| Message ID | 1307418559-3329-1-git-send-email-tm@tao.ma |
|---|---|
| State | Accepted, archived |
| Headers | show |
Hi Ted, Any comments for this patch? Jan is OK with it and wait for the jbd2 part to be committed first. Thanks. Tao On 06/07/2011 11:49 AM, Tao Ma wrote: > From: Tao Ma <boyu.mt@taobao.com> > > 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. > > Cc: Jan Kara <jack@suse.cz> > Cc: "Theodore Ts'o" <tytso@mit.edu> > Reported-by: Robin Dong <sanbai@taobao.com> > Signed-off-by: Tao Ma <boyu.mt@taobao.com> > --- > 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 6a79fd0..b372ea2 100644 > --- a/fs/jbd2/checkpoint.c > +++ b/fs/jbd2/checkpoint.c > @@ -254,9 +254,12 @@ 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]; -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jun 07, 2011 at 11:49:19AM +0800, Tao Ma wrote: > From: Tao Ma <boyu.mt@taobao.com> > > 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: Thanks, added to the ext4 patch tree. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 6a79fd0..b372ea2 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -254,9 +254,12 @@ 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];