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authorKen Chen <kenchen@google.com>2007-10-16 23:30:38 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:43:02 -0700
commit0e0f4fc22ece8e593167eccbb1a4154565c11faa (patch)
tree564ab2eabb31ab945c334706662854bb227f45e9 /include/linux
parent670e4def6ef5f44315d62748134e535b479c784f (diff)
writeback: fix periodic superblock dirty inode flushing
Current -mm tree has bucketful of bug fixes in periodic writeback path. However, we still hit a glitch where dirty pages on a given inode aren't completely flushed to the disk, and system will accumulate large amount of dirty pages beyond what dirty_expire_interval is designed for. The problem is __sync_single_inode() will move an inode to sb->s_dirty list even when there are more pending dirty pages on that inode. If there is another inode with a small number of dirty pages, we hit a case where the loop iteration in wb_kupdate() terminates prematurely because wbc.nr_to_write > 0. Thus leaving the inode that has large amount of dirty pages behind and it has to wait for another dirty_writeback_interval before we flush it again. We effectively only write out MAX_WRITEBACK_PAGES every dirty_writeback_interval. If the rate of dirtying is sufficiently high, the system will start accumulate a large number of dirty pages. So fix it by having another sb->s_more_io list on which to park the inode while we iterate through sb->s_io and to allow each dirty inode which resides on that sb to have an equal chance of flushing some amount of dirty pages. Signed-off-by: Ken Chen <kenchen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/fs.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 30aca339945..0b38a897c11 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1002,6 +1002,7 @@ struct super_block {
struct list_head s_inodes; /* all inodes */
struct list_head s_dirty; /* dirty inodes */
struct list_head s_io; /* parked for writeback */
+ struct list_head s_more_io; /* parked for more writeback */
struct hlist_head s_anon; /* anonymous dentries for (nfs) exporting */
struct list_head s_files;