_t gfp)
+{
+	struct mem_cgroup *memcg;
+	struct cgroup_subsys_state *blkcg_css;
+	struct blkcg *blkcg;
+	struct list_head *memcg_cgwb_list, *blkcg_cgwb_list;
+	struct bdi_writeback *wb;
+	unsigned long flags;
+	int ret = 0;
+
+	memcg = mem_cgroup_from_css(memcg_css);
+	blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &blkio_cgrp_subsys);
+	blkcg = css_to_blkcg(blkcg_css);
+	memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
+	blkcg_cgwb_list = &blkcg->cgwb_list;
+
+	/* look up again under lock and discard on blkcg mismatch */
+	spin_lock_irqsave(&cgwb_lock, flags);
+	wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
+	if (wb && wb->blkcg_css != blkcg_css) {
+		cgwb_kill(wb);
+		wb = NULL;
+	}
+	spin_unlock_irqrestore(&cgwb_lock, flags);
+	if (wb)
+		goto out_put;
+
+	/* need to create a new one */
+	wb = kmalloc(sizeof(*wb), gfp);
+	if (!wb)
+		return -ENOMEM;
+
+	ret = wb_init(wb, bdi, gfp);
+	if (ret)
+		goto err_free;
+
+	ret = percpu_ref_init(&wb->refcnt, cgwb_release, 0, gfp);
+	if (ret)
+		goto err_wb_exit;
+
+	ret = fprop_local_init_percpu(&wb->memcg_completions, gfp);
+	if (ret)
+		goto err_ref_exit;
+
+	wb->congested = wb_congested_get_create(bdi, blkcg_css->id, gfp);
+	if (!wb->congested) {
+		ret = -ENOMEM;
+		goto err_fprop_exit;
+	}
+
+	wb->memcg_css = memcg_css;
+	wb->blkcg_css = blkcg_css;
+	INIT_WORK(&wb->release_work, cgwb_release_workfn);
+	set_bit(WB_registered, &wb->state);
+
+	/*
+	 * The root wb determines the registered state of the whole bdi and
+	 * memcg_cgwb_list and blkcg_cgwb_list's next pointers indicate
+	 * whether they're still online.  Don't link @wb if any is dead.
+	 * See wb_memcg_offline() and wb_blkcg_offline().
+	 */
+	ret = -ENODEV;
+	spin_lock_irqsave(&cgwb_lock, flags);
+	if (test_bit(WB_registered, &bdi->wb.state) &&
+	    blkcg_cgwb_list->next && memcg_cgwb_list->next) {
+		/* we might have raced another instance of this function */
+		ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb);
+		if (!ret) {
+			atomic_inc(&bdi->usage_cnt);
+			list_add(&wb->memcg_node, memcg_cgwb_list);
+			list_add(&wb->blkcg_node, blkcg_cgwb_list);
+			css_get(memcg_css);
+			css_get(blkcg_css);
+		}
+	}
+	spin_unlock_irqrestore(&cgwb_lock, flags);
+	if (ret) {
+		if (ret == -EEXIST)
+			ret = 0;
+		goto err_put_congested;
+	}
+	goto out_put;
+
+err_put_congested:
+	wb_congested_put(wb->congested);
+err_fprop_exit:
+	fprop_local_destroy_percpu(&wb->memcg_completions);
+err_ref_exit:
+	percpu_ref_exit(&wb->refcnt);
+err_wb_exit:
+	wb_exit(wb);
+err_free:
+	kfree(wb);
+out_put:
+	css_put(blkcg_css);
+	return ret;
+}
+
+/**
+ * wb_get_create - get wb for a given memcg, create if necessary
+ * @bdi: target bdi
+ * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref)
+ * @gfp: allocation mask to use
+ *
+ * Try to get the wb for @memcg_css on @bdi.  If it doesn't exist, try to
+ * create one.  The returned wb has its refcount incremented.
+ *
+ * This function uses css_get() on @memcg_css and thus expects its refcnt
+ * to be positive on invocation.  IOW, rcu_read_lock() protection on
+ * @memcg_css isn't enough.  try_get it before calling this function.
+ *
+ * A wb is keyed by its associated memcg.  As blkcg implicitly enables
+ * memcg on the default hierarchy, memcg association is guaranteed to be
+ * more specific (equal or descendant to the associated blkcg) and thus can
+ * identify both the memcg and blkcg associations.
+ *
+ * Because the blkcg associated with a memcg may change as blkcg is enabled
+ * and disabled closer to root in the hierarchy, each wb keeps track of
+ * both the memcg and blkcg associated with it and verifies the blkcg on
