The patch titled
writeback: avoid extra sync work at enqueue time
has been added to the -mm tree. Its filename is
writeback-avoid-extra-sync-work-at-enqueue-time.patch
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------------------------------------------------------
Subject: writeback: avoid extra sync work at enqueue time
From: Wu Fengguang <fengguang.wu@xxxxxxxxx>
This removes writeback_control.wb_start and does more straightforward sync
livelock prevention by setting .older_than_this to prevent extra inodes
from being enqueued in the first place.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/fs-writeback.c | 17 ++++-------------
include/linux/writeback.h | 3 ---
2 files changed, 4 insertions(+), 16 deletions(-)
diff -puN fs/fs-writeback.c~writeback-avoid-extra-sync-work-at-enqueue-time fs/fs-writeback.c
--- a/fs/fs-writeback.c~writeback-avoid-extra-sync-work-at-enqueue-time
+++ a/fs/fs-writeback.c
@@ -544,15 +544,6 @@ static int writeback_sb_inodes(struct su
continue;
}
- /*
- * Was this inode dirtied after sync_sb_inodes was called?
- * This keeps sync from extra jobs and livelock.
- */
- if (inode_dirtied_after(inode, wbc->wb_start)) {
- spin_unlock(&inode->i_lock);
- return 1;
- }
-
__iget(inode);
pages_skipped = wbc->pages_skipped;
@@ -585,8 +576,6 @@ static void __writeback_inodes_wb(struct
{
int ret = 0;
- if (!wbc->wb_start)
- wbc->wb_start = jiffies; /* livelock avoidance */
while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
@@ -683,10 +672,12 @@ static long wb_writeback(struct bdi_writ
* (quickly) tag currently dirty pages
* (maybe slowly) sync all tagged pages
*/
- if (wbc.sync_mode == WB_SYNC_ALL || wbc.tagged_sync)
+ if (wbc.sync_mode == WB_SYNC_ALL || wbc.tagged_sync) {
write_chunk = LONG_MAX;
+ oldest_jif = jiffies;
+ wbc.older_than_this = &oldest_jif;
+ }
- wbc.wb_start = jiffies; /* livelock avoidance */
for (;;) {
/*
* Stop writeback when nr_pages has been consumed
diff -puN include/linux/writeback.h~writeback-avoid-extra-sync-work-at-enqueue-time include/linux/writeback.h
--- a/include/linux/writeback.h~writeback-avoid-extra-sync-work-at-enqueue-time
+++ a/include/linux/writeback.h
@@ -26,9 +26,6 @@ struct writeback_control {
enum writeback_sync_modes sync_mode;
unsigned long *older_than_this; /* If !NULL, only write back inodes
older than this */
- unsigned long wb_start; /* Time writeback_inodes_wb was
- called. This is needed to avoid
- extra jobs and livelock */
long nr_to_write; /* Write this many pages, and decrement
this for each page written */
long pages_skipped; /* Pages which were not written */
_
Patches currently in -mm which might be from fengguang.wu@xxxxxxxxx are
mm-per-node-vmstat-show-proper-vmstats.patch
mm-per-node-vmstat-show-proper-vmstats-fix.patch
writeback-pass-writeback_control-down-to-move_expired_inodes.patch
writeback-introduce-writeback_controlinodes_cleaned.patch
writeback-try-more-writeback-as-long-as-something-was-written.patch
writeback-the-kupdate-expire-timestamp-should-be-a-moving-target.patch
writeback-sync-expired-inodes-first-in-background-writeback.patch
writeback-sync-expired-inodes-first-in-background-writeback-fix.patch
writeback-refill-b_io-iff-empty.patch
writeback-split-inode_wb_list_lock-into-bdi_writebacklist_lock.patch
writeback-split-inode_wb_list_lock-into-bdi_writebacklist_lock-fix.patch
writeback-split-inode_wb_list_lock-into-bdi_writebacklist_lock-fix-fix.patch
writeback-split-inode_wb_list_lock-into-bdi_writebacklist_lock-fix-fix-fix.patch
writeback-elevate-queue_io-into-wb_writeback.patch
writeback-introduce-wbctagged_sync-for-the-wb_sync_none-sync-stage.patch
writeback-update-dirtied_when-for-synced-inode-to-prevent-livelock.patch
writeback-avoid-extra-sync-work-at-enqueue-time.patch
readahead-readahead-page-allocations-are-ok-to-fail.patch
readahead-return-early-when-readahead-is-disabled.patch
readahead-reduce-unnecessary-mmap_miss-increases.patch
readahead-trigger-mmap-sequential-readahead-on-pg_readahead.patch
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