License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 17:07:57 +03:00
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/* SPDX-License-Identifier: GPL-2.0 */
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2009-12-03 20:59:42 +03:00
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#ifndef _BLK_CGROUP_H
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#define _BLK_CGROUP_H
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/*
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* Common Block IO controller cgroup interface
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*
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* Based on ideas and code from CFQ, CFS and BFQ:
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* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
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*
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* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
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* Paolo Valente <paolo.valente@unimore.it>
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*
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* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
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* Nauman Rafique <nauman@google.com>
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*/
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#include <linux/cgroup.h>
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2015-08-19 00:55:22 +03:00
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#include <linux/percpu_counter.h>
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2012-04-02 01:38:43 +04:00
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#include <linux/seq_file.h>
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2012-04-20 03:29:24 +04:00
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#include <linux/radix-tree.h>
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blkcg: implement per-blkg request allocation
Currently, request_queue has one request_list to allocate requests
from regardless of blkcg of the IO being issued. When the unified
request pool is used up, cfq proportional IO limits become meaningless
- whoever grabs the next request being freed wins the race regardless
of the configured weights.
This can be easily demonstrated by creating a blkio cgroup w/ very low
weight, put a program which can issue a lot of random direct IOs there
and running a sequential IO from a different cgroup. As soon as the
request pool is used up, the sequential IO bandwidth crashes.
This patch implements per-blkg request_list. Each blkg has its own
request_list and any IO allocates its request from the matching blkg
making blkcgs completely isolated in terms of request allocation.
* Root blkcg uses the request_list embedded in each request_queue,
which was renamed to @q->root_rl from @q->rq. While making blkcg rl
handling a bit harier, this enables avoiding most overhead for root
blkcg.
* Queue fullness is properly per request_list but bdi isn't blkcg
aware yet, so congestion state currently just follows the root
blkcg. As writeback isn't aware of blkcg yet, this works okay for
async congestion but readahead may get the wrong signals. It's
better than blkcg completely collapsing with shared request_list but
needs to be improved with future changes.
* After this change, each block cgroup gets a full request pool making
resource consumption of each cgroup higher. This makes allowing
non-root users to create cgroups less desirable; however, note that
allowing non-root users to directly manage cgroups is already
severely broken regardless of this patch - each block cgroup
consumes kernel memory and skews IO weight (IO weights are not
hierarchical).
v2: queue-sysfs.txt updated and patch description udpated as suggested
by Vivek.
v3: blk_get_rl() wasn't checking error return from
blkg_lookup_create() and may cause oops on lookup failure. Fix it
by falling back to root_rl on blkg lookup failures. This problem
was spotted by Rakesh Iyer <rni@google.com>.
v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in
request waitqueue". blk_drain_queue() now wakes up waiters on all
blkg->rl on the target queue.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-27 02:05:44 +04:00
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#include <linux/blkdev.h>
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blkcg: fix use-after-free in __blkg_release_rcu() by making blkcg_gq refcnt an atomic_t
Hello,
So, this patch should do. Joe, Vivek, can one of you guys please
verify that the oops goes away with this patch?
Jens, the original thread can be read at
http://thread.gmane.org/gmane.linux.kernel/1720729
The fix converts blkg->refcnt from int to atomic_t. It does some
overhead but it should be minute compared to everything else which is
going on and the involved cacheline bouncing, so I think it's highly
unlikely to cause any noticeable difference. Also, the refcnt in
question should be converted to a perpcu_ref for blk-mq anyway, so the
atomic_t is likely to go away pretty soon anyway.
Thanks.
------- 8< -------
__blkg_release_rcu() may be invoked after the associated request_queue
is released with a RCU grace period inbetween. As such, the function
and callbacks invoked from it must not dereference the associated
request_queue. This is clearly indicated in the comment above the
function.
Unfortunately, while trying to fix a different issue, 2a4fd070ee85
("blkcg: move bulk of blkcg_gq release operations to the RCU
callback") ignored this and added [un]locking of @blkg->q->queue_lock
to __blkg_release_rcu(). This of course can cause oops as the
request_queue may be long gone by the time this code gets executed.
general protection fault: 0000 [#1] SMP
CPU: 21 PID: 30 Comm: rcuos/21 Not tainted 3.15.0 #1
Hardware name: Stratus ftServer 6400/G7LAZ, BIOS BIOS Version 6.3:57 12/25/2013
task: ffff880854021de0 ti: ffff88085403c000 task.ti: ffff88085403c000
RIP: 0010:[<ffffffff8162e9e5>] [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
RSP: 0018:ffff88085403fdf0 EFLAGS: 00010086
RAX: 0000000000020000 RBX: 0000000000000010 RCX: 0000000000000000
RDX: 000060ef80008248 RSI: 0000000000000286 RDI: 6b6b6b6b6b6b6b6b
RBP: ffff88085403fdf0 R08: 0000000000000286 R09: 0000000000009f39
R10: 0000000000020001 R11: 0000000000020001 R12: ffff88103c17a130
R13: ffff88103c17a080 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88107fca0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006e5ab8 CR3: 000000000193d000 CR4: 00000000000407e0
Stack:
ffff88085403fe18 ffffffff812cbfc2 ffff88103c17a130 0000000000000000
ffff88103c17a130 ffff88085403fec0 ffffffff810d1d28 ffff880854021de0
ffff880854021de0 ffff88107fcaec58 ffff88085403fe80 ffff88107fcaec30
Call Trace:
[<ffffffff812cbfc2>] __blkg_release_rcu+0x72/0x150
[<ffffffff810d1d28>] rcu_nocb_kthread+0x1e8/0x300
[<ffffffff81091d81>] kthread+0xe1/0x100
[<ffffffff8163813c>] ret_from_fork+0x7c/0xb0
Code: ff 47 04 48 8b 7d 08 be 00 02 00 00 e8 55 48 a4 ff 5d c3 0f 1f 00 66 66 66 66 90 55 48 89 e5
+fa 66 66 90 66 66 90 b8 00 00 02 00 <f0> 0f c1 07 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f
+b7
RIP [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
RSP <ffff88085403fdf0>
The request_queue locking was added because blkcg_gq->refcnt is an int
protected with the queue lock and __blkg_release_rcu() needs to put
the parent. Let's fix it by making blkcg_gq->refcnt an atomic_t and
dropping queue locking in the function.
Given the general heavy weight of the current request_queue and blkcg
operations, this is unlikely to cause any noticeable overhead.
Moreover, blkcg_gq->refcnt is likely to be converted to percpu_ref in
the near future, so whatever (most likely negligible) overhead it may
add is temporary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/g/alpine.DEB.2.02.1406081816540.17948@jlaw-desktop.mno.stratus.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-20 01:42:57 +04:00
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#include <linux/atomic.h>
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2017-09-15 00:02:06 +03:00
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#include <linux/kthread.h>
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2018-12-05 20:10:31 +03:00
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#include <linux/fs.h>
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2009-12-03 20:59:42 +03:00
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2015-08-19 00:55:22 +03:00
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/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
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#define BLKG_STAT_CPU_BATCH (INT_MAX / 2)
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2010-10-01 23:16:41 +04:00
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/* Max limits for throttle policy */
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#define THROTL_IOPS_MAX UINT_MAX
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2012-04-14 00:11:25 +04:00
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#ifdef CONFIG_BLK_CGROUP
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2012-04-02 01:38:42 +04:00
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enum blkg_rwstat_type {
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BLKG_RWSTAT_READ,
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BLKG_RWSTAT_WRITE,
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BLKG_RWSTAT_SYNC,
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BLKG_RWSTAT_ASYNC,
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2018-07-18 14:47:41 +03:00
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BLKG_RWSTAT_DISCARD,
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2012-04-02 01:38:42 +04:00
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BLKG_RWSTAT_NR,
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BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
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2010-04-02 02:01:24 +04:00
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};
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2012-04-20 03:29:24 +04:00
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struct blkcg_gq;
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2012-04-17 00:57:25 +04:00
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struct blkcg {
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2012-04-17 00:57:24 +04:00
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struct cgroup_subsys_state css;
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spinlock_t lock;
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2012-04-20 03:29:24 +04:00
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struct radix_tree_root blkg_tree;
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2016-09-23 19:07:56 +03:00
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struct blkcg_gq __rcu *blkg_hint;
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2012-04-17 00:57:24 +04:00
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struct hlist_head blkg_list;
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2012-03-20 02:10:56 +04:00
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2015-08-19 00:55:15 +03:00
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struct blkcg_policy_data *cpd[BLKCG_MAX_POLS];
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2015-05-23 00:13:37 +03:00
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2015-07-09 23:39:49 +03:00
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struct list_head all_blkcgs_node;
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2015-05-23 00:13:37 +03:00
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#ifdef CONFIG_CGROUP_WRITEBACK
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struct list_head cgwb_list;
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2018-08-31 23:22:43 +03:00
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refcount_t cgwb_refcnt;
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2015-05-23 00:13:37 +03:00
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#endif
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2009-12-03 20:59:42 +03:00
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};
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2015-08-19 00:55:21 +03:00
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/*
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* blkg_[rw]stat->aux_cnt is excluded for local stats but included for
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2019-06-06 13:26:21 +03:00
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* recursive. Used to carry stats of dead children.