+ * each lookup.  On mismatch, the existing wb is discarded and a new one is
+ * created.
+ */
+struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
+				    struct cgroup_subsys_state *memcg_css,
+				    gfp_t gfp)
+{
+	struct bdi_writeback *wb;
+
+	might_sleep_if(gfp & __GFP_WAIT);
+
+	if (!memcg_css->parent)
+		return &bdi->wb;
+
+	do {
+		rcu_read_lock();
+		wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
+		if (wb) {
+			struct cgroup_subsys_state *blkcg_css;
+
+			/* see whether the blkcg association has changed */
+			blkcg_css = cgroup_get_e_css(memcg_css->cgroup,
+						     &blkio_cgrp_subsys);
+			if (unlikely(wb->blkcg_css != blkcg_css ||
+				     !wb_tryget(wb)))
+				wb = NULL;
+			css_put(blkcg_css);
+		}
+		rcu_read_unlock();
+	} while (!wb && !cgwb_create(bdi, memcg_css, gfp));
+
+	return wb;
+}
+
+static void cgwb_bdi_init(struct backing_dev_info *bdi)
+{
+	bdi->wb.memcg_css = mem_cgroup_root_css;
+	bdi->wb.blkcg_css = blkcg_root_css;
+	bdi->wb_congested.blkcg_id = 1;
+	INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC);
+	bdi->cgwb_congested_tree = RB_ROOT;
+	atomic_set(&bdi->usage_cnt, 1);
+}
+
+static void cgwb_bdi_destroy(struct backing_dev_info *bdi)
+{
+	struct radix_tree_iter iter;
+	void **slot;
+
+	WARN_ON(test_bit(WB_registered, &bdi->wb.state));
+
+	spin_lock_irq(&cgwb_lock);
+	radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
+		cgwb_kill(*slot);
+	spin_unlock_irq(&cgwb_lock);
+
+	/*
+	 * All cgwb's and their congested states must be shutdown and
+	 * released before returning.  Drain the usage counter to wait for
+	 * all cgwb's and cgwb_congested's ever created on @bdi.
+	 */
+	atomic_dec(&bdi->usage_cnt);
+	wait_event(cgwb_release_wait, !atomic_read(&bdi->usage_cnt));
+}
+
+/**
+ * wb_memcg_offline - kill all wb's associated with a memcg being offlined
+ * @memcg: memcg being offlined
+ *
+ * Also prevents creation of any new wb's associated with @memcg.
+ */
+void wb_memcg_offline(struct mem_cgroup *memcg)
+{
+	LIST_HEAD(to_destroy);
+	struct list_head *memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
+	struct bdi_writeback *wb, *next;
+
+	spin_lock_irq(&cgwb_lock);
+	list_for_each_entry_safe(wb, next, memcg_cgwb_list, memcg_node)
+		cgwb_kill(wb);
+	memcg_cgwb_list->next = NULL;	/* prevent new wb's */
+	spin_unlock_irq(&cgwb_lock);
+}
+
+/**
+ * wb_blkcg_offline - kill all wb's associated with a blkcg being offlined
+ * @blkcg: blkcg being offlined
+ *
+ * Also prevents creation of any new wb's associated with @blkcg.
+ */
+void wb_blkcg_offline(struct blkcg *blkcg)
+{
+	LIST_HEAD(to_destroy);
+	struct bdi_writeback *wb, *next;
+
+	spin_lock_irq(&cgwb_lock);
+	list_for_each_entry_safe(wb, next, &blkcg->cgwb_list, blkcg_node)
+		cgwb_kill(wb);
+	blkcg->cgwb_list.next = NULL;	/* prevent new wb's */
+	spin_unlock_irq(&cgwb_lock);
+}
+
+#else	/* CONFIG_CGROUP_WRITEBACK */
+
+static void cgwb_bdi_init(struct backing_dev_info *bdi) { }
+static void cgwb_bdi_destroy(struct backing_dev_info *bdi) { }
+
+#endif	/* CONFIG_CGROUP_WRITEBACK */
+
+int bdi_init(struct backing_dev_info *bdi)
+{
+	int err;
+
+	bdi->dev = NULL;
+
+	bdi->min_ratio = 0;
+	bdi->max_ratio = 100;
+	bdi->max_prop_frac = FPROP_FRAC_BASE;
+	INIT_LIST_HEAD(&bdi->bdi_list);
+	init_waitqueue_head(&bdi->wb_waitq);
+
+	err = wb_init(&bdi->wb, bdi, GFP_KERNEL);
+	if (err)
+		return err;
+
+	bdi->wb_congested.state = 0;
+	bdi->wb.congested = &bdi->wb_congested;
+
+	cgwb_bdi_init(bdi);
+	return 0;
+}
+EXPORT_SYMBOL(bdi_init);
+
 int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 		const char *fmt, ...)
 {
@@ -315,7 +779,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 	bdi->dev = dev;
 
