From: Zhihao Cheng chengzhihao@huaweicloud.com
Kemeng Shi (6): fs/writeback: avoid to writeback non-expired inode in kupdate writeback fs/writeback: bail out if there is no more inodes for IO and queued once fs/writeback: remove unused parameter wb of finish_writeback_work fs/writeback: only calculate dirtied_before when b_io is empty fs/writeback: correct comment of __wakeup_flusher_threads_bdi fs/writeback: remove unnecessary return in writeback_inodes_sb
fs/fs-writeback.c | 57 +++++++++++++++++++++++++++-------------------- 1 file changed, 33 insertions(+), 24 deletions(-)
From: Kemeng Shi shikemeng@huaweicloud.com
mainline inclusion from mainline-next-20240508 commit ac0c18f2c693f0e7a44dbbb36b14d5141e5d20e5 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9NOHO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/f...
--------------------------------
In kupdate writeback, only expired inode (have been dirty for longer than dirty_expire_interval) is supposed to be written back. However, kupdate writeback will writeback non-expired inode left in b_io or b_more_io from last wb_writeback. As a result, writeback will keep being triggered unexpected when we keep dirtying pages even dirty memory is under threshold and inode is not expired. To be more specific: Assume dirty background threshold is > 1G and dirty_expire_centisecs is
60s. When we running fio -size=1G -invalidate=0 -ioengine=libaio
--time_based -runtime=60... (keep dirtying), the writeback will keep being triggered as following: wb_workfn wb_do_writeback wb_check_background_flush /* * Wb dirty background threshold starts at 0 if device was idle and * grows up when bandwidth of wb is updated. So a background * writeback is triggered. */ wb_over_bg_thresh /* * Dirtied inode will be written back and added to b_more_io list * after slice used up (because we keep dirtying the inode). */ wb_writeback
Writeback is triggered per dirty_writeback_centisecs as following: wb_workfn wb_do_writeback wb_check_old_data_flush /* * Write back inode left in b_io and b_more_io from last wb_writeback * even the inode is non-expired and it will be added to b_more_io * again as slice will be used up (because we keep dirtying the * inode) */ wb_writeback
Fix this by moving non-expired inode to dirty list instead of more io list for kupdate writeback in requeue_inode.
Test as following: /* make it more easier to observe the issue */ echo 300000 > /proc/sys/vm/dirty_expire_centisecs echo 100 > /proc/sys/vm/dirty_writeback_centisecs /* create a idle device */ mkfs.ext4 -F /dev/vdb mount /dev/vdb /bdi1/ /* run buffer write with fio */ fio -name test -filename=/bdi1/file -size=800M -ioengine=libaio -bs=4K \ -iodepth=1 -rw=write -direct=0 --time_based -runtime=60 -invalidate=0
Fio result before fix (run three tests): 1360MB/s 1329MB/s 1455MB/s
Fio result after fix (run three tests): 1737MB/s 1729MB/s 1789MB/s
Writeback for non-expired inode is gone as expeted. Observe this with trace writeback_start and writeback_written as following: echo 1 > /sys/kernel/debug/tracing/events/writeback/writeback_start/enab echo 1 > /sys/kernel/debug/tracing/events/writeback/writeback_written/enable cat /sys/kernel/tracing/trace_pipe
Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Link: https://lore.kernel.org/r/20240228091958.288260-2-shikemeng@huaweicloud.com Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Zhihao Cheng chengzhihao@huaweicloud.com --- fs/fs-writeback.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 1767493dffda..c66e18e53c5f 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1536,7 +1536,8 @@ static void inode_sleep_on_writeback(struct inode *inode) * thread's back can have unexpected consequences. */ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, - struct writeback_control *wbc) + struct writeback_control *wbc, + unsigned long dirtied_before) { if (inode->i_state & I_FREEING) return; @@ -1569,7 +1570,8 @@ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, * We didn't write back all the pages. nfs_writepages() * sometimes bales out without doing anything. */ - if (wbc->nr_to_write <= 0) { + if (wbc->nr_to_write <= 0 && + !inode_dirtied_after(inode, dirtied_before)) { /* Slice used up. Queue for next turn. */ requeue_io(inode, wb); } else { @@ -1837,6 +1839,11 @@ static long writeback_sb_inodes(struct super_block *sb, unsigned long start_time = jiffies; long write_chunk; long total_wrote = 0; /* count both pages and inodes */ + unsigned long dirtied_before = jiffies; + + if (work->for_kupdate) + dirtied_before = jiffies - + msecs_to_jiffies(dirty_expire_interval * 10);
while (!list_empty(&wb->b_io)) { struct inode *inode = wb_inode(wb->b_io.prev); @@ -1942,7 +1949,7 @@ static long writeback_sb_inodes(struct super_block *sb, spin_lock(&inode->i_lock); if (!(inode->i_state & I_DIRTY_ALL)) total_wrote++; - requeue_inode(inode, tmp_wb, &wbc); + requeue_inode(inode, tmp_wb, &wbc, dirtied_before); inode_sync_complete(inode); spin_unlock(&inode->i_lock);
From: Kemeng Shi shikemeng@huaweicloud.com
mainline inclusion from mainline-next-20240508 commit d92109891f21cf367caa2cc6dff11a4411d917f4 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9NOHO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/f...