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2015-08-19 00:55:21 +03:00
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*/
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2012-04-02 01:38:42 +04:00
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struct blkg_rwstat {
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2015-08-19 00:55:22 +03:00
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struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR];
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2015-08-19 00:55:21 +03:00
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atomic64_t aux_cnt[BLKG_RWSTAT_NR];
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2012-04-02 01:38:42 +04:00
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};
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2019-06-06 13:26:21 +03:00
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struct blkg_rwstat_sample {
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u64 cnt[BLKG_RWSTAT_NR];
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};
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2012-04-17 00:57:26 +04:00
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/*
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* A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
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* request_queue (q). This is used by blkcg policies which need to track
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* information per blkcg - q pair.
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*
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2015-08-19 00:55:11 +03:00
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* There can be multiple active blkcg policies and each blkg:policy pair is
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* represented by a blkg_policy_data which is allocated and freed by each
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* policy's pd_alloc/free_fn() methods. A policy can allocate private data
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* area by allocating larger data structure which embeds blkg_policy_data
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* at the beginning.
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2012-04-17 00:57:26 +04:00
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*/
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2012-03-06 01:15:14 +04:00
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struct blkg_policy_data {
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2013-01-09 20:05:12 +04:00
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/* the blkg and policy id this per-policy data belongs to */
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2012-04-17 00:57:25 +04:00
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struct blkcg_gq *blkg;
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2013-01-09 20:05:12 +04:00
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int plid;
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2012-03-06 01:15:14 +04:00
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};
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block, cgroup: implement policy-specific per-blkcg data
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-06 00:38:42 +03:00
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/*
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2015-08-19 00:55:16 +03:00
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* Policies that need to keep per-blkcg data which is independent from any
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* request_queue associated to it should implement cpd_alloc/free_fn()
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* methods. A policy can allocate private data area by allocating larger
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* data structure which embeds blkcg_policy_data at the beginning.
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* cpd_init() is invoked to let each policy handle per-blkcg data.
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block, cgroup: implement policy-specific per-blkcg data
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-06 00:38:42 +03:00
|
|
|
*/
|
|
|
|
struct blkcg_policy_data {
|
2015-08-19 00:55:15 +03:00
|
|
|
/* the blkcg and policy id this per-policy data belongs to */
|
|
|
|
struct blkcg *blkcg;
|
block, cgroup: implement policy-specific per-blkcg data
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-06 00:38:42 +03:00
|
|
|
int plid;
|
|
|
|
};
|
|
|
|
|
2012-04-17 00:57:25 +04:00
|
|
|
/* association between a blk cgroup and a request queue */
|
|
|
|
struct blkcg_gq {
|
2012-03-06 01:15:22 +04:00
|
|
|
/* Pointer to the associated request_queue */
|
2012-04-17 00:57:24 +04:00
|
|
|
struct request_queue *q;
|
|
|
|
struct list_head q_node;
|
|
|
|
struct hlist_node blkcg_node;
|
2012-04-17 00:57:25 +04:00
|
|
|
struct blkcg *blkcg;
|
2013-01-09 20:05:10 +04:00
|
|
|
|
2015-05-23 00:13:38 +03:00
|
|
|
/*
|
|
|
|
* Each blkg gets congested separately and the congestion state is
|
|
|
|
* propagated to the matching bdi_writeback_congested.
|
|
|
|
*/
|
|
|
|
struct bdi_writeback_congested *wb_congested;
|
|
|
|
|
2013-01-09 20:05:10 +04:00
|
|
|
/* all non-root blkcg_gq's are guaranteed to have access to parent */
|
|
|
|
struct blkcg_gq *parent;
|
|
|
|
|
2012-03-06 01:15:15 +04:00
|
|
|
/* reference count */
|
2018-12-05 20:10:38 +03:00
|
|
|
struct percpu_ref refcnt;
|
2009-12-03 20:59:49 +03:00
|
|
|
|
2013-01-09 20:05:12 +04:00
|
|
|
/* is this blkg online? protected by both blkcg and q locks */
|
|
|
|
bool online;
|
|
|
|
|
2015-08-19 00:55:24 +03:00
|
|
|
struct blkg_rwstat stat_bytes;
|
|
|
|
struct blkg_rwstat stat_ios;
|
|
|
|
|
2012-04-17 00:57:24 +04:00
|
|
|
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
|
2012-03-06 01:15:15 +04:00
|
|
|
|
2019-06-27 23:39:52 +03:00
|
|
|
spinlock_t async_bio_lock;
|
|
|
|
struct bio_list async_bios;
|
|
|
|
struct work_struct async_bio_work;
|
2018-07-03 18:14:55 +03:00
|
|
|
|
|
|
|
atomic_t use_delay;
|
|
|
|
atomic64_t delay_nsec;
|
|
|
|
atomic64_t delay_start;
|
|
|
|
u64 last_delay;
|
|
|
|
int last_use;
|
2019-06-27 23:39:52 +03:00
|
|
|
|
|
|
|
struct rcu_head rcu_head;
|
2009-12-03 20:59:42 +03:00
|
|
|
};
|
|
|
|
|
2015-08-19 00:55:16 +03:00
|
|
|
typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
|
2015-08-19 00:55:15 +03:00
|
|
|
typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
|
2015-08-19 00:55:16 +03:00
|
|
|
typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
|
2015-08-19 00:55:36 +03:00
|
|
|
typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd);
|
2019-08-29 01:05:51 +03:00
|
|
|
typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp,
|
|
|
|
struct request_queue *q, struct blkcg *blkcg);
|
2015-08-19 00:55:14 +03:00
|
|
|
typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
|
|
|
|
typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
|
|
|
|
typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
|
2015-08-19 00:55:11 +03:00
|
|
|
typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
|
2015-08-19 00:55:14 +03:00
|
|
|
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
|
2018-07-03 18:14:52 +03:00