 	bdi_debug_register(bdi, dev_name(dev));
-	set_bit(BDI_registered, &bdi->state);
+	set_bit(WB_registered, &bdi->wb.state);
 
 	spin_lock_bh(&bdi_lock);
 	list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
@@ -333,103 +797,23 @@ int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
 EXPORT_SYMBOL(bdi_register_dev);
 
 /*
- * Remove bdi from the global list and shutdown any threads we have running
+ * Remove bdi from bdi_list, and ensure that it is no longer visible
  */
-static void bdi_wb_shutdown(struct backing_dev_info *bdi)
+static void bdi_remove_from_list(struct backing_dev_info *bdi)
 {
-	/* Make sure nobody queues further work */
+	spin_lock_bh(&bdi_lock);
-	spin_lock_bh(&bdi->wb_lock);
+	list_del_rcu(&bdi->bdi_list);
-	if (!test_and_clear_bit(BDI_registered, &bdi->state)) {
+	spin_unlock_bh(&bdi_lock);
-		spin_unlock_bh(&bdi->wb_lock);
-		return;
-	}
-	spin_unlock_bh(&bdi->wb_lock);
 
-	/*
+	synchronize_rcu_expedited();
-	 * Make sure nobody finds us on the bdi_list anymore
-	 */
-	bdi_remove_from_list(bdi);
-
-	/*
-	 * Drain work list and shutdown the delayed_work.  At this point,
-	 * @bdi->bdi_list is empty telling bdi_Writeback_workfn() that @bdi
-	 * is dying and its work_list needs to be drained no matter what.
-	 */
-	mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0);
-	flush_delayed_work(&bdi->wb.dwork);
 }
 
-static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
-{
-	memset(wb, 0, sizeof(*wb));
-
-	wb->bdi = bdi;
-	wb->last_old_flush = jiffies;
-	INIT_LIST_HEAD(&wb->b_dirty);
-	INIT_LIST_HEAD(&wb->b_io);
-	INIT_LIST_HEAD(&wb->b_more_io);
-	INIT_LIST_HEAD(&wb->b_dirty_time);
-	spin_lock_init(&wb->list_lock);
-	INIT_DELAYED_WORK(&wb->dwork, bdi_writeback_workfn);
-}
-
-/*
- * Initial write bandwidth: 100 MB/s
- */
-#define INIT_BW		(100 << (20 - PAGE_SHIFT))
-
-int bdi_init(struct backing_dev_info *bdi)
-{
-	int i, err;
-
-	bdi->dev = NULL;
-
-	bdi->min_ratio = 0;
-	bdi->max_ratio = 100;
-	bdi->max_prop_frac = FPROP_FRAC_BASE;
-	spin_lock_init(&bdi->wb_lock);
-	INIT_LIST_HEAD(&bdi->bdi_list);
-	INIT_LIST_HEAD(&bdi->work_list);
-
-	bdi_wb_init(&bdi->wb, bdi);
-
-	for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
-		err = percpu_counter_init(&bdi->bdi_stat[i], 0, GFP_KERNEL);
-		if (err)
-			goto err;
-	}
-
-	bdi->dirty_exceeded = 0;
-
-	bdi->bw_time_stamp = jiffies;
-	bdi->written_stamp = 0;
-
-	bdi->balanced_dirty_ratelimit = INIT_BW;
-	bdi->dirty_ratelimit = INIT_BW;
-	bdi->write_bandwidth = INIT_BW;
-	bdi->avg_write_bandwidth = INIT_BW;
-
-	err = fprop_local_init_percpu(&bdi->completions, GFP_KERNEL);
-
-	if (err) {
-err:
-		while (i--)
-			percpu_counter_destroy(&bdi->bdi_stat[i]);
-	}
-
-	return err;
-}
-EXPORT_SYMBOL(bdi_init);
-
 void bdi_destroy(struct backing_dev_info *bdi)
 {
-	int i;
+	/* make sure nobody finds us on the bdi_list anymore */
-
+	bdi_remove_from_list(bdi);
-	bdi_wb_shutdown(bdi);
+	wb_shutdown(&bdi->wb);
-	bdi_set_min_ratio(bdi, 0);
+	cgwb_bdi_destroy(bdi);
-
-	WARN_ON(!list_empty(&bdi->work_list));
-	WARN_ON(delayed_work_pending(&bdi->wb.dwork));
 
 	if (bdi->dev) {
 		bdi_debug_unregister(bdi);
@@ -437,9 +821,7 @@ void bdi_destroy(struct backing_dev_info *bdi)
 		bdi->dev = NULL;
 	}
 
-	for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
+	wb_exit(&bdi->wb);
-		percpu_counter_destroy(&bdi->bdi_stat[i]);
-	fprop_local_destroy_percpu(&bdi->completions);
 }
 EXPORT_SYMBOL(bdi_destroy);
 
@@ -472,31 +854,31 @@ static wait_queue_head_t congestion_wqh[2] = {
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
 	};
-static atomic_t nr_bdi_congested[2];
+static atomic_t nr_wb_congested[2];
 
-void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
+void clear_wb_congested(struct bdi_writeback_congested *congested, int sync)
 {
-	enum bdi_state bit;
 	wait_queue_head_t *wqh = &congestion_wqh[sync];
+	enum wb_state bit;
 
-	bit = sync ? BDI_sync_congested : BDI_async_congested;
+	bit = sync ? WB_sync_congested : WB_async_congested;
-	if (test_and_clear_bit(bit, &bdi->state))
+	if (test_and_clear_bit(bit, &congested->state))
-		atomic_dec(&nr_bdi_congested[sync]);
+		atomic_dec(&nr_wb_congested[sync]);
 	smp_mb__after_atomic();
 	if (waitqueue_active(wqh))
 		wake_up(wqh);
 }
-EXPORT_SYMBOL(clear_bdi_congested);
+EXPORT_SYMBOL(clear_wb_congested);
 
-void set_bdi_congested(struct backing_dev_info *bdi, int sync)
+void set_wb_congested(struct bdi_writeback_congested *congested, int sync)
 {
-	enum bdi_state bit;
+	enum wb_state bit;
 
-	bit = sync ? BDI_sync_congested : BDI_async_congested;
+	bit = sync ? WB_sync_congested : WB_async_congested;
-	if (!test_and_set_bit(bit, &bdi->state))
+	if (!test_and_set_bit(bit, &congested->state))
-		atomic_inc(&nr_bdi_congested[sync]);
+		atomic_inc(&nr_wb_congested[sync]);
 }
-EXPORT_SYMBOL(set_bdi_congested);
+EXPORT_SYMBOL(set_wb_congested);
 