--------------------------------
For case there is no more inodes for IO in io list from last wb_writeback, We may bail out early even there is inode in dirty list should be written back. Only bail out when we queued once to avoid missing dirtied inode.
This is from code reading...
Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Link: https://lore.kernel.org/r/20240228091958.288260-3-shikemeng@huaweicloud.com Reviewed-by: Jan Kara jack@suse.cz [brauner@kernel.org: fold in memory corruption fix from Jan in [1]] Link: https://lore.kernel.org/r/20240405132346.bid7gibby3lxxhez@quack3 [1] Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Zhihao Cheng chengzhihao@huaweicloud.com --- fs/fs-writeback.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index c66e18e53c5f..fecf600e91dc 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2051,6 +2051,7 @@ static long wb_writeback(struct bdi_writeback *wb, struct inode *inode; long progress; struct blk_plug plug; + bool queued = false;
blk_start_plug(&plug); for (;;) { @@ -2093,8 +2094,10 @@ static long wb_writeback(struct bdi_writeback *wb, dirtied_before = jiffies;
trace_writeback_start(wb, work); - if (list_empty(&wb->b_io)) + if (list_empty(&wb->b_io)) { queue_io(wb, work, dirtied_before); + queued = true; + } if (work->sb) progress = writeback_sb_inodes(work->sb, wb, work); else @@ -2109,7 +2112,7 @@ static long wb_writeback(struct bdi_writeback *wb, * mean the overall work is done. So we keep looping as long * as made some progress on cleaning pages or inodes. */ - if (progress) { + if (progress || !queued) { spin_unlock(&wb->list_lock); continue; }
From: Kemeng Shi shikemeng@huaweicloud.com
mainline inclusion from mainline-next-20240508 commit 2ddc93461214507b8e50ba7218d6260be8d623d1 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9NOHO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/f...
--------------------------------
Remove unused parameter wb of finish_writeback_work.
Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Link: https://lore.kernel.org/r/20240228091958.288260-4-shikemeng@huaweicloud.com Reviewed-by: Tim Chen tim.c.chen@linux.intel.com Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Zhihao Cheng chengzhihao@huaweicloud.com --- fs/fs-writeback.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index fecf600e91dc..a5f168fb02f1 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -141,8 +141,7 @@ static void wb_wakeup(struct bdi_writeback *wb) spin_unlock_irq(&wb->work_lock); }
-static void finish_writeback_work(struct bdi_writeback *wb, - struct wb_writeback_work *work) +static void finish_writeback_work(struct wb_writeback_work *work) { struct wb_completion *done = work->done;
@@ -171,7 +170,7 @@ static void wb_queue_work(struct bdi_writeback *wb, list_add_tail(&work->list, &wb->work_list); mod_delayed_work(bdi_wq, &wb->dwork, 0); } else - finish_writeback_work(wb, work); + finish_writeback_work(work);
spin_unlock_irq(&wb->work_lock); } @@ -2247,7 +2246,7 @@ static long wb_do_writeback(struct bdi_writeback *wb) while ((work = get_next_work_item(wb)) != NULL) { trace_writeback_exec(wb, work); wrote += wb_writeback(wb, work); - finish_writeback_work(wb, work); + finish_writeback_work(work); }
/*
From: Kemeng Shi shikemeng@huaweicloud.com
mainline inclusion from mainline-next-20240508 commit 639924abc1ae28eb05893a402081e8e6cff23b8a category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9NOHO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/f...