|
|
|
typedef size_t (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd, char *buf,
|
|
|
|
size_t size);
|
2009-12-04 18:36:42 +03:00
|
|
|
|
2012-04-17 00:57:25 +04:00
|
|
|
struct blkcg_policy {
|
2012-04-17 00:57:24 +04:00
|
|
|
int plid;
|
|
|
|
/* cgroup files for the policy */
|
2015-08-19 00:55:34 +03:00
|
|
|
struct cftype *dfl_cftypes;
|
2015-08-19 00:55:30 +03:00
|
|
|
struct cftype *legacy_cftypes;
|
2012-04-17 00:57:27 +04:00
|
|
|
|
|
|
|
/* operations */
|
2015-08-19 00:55:16 +03:00
|
|
|
blkcg_pol_alloc_cpd_fn *cpd_alloc_fn;
|
block, cgroup: implement policy-specific per-blkcg data
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-06 00:38:42 +03:00
|
|
|
blkcg_pol_init_cpd_fn *cpd_init_fn;
|
2015-08-19 00:55:16 +03:00
|
|
|
blkcg_pol_free_cpd_fn *cpd_free_fn;
|
2015-08-19 00:55:36 +03:00
|
|
|
blkcg_pol_bind_cpd_fn *cpd_bind_fn;
|
2015-08-19 00:55:16 +03:00
|
|
|
|
2015-08-19 00:55:11 +03:00
|
|
|
blkcg_pol_alloc_pd_fn *pd_alloc_fn;
|
2012-04-17 00:57:27 +04:00
|
|
|
blkcg_pol_init_pd_fn *pd_init_fn;
|
2013-01-09 20:05:12 +04:00
|
|
|
blkcg_pol_online_pd_fn *pd_online_fn;
|
|
|
|
blkcg_pol_offline_pd_fn *pd_offline_fn;
|
2015-08-19 00:55:11 +03:00
|
|
|
blkcg_pol_free_pd_fn *pd_free_fn;
|
2012-04-17 00:57:27 +04:00
|
|
|
blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
|
2018-07-03 18:14:52 +03:00
|
|
|
blkcg_pol_stat_pd_fn *pd_stat_fn;
|
2009-12-04 18:36:42 +03:00
|
|
|
};
|
|
|
|
|
2012-04-17 00:57:25 +04:00
|
|
|
extern struct blkcg blkcg_root;
|
2015-05-23 00:13:21 +03:00
|
|
|
extern struct cgroup_subsys_state * const blkcg_root_css;
|
2019-07-16 17:58:31 +03:00
|
|
|
extern bool blkcg_debug_stats;
|
2012-04-17 00:57:24 +04:00
|
|
|
|
2015-08-19 00:55:17 +03:00
|
|
|
struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
|
|
|
|
struct request_queue *q, bool update_hint);
|
2018-12-05 20:10:27 +03:00
|
|
|
struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
|
|
|
|
struct request_queue *q);
|
2012-04-17 00:57:25 +04:00
|
|
|
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
|
|
|
|
struct request_queue *q);
|
2012-04-17 00:57:24 +04:00
|
|
|
int blkcg_init_queue(struct request_queue *q);
|
|
|
|
void blkcg_drain_queue(struct request_queue *q);
|
|
|
|
void blkcg_exit_queue(struct request_queue *q);
|
2012-03-06 01:15:12 +04:00
|
|
|
|
2009-12-04 18:36:42 +03:00
|
|
|
/* Blkio controller policy registration */
|
2014-06-23 02:31:56 +04:00
|
|
|
int blkcg_policy_register(struct blkcg_policy *pol);
|
2012-04-17 00:57:25 +04:00
|
|
|
void blkcg_policy_unregister(struct blkcg_policy *pol);
|
2012-04-17 00:57:24 +04:00
|
|
|
int blkcg_activate_policy(struct request_queue *q,
|
2012-04-17 00:57:25 +04:00
|
|
|
const struct blkcg_policy *pol);
|
2012-04-17 00:57:24 +04:00
|
|
|
void blkcg_deactivate_policy(struct request_queue *q,
|
2012-04-17 00:57:25 +04:00
|
|
|
const struct blkcg_policy *pol);
|
2009-12-04 18:36:42 +03:00
|
|
|
|
2019-06-06 13:26:19 +03:00
|
|
|
static inline u64 blkg_rwstat_read_counter(struct blkg_rwstat *rwstat,
|
|
|
|
unsigned int idx)
|
|
|
|
{
|
|
|
|
return atomic64_read(&rwstat->aux_cnt[idx]) +
|
|
|
|
percpu_counter_sum_positive(&rwstat->cpu_cnt[idx]);
|
|
|
|
}
|
|
|
|
|
2015-08-19 00:55:33 +03:00
|
|
|
const char *blkg_dev_name(struct blkcg_gq *blkg);
|
2012-04-17 00:57:25 +04:00
|
|
|
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
|
2012-04-17 00:57:26 +04:00
|
|
|
u64 (*prfill)(struct seq_file *,
|
|
|
|
struct blkg_policy_data *, int),
|
2012-04-17 00:57:25 +04:00
|
|
|
const struct blkcg_policy *pol, int data,
|
2012-04-14 00:11:27 +04:00
|
|
|
bool show_total);
|
2012-04-17 00:57:26 +04:00
|
|
|
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
|
|
|
|
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
|
2019-06-06 13:26:21 +03:00
|
|
|
const struct blkg_rwstat_sample *rwstat);
|
2012-04-17 00:57:26 +04:00
|
|
|
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
|
|
|
|
int off);
|
2015-08-19 00:55:24 +03:00
|
|
|
int blkg_print_stat_bytes(struct seq_file *sf, void *v);
|
|
|
|
int blkg_print_stat_ios(struct seq_file *sf, void *v);
|
|
|
|
int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v);
|
|
|
|
int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v);
|
2012-04-02 01:38:43 +04:00
|
|
|
|
2019-06-06 13:26:20 +03:00
|
|
|
void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
|
2019-06-06 13:26:21 +03:00
|
|
|
int off, struct blkg_rwstat_sample *sum);
|
2013-01-09 20:05:12 +04:00
|
|
|
|
2012-04-02 01:38:43 +04:00
|
|
|
struct blkg_conf_ctx {
|
2012-04-17 00:57:24 +04:00
|
|
|
struct gendisk *disk;
|
2012-04-17 00:57:25 +04:00
|
|
|
struct blkcg_gq *blkg;
|
2015-08-19 00:55:31 +03:00
|
|
|
char *body;
|
2012-04-02 01:38:43 +04:00
|
|
|
};
|
|
|
|
|
2019-08-29 01:05:53 +03:00
|
|
|
struct gendisk *blkcg_conf_get_disk(char **inputp);
|
2012-04-17 00:57:25 +04:00
|
|
|
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
|
2015-08-19 00:55:31 +03:00
|
|
|
char *input, struct blkg_conf_ctx *ctx);
|
2012-04-02 01:38:43 +04:00
|
|
|
void blkg_conf_finish(struct blkg_conf_ctx *ctx);
|
|
|
|
|
2018-12-05 20:10:26 +03:00
|
|
|
/**
|
|
|
|
* blkcg_css - find the current css
|
|
|
|
*
|
|
|
|
* Find the css associated with either the kthread or the current task.
|
|
|
|
* This may return a dying css, so it is up to the caller to use tryget logic
|
|
|
|
* to confirm it is alive and well.
|
|
|
|
*/
|
|
|
|
static inline struct cgroup_subsys_state *blkcg_css(void)
|
|
|
|
{
|
|
|
|
struct cgroup_subsys_state *css;
|
|
|
|
|
|
|
|
css = kthread_blkcg();
|
|
|
|
if (css)
|
|
|
|
return css;
|
|
|
|
return task_css(current, io_cgrp_id);
|
|
|
|
}
|
|
|
|
|
2013-08-09 04:11:23 +04:00
|
|
|
static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
|
|
|
|
{
|
|
|
|
return css ? container_of(css, struct blkcg, css) : NULL;
|
|
|
|
}
|
|
|
|
|
2018-12-05 20:10:26 +03:00
|
|
|
/**
|
|
|
|
* __bio_blkcg - internal, inconsistent version to get blkcg
|
|
|
|
*
|
|
|
|
* DO NOT USE.
|
|
|
|
* This function is inconsistent and consequently is dangerous to use. The
|
|
|
|
* first part of the function returns a blkcg where a reference is owned by the
|
|
|
|
* bio. This means it does not need to be rcu protected as it cannot go away
|
|
|
|
* with the bio owning a reference to it. However, the latter potentially gets
|
|
|
|
* it from task_css(). This can race against task migration and the cgroup
|
|
|
|
* dying. It is also semantically different as it must be called rcu protected
|
|
|
|
* and is susceptible to failure when trying to get a reference to it.
|
|
|
|
* Therefore, it is not ok to assume that *_get() will always succeed on the
|
|
|
|
* blkcg returned here.
|
|
|
|
*/
|
|
|
|
static inline struct blkcg *__bio_blkcg(struct bio *bio)
|
2018-09-11 21:41:26 +03:00
|
|
|
{
|
2018-12-05 20:10:35 +03:00
|
|
|
if (bio && bio->bi_blkg)
|
|
|
|
return bio->bi_blkg->blkcg;
|
2018-12-05 20:10:26 +03:00
|
|
|
return css_to_blkcg(blkcg_css());
|
|
|
|
}
|
blkcg: revert blkcg cleanups series
This reverts a series committed earlier due to null pointer exception
bug report in [1]. It seems there are edge case interactions that I did
not consider and will need some time to understand what causes the
adverse interactions.
The original series can be found in [2] with a follow up series in [3].