 /**
  * congestion_wait - wait for a backing_dev to become uncongested
@@ -555,7 +937,7 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout)
 	 * encountered in the current zone, yield if necessary instead
 	 * of sleeping on the congestion queue
 	 */
-	if (atomic_read(&nr_bdi_congested[sync]) == 0 ||
+	if (atomic_read(&nr_wb_congested[sync]) == 0 ||
 	    !test_bit(ZONE_CONGESTED, &zone->flags)) {
 		cond_resched();
 

mm/fadvise.c

@@ -115,7 +115,7 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
 	case POSIX_FADV_NOREUSE:
 		break;
 	case POSIX_FADV_DONTNEED:
-		if (!bdi_write_congested(bdi))
+		if (!inode_write_congested(mapping->host))
 			__filemap_fdatawrite_range(mapping, offset, endbyte,
 						   WB_SYNC_NONE);
 

mm/filemap.c

@@ -100,6 +100,7 @@
  *    ->tree_lock		(page_remove_rmap->set_page_dirty)
  *    bdi.wb->list_lock		(page_remove_rmap->set_page_dirty)
  *    ->inode->i_lock		(page_remove_rmap->set_page_dirty)
+ *    ->memcg->move_lock	(page_remove_rmap->mem_cgroup_begin_page_stat)
  *    bdi.wb->list_lock		(zap_pte_range->set_page_dirty)
  *    ->inode->i_lock		(zap_pte_range->set_page_dirty)
  *    ->private_lock		(zap_pte_range->__set_page_dirty_buffers)
@@ -174,9 +175,11 @@ static void page_cache_tree_delete(struct address_space *mapping,
 /*
  * Delete a page from the page cache and free it. Caller has to make
  * sure the page is locked and that nobody else uses it - or that usage
- * is safe.  The caller must hold the mapping's tree_lock.
+ * is safe.  The caller must hold the mapping's tree_lock and
+ * mem_cgroup_begin_page_stat().
  */
-void __delete_from_page_cache(struct page *page, void *shadow)
+void __delete_from_page_cache(struct page *page, void *shadow,
+			      struct mem_cgroup *memcg)
 {
 	struct address_space *mapping = page->mapping;
 
@@ -212,7 +215,8 @@ void __delete_from_page_cache(struct page *page, void *shadow)
 	 * anyway will be cleared before returning page into buddy allocator.
 	 */
 	if (WARN_ON_ONCE(PageDirty(page)))
-		account_page_cleaned(page, mapping);
+		account_page_cleaned(page, mapping, memcg,
+				     inode_to_wb(mapping->host));
 }
 
 /**
@@ -226,14 +230,20 @@ void __delete_from_page_cache(struct page *page, void *shadow)
 void delete_from_page_cache(struct page *page)
 {
 	struct address_space *mapping = page->mapping;
+	struct mem_cgroup *memcg;
+	unsigned long flags;
+
 	void (*freepage)(struct page *);
 
 	BUG_ON(!PageLocked(page));
 
 	freepage = mapping->a_ops->freepage;
-	spin_lock_irq(&mapping->tree_lock);
+
-	__delete_from_page_cache(page, NULL);
+	memcg = mem_cgroup_begin_page_stat(page);
-	spin_unlock_irq(&mapping->tree_lock);
+	spin_lock_irqsave(&mapping->tree_lock, flags);
+	__delete_from_page_cache(page, NULL, memcg);
+	spin_unlock_irqrestore(&mapping->tree_lock, flags);
+	mem_cgroup_end_page_stat(memcg);
 
 	if (freepage)
 		freepage(page);
@@ -283,7 +293,9 @@ int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
 	if (!mapping_cap_writeback_dirty(mapping))
 		return 0;
 
+	wbc_attach_fdatawrite_inode(&wbc, mapping->host);
 	ret = do_writepages(mapping, &wbc);
+	wbc_detach_inode(&wbc);
 	return ret;
 }
 
@@ -472,6 +484,8 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 	if (!error) {
 		struct address_space *mapping = old->mapping;
 		void (*freepage)(struct page *);
+		struct mem_cgroup *memcg;
+		unsigned long flags;
 
 		pgoff_t offset = old->index;
 		freepage = mapping->a_ops->freepage;
@@ -480,8 +494,9 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 		new->mapping = mapping;
 		new->index = offset;
 
-		spin_lock_irq(&mapping->tree_lock);
+		memcg = mem_cgroup_begin_page_stat(old);
-		__delete_from_page_cache(old, NULL);
+		spin_lock_irqsave(&mapping->tree_lock, flags);
+		__delete_from_page_cache(old, NULL, memcg);
 		error = radix_tree_insert(&mapping->page_tree, offset, new);
 		BUG_ON(error);
 		mapping->nrpages++;
@@ -493,7 +508,8 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 			__inc_zone_page_state(new, NR_FILE_PAGES);
 		if (PageSwapBacked(new))
 			__inc_zone_page_state(new, NR_SHMEM);
-		spin_unlock_irq(&mapping->tree_lock);
+		spin_unlock_irqrestore(&mapping->tree_lock, flags);
+		mem_cgroup_end_page_stat(memcg);
 		mem_cgroup_migrate(old, new, true);
 		radix_tree_preload_end();
 		if (freepage)

mm/madvise.c

@@ -17,6 +17,7 @@
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>
 

mm/memcontrol.c

@@ -77,6 +77,7 @@ EXPORT_SYMBOL(memory_cgrp_subsys);
 
