diff options
author | Wu Fengguang <fengguang.wu@intel.com> | 2010-06-06 12:38:15 -0400 |
---|---|---|
committer | Wu Fengguang <fengguang.wu@intel.com> | 2011-06-07 20:25:20 -0400 |
commit | 6e6938b6d3130305a5960c86b1a9b21e58cf6144 (patch) | |
tree | de5546e8390ce31cd31412d2ef78ce732a42191c /fs/ext4/inode.c | |
parent | 59c5f46fbe01a00eedf54a23789634438bb80603 (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 'fs/ext4/inode.c')
-rw-r--r-- | fs/ext4/inode.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index a5763e3505ba..8558b6c3450a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c | |||
@@ -2741,7 +2741,7 @@ static int write_cache_pages_da(struct address_space *mapping, | |||
2741 | index = wbc->range_start >> PAGE_CACHE_SHIFT; | 2741 | index = wbc->range_start >> PAGE_CACHE_SHIFT; |
2742 | end = wbc->range_end >> PAGE_CACHE_SHIFT; | 2742 | end = wbc->range_end >> PAGE_CACHE_SHIFT; |
2743 | 2743 | ||
2744 | if (wbc->sync_mode == WB_SYNC_ALL) | 2744 | if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) |
2745 | tag = PAGECACHE_TAG_TOWRITE; | 2745 | tag = PAGECACHE_TAG_TOWRITE; |
2746 | else | 2746 | else |
2747 | tag = PAGECACHE_TAG_DIRTY; | 2747 | tag = PAGECACHE_TAG_DIRTY; |
@@ -2973,7 +2973,7 @@ static int ext4_da_writepages(struct address_space *mapping, | |||
2973 | } | 2973 | } |
2974 | 2974 | ||
2975 | retry: | 2975 | retry: |
2976 | if (wbc->sync_mode == WB_SYNC_ALL) | 2976 | if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) |
2977 | tag_pages_for_writeback(mapping, index, end); | 2977 | tag_pages_for_writeback(mapping, index, end); |
2978 | 2978 | ||
2979 | while (!ret && wbc->nr_to_write > 0) { | 2979 | while (!ret && wbc->nr_to_write > 0) { |