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authorWu Fengguang <fengguang.wu@intel.com>2010-06-06 10:38:15 -0600
committerWu Fengguang <fengguang.wu@intel.com>2011-06-08 08:25:20 +0800
commit6e6938b6d3130305a5960c86b1a9b21e58cf6144 (patch)
treede5546e8390ce31cd31412d2ef78ce732a42191c /mm
parent59c5f46fbe01a00eedf54a23789634438bb80603 (diff)
writeback: introduce .tagged_writepages for the WB_SYNC_NONE sync stage
sync(2) is performed in two stages: the WB_SYNC_NONE sync and the WB_SYNC_ALL sync. Identify the first stage with .tagged_writepages and do livelock prevention for it, too. Jan's commit f446daaea9 ("mm: implement writeback livelock avoidance using page tagging") is a partial fix in that it only fixed the WB_SYNC_ALL phase livelock. Although ext4 is tested to no longer livelock with commit f446daaea9, it may due to some "redirty_tail() after pages_skipped" effect which is by no means a guarantee for _all_ the file systems. Note that writeback_inodes_sb() is called by not only sync(), they are treated the same because the other callers also need livelock prevention. Impact: It changes the order in which pages/inodes are synced to disk. Now in the WB_SYNC_NONE stage, it won't proceed to write the next inode until finished with the current inode. Acked-by: Jan Kara <jack@suse.cz> CC: Dave Chinner <david@fromorbit.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/page-writeback.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 31f698862420..955fe35d01e0 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -892,12 +892,12 @@ int write_cache_pages(struct address_space *mapping,
range_whole = 1;
cycled = 1; /* ignore range_cyclic tests */
}
- if (wbc->sync_mode == WB_SYNC_ALL)
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
retry:
- if (wbc->sync_mode == WB_SYNC_ALL)
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag_pages_for_writeback(mapping, index, end);
done_index = index;
while (!done && (index <= end)) {