 #define MEM_CGROUP_RECLAIM_RETRIES	5
 static struct mem_cgroup *root_mem_cgroup __read_mostly;
+struct cgroup_subsys_state *mem_cgroup_root_css __read_mostly;
 
 /* Whether the swap controller is active */
 #ifdef CONFIG_MEMCG_SWAP
@@ -90,6 +91,7 @@ static const char * const mem_cgroup_stat_names[] = {
 	"rss",
 	"rss_huge",
 	"mapped_file",
+	"dirty",
 	"writeback",
 	"swap",
 };
@@ -322,11 +324,6 @@ struct mem_cgroup {
 	 * percpu counter.
 	 */
 	struct mem_cgroup_stat_cpu __percpu *stat;
-	/*
-	 * used when a cpu is offlined or other synchronizations
-	 * See mem_cgroup_read_stat().
-	 */
-	struct mem_cgroup_stat_cpu nocpu_base;
 	spinlock_t pcp_counter_lock;
 
 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
@@ -346,6 +343,11 @@ struct mem_cgroup {
 	atomic_t	numainfo_updating;
 #endif
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct list_head cgwb_list;
+	struct wb_domain cgwb_domain;
+#endif
+
 	/* List of events which userspace want to receive */
 	struct list_head event_list;
 	spinlock_t event_list_lock;
@@ -596,6 +598,39 @@ struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
 	return &memcg->css;
 }
 
+/**
+ * mem_cgroup_css_from_page - css of the memcg associated with a page
+ * @page: page of interest
+ *
+ * If memcg is bound to the default hierarchy, css of the memcg associated
+ * with @page is returned.  The returned css remains associated with @page
+ * until it is released.
+ *
+ * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
+ * is returned.
+ *
+ * XXX: The above description of behavior on the default hierarchy isn't
+ * strictly true yet as replace_page_cache_page() can modify the
+ * association before @page is released even on the default hierarchy;
+ * however, the current and planned usages don't mix the the two functions
+ * and replace_page_cache_page() will soon be updated to make the invariant
+ * actually true.
+ */
+struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page)
+{
+	struct mem_cgroup *memcg;
+
+	rcu_read_lock();
+
+	memcg = page->mem_cgroup;
+
+	if (!memcg || !cgroup_on_dfl(memcg->css.cgroup))
+		memcg = root_mem_cgroup;
+
+	rcu_read_unlock();
+	return &memcg->css;
+}
+
 static struct mem_cgroup_per_zone *
 mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
 {
@@ -795,15 +830,8 @@ static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
 	long val = 0;
 	int cpu;
 
-	get_online_cpus();
+	for_each_possible_cpu(cpu)
-	for_each_online_cpu(cpu)
 		val += per_cpu(memcg->stat->count[idx], cpu);
-#ifdef CONFIG_HOTPLUG_CPU
-	spin_lock(&memcg->pcp_counter_lock);
-	val += memcg->nocpu_base.count[idx];
-	spin_unlock(&memcg->pcp_counter_lock);
-#endif
-	put_online_cpus();
 	return val;
 }
 
@@ -813,15 +841,8 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 	unsigned long val = 0;
 	int cpu;
 
-	get_online_cpus();
+	for_each_possible_cpu(cpu)
-	for_each_online_cpu(cpu)
 		val += per_cpu(memcg->stat->events[idx], cpu);
-#ifdef CONFIG_HOTPLUG_CPU
-	spin_lock(&memcg->pcp_counter_lock);
-	val += memcg->nocpu_base.events[idx];
-	spin_unlock(&memcg->pcp_counter_lock);
-#endif
-	put_online_cpus();
 	return val;
 }
 
@@ -2020,6 +2041,7 @@ again:
 
 	return memcg;
 }
+EXPORT_SYMBOL(mem_cgroup_begin_page_stat);
 
 /**
  * mem_cgroup_end_page_stat - finish a page state statistics transaction
@@ -2038,6 +2060,7 @@ void mem_cgroup_end_page_stat(struct mem_cgroup *memcg)
 
 	rcu_read_unlock();
 }
+EXPORT_SYMBOL(mem_cgroup_end_page_stat);
 
 /**
  * mem_cgroup_update_page_stat - update page state statistics
@@ -2178,37 +2201,12 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
 	mutex_unlock(&percpu_charge_mutex);
 }
 
-/*
- * This function drains percpu counter value from DEAD cpu and
- * move it to local cpu. Note that this function can be preempted.
- */
-static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
-{
-	int i;
-
-	spin_lock(&memcg->pcp_counter_lock);
-	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
-		long x = per_cpu(memcg->stat->count[i], cpu);
-
-		per_cpu(memcg->stat->count[i], cpu) = 0;
-		memcg->nocpu_base.count[i] += x;
-	}
-	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
-		unsigned long x = per_cpu(memcg->stat->events[i], cpu);
-
-		per_cpu(memcg->stat->events[i], cpu) = 0;
-		memcg->nocpu_base.events[i] += x;
-	}
-	spin_unlock(&memcg->pcp_counter_lock);
-}
-
 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
 					unsigned long action,
 					void *hcpu)
 {
 	int cpu = (unsigned long)hcpu;
 	struct memcg_stock_pcp *stock;
-	struct mem_cgroup *iter;
 
 	if (action == CPU_ONLINE)
 		return NOTIFY_OK;
@@ -2216,9 +2214,6 @@ static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
 	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
 		return NOTIFY_OK;
 
