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| author | Wu Fengguang <fengguang.wu@intel.com> | 2010-06-06 10:38:15 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-10-03 11:40:43 -0700 |
| commit | ac693061b11c33d5a5c5ec1925de7abd3fcb0971 (patch) | |
| tree | 968e4efb688a21caedd5a3e7baea3d6343abf4bd /fs/ext4 | |
| parent | 0d39ea76fa3b9a97e9dc45282613bc239ffa8509 (diff) | |
| download | kernel_samsung_crespo-ac693061b11c33d5a5c5ec1925de7abd3fcb0971.zip kernel_samsung_crespo-ac693061b11c33d5a5c5ec1925de7abd3fcb0971.tar.gz kernel_samsung_crespo-ac693061b11c33d5a5c5ec1925de7abd3fcb0971.tar.bz2 | |
writeback: introduce .tagged_writepages for the WB_SYNC_NONE sync stage
commit 6e6938b6d3130305a5960c86b1a9b21e58cf6144 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/ext4')
| -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 b864839..c94774c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2756,7 +2756,7 @@ static int write_cache_pages_da(struct address_space *mapping, index = wbc->range_start >> PAGE_CACHE_SHIFT; end = wbc->range_end >> PAGE_CACHE_SHIFT; - 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; @@ -2988,7 +2988,7 @@ static int ext4_da_writepages(struct address_space *mapping, } 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); while (!ret && wbc->nr_to_write > 0) { |