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| author | Tao Ma <boyu.mt@taobao.com> | 2011-06-27 20:36:29 +0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-06-27 20:36:29 +0400 |
| commit | d3ad8434aa83ef7c88bc91edcfe012cdcbab9f3e (patch) | |
| tree | f94f65f0191334b8d7d071ff3f9342621d82f9cc | |
| parent | 890879cfa08f5ceaa09810611f46e890f7d57ff6 (diff) | |
| download | linux-d3ad8434aa83ef7c88bc91edcfe012cdcbab9f3e.tar.xz | |
jbd2: use WRITE_SYNC in journal checkpoint
In journal checkpoint, we write the buffer and wait for its finish.
But in cfq, the async queue has a very low priority, and in our test,
if there are too many sync queues and every queue is filled up with
requests, the write request will be delayed for quite a long time and
all the tasks which are waiting for journal space will end with errors like:
INFO: task attr_set:3816 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
attr_set D ffff880028393480 0 3816 1 0x00000000
ffff8802073fbae8 0000000000000086 ffff8802140847c8 ffff8800283934e8
ffff8802073fb9d8 ffffffff8103e456 ffff8802140847b8 ffff8801ed728080
ffff8801db4bc080 ffff8801ed728450 ffff880028393480 0000000000000002
Call Trace:
[<ffffffff8103e456>] ? __dequeue_entity+0x33/0x38
[<ffffffff8103caad>] ? need_resched+0x23/0x2d
[<ffffffff814006a6>] ? thread_return+0xa2/0xbc
[<ffffffffa01f6224>] ? jbd2_journal_dirty_metadata+0x116/0x126 [jbd2]
[<ffffffffa01f6224>] ? jbd2_journal_dirty_metadata+0x116/0x126 [jbd2]
[<ffffffff81400d31>] __mutex_lock_common+0x14e/0x1a9
[<ffffffffa021dbfb>] ? brelse+0x13/0x15 [ext4]
[<ffffffff81400ddb>] __mutex_lock_slowpath+0x19/0x1b
[<ffffffff81400b2d>] mutex_lock+0x1b/0x32
[<ffffffffa01f927b>] __jbd2_journal_insert_checkpoint+0xe3/0x20c [jbd2]
[<ffffffffa01f547b>] start_this_handle+0x438/0x527 [jbd2]
[<ffffffff8106f491>] ? autoremove_wake_function+0x0/0x3e
[<ffffffffa01f560b>] jbd2_journal_start+0xa1/0xcc [jbd2]
[<ffffffffa02353be>] ext4_journal_start_sb+0x57/0x81 [ext4]
[<ffffffffa024a314>] ext4_xattr_set+0x6c/0xe3 [ext4]
[<ffffffffa024aaff>] ext4_xattr_user_set+0x42/0x4b [ext4]
[<ffffffff81145adb>] generic_setxattr+0x6b/0x76
[<ffffffff81146ac0>] __vfs_setxattr_noperm+0x47/0xc0
[<ffffffff81146bb8>] vfs_setxattr+0x7f/0x9a
[<ffffffff81146c88>] setxattr+0xb5/0xe8
[<ffffffff81137467>] ? do_filp_open+0x571/0xa6e
[<ffffffff81146d26>] sys_fsetxattr+0x6b/0x91
[<ffffffff81002d32>] system_call_fastpath+0x16/0x1b
So this patch tries to use WRITE_SYNC in __flush_batch so that the request will
be moved into sync queue and handled by cfq timely. We also use the new plug,
sot that all the WRITE_SYNC requests can be given as a whole when we unplug it.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Reported-by: Robin Dong <sanbai@taobao.com>
| -rw-r--r-- | fs/jbd2/checkpoint.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 2c62c5aae82f..16a698bd906d 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -257,9 +257,12 @@ static void __flush_batch(journal_t *journal, int *batch_count) { int i; + struct blk_plug plug; + blk_start_plug(&plug); for (i = 0; i < *batch_count; i++) - write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE); + write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE_SYNC); + blk_finish_plug(&plug); for (i = 0; i < *batch_count; i++) { struct buffer_head *bh = journal->j_chkpt_bhs[i]; |