-	for_each_mem_cgroup(iter)
-		mem_cgroup_drain_pcp_counter(iter, cpu);
-
 	stock = &per_cpu(memcg_stock, cpu);
 	drain_stock(stock);
 	return NOTIFY_OK;
@@ -4004,6 +3999,98 @@ static void memcg_destroy_kmem(struct mem_cgroup *memcg)
 }
 #endif
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg)
+{
+	return &memcg->cgwb_list;
+}
+
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+	return wb_domain_init(&memcg->cgwb_domain, gfp);
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+	wb_domain_exit(&memcg->cgwb_domain);
+}
+
+static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
+{
+	wb_domain_size_changed(&memcg->cgwb_domain);
+}
+
+struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+
+	if (!memcg->css.parent)
+		return NULL;
+
+	return &memcg->cgwb_domain;
+}
+
+/**
+ * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
+ * @wb: bdi_writeback in question
+ * @pavail: out parameter for number of available pages
+ * @pdirty: out parameter for number of dirty pages
+ * @pwriteback: out parameter for number of pages under writeback
+ *
+ * Determine the numbers of available, dirty, and writeback pages in @wb's
+ * memcg.  Dirty and writeback are self-explanatory.  Available is a bit
+ * more involved.
+ *
+ * A memcg's headroom is "min(max, high) - used".  The available memory is
+ * calculated as the lowest headroom of itself and the ancestors plus the
+ * number of pages already being used for file pages.  Note that this
+ * doesn't consider the actual amount of available memory in the system.
+ * The caller should further cap *@pavail accordingly.
+ */
+void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pavail,
+			 unsigned long *pdirty, unsigned long *pwriteback)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+	struct mem_cgroup *parent;
+	unsigned long head_room = PAGE_COUNTER_MAX;
+	unsigned long file_pages;
+
+	*pdirty = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_DIRTY);
+
+	/* this should eventually include NR_UNSTABLE_NFS */
+	*pwriteback = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+
+	file_pages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
+						    (1 << LRU_ACTIVE_FILE));
+	while ((parent = parent_mem_cgroup(memcg))) {
+		unsigned long ceiling = min(memcg->memory.limit, memcg->high);
+		unsigned long used = page_counter_read(&memcg->memory);
+
+		head_room = min(head_room, ceiling - min(ceiling, used));
+		memcg = parent;
+	}
+
+	*pavail = file_pages + head_room;
+}
+
+#else	/* CONFIG_CGROUP_WRITEBACK */
+
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+	return 0;
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+}
+
+static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
+{
+}
+
+#endif	/* CONFIG_CGROUP_WRITEBACK */
+
 /*
  * DO NOT USE IN NEW FILES.
  *
@@ -4388,9 +4475,15 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 	memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
 	if (!memcg->stat)
 		goto out_free;
+
+	if (memcg_wb_domain_init(memcg, GFP_KERNEL))
+		goto out_free_stat;
+
 	spin_lock_init(&memcg->pcp_counter_lock);
 	return memcg;
 
+out_free_stat:
+	free_percpu(memcg->stat);
 out_free:
 	kfree(memcg);
 	return NULL;
@@ -4417,6 +4510,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
 		free_mem_cgroup_per_zone_info(memcg, node);
 
 	free_percpu(memcg->stat);
+	memcg_wb_domain_exit(memcg);
 	kfree(memcg);
 }
 
@@ -4449,6 +4543,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
 	/* root ? */
 	if (parent_css == NULL) {
 		root_mem_cgroup = memcg;
+		mem_cgroup_root_css = &memcg->css;
 		page_counter_init(&memcg->memory, NULL);
 		memcg->high = PAGE_COUNTER_MAX;
 		memcg->soft_limit = PAGE_COUNTER_MAX;
@@ -4467,7 +4562,9 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
 #ifdef CONFIG_MEMCG_KMEM
 	memcg->kmemcg_id = -1;
 #endif
-
+#ifdef CONFIG_CGROUP_WRITEBACK
+	INIT_LIST_HEAD(&memcg->cgwb_list);
+#endif
 	return &memcg->css;
 
 free_out:
@@ -4555,6 +4652,8 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
 	vmpressure_cleanup(&memcg->vmpressure);
 
 	memcg_deactivate_kmem(memcg);
+
+	wb_memcg_offline(memcg);
 }
 
 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
@@ -4588,6 +4687,7 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
 	memcg->low = 0;
 	memcg->high = PAGE_COUNTER_MAX;
 	memcg->soft_limit = PAGE_COUNTER_MAX;
+	memcg_wb_domain_size_changed(memcg);
 }
 
 #ifdef CONFIG_MMU
@@ -4757,6 +4857,7 @@ static int mem_cgroup_move_account(struct page *page,
 {
 	unsigned long flags;
 	int ret;
+	bool anon;
 
 	VM_BUG_ON(from == to);
 	VM_BUG_ON_PAGE(PageLRU(page), page);
@@ -4782,15 +4883,33 @@ static int mem_cgroup_move_account(struct page *page,
 	if (page->mem_cgroup != from)
 		goto out_unlock;
 
+	anon = PageAnon(page);
+
 	spin_lock_irqsave(&from->move_lock, flags);
 
-	if (!PageAnon(page) && page_mapped(page)) {
+	if (!anon && page_mapped(page)) {
 		__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
 			       nr_pages);
 		__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
 			       nr_pages);
 	}
 
