From 1b430beee5e388605dfb092b214ef0320f752cf6 Mon Sep 17 00:00:00 2001 From: Wu Fengguang Date: Tue, 26 Oct 2010 14:21:26 -0700 Subject: [PATCH] writeback: remove nonblocking/encountered_congestion references This removes more dead code that was somehow missed by commit 0d99519efef (writeback: remove unused nonblocking and congestion checks). There are no behavior change except for the removal of two entries from one of the ext4 tracing interface. The nonblocking checks in ->writepages are no longer used because the flusher now prefer to block on get_request_wait() than to skip inodes on IO congestion. The latter will lead to more seeky IO. The nonblocking checks in ->writepage are no longer used because it's redundant with the WB_SYNC_NONE check. We no long set ->nonblocking in VM page out and page migration, because a) it's effectively redundant with WB_SYNC_NONE in current code b) it's old semantic of "Don't get stuck on request queues" is mis-behavior: that would skip some dirty inodes on congestion and page out others, which is unfair in terms of LRU age. Inspired by Christoph Hellwig. Thanks! Signed-off-by: Wu Fengguang Cc: Theodore Ts'o Cc: David Howells Cc: Sage Weil Cc: Steve French Cc: Chris Mason Cc: Jens Axboe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/afs/write.c | 19 +------------------ fs/buffer.c | 2 +- fs/ceph/addr.c | 9 --------- fs/cifs/file.c | 10 ---------- fs/gfs2/meta_io.c | 2 +- fs/nfs/write.c | 4 +--- fs/reiserfs/inode.c | 2 +- fs/xfs/linux-2.6/xfs_aops.c | 3 +-- include/trace/events/ext4.h | 8 +++++--- include/trace/events/writeback.h | 2 -- mm/migrate.c | 1 - mm/vmscan.c | 1 - 12 files changed, 11 insertions(+), 52 deletions(-) diff --git a/fs/afs/write.c b/fs/afs/write.c index 722743b152d8..15690bb1d3b5 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -438,7 +438,6 @@ no_more: */ int afs_writepage(struct page *page, struct writeback_control *wbc) { - struct backing_dev_info *bdi = page->mapping->backing_dev_info; struct afs_writeback *wb; int ret; @@ -455,8 +454,6 @@ int afs_writepage(struct page *page, struct writeback_control *wbc) } wbc->nr_to_write -= ret; - if (wbc->nonblocking && bdi_write_congested(bdi)) - wbc->encountered_congestion = 1; _leave(" = 0"); return 0; @@ -469,7 +466,6 @@ static int afs_writepages_region(struct address_space *mapping, struct writeback_control *wbc, pgoff_t index, pgoff_t end, pgoff_t *_next) { - struct backing_dev_info *bdi = mapping->backing_dev_info; struct afs_writeback *wb; struct page *page; int ret, n; @@ -529,11 +525,6 @@ static int afs_writepages_region(struct address_space *mapping, wbc->nr_to_write -= ret; - if (wbc->nonblocking && bdi_write_congested(bdi)) { - wbc->encountered_congestion = 1; - break; - } - cond_resched(); } while (index < end && wbc->nr_to_write > 0); @@ -548,24 +539,16 @@ static int afs_writepages_region(struct address_space *mapping, int afs_writepages(struct address_space *mapping, struct writeback_control *wbc) { - struct backing_dev_info *bdi = mapping->backing_dev_info; pgoff_t start, end, next; int ret; _enter(""); - if (wbc->nonblocking && bdi_write_congested(bdi)) { - wbc->encountered_congestion = 1; - _leave(" = 0 [congest]"); - return 0; - } - if (wbc->range_cyclic) { start = mapping->writeback_index; end = -1; ret = afs_writepages_region(mapping, wbc, start, end, &next); - if (start > 0 && wbc->nr_to_write > 0 && ret == 0 && - !(wbc->nonblocking && wbc->encountered_congestion)) + if (start > 0 && wbc->nr_to_write > 0 && ret == 0) ret = afs_writepages_region(mapping, wbc, 0, start, &next); mapping->writeback_index = next; diff --git a/fs/buffer.c b/fs/buffer.c index 7f0b9b083f77..ec21a92e08b4 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1706,7 +1706,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page, * and kswapd activity, but those code paths have their own * higher-level throttling. */ - if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { + if (wbc->sync_mode != WB_SYNC_NONE) { lock_buffer(bh); } else if (!trylock_buffer(bh)) { redirty_page_for_writepage(wbc, page); diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 51bcc5ce3230..e9c874abc9e1 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -591,7 +591,6 @@ static int ceph_writepages_start(struct address_space *mapping, struct writeback_control *wbc) { struct inode *inode = mapping->host; - struct backing_dev_info *bdi = mapping->backing_dev_info; struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_fs_client *fsc; pgoff_t index, start, end; @@ -633,13 +632,6 @@ static int ceph_writepages_start(struct address_space *mapping, pagevec_init(&pvec, 0); - /* ?? */ - if (wbc->nonblocking && bdi_write_congested(bdi)) { - dout(" writepages congested\n"); - wbc->encountered_congestion = 1; - goto out_final; - } - /* where to start/end? */ if (wbc->range_cyclic) { start = mapping->writeback_index; /* Start from prev offset */ @@ -885,7 +877,6 @@ out: rc = 0; /* vfs expects us to return 0 */ ceph_put_snap_context(snapc); dout("writepages done, rc = %d\n", rc); -out_final: return rc; } diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 8c81e7b14d53..45af003865d2 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1303,7 +1303,6 @@ static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to) static int cifs_writepages(struct address_space *mapping, struct writeback_control *wbc) { - struct backing_dev_info *bdi = mapping->backing_dev_info; unsigned int bytes_to_write; unsigned int bytes_written; struct cifs_sb_info *cifs_sb; @@ -1326,15 +1325,6 @@ static int cifs_writepages(struct address_space *mapping, int scanned = 0; int xid, long_op; - /* - * BB: Is this meaningful for a non-block-device file system? - * If it is, we should test it again after we do I/O - */ - if (wbc->nonblocking && bdi_write_congested(bdi)) { - wbc->encountered_congestion = 1; - return 0; - } - cifs_sb = CIFS_SB(mapping->host->i_sb); /* diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c index f3b071f921aa..939739c7b3f9 100644 --- a/fs/gfs2/meta_io.c +++ b/fs/gfs2/meta_io.c @@ -55,7 +55,7 @@ static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wb * activity, but those code paths have their own higher-level * throttling. */ - if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { + if (wbc->sync_mode != WB_SYNC_NONE) { lock_buffer(bh); } else if (!trylock_buffer(bh)) { redirty_page_for_writepage(wbc, page); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 605e292501f4..4c14c17a5276 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -290,9 +290,7 @@ static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, st nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1); nfs_pageio_cond_complete(pgio, page->index); - ret = nfs_page_async_flush(pgio, page, - wbc->sync_mode == WB_SYNC_NONE || - wbc->nonblocking != 0); + ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE); if (ret == -EAGAIN) { redirty_page_for_writepage(wbc, page); ret = 0; diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c index caa758377d66..c1f93896cb53 100644 --- a/fs/reiserfs/inode.c +++ b/fs/reiserfs/inode.c @@ -2438,7 +2438,7 @@ static int reiserfs_write_full_page(struct page *page, /* from this point on, we know the buffer is mapped to a * real block and not a direct item */ - if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { + if (wbc->sync_mode != WB_SYNC_NONE) { lock_buffer(bh); } else { if (!trylock_buffer(bh)) { diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c index b552f816de15..c9af48fffcd7 100644 --- a/fs/xfs/linux-2.6/xfs_aops.c +++ b/fs/xfs/linux-2.6/xfs_aops.c @@ -1139,8 +1139,7 @@ xfs_vm_writepage( type = IO_DELAY; flags = BMAPI_ALLOCATE; - if (wbc->sync_mode == WB_SYNC_NONE && - wbc->nonblocking) + if (wbc->sync_mode == WB_SYNC_NONE) flags |= BMAPI_TRYLOCK; } diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h index 01e9e0076a92..6bcb00645de4 100644 --- a/include/trace/events/ext4.h +++ b/include/trace/events/ext4.h @@ -242,18 +242,20 @@ TRACE_EVENT(ext4_da_writepages, __entry->pages_skipped = wbc->pages_skipped; __entry->range_start = wbc->range_start; __entry->range_end = wbc->range_end; - __entry->nonblocking = wbc->nonblocking; __entry->for_kupdate = wbc->for_kupdate; __entry->for_reclaim = wbc->for_reclaim; __entry->range_cyclic = wbc->range_cyclic; __entry->writeback_index = inode->i_mapping->writeback_index; ), - TP_printk("dev %s ino %lu nr_to_write %ld pages_skipped %ld range_start %llu range_end %llu nonblocking %d for_kupdate %d for_reclaim %d range_cyclic %d writeback_index %lu", + TP_printk("dev %s ino %lu nr_to_write %ld pages_skipped %ld " + "range_start %llu range_end %llu " + "for_kupdate %d for_reclaim %d " + "range_cyclic %d writeback_index %lu", jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino, __entry->nr_to_write, __entry->pages_skipped, __entry->range_start, - __entry->range_end, __entry->nonblocking, + __entry->range_end, __entry->for_kupdate, __entry->for_reclaim, __entry->range_cyclic, (unsigned long) __entry->writeback_index) diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h index f345f66ae9d1..0bb01ab2e984 100644 --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -96,8 +96,6 @@ DECLARE_EVENT_CLASS(wbc_class, __field(long, nr_to_write) __field(long, pages_skipped) __field(int, sync_mode) - __field(int, nonblocking) - __field(int, encountered_congestion) __field(int, for_kupdate) __field(int, for_background) __field(int, for_reclaim) diff --git a/mm/migrate.c b/mm/migrate.c index f8c9bccf2520..d917ac3207f5 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -497,7 +497,6 @@ static int writeout(struct address_space *mapping, struct page *page) .nr_to_write = 1, .range_start = 0, .range_end = LLONG_MAX, - .nonblocking = 1, .for_reclaim = 1 }; int rc; diff --git a/mm/vmscan.c b/mm/vmscan.c index b94c9464f262..6cbc1aac23ae 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -376,7 +376,6 @@ static pageout_t pageout(struct page *page, struct address_space *mapping, .nr_to_write = SWAP_CLUSTER_MAX, .range_start = 0, .range_end = LLONG_MAX, - .nonblocking = 1, .for_reclaim = 1, };