[1] https://www.spinics.net/lists/cgroups/msg20719.html
[2] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/
[3] https://lore.kernel.org/lkml/20181020185612.51587-1-dennis@kernel.org/
This reverts the following commits:
d459d853c2ed, b2c3fa546705, 101246ec02b5, b3b9f24f5fcc, e2b0989954ae,
f0fcb3ec89f3, c839e7a03f92, bdc2491708c4, 74b7c02a9bc1, 5bf9a1f3b4ef,
a7b39b4e961c, 07b05bcc3213, 49f4c2dc2b50, 27e6fa996c53
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-02 00:24:10 +03:00
|
|
|
|
2018-12-05 20:10:26 +03:00
|
|
|
/**
|
|
|
|
* bio_blkcg - grab the blkcg associated with a bio
|
|
|
|
* @bio: target bio
|
|
|
|
*
|
|
|
|
* This returns the blkcg associated with a bio, %NULL if not associated.
|
|
|
|
* Callers are expected to either handle %NULL or know association has been
|
|
|
|
* done prior to calling this.
|
|
|
|
*/
|
|
|
|
static inline struct blkcg *bio_blkcg(struct bio *bio)
|
|
|
|
{
|
2018-12-05 20:10:35 +03:00
|
|
|
if (bio && bio->bi_blkg)
|
|
|
|
return bio->bi_blkg->blkcg;
|
2018-12-05 20:10:26 +03:00
|
|
|
return NULL;
|
2015-05-23 00:13:23 +03:00
|
|
|
}
|
|
|
|
|
2018-07-03 18:14:55 +03:00
|
|
|
static inline bool blk_cgroup_congested(void)
|
|
|
|
{
|
|
|
|
struct cgroup_subsys_state *css;
|
|
|
|
bool ret = false;
|
|
|
|
|
|
|
|
rcu_read_lock();
|
|
|
|
css = kthread_blkcg();
|
|
|
|
if (!css)
|
|
|
|
css = task_css(current, io_cgrp_id);
|
|
|
|
while (css) {
|
|
|
|
if (atomic_read(&css->cgroup->congestion_count)) {
|
|
|
|
ret = true;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
css = css->parent;
|
|
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2018-07-03 18:14:51 +03:00
|
|
|
/**
|
|
|
|
* bio_issue_as_root_blkg - see if this bio needs to be issued as root blkg
|
|
|
|
* @return: true if this bio needs to be submitted with the root blkg context.
|
|
|
|
*
|
|
|
|
* In order to avoid priority inversions we sometimes need to issue a bio as if
|
|
|
|
* it were attached to the root blkg, and then backcharge to the actual owning
|
|
|
|
* blkg. The idea is we do bio_blkcg() to look up the actual context for the
|
|
|
|
* bio and attach the appropriate blkg to the bio. Then we call this helper and
|
|
|
|
* if it is true run with the root blkg for that queue and then do any
|
|
|
|
* backcharging to the originating cgroup once the io is complete.
|
|
|
|
*/
|
|
|
|
static inline bool bio_issue_as_root_blkg(struct bio *bio)
|
|
|
|
{
|
2018-07-03 18:14:53 +03:00
|
|
|
return (bio->bi_opf & (REQ_META | REQ_SWAP)) != 0;
|
2018-07-03 18:14:51 +03:00
|
|
|
}
|
|
|
|
|
2013-01-09 20:05:10 +04:00
|
|
|
/**
|
|
|
|
* blkcg_parent - get the parent of a blkcg
|
|
|
|
* @blkcg: blkcg of interest
|
|
|
|
*
|
|
|
|
* Return the parent blkcg of @blkcg. Can be called anytime.
|
|
|
|
*/
|
|
|
|
static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
|
|
|
|
{
|
2014-05-16 21:22:48 +04:00
|
|
|
return css_to_blkcg(blkcg->css.parent);
|
2013-01-09 20:05:10 +04:00
|
|
|
}
|
|
|
|
|
2015-08-19 00:55:17 +03:00
|
|
|
/**
|
|
|
|
* __blkg_lookup - internal version of blkg_lookup()
|
|
|
|
* @blkcg: blkcg of interest
|
|
|
|
* @q: request_queue of interest
|
|
|
|
* @update_hint: whether to update lookup hint with the result or not
|
|
|
|
*
|
|
|
|
* This is internal version and shouldn't be used by policy
|
|
|
|
* implementations. Looks up blkgs for the @blkcg - @q pair regardless of
|
|
|
|
* @q's bypass state. If @update_hint is %true, the caller should be
|
|
|
|
* holding @q->queue_lock and lookup hint is updated on success.
|
|
|
|
*/
|
|
|
|
static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
|
|
|
|
struct request_queue *q,
|
|
|
|
bool update_hint)
|
|
|
|
{
|
|
|
|
struct blkcg_gq *blkg;
|
|
|
|
|
2015-08-19 00:55:18 +03:00
|
|
|
if (blkcg == &blkcg_root)
|
|
|
|
return q->root_blkg;
|
|
|
|
|
2015-08-19 00:55:17 +03:00
|
|
|
blkg = rcu_dereference(blkcg->blkg_hint);
|
|
|
|
if (blkg && blkg->q == q)
|
|
|
|
return blkg;
|
|
|
|
|
|
|
|
return blkg_lookup_slowpath(blkcg, q, update_hint);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* blkg_lookup - lookup blkg for the specified blkcg - q pair
|
|
|
|
* @blkcg: blkcg of interest
|
|
|
|
* @q: request_queue of interest
|
|
|
|
*
|
|
|
|
* Lookup blkg for the @blkcg - @q pair. This function should be called
|
2019-08-02 01:39:07 +03:00
|
|
|
* under RCU read lock.
|
2015-08-19 00:55:17 +03:00
|
|
|
*/
|
|
|
|
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
|
|
|
|
struct request_queue *q)
|
|
|
|
{
|
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
return __blkg_lookup(blkcg, q, false);
|
|
|
|
}
|
|
|
|
|
2018-08-09 17:53:36 +03:00
|
|
|
/**
|
2018-08-10 23:28:07 +03:00
|
|
|
* blk_queue_root_blkg - return blkg for the (blkcg_root, @q) pair
|
2018-08-09 17:53:36 +03:00
|
|
|
* @q: request_queue of interest
|
|
|
|
*
|
|
|
|
* Lookup blkg for @q at the root level. See also blkg_lookup().
|
|
|
|
*/
|
2018-08-10 23:28:07 +03:00
|
|
|
static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q)
|
2018-08-09 17:53:36 +03:00
|
|
|
{
|
2018-08-10 23:28:07 +03:00
|
|
|
return q->root_blkg;
|
2018-08-09 17:53:36 +03:00
|
|
|
}
|
|
|
|
|
2012-03-06 01:15:14 +04:00
|
|
|
/**
|
|
|
|
* blkg_to_pdata - get policy private data
|
|
|
|
* @blkg: blkg of interest
|
|
|
|
* @pol: policy of interest
|
|
|
|
*
|
|
|
|
* Return pointer to private data associated with the @blkg-@pol pair.
|
|
|
|
*/
|
2012-04-17 00:57:26 +04:00
|
|
|
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
|
|
|
|
struct blkcg_policy *pol)
|
2012-03-06 01:15:14 +04:00
|
|
|
{
|
2012-04-17 00:57:26 +04:00
|
|
|
return blkg ? blkg->pd[pol->plid] : NULL;
|
2012-03-06 01:15:14 +04:00
|
|
|
}
|
|
|
|
|
block, cgroup: implement policy-specific per-blkcg data
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-06 00:38:42 +03:00
|
|
|
static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
|
|
|
|
struct blkcg_policy *pol)
|
|
|
|
{
|
2015-08-19 00:55:15 +03:00
|
|
|
return blkcg ? blkcg->cpd[pol->plid] : NULL;
|
block, cgroup: implement policy-specific per-blkcg data
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-06 00:38:42 +03:00
|
|
|
}
|
|
|
|
|
2012-03-06 01:15:14 +04:00
|
|
|
/**
|
|
|
|
* pdata_to_blkg - get blkg associated with policy private data
|
2012-04-17 00:57:26 +04:00
|
|
|
* @pd: policy private data of interest
|
2012-03-06 01:15:14 +04:00
|
|
|
*
|
2012-04-17 00:57:26 +04:00
|
|
|
* @pd is policy private data. Determine the blkg it's associated with.
|
2012-03-06 01:15:14 +04:00
|
|
|
*/
|
2012-04-17 00:57:26 +04:00
|
|
|
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
|
2012-03-06 01:15:14 +04:00
|
|
|
{
|
2012-04-17 00:57:26 +04:00
|
|
|
return pd ? pd->blkg : NULL;
|
2012-03-06 01:15:14 +04:00
|
|
|
}
|
|
|
|
|
2015-08-19 00:55:15 +03:00
|
|
|
static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
|
|
|
|
{
|
|
|
|
return cpd ? cpd->blkcg : NULL;
|
|
|
|
}
|
|
|
|
|
2018-08-31 23:22:43 +03:00
|
|
|
extern void blkcg_destroy_blkgs(struct blkcg *blkcg);
|
|
|
|
|
|
|
|
#ifdef CONFIG_CGROUP_WRITEBACK
|
|
|
|
|
|
|
|
/**
|
|
|
|
* blkcg_cgwb_get - get a reference for blkcg->cgwb_list
|
|
|
|
* @blkcg: blkcg of interest
|
|
|
|
*
|
|
|
|
* This is used to track the number of active wb's related to a blkcg.