+	/*
+	 * move_lock grabbed above and caller set from->moving_account, so
+	 * mem_cgroup_update_page_stat() will serialize updates to PageDirty.
+	 * So mapping should be stable for dirty pages.
+	 */
+	if (!anon && PageDirty(page)) {
+		struct address_space *mapping = page_mapping(page);
+
+		if (mapping_cap_account_dirty(mapping)) {
+			__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_DIRTY],
+				       nr_pages);
+			__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_DIRTY],
+				       nr_pages);
+		}
+	}
+
 	if (PageWriteback(page)) {
 		__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
 			       nr_pages);
@@ -5306,6 +5425,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
 
 	memcg->high = high;
 
+	memcg_wb_domain_size_changed(memcg);
 	return nbytes;
 }
 
@@ -5338,6 +5458,7 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
 	if (err)
 		return err;
 
+	memcg_wb_domain_size_changed(memcg);
 	return nbytes;
 }
 

mm/readahead.c

@@ -541,7 +541,7 @@ page_cache_async_readahead(struct address_space *mapping,
 	/*
 	 * Defer asynchronous read-ahead on IO congestion.
 	 */
-	if (bdi_read_congested(inode_to_bdi(mapping->host)))
+	if (inode_read_congested(mapping->host))
 		return;
 
 	/* do read-ahead */

mm/rmap.c

@@ -30,6 +30,8 @@
  *             swap_lock (in swap_duplicate, swap_info_get)
  *               mmlist_lock (in mmput, drain_mmlist and others)
  *               mapping->private_lock (in __set_page_dirty_buffers)
+ *                 mem_cgroup_{begin,end}_page_stat (memcg->move_lock)
+ *                   mapping->tree_lock (widely used)
  *               inode->i_lock (in set_page_dirty's __mark_inode_dirty)
  *               bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
  *                 sb_lock (within inode_lock in fs/fs-writeback.c)

mm/truncate.c

@@ -116,9 +116,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
 	 * the VM has canceled the dirty bit (eg ext3 journaling).
 	 * Hence dirty accounting check is placed after invalidation.
 	 */
-	if (TestClearPageDirty(page))
+	cancel_dirty_page(page);
-		account_page_cleaned(page, mapping);
-
 	ClearPageMappedToDisk(page);
 	delete_from_page_cache(page);
 	return 0;
@@ -512,19 +510,24 @@ EXPORT_SYMBOL(invalidate_mapping_pages);
 static int
 invalidate_complete_page2(struct address_space *mapping, struct page *page)
 {
+	struct mem_cgroup *memcg;
+	unsigned long flags;
+
 	if (page->mapping != mapping)
 		return 0;
 
 	if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
 		return 0;
 
-	spin_lock_irq(&mapping->tree_lock);
+	memcg = mem_cgroup_begin_page_stat(page);
+	spin_lock_irqsave(&mapping->tree_lock, flags);
 	if (PageDirty(page))
 		goto failed;
 
 	BUG_ON(page_has_private(page));
-	__delete_from_page_cache(page, NULL);
+	__delete_from_page_cache(page, NULL, memcg);
-	spin_unlock_irq(&mapping->tree_lock);
+	spin_unlock_irqrestore(&mapping->tree_lock, flags);
+	mem_cgroup_end_page_stat(memcg);
 
 	if (mapping->a_ops->freepage)
 		mapping->a_ops->freepage(page);
@@ -532,7 +535,8 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
 	page_cache_release(page);	/* pagecache ref */
 	return 1;
 failed:
-	spin_unlock_irq(&mapping->tree_lock);
+	spin_unlock_irqrestore(&mapping->tree_lock, flags);
+	mem_cgroup_end_page_stat(memcg);
 	return 0;
 }
 

mm/vmscan.c

@@ -154,11 +154,42 @@ static bool global_reclaim(struct scan_control *sc)
 {
 	return !sc->target_mem_cgroup;
 }
+
+/**
+ * sane_reclaim - is the usual dirty throttling mechanism operational?
+ * @sc: scan_control in question
+ *
+ * The normal page dirty throttling mechanism in balance_dirty_pages() is
+ * completely broken with the legacy memcg and direct stalling in
+ * shrink_page_list() is used for throttling instead, which lacks all the
+ * niceties such as fairness, adaptive pausing, bandwidth proportional
+ * allocation and configurability.
+ *
+ * This function tests whether the vmscan currently in progress can assume
+ * that the normal dirty throttling mechanism is operational.
+ */
+static bool sane_reclaim(struct scan_control *sc)
+{
+	struct mem_cgroup *memcg = sc->target_mem_cgroup;
+
+	if (!memcg)
+		return true;
+#ifdef CONFIG_CGROUP_WRITEBACK
+	if (cgroup_on_dfl(mem_cgroup_css(memcg)->cgroup))
+		return true;
+#endif
+	return false;
+}
 #else
 static bool global_reclaim(struct scan_control *sc)
 {
 	return true;
 }
+
+static bool sane_reclaim(struct scan_control *sc)
+{
+	return true;
+}
 #endif
 
 static unsigned long zone_reclaimable_pages(struct zone *zone)
@@ -452,14 +483,13 @@ static inline int is_page_cache_freeable(struct page *page)
 	return page_count(page) - page_has_private(page) == 2;
 }
 