--------------------------------
The dirtied_before is only used when b_io is not empty, so only calculate when b_io is not empty.
Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Link: https://lore.kernel.org/r/20240228091958.288260-5-shikemeng@huaweicloud.com Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Zhihao Cheng chengzhihao@huaweicloud.com --- fs/fs-writeback.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index a5f168fb02f1..82f3101ba8eb 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2080,20 +2080,21 @@ static long wb_writeback(struct bdi_writeback *wb,
spin_lock(&wb->list_lock);
- /* - * Kupdate and background works are special and we want to - * include all inodes that need writing. Livelock avoidance is - * handled by these works yielding to any other work so we are - * safe. - */ - if (work->for_kupdate) { - dirtied_before = jiffies - - msecs_to_jiffies(dirty_expire_interval * 10); - } else if (work->for_background) - dirtied_before = jiffies; - trace_writeback_start(wb, work); if (list_empty(&wb->b_io)) { + /* + * Kupdate and background works are special and we want + * to include all inodes that need writing. Livelock + * avoidance is handled by these works yielding to any + * other work so we are safe. + */ + if (work->for_kupdate) { + dirtied_before = jiffies - + msecs_to_jiffies(dirty_expire_interval * + 10); + } else if (work->for_background) + dirtied_before = jiffies; + queue_io(wb, work, dirtied_before); queued = true; }
From: Kemeng Shi shikemeng@huaweicloud.com
mainline inclusion from mainline-next-20240508 commit ba679de9c3fc511f457ea0ad8f5a22e9152fa07b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9NOHO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/f...
--------------------------------
Commit e8e8a0c6c9bfc ("writeback: move nr_pages == 0 logic to one location") removed parameter nr_pages of __wakeup_flusher_threads_bdi and we try to writeback all dirty pages in __wakeup_flusher_threads_bdi now. Just correct stale comment.
Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Link: https://lore.kernel.org/r/20240228091958.288260-6-shikemeng@huaweicloud.com Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Zhihao Cheng chengzhihao@huaweicloud.com --- fs/fs-writeback.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 82f3101ba8eb..7b13a430860a 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2307,8 +2307,7 @@ void wb_workfn(struct work_struct *work) }
/* - * Start writeback of `nr_pages' pages on this bdi. If `nr_pages' is zero, - * write back the whole world. + * Start writeback of all dirty pages on this bdi. */ static void __wakeup_flusher_threads_bdi(struct backing_dev_info *bdi, enum wb_reason reason)
From: Kemeng Shi shikemeng@huaweicloud.com
mainline inclusion from mainline-next-20240508 commit 6a1ee87176ffed1d9e749bc66a2ad85be2d7dbb7 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9NOHO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/f...
--------------------------------
writeback_inodes_sb doesn't have return value, just remove unnecessary return in it.
Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Link: https://lore.kernel.org/r/20240228091958.288260-7-shikemeng@huaweicloud.com Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Zhihao Cheng chengzhihao@huaweicloud.com --- fs/fs-writeback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 7b13a430860a..c79f04ad646e 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2710,7 +2710,7 @@ EXPORT_SYMBOL(writeback_inodes_sb_nr); */ void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) { - return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); + writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); } EXPORT_SYMBOL(writeback_inodes_sb);
反馈： 您发送到kernel@openeuler.org的补丁/补丁集，已成功转换为PR！ PR链接地址： https://gitee.com/openeuler/kernel/pulls/7015 邮件列表地址：https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/O...
FeedBack: The patch(es) which you have sent to kernel@openeuler.org mailing list has been converted to a pull request successfully! Pull request link: https://gitee.com/openeuler/kernel/pulls/7015 Mailing list address: https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/O...
-
patchwork bot -
Zhihao Cheng