From 503d4fa6ee28e8d4d201c92ac3922d1b3526f844 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 22 Mar 2022 14:39:04 -0700 Subject: [PATCH] ceph: remove reliance on bdi congestion The bdi congestion tracking in not widely used and will be removed. CEPHfs is one of a small number of filesystems that uses it, setting just the async (write) congestion flags at what it determines are appropriate times. The only remaining effect of the async flag is to cause (some) WB_SYNC_NONE writes to be skipped. So instead of setting the flag, set an internal flag and change: - .writepages to do nothing if WB_SYNC_NONE and the flag is set - .writepage to return AOP_WRITEPAGE_ACTIVATE if WB_SYNC_NONE and the flag is set. The writepages change causes a behavioural change in that pageout() can now return PAGE_ACTIVATE instead of PAGE_KEEP, so SetPageActive() will be called on the page which (I think) wil further delay the next attempt at writeout. This might be a good thing. Link: https://lkml.kernel.org/r/164549983739.9187.14895675781408171186.stgit@noble.brown Signed-off-by: NeilBrown Cc: Anna Schumaker Cc: Chao Yu Cc: Darrick J. Wong Cc: Ilya Dryomov Cc: Jaegeuk Kim Cc: Jan Kara Cc: Jeff Layton Cc: Jens Axboe Cc: Lars Ellenberg Cc: Miklos Szeredi Cc: Paolo Valente Cc: Philipp Reisner Cc: Ryusuke Konishi Cc: Trond Myklebust Cc: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ceph/addr.c | 22 +++++++++++++--------- fs/ceph/super.c | 1 + fs/ceph/super.h | 1 + 3 files changed, 15 insertions(+), 9 deletions(-) diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index c98e523..dc7af34 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -563,7 +563,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) if (atomic_long_inc_return(&fsc->writeback_count) > CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb)) - set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC); + fsc->write_congested = true; req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), page_off, &len, 0, 1, CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE, snapc, @@ -623,7 +623,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) if (atomic_long_dec_return(&fsc->writeback_count) < CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb)) - clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC); + fsc->write_congested = false; return err; } @@ -635,6 +635,10 @@ static int ceph_writepage(struct page *page, struct writeback_control *wbc) BUG_ON(!inode); ihold(inode); + if (wbc->sync_mode == WB_SYNC_NONE && + ceph_inode_to_client(inode)->write_congested) + return AOP_WRITEPAGE_ACTIVATE; + wait_on_page_fscache(page); err = writepage_nounlock(page, wbc); @@ -707,8 +711,7 @@ static void writepages_finish(struct ceph_osd_request *req) if (atomic_long_dec_return(&fsc->writeback_count) < CONGESTION_OFF_THRESH( fsc->mount_options->congestion_kb)) - clear_bdi_congested(inode_to_bdi(inode), - BLK_RW_ASYNC); + fsc->write_congested = false; ceph_put_snap_context(detach_page_private(page)); end_page_writeback(page); @@ -760,6 +763,10 @@ static int ceph_writepages_start(struct address_space *mapping, bool done = false; bool caching = ceph_is_cache_enabled(inode); + if (wbc->sync_mode == WB_SYNC_NONE && + fsc->write_congested) + return 0; + dout("writepages_start %p (mode=%s)\n", inode, wbc->sync_mode == WB_SYNC_NONE ? "NONE" : (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD")); @@ -954,11 +961,8 @@ get_more_pages: if (atomic_long_inc_return(&fsc->writeback_count) > CONGESTION_ON_THRESH( - fsc->mount_options->congestion_kb)) { - set_bdi_congested(inode_to_bdi(inode), - BLK_RW_ASYNC); - } - + fsc->mount_options->congestion_kb)) + fsc->write_congested = true; pages[locked_pages++] = page; pvec.pages[i] = NULL; diff --git a/fs/ceph/super.c b/fs/ceph/super.c index bf79f36..4a3b77d 100644 --- a/fs/ceph/super.c +++ b/fs/ceph/super.c @@ -802,6 +802,7 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt, fsc->have_copy_from2 = true; atomic_long_set(&fsc->writeback_count, 0); + fsc->write_congested = false; err = -ENOMEM; /* diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 67f145e..0bd97ae 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -121,6 +121,7 @@ struct ceph_fs_client { struct ceph_mds_client *mdsc; atomic_long_t writeback_count; + bool write_congested; struct workqueue_struct *inode_wq; struct workqueue_struct *cap_wq; -- 2.7.4