|
|
|
|
*/
|
|
|
|
static inline void blkcg_cgwb_get(struct blkcg *blkcg)
|
|
|
|
{
|
|
|
|
refcount_inc(&blkcg->cgwb_refcnt);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* blkcg_cgwb_put - put a reference for @blkcg->cgwb_list
|
|
|
|
* @blkcg: blkcg of interest
|
|
|
|
*
|
|
|
|
* This is used to track the number of active wb's related to a blkcg.
|
|
|
|
* When this count goes to zero, all active wb has finished so the
|
|
|
|
* blkcg can continue destruction by calling blkcg_destroy_blkgs().
|
|
|
|
* This work may occur in cgwb_release_workfn() on the cgwb_release
|
|
|
|
* workqueue.
|
|
|
|
*/
|
|
|
|
static inline void blkcg_cgwb_put(struct blkcg *blkcg)
|
|
|
|
{
|
|
|
|
if (refcount_dec_and_test(&blkcg->cgwb_refcnt))
|
|
|
|
blkcg_destroy_blkgs(blkcg);
|
|
|
|
}
|
|
|
|
|
|
|
|
#else
|
|
|
|
|
|
|
|
static inline void blkcg_cgwb_get(struct blkcg *blkcg) { }
|
|
|
|
|
|
|
|
static inline void blkcg_cgwb_put(struct blkcg *blkcg)
|
|
|
|
{
|
|
|
|
/* wb isn't being accounted, so trigger destruction right away */
|
|
|
|
blkcg_destroy_blkgs(blkcg);
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif
|
|
|
|
|
2012-04-17 00:57:23 +04:00
|
|
|
/**
|
|
|
|
* blkg_path - format cgroup path of blkg
|
|
|
|
* @blkg: blkg of interest
|
|
|
|
* @buf: target buffer
|
|
|
|
* @buflen: target buffer length
|
|
|
|
*
|
|
|
|
* Format the path of the cgroup of @blkg into @buf.
|
|
|
|
*/
|
2012-04-17 00:57:25 +04:00
|
|
|
static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
|
2010-04-26 21:27:56 +04:00
|
|
|
{
|
2016-08-10 18:23:44 +03:00
|
|
|
return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
|
2010-04-26 21:27:56 +04:00
|
|
|
}
|
|
|
|
|
2012-03-06 01:15:15 +04:00
|
|
|
/**
|
|
|
|
* blkg_get - get a blkg reference
|
|
|
|
* @blkg: blkg to get
|
|
|
|
*
|
blkcg: fix use-after-free in __blkg_release_rcu() by making blkcg_gq refcnt an atomic_t
Hello,
So, this patch should do. Joe, Vivek, can one of you guys please
verify that the oops goes away with this patch?
Jens, the original thread can be read at
http://thread.gmane.org/gmane.linux.kernel/1720729
The fix converts blkg->refcnt from int to atomic_t. It does some
overhead but it should be minute compared to everything else which is
going on and the involved cacheline bouncing, so I think it's highly
unlikely to cause any noticeable difference. Also, the refcnt in
question should be converted to a perpcu_ref for blk-mq anyway, so the
atomic_t is likely to go away pretty soon anyway.
Thanks.
------- 8< -------
__blkg_release_rcu() may be invoked after the associated request_queue
is released with a RCU grace period inbetween. As such, the function
and callbacks invoked from it must not dereference the associated
request_queue. This is clearly indicated in the comment above the
function.
Unfortunately, while trying to fix a different issue, 2a4fd070ee85
("blkcg: move bulk of blkcg_gq release operations to the RCU
callback") ignored this and added [un]locking of @blkg->q->queue_lock
to __blkg_release_rcu(). This of course can cause oops as the
request_queue may be long gone by the time this code gets executed.
general protection fault: 0000 [#1] SMP
CPU: 21 PID: 30 Comm: rcuos/21 Not tainted 3.15.0 #1
Hardware name: Stratus ftServer 6400/G7LAZ, BIOS BIOS Version 6.3:57 12/25/2013
task: ffff880854021de0 ti: ffff88085403c000 task.ti: ffff88085403c000
RIP: 0010:[<ffffffff8162e9e5>] [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
RSP: 0018:ffff88085403fdf0 EFLAGS: 00010086
RAX: 0000000000020000 RBX: 0000000000000010 RCX: 0000000000000000
RDX: 000060ef80008248 RSI: 0000000000000286 RDI: 6b6b6b6b6b6b6b6b
RBP: ffff88085403fdf0 R08: 0000000000000286 R09: 0000000000009f39
R10: 0000000000020001 R11: 0000000000020001 R12: ffff88103c17a130
R13: ffff88103c17a080 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88107fca0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006e5ab8 CR3: 000000000193d000 CR4: 00000000000407e0
Stack:
ffff88085403fe18 ffffffff812cbfc2 ffff88103c17a130 0000000000000000
ffff88103c17a130 ffff88085403fec0 ffffffff810d1d28 ffff880854021de0
ffff880854021de0 ffff88107fcaec58 ffff88085403fe80 ffff88107fcaec30
Call Trace:
[<ffffffff812cbfc2>] __blkg_release_rcu+0x72/0x150
[<ffffffff810d1d28>] rcu_nocb_kthread+0x1e8/0x300
[<ffffffff81091d81>] kthread+0xe1/0x100
[<ffffffff8163813c>] ret_from_fork+0x7c/0xb0
Code: ff 47 04 48 8b 7d 08 be 00 02 00 00 e8 55 48 a4 ff 5d c3 0f 1f 00 66 66 66 66 90 55 48 89 e5
+fa 66 66 90 66 66 90 b8 00 00 02 00 <f0> 0f c1 07 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f
+b7
RIP [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
RSP <ffff88085403fdf0>
The request_queue locking was added because blkcg_gq->refcnt is an int
protected with the queue lock and __blkg_release_rcu() needs to put
the parent. Let's fix it by making blkcg_gq->refcnt an atomic_t and
dropping queue locking in the function.
Given the general heavy weight of the current request_queue and blkcg
operations, this is unlikely to cause any noticeable overhead.
Moreover, blkcg_gq->refcnt is likely to be converted to percpu_ref in
the near future, so whatever (most likely negligible) overhead it may
add is temporary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/g/alpine.DEB.2.02.1406081816540.17948@jlaw-desktop.mno.stratus.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-20 01:42:57 +04:00
|
|
|
* The caller should be holding an existing reference.
|
2012-03-06 01:15:15 +04:00
|
|
|
*/
|
2012-04-17 00:57:25 +04:00
|
|
|
static inline void blkg_get(struct blkcg_gq *blkg)
|
2012-03-06 01:15:15 +04:00
|
|
|
{
|
2018-12-05 20:10:38 +03:00
|
|
|
percpu_ref_get(&blkg->refcnt);
|
2012-03-06 01:15:15 +04:00
|
|
|
}
|
|
|
|
|
2018-07-03 18:14:55 +03:00
|
|
|
/**
|
2018-12-05 20:10:39 +03:00
|
|
|
* blkg_tryget - try and get a blkg reference
|
2018-07-03 18:14:55 +03:00
|
|
|
* @blkg: blkg to get
|
|
|
|
*
|
|
|
|
* This is for use when doing an RCU lookup of the blkg. We may be in the midst
|
|
|
|
* of freeing this blkg, so we can only use it if the refcnt is not zero.
|
|
|
|
*/
|
2018-12-05 20:10:39 +03:00
|
|
|
static inline bool blkg_tryget(struct blkcg_gq *blkg)
|
2018-07-03 18:14:55 +03:00
|
|
|
{
|
2018-12-20 01:43:21 +03:00
|
|
|
return blkg && percpu_ref_tryget(&blkg->refcnt);
|
2018-07-03 18:14:55 +03:00
|
|
|
}
|
|
|
|
|
2018-12-05 20:10:28 +03:00
|
|
|
/**
|
2018-12-05 20:10:39 +03:00
|
|
|
* blkg_tryget_closest - try and get a blkg ref on the closet blkg
|
2018-12-05 20:10:28 +03:00
|
|
|
* @blkg: blkg to get
|
|
|
|
*
|
2018-12-20 01:43:21 +03:00
|
|
|
* This needs to be called rcu protected. As the failure mode here is to walk
|
|
|
|
* up the blkg tree, this ensure that the blkg->parent pointers are always
|
|
|
|
* valid. This returns the blkg that it ended up taking a reference on or %NULL
|
|
|
|
* if no reference was taken.