-static int may_write_to_queue(struct backing_dev_info *bdi,
+static int may_write_to_inode(struct inode *inode, struct scan_control *sc)
-			      struct scan_control *sc)
 {
 	if (current->flags & PF_SWAPWRITE)
 		return 1;
-	if (!bdi_write_congested(bdi))
+	if (!inode_write_congested(inode))
 		return 1;
-	if (bdi == current->backing_dev_info)
+	if (inode_to_bdi(inode) == current->backing_dev_info)
 		return 1;
 	return 0;
 }
@@ -538,7 +568,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
 	}
 	if (mapping->a_ops->writepage == NULL)
 		return PAGE_ACTIVATE;
-	if (!may_write_to_queue(inode_to_bdi(mapping->host), sc))
+	if (!may_write_to_inode(mapping->host, sc))
 		return PAGE_KEEP;
 
 	if (clear_page_dirty_for_io(page)) {
@@ -579,10 +609,14 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
 static int __remove_mapping(struct address_space *mapping, struct page *page,
 			    bool reclaimed)
 {
+	unsigned long flags;
+	struct mem_cgroup *memcg;
+
 	BUG_ON(!PageLocked(page));
 	BUG_ON(mapping != page_mapping(page));
 
-	spin_lock_irq(&mapping->tree_lock);
+	memcg = mem_cgroup_begin_page_stat(page);
+	spin_lock_irqsave(&mapping->tree_lock, flags);
 	/*
 	 * The non racy check for a busy page.
 	 *
@@ -620,7 +654,8 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
 		swp_entry_t swap = { .val = page_private(page) };
 		mem_cgroup_swapout(page, swap);
 		__delete_from_swap_cache(page);
-		spin_unlock_irq(&mapping->tree_lock);
+		spin_unlock_irqrestore(&mapping->tree_lock, flags);
+		mem_cgroup_end_page_stat(memcg);
 		swapcache_free(swap);
 	} else {
 		void (*freepage)(struct page *);
@@ -640,8 +675,9 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
 		if (reclaimed && page_is_file_cache(page) &&
 		    !mapping_exiting(mapping))
 			shadow = workingset_eviction(mapping, page);
-		__delete_from_page_cache(page, shadow);
+		__delete_from_page_cache(page, shadow, memcg);
-		spin_unlock_irq(&mapping->tree_lock);
+		spin_unlock_irqrestore(&mapping->tree_lock, flags);
+		mem_cgroup_end_page_stat(memcg);
 
 		if (freepage != NULL)
 			freepage(page);
@@ -650,7 +686,8 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
 	return 1;
 
 cannot_free:
-	spin_unlock_irq(&mapping->tree_lock);
+	spin_unlock_irqrestore(&mapping->tree_lock, flags);
+	mem_cgroup_end_page_stat(memcg);
 	return 0;
 }
 
@@ -917,7 +954,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		 */
 		mapping = page_mapping(page);
 		if (((dirty || writeback) && mapping &&
-		     bdi_write_congested(inode_to_bdi(mapping->host))) ||
+		     inode_write_congested(mapping->host)) ||
 		    (writeback && PageReclaim(page)))
 			nr_congested++;
 
@@ -935,10 +972,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		 *    note that the LRU is being scanned too quickly and the
 		 *    caller can stall after page list has been processed.
 		 *
-		 * 2) Global reclaim encounters a page, memcg encounters a
+		 * 2) Global or new memcg reclaim encounters a page that is
-		 *    page that is not marked for immediate reclaim or
+		 *    not marked for immediate reclaim or the caller does not
-		 *    the caller does not have __GFP_IO. In this case mark
+		 *    have __GFP_IO. In this case mark the page for immediate
-		 *    the page for immediate reclaim and continue scanning.
+		 *    reclaim and continue scanning.
 		 *
 		 *    __GFP_IO is checked  because a loop driver thread might
 		 *    enter reclaim, and deadlock if it waits on a page for
@@ -952,7 +989,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		 *    grab_cache_page_write_begin(,,AOP_FLAG_NOFS), so testing
 		 *    may_enter_fs here is liable to OOM on them.
 		 *
-		 * 3) memcg encounters a page that is not already marked
+		 * 3) Legacy memcg encounters a page that is not already marked
 		 *    PageReclaim. memcg does not have any dirty pages
 		 *    throttling so we could easily OOM just because too many
 		 *    pages are in writeback and there is nothing else to
@@ -967,7 +1004,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 				goto keep_locked;
 
 			/* Case 2 above */
-			} else if (global_reclaim(sc) ||
+			} else if (sane_reclaim(sc) ||
 			    !PageReclaim(page) || !(sc->gfp_mask & __GFP_IO)) {
 				/*
 				 * This is slightly racy - end_page_writeback()
@@ -1416,7 +1453,7 @@ static int too_many_isolated(struct zone *zone, int file,
 	if (current_is_kswapd())
 		return 0;
 
-	if (!global_reclaim(sc))
+	if (!sane_reclaim(sc))
 		return 0;
 
 	if (file) {
@@ -1608,10 +1645,10 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 		set_bit(ZONE_WRITEBACK, &zone->flags);
 
 	/*
-	 * memcg will stall in page writeback so only consider forcibly
+	 * Legacy memcg will stall in page writeback so avoid forcibly
-	 * stalling for global reclaim
+	 * stalling here.
 	 */
-	if (global_reclaim(sc)) {
+	if (sane_reclaim(sc)) {
 		/*
 		 * Tag a zone as congested if all the dirty pages scanned were
 		 * backed by a congested BDI and wait_iff_congested will stall.