|
2018-12-05 20:10:28 +03:00
|
|
|
*/
|
2018-12-05 20:10:39 +03:00
|
|
|
static inline struct blkcg_gq *blkg_tryget_closest(struct blkcg_gq *blkg)
|
2018-12-05 20:10:28 +03:00
|
|
|
{
|
2018-12-20 01:43:21 +03:00
|
|
|
struct blkcg_gq *ret_blkg = NULL;
|
|
|
|
|
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
|
|
|
|
while (blkg) {
|
|
|
|
if (blkg_tryget(blkg)) {
|
|
|
|
ret_blkg = blkg;
|
|
|
|
break;
|
|
|
|
}
|
2018-12-05 20:10:28 +03:00
|
|
|
blkg = blkg->parent;
|
2018-12-20 01:43:21 +03:00
|
|
|
}
|
2018-12-05 20:10:28 +03:00
|
|
|
|
2018-12-20 01:43:21 +03:00
|
|
|
return ret_blkg;
|
2018-12-05 20:10:28 +03:00
|
|
|
}
|
2018-09-11 21:41:28 +03:00
|
|
|
|
2012-03-06 01:15:15 +04:00
|
|
|
/**
|
|
|
|
* blkg_put - put a blkg reference
|
|
|
|
* @blkg: blkg to put
|
|
|
|
*/
|
2012-04-17 00:57:25 +04:00
|
|
|
static inline void blkg_put(struct blkcg_gq *blkg)
|
2012-03-06 01:15:15 +04:00
|
|
|
{
|
2018-12-05 20:10:38 +03:00
|
|
|
percpu_ref_put(&blkg->refcnt);
|
2012-03-06 01:15:15 +04:00
|
|
|
}
|
|
|
|
|
2013-05-15 00:52:30 +04:00
|
|
|
/**
|
|
|
|
* blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
|
|
|
|
* @d_blkg: loop cursor pointing to the current descendant
|
2013-08-09 04:11:25 +04:00
|
|
|
* @pos_css: used for iteration
|
2013-05-15 00:52:30 +04:00
|
|
|
* @p_blkg: target blkg to walk descendants of
|
|
|
|
*
|
|
|
|
* Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
|
|
|
|
* read locked. If called under either blkcg or queue lock, the iteration
|
|
|
|
* is guaranteed to include all and only online blkgs. The caller may
|
2013-08-09 04:11:25 +04:00
|
|
|
* update @pos_css by calling css_rightmost_descendant() to skip subtree.
|
2013-08-09 04:11:27 +04:00
|
|
|
* @p_blkg is included in the iteration and the first node to be visited.
|
2013-05-15 00:52:30 +04:00
|
|
|
*/
|
2013-08-09 04:11:25 +04:00
|
|
|
#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
|
|
|
|
css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
|
|
|
|
if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
|
2013-05-15 00:52:30 +04:00
|
|
|
(p_blkg)->q, false)))
|
|
|
|
|
2013-05-15 00:52:31 +04:00
|
|
|
/**
|
|
|
|
* blkg_for_each_descendant_post - post-order walk of a blkg's descendants
|
|
|
|
* @d_blkg: loop cursor pointing to the current descendant
|
2013-08-09 04:11:25 +04:00
|
|
|
* @pos_css: used for iteration
|
2013-05-15 00:52:31 +04:00
|
|
|
* @p_blkg: target blkg to walk descendants of
|
|
|
|
*
|
|
|
|
* Similar to blkg_for_each_descendant_pre() but performs post-order
|
2013-08-09 04:11:27 +04:00
|
|
|
* traversal instead. Synchronization rules are the same. @p_blkg is
|
|
|
|
* included in the iteration and the last node to be visited.
|
2013-05-15 00:52:31 +04:00
|
|
|
*/
|
2013-08-09 04:11:25 +04:00
|
|
|
#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
|
|
|
|
css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
|
|
|
|
if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
|
2013-05-15 00:52:31 +04:00
|
|
|
(p_blkg)->q, false)))
|
|
|
|
|
2015-08-19 00:55:22 +03:00
|
|
|
static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
|
2013-11-13 07:42:14 +04:00
|
|
|
{
|
2015-08-19 00:55:22 +03:00
|
|
|
int i, ret;
|
|
|
|
|
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++) {
|
|
|
|
ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
|
|
|
|
if (ret) {
|
|
|
|
while (--i >= 0)
|
|
|
|
percpu_counter_destroy(&rwstat->cpu_cnt[i]);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
atomic64_set(&rwstat->aux_cnt[i], 0);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
2015-08-19 00:55:21 +03:00
|
|
|
|
2015-08-19 00:55:22 +03:00
|
|
|
static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
|
|
|
|
{
|
|
|
|
int i;
|
2015-08-19 00:55:21 +03:00
|
|
|
|
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++)
|
2015-08-19 00:55:22 +03:00
|
|
|
percpu_counter_destroy(&rwstat->cpu_cnt[i]);
|
2013-11-13 07:42:14 +04:00
|
|
|
}
|
|
|
|
|
2012-04-02 01:38:42 +04:00
|
|
|
/**
|
|
|
|
* blkg_rwstat_add - add a value to a blkg_rwstat
|
|
|
|
* @rwstat: target blkg_rwstat
|
2016-10-28 17:48:16 +03:00
|
|
|
* @op: REQ_OP and flags
|
2012-04-02 01:38:42 +04:00
|
|
|
* @val: value to add
|
|
|
|
*
|
|
|
|
* Add @val to @rwstat. The counters are chosen according to @rw. The
|
|
|
|
* caller is responsible for synchronizing calls to this function.
|
|
|
|
*/
|
|
|
|
static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
|
2016-10-28 17:48:16 +03:00
|
|
|
unsigned int op, uint64_t val)
|
2012-04-02 01:38:42 +04:00
|
|
|
{
|
2015-08-19 00:55:22 +03:00
|
|
|
struct percpu_counter *cnt;
|
2012-04-02 01:38:42 +04:00
|
|
|
|
2018-07-18 14:47:41 +03:00
|
|
|
if (op_is_discard(op))
|
|
|
|
cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_DISCARD];
|
|
|
|
else if (op_is_write(op))
|
2015-08-19 00:55:22 +03:00
|
|
|
cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
|
2012-04-02 01:38:42 +04:00
|
|
|
else
|
2015-08-19 00:55:22 +03:00
|
|
|
cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];
|
|
|
|
|
2017-06-20 21:01:20 +03:00
|
|
|
percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
|
2015-08-19 00:55:22 +03:00
|
|
|
|
2016-11-01 16:40:03 +03:00
|
|
|
if (op_is_sync(op))
|
2015-08-19 00:55:22 +03:00
|
|
|
cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
|
2012-04-02 01:38:42 +04:00
|
|
|
else
|
2015-08-19 00:55:22 +03:00
|
|
|
cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
|
2012-04-02 01:38:42 +04:00
|
|
|
|
2017-06-20 21:01:20 +03:00
|
|
|
percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
|
2012-04-02 01:38:42 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* blkg_rwstat_read - read the current values of a blkg_rwstat
|
|
|
|
* @rwstat: blkg_rwstat to read
|
|
|
|
*
|
2015-08-19 00:55:22 +03:00
|
|
|
* Read the current snapshot of @rwstat and return it in the aux counts.
|
2012-04-02 01:38:42 +04:00
|
|
|
*/
|
2019-06-06 13:26:20 +03:00
|
|
|
static inline void blkg_rwstat_read(struct blkg_rwstat *rwstat,
|
2019-06-06 13:26:21 +03:00
|
|
|
struct blkg_rwstat_sample *result)
|
2012-04-02 01:38:42 +04:00
|
|
|
{
|
2015-08-19 00:55:22 +03:00
|
|
|
int i;
|
2012-04-02 01:38:42 +04:00
|
|
|
|
2015-08-19 00:55:22 +03:00
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++)
|
2019-06-06 13:26:21 +03:00
|
|
|
result->cnt[i] =
|
|
|
|
percpu_counter_sum_positive(&rwstat->cpu_cnt[i]);
|
2012-04-02 01:38:42 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
2013-01-09 20:05:12 +04:00
|
|
|
* blkg_rwstat_total - read the total count of a blkg_rwstat
|
2012-04-02 01:38:42 +04:00
|
|
|
* @rwstat: blkg_rwstat to read
|
|
|
|
*
|
|
|
|
* Return the total count of @rwstat regardless of the IO direction. This
|
|
|
|
* function can be called without synchronization and takes care of u64
|
|
|
|
* atomicity.
|
|
|
|
*/
|
2013-01-09 20:05:12 +04:00
|
|
|
static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
|
2012-04-02 01:38:42 +04:00
|
|
|
{
|
2019-06-06 13:26:21 +03:00
|
|
|
struct blkg_rwstat_sample tmp = { };
|
2012-04-02 01:38:42 +04:00
|
|
|
|
2019-06-06 13:26:20 +03:00
|
|
|
blkg_rwstat_read(rwstat, &tmp);
|
2019-06-06 13:26:21 +03:00
|
|
|
return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
|
2012-04-02 01:38:42 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* blkg_rwstat_reset - reset a blkg_rwstat
|
|
|
|
* @rwstat: blkg_rwstat to reset
|
|
|
|
*/
|
|
|
|
static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
|
|
|
|
{
|
2015-08-19 00:55:21 +03:00
|
|
|
int i;
|
|
|
|
|
2015-08-19 00:55:22 +03:00
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++) {
|
|
|
|
percpu_counter_set(&rwstat->cpu_cnt[i], 0);
|
2015-08-19 00:55:21 +03:00
|
|
|
atomic64_set(&rwstat->aux_cnt[i], 0);
|
2015-08-19 00:55:22 +03:00
|
|
|
}
|
2012-04-02 01:38:42 +04:00
|
|
|
}
|
|
|
|
|
2013-01-09 20:05:12 +04:00
|
|
|
/**
|
2015-08-19 00:55:21 +03:00
|
|
|
* blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
|
2013-01-09 20:05:12 +04:00
|
|
|
* @to: the destination blkg_rwstat
|
|
|
|
* @from: the source
|
|
|
|
*
|
2015-08-19 00:55:21 +03:00
|
|
|
* Add @from's count including the aux one to @to's aux count.
|
2013-01-09 20:05:12 +04:00
|
|
|
*/
|
2015-08-19 00:55:21 +03:00
|
|
|
static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
|
|
|
|
struct blkg_rwstat *from)
|
2013-01-09 20:05:12 +04:00
|
|
|
{
|
2018-01-16 18:01:36 +03:00
|
|
|
u64 sum[BLKG_RWSTAT_NR];
|
2013-01-09 20:05:12 +04:00
|
|
|
int i;
|
|
|
|
|
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++)
|
2018-01-16 18:01:36 +03:00
|
|
|
sum[i] = percpu_counter_sum_positive(&from->cpu_cnt[i]);
|
|
|
|
|
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++)
|
|
|
|
atomic64_add(sum[i] + atomic64_read(&from->aux_cnt[i]),
|
2015-08-19 00:55:21 +03:00
|
|
|
&to->aux_cnt[i]);
|
2013-01-09 20:05:12 +04:00
|
|
|
}
|
|
|
|
|
2015-08-19 00:55:20 +03:00
|
|
|
#ifdef CONFIG_BLK_DEV_THROTTLING
|
|
|
|
extern bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
|
|
|
|
struct bio *bio);
|
|
|
|
#else
|
|
|
|
static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
|
|
|
|
struct bio *bio) { return false; }
|
|
|
|
#endif
|
|
|
|
|
2019-06-27 23:39:52 +03:00
|
|
|
bool __blkcg_punt_bio_submit(struct bio *bio);
|
|
|
|
|
|
|
|
static inline bool blkcg_punt_bio_submit(struct bio *bio)
|
|
|
|
{
|
|
|
|
if (bio->bi_opf & REQ_CGROUP_PUNT)
|
|
|
|
return __blkcg_punt_bio_submit(bio);
|
|
|
|
else
|
|
|
|
return false;
|
|
|
|
}
|
2018-12-05 20:10:32 +03:00
|
|
|
|
|
|
|
static inline void blkcg_bio_issue_init(struct bio *bio)
|
|
|
|
{
|
|
|
|
bio_issue_init(&bio->bi_issue, bio_sectors(bio));
|
|
|
|
}
|
|
|
|
|
2015-08-19 00:55:20 +03:00
|
|
|
static inline bool blkcg_bio_issue_check(struct request_queue *q,
|
|
|
|
struct bio *bio)
|
|
|
|
{
|
|
|
|
struct blkcg_gq *blkg;
|
|
|
|
bool throtl = false;
|
|
|
|
|
2018-12-06 20:49:38 +03:00
|
|
|
rcu_read_lock();
|
|
|
|
|
2018-12-05 20:10:31 +03:00
|
|
|
if (!bio->bi_blkg) {
|
|
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
|
|
|
|
WARN_ONCE(1,
|
|
|
|
"no blkg associated for bio on block-device: %s\n",
|
|
|
|
bio_devname(bio, b));
|
|
|
|
bio_associate_blkg(bio);
|
|
|
|
}
|
blkcg: revert blkcg cleanups series
This reverts a series committed earlier due to null pointer exception
bug report in [1]. It seems there are edge case interactions that I did
not consider and will need some time to understand what causes the
adverse interactions.
The original series can be found in [2] with a follow up series in [3].
[1] https://www.spinics.net/lists/cgroups/msg20719.html
[2] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/
[3] https://lore.kernel.org/lkml/20181020185612.51587-1-dennis@kernel.org/
This reverts the following commits:
d459d853c2ed, b2c3fa546705, 101246ec02b5, b3b9f24f5fcc, e2b0989954ae,
f0fcb3ec89f3, c839e7a03f92, bdc2491708c4, 74b7c02a9bc1, 5bf9a1f3b4ef,
a7b39b4e961c, 07b05bcc3213, 49f4c2dc2b50, 27e6fa996c53
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-02 00:24:10 +03:00
|
|
|
|
2018-12-05 20:10:31 +03:00
|
|
|
blkg = bio->bi_blkg;
|
2015-08-19 00:55:20 +03:00
|
|
|
|
|
|
|
throtl = blk_throtl_bio(q, blkg, bio);
|
|
|
|
|
2015-08-19 00:55:24 +03:00
|
|
|
if (!throtl) {
|
2018-07-30 17:10:01 +03:00
|
|
|
/*
|
|
|
|
* If the bio is flagged with BIO_QUEUE_ENTERED it means this
|
|
|
|
* is a split bio and we would have already accounted for the
|
|
|
|
* size of the bio.
|
|
|
|
*/
|
|
|
|
if (!bio_flagged(bio, BIO_QUEUE_ENTERED))
|
|
|
|
blkg_rwstat_add(&blkg->stat_bytes, bio->bi_opf,
|
|
|
|
bio->bi_iter.bi_size);
|
2016-10-28 17:48:16 +03:00
|
|
|
blkg_rwstat_add(&blkg->stat_ios, bio->bi_opf, 1);
|
2015-08-19 00:55:24 +03:00
|
|
|
}
|
|
|
|
|
2018-12-05 20:10:32 +03:00
|
|
|
blkcg_bio_issue_init(bio);
|
|
|
|
|
2018-12-06 20:49:38 +03:00
|
|
|
rcu_read_unlock();
|
2015-08-19 00:55:20 +03:00
|
|
|
return !throtl;
|
|
|
|
}
|
|
|
|
|
2018-07-03 18:14:55 +03:00
|
|
|
static inline void blkcg_use_delay(struct blkcg_gq *blkg)
|
|
|
|
{
|
|
|
|
if (atomic_add_return(1, &blkg->use_delay) == 1)
|
|
|
|
atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int blkcg_unuse_delay(struct blkcg_gq *blkg)
|
|
|
|
{
|
|
|
|
int old = atomic_read(&blkg->use_delay);
|
|
|
|
|
|
|
|
if (old == 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We do this song and dance because we can race with somebody else
|
|
|
|
* adding or removing delay. If we just did an atomic_dec we'd end up
|
|
|
|
* negative and we'd already be in trouble. We need to subtract 1 and
|
|
|
|
* then check to see if we were the last delay so we can drop the
|
|
|
|
* congestion count on the cgroup.
|
|
|
|
*/
|
|
|
|
while (old) {
|
|
|
|
int cur = atomic_cmpxchg(&blkg->use_delay, old, old - 1);
|
|
|
|
if (cur == old)
|
|
|
|
break;
|
|
|
|
old = cur;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (old == 0)
|
|
|
|
return 0;
|
|
|
|
if (old == 1)
|
|
|
|
atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void blkcg_clear_delay(struct blkcg_gq *blkg)
|
|
|
|
{
|
|
|
|
int old = atomic_read(&blkg->use_delay);
|
|
|
|
if (!old)
|
|
|
|
return;
|
|
|
|
/* We only want 1 person clearing the congestion count for this blkg. */
|
|
|
|
while (old) {
|
|
|
|
int cur = atomic_cmpxchg(&blkg->use_delay, old, 0);
|
|
|
|
if (cur == old) {
|
|
|
|
atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
old = cur;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta);
|
|
|
|
void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay);
|
|
|
|
void blkcg_maybe_throttle_current(void);
|
2012-04-17 00:57:24 +04:00
|
|
|
#else /* CONFIG_BLK_CGROUP */
|
|
|
|
|
2015-05-23 00:13:18 +03:00
|
|
|
struct blkcg {
|
|
|
|
};
|
2009-12-03 23:06:43 +03:00
|
|
|
|
2012-04-17 00:57:26 +04:00
|
|
|
struct blkg_policy_data {
|
|
|
|
};
|
|
|
|
|
block, cgroup: implement policy-specific per-blkcg data
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-06 00:38:42 +03:00
|
|
|
struct blkcg_policy_data {
|
|
|
|
};
|
|
|
|
|
2012-04-17 00:57:25 +04:00
|
|
|
struct blkcg_gq {
|
2009-12-03 23:06:43 +03:00
|
|
|
};
|
|
|
|
|
2012-04-17 00:57:25 +04:00
|
|
|
struct blkcg_policy {
|
2009-12-04 18:36:42 +03:00
|
|
|
};
|
|
|
|
|
2015-05-23 00:13:21 +03:00
|
|
|
#define blkcg_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
|
|
|
|
|
2018-07-03 18:14:55 +03:00
|
|
|
static inline void blkcg_maybe_throttle_current(void) { }
|
|
|
|
static inline bool blk_cgroup_congested(void) { return false; }
|
|
|
|
|
2015-05-23 00:13:18 +03:00
|
|
|
#ifdef CONFIG_BLOCK
|
|
|
|
|
2018-07-03 18:14:55 +03:00
|
|
|
static inline void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay) { }
|
|
|
|
|
2012-04-17 00:57:25 +04:00
|
|
|
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
|
2018-08-10 23:28:07 +03:00
|
|
|
static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q)
|
|
|
|
{ return NULL; }
|
2012-03-06 01:15:12 +04:00
|
|
|
static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
|
|
|
|
static inline void blkcg_drain_queue(struct request_queue *q) { }
|
|
|
|
static inline void blkcg_exit_queue(struct request_queue *q) { }
|
2014-06-23 02:31:56 +04:00
|
|
|
static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
|
2012-04-17 00:57:25 +04:00
|
|
|
static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
|
2012-04-14 00:11:33 +04:00
|
|
|
static inline int blkcg_activate_policy(struct request_queue *q,
|
2012-04-17 00:57:25 +04:00
|
|
|
const struct blkcg_policy *pol) { return 0; }
|
2012-04-14 00:11:33 +04:00
|
|
|
static inline void blkcg_deactivate_policy(struct request_queue *q,
|
2012-04-17 00:57:25 +04:00
|
|
|
const struct blkcg_policy *pol) { }
|
|
|
|
|
2018-12-05 20:10:26 +03:00
|
|
|
static inline struct blkcg *__bio_blkcg(struct bio *bio) { return NULL; }
|
2012-06-05 07:40:57 +04:00
|
|
|
static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
|
blkcg: implement per-blkg request allocation
Currently, request_queue has one request_list to allocate requests
from regardless of blkcg of the IO being issued. When the unified
request pool is used up, cfq proportional IO limits become meaningless
- whoever grabs the next request being freed wins the race regardless
of the configured weights.
This can be easily demonstrated by creating a blkio cgroup w/ very low
weight, put a program which can issue a lot of random direct IOs there
and running a sequential IO from a different cgroup. As soon as the
request pool is used up, the sequential IO bandwidth crashes.
This patch implements per-blkg request_list. Each blkg has its own
request_list and any IO allocates its request from the matching blkg
making blkcgs completely isolated in terms of request allocation.
* Root blkcg uses the request_list embedded in each request_queue,
which was renamed to @q->root_rl from @q->rq. While making blkcg rl
handling a bit harier, this enables avoiding most overhead for root
blkcg.
* Queue fullness is properly per request_list but bdi isn't blkcg
aware yet, so congestion state currently just follows the root
blkcg. As writeback isn't aware of blkcg yet, this works okay for
async congestion but readahead may get the wrong signals. It's
better than blkcg completely collapsing with shared request_list but
needs to be improved with future changes.
* After this change, each block cgroup gets a full request pool making
resource consumption of each cgroup higher. This makes allowing
non-root users to create cgroups less desirable; however, note that
allowing non-root users to directly manage cgroups is already
severely broken regardless of this patch - each block cgroup
consumes kernel memory and skews IO weight (IO weights are not
hierarchical).
v2: queue-sysfs.txt updated and patch description udpated as suggested
by Vivek.
v3: blk_get_rl() wasn't checking error return from
blkg_lookup_create() and may cause oops on lookup failure. Fix it
by falling back to root_rl on blkg lookup failures. This problem
was spotted by Rakesh Iyer <rni@google.com>.
v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in
request waitqueue". blk_drain_queue() now wakes up waiters on all
blkg->rl on the target queue.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-27 02:05:44 +04:00
|
|
|
|
2012-04-17 00:57:26 +04:00
|
|
|
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
|
|
|
|
struct blkcg_policy *pol) { return NULL; }
|
|
|
|
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
|
2012-04-17 00:57:25 +04:00
|
|
|
static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
|
|
|
|
static inline void blkg_get(struct blkcg_gq *blkg) { }
|
|
|
|
static inline void blkg_put(struct blkcg_gq *blkg) { }
|
2010-04-26 21:27:56 +04:00
|
|
|
|
2019-06-27 23:39:52 +03:00
|
|
|
static inline bool blkcg_punt_bio_submit(struct bio *bio) { return false; }
|
2018-12-05 20:10:32 +03:00
|
|
|
static inline void blkcg_bio_issue_init(struct bio *bio) { }
|
2015-08-19 00:55:20 +03:00
|
|
|
static inline bool blkcg_bio_issue_check(struct request_queue *q,
|
|
|
|
struct bio *bio) { return true; }
|
|
|
|
|
blkcg: implement per-blkg request allocation
Currently, request_queue has one request_list to allocate requests
from regardless of blkcg of the IO being issued. When the unified
request pool is used up, cfq proportional IO limits become meaningless
- whoever grabs the next request being freed wins the race regardless
of the configured weights.
This can be easily demonstrated by creating a blkio cgroup w/ very low
weight, put a program which can issue a lot of random direct IOs there
and running a sequential IO from a different cgroup. As soon as the
request pool is used up, the sequential IO bandwidth crashes.
This patch implements per-blkg request_list. Each blkg has its own
request_list and any IO allocates its request from the matching blkg
making blkcgs completely isolated in terms of request allocation.
* Root blkcg uses the request_list embedded in each request_queue,
which was renamed to @q->root_rl from @q->rq. While making blkcg rl
handling a bit harier, this enables avoiding most overhead for root
blkcg.
* Queue fullness is properly per request_list but bdi isn't blkcg
aware yet, so congestion state currently just follows the root
blkcg. As writeback isn't aware of blkcg yet, this works okay for
async congestion but readahead may get the wrong signals. It's
better than blkcg completely collapsing with shared request_list but
needs to be improved with future changes.
* After this change, each block cgroup gets a full request pool making
resource consumption of each cgroup higher. This makes allowing
non-root users to create cgroups less desirable; however, note that
allowing non-root users to directly manage cgroups is already
severely broken regardless of this patch - each block cgroup
consumes kernel memory and skews IO weight (IO weights are not
hierarchical).
v2: queue-sysfs.txt updated and patch description udpated as suggested
by Vivek.
v3: blk_get_rl() wasn't checking error return from
blkg_lookup_create() and may cause oops on lookup failure. Fix it
by falling back to root_rl on blkg lookup failures. This problem
was spotted by Rakesh Iyer <rni@google.com>.
v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in
request waitqueue". blk_drain_queue() now wakes up waiters on all
blkg->rl on the target queue.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-27 02:05:44 +04:00
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#define blk_queue_for_each_rl(rl, q) \
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for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
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2015-05-23 00:13:18 +03:00
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#endif /* CONFIG_BLOCK */
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2012-04-17 00:57:24 +04:00
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#endif /* CONFIG_BLK_CGROUP */
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#endif /* _BLK_CGROUP_H */
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