Jianpeng Ma 975927b942 block: Add blk_rq_pos(rq) to sort rq when plushing ... My workload is a raid5 which had 16 disks. And used our filesystem to write using direct-io mode. I used the blktrace to find those message: 8,16 0 6647 2.453665504 2579 M W 7493152 + 8 [md0_raid5] 8,16 0 6648 2.453672411 2579 Q W 7493160 + 8 [md0_raid5] 8,16 0 6649 2.453672606 2579 M W 7493160 + 8 [md0_raid5] 8,16 0 6650 2.453679255 2579 Q W 7493168 + 8 [md0_raid5] 8,16 0 6651 2.453679441 2579 M W 7493168 + 8 [md0_raid5] 8,16 0 6652 2.453685948 2579 Q W 7493176 + 8 [md0_raid5] 8,16 0 6653 2.453686149 2579 M W 7493176 + 8 [md0_raid5] 8,16 0 6654 2.453693074 2579 Q W 7493184 + 8 [md0_raid5] 8,16 0 6655 2.453693254 2579 M W 7493184 + 8 [md0_raid5] 8,16 0 6656 2.453704290 2579 Q W 7493192 + 8 [md0_raid5] 8,16 0 6657 2.453704482 2579 M W 7493192 + 8 [md0_raid5] 8,16 0 6658 2.453715016 2579 Q W 7493200 + 8 [md0_raid5] 8,16 0 6659 2.453715247 2579 M W 7493200 + 8 [md0_raid5] 8,16 0 6660 2.453721730 2579 Q W 7493208 + 8 [md0_raid5] 8,16 0 6661 2.453721974 2579 M W 7493208 + 8 [md0_raid5] 8,16 0 6662 2.453728202 2579 Q W 7493216 + 8 [md0_raid5] 8,16 0 6663 2.453728436 2579 M W 7493216 + 8 [md0_raid5] 8,16 0 6664 2.453734782 2579 Q W 7493224 + 8 [md0_raid5] 8,16 0 6665 2.453735019 2579 M W 7493224 + 8 [md0_raid5] 8,16 0 6666 2.453741401 2579 Q W 7493232 + 8 [md0_raid5] 8,16 0 6667 2.453741632 2579 M W 7493232 + 8 [md0_raid5] 8,16 0 6668 2.453748148 2579 Q W 7493240 + 8 [md0_raid5] 8,16 0 6669 2.453748386 2579 M W 7493240 + 8 [md0_raid5] 8,16 0 6670 2.453851843 2579 I W 7493144 + 104 [md0_raid5] 8,16 0 0 2.453853661 0 m N cfq2579 insert_request 8,16 0 6671 2.453854064 2579 I W 7493120 + 24 [md0_raid5] 8,16 0 0 2.453854439 0 m N cfq2579 insert_request 8,16 0 6672 2.453854793 2579 U N [md0_raid5] 2 8,16 0 0 2.453855513 0 m N cfq2579 Not idling.st->count:1 8,16 0 0 2.453855927 0 m N cfq2579 dispatch_insert 8,16 0 0 2.453861771 0 m N cfq2579 dispatched a request 8,16 0 0 2.453862248 0 m N cfq2579 activate rq,drv=1 8,16 0 6673 2.453862332 2579 D W 7493120 + 24 [md0_raid5] 8,16 0 0 2.453865957 0 m N cfq2579 Not idling.st->count:1 8,16 0 0 2.453866269 0 m N cfq2579 dispatch_insert 8,16 0 0 2.453866707 0 m N cfq2579 dispatched a request 8,16 0 0 2.453867061 0 m N cfq2579 activate rq,drv=2 8,16 0 6674 2.453867145 2579 D W 7493144 + 104 [md0_raid5] 8,16 0 6675 2.454147608 0 C W 7493120 + 24 [0] 8,16 0 0 2.454149357 0 m N cfq2579 complete rqnoidle 0 8,16 0 6676 2.454791505 0 C W 7493144 + 104 [0] 8,16 0 0 2.454794803 0 m N cfq2579 complete rqnoidle 0 8,16 0 0 2.454795160 0 m N cfq schedule dispatch From above messages,we can find rq[W 7493144 + 104] and rq[W 7493120 + 24] do not merge. Because the bio order is: 8,16 0 6638 2.453619407 2579 Q W 7493144 + 8 [md0_raid5] 8,16 0 6639 2.453620460 2579 G W 7493144 + 8 [md0_raid5] 8,16 0 6640 2.453639311 2579 Q W 7493120 + 8 [md0_raid5] 8,16 0 6641 2.453639842 2579 G W 7493120 + 8 [md0_raid5] The bio(7493144) first and bio(7493120) later.So the subsequent bios will be divided into two parts. When flushing plug-list,because elv_attempt_insert_merge only support backmerge,not supporting frontmerge. So rq[7493120 + 24] can't merge with rq[7493144 + 104]. From my test,i found those situation can count 25% in our system. Using this patch, there is no this situation. Signed-off-by: Jianpeng Ma <majianpeng@gmail.com> CC:Shaohua Li <shli@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2012-10-25 21:58:17 +02:00
..
partitions	s390/partitions: make partition detection independent from DASD ioctls	2012-09-26 15:45:05 +02:00
blk-cgroup.c	blkcg: stop iteration early if root_rl is the only request list	2012-10-22 22:00:26 +02:00
blk-cgroup.h	blkcg: implement per-blkg request allocation	2012-06-26 18:42:49 -04:00
blk-core.c	block: Add blk_rq_pos(rq) to sort rq when plushing	2012-10-25 21:58:17 +02:00
blk-exec.c	[SCSI] block: Fix blk_execute_rq_nowait() dead queue handling	2012-07-20 08:58:39 +01:00
blk-flush.c
blk-integrity.c
blk-ioc.c	block: uninitialized ioc->nr_tasks triggers WARN_ON	2012-08-01 12:17:27 +02:00
blk-iopoll.c
blk-lib.c	block: Make blkdev_issue_zeroout use WRITE SAME	2012-09-20 14:31:49 +02:00
blk-map.c
blk-merge.c	block: Implement support for WRITE SAME	2012-09-20 14:31:45 +02:00
blk-settings.c	block: Implement support for WRITE SAME	2012-09-20 14:31:45 +02:00
blk-softirq.c
blk-sysfs.c	block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()	2012-09-21 15:32:57 +02:00
blk-tag.c	block/blk-tag.c: Remove useless kfree	2012-09-12 22:25:12 +02:00
blk-throttle.c	workqueue: use mod_delayed_work() instead of __cancel + queue	2012-08-21 13:18:24 -07:00
blk-timeout.c	block: Drop dead function blk_abort_queue()	2012-06-15 08:46:23 +02:00
blk.h	block: Clean up special command handling logic	2012-09-20 14:31:38 +02:00
bsg-lib.c	block: drop custom queue draining used by scsi_transport_{iscsi|fc}	2012-06-25 11:53:48 +02:00
bsg.c
cfq-iosched.c	block: blkcg_policy_cfq shouldn't be used if !CONFIG_CFQ_GROUP_IOSCHED	2012-06-04 10:02:29 +02:00
compat_ioctl.c
deadline-iosched.c
elevator.c	block: Clean up special command handling logic	2012-09-20 14:31:38 +02:00
genhd.c	Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq	2012-10-02 09:54:49 -07:00
ioctl.c	Merge branch 'for-3.7/core' of git://git.kernel.dk/linux-block	2012-10-11 09:04:23 +09:00
Kconfig	block: remove CONFIG_EXPERIMENTAL	2012-10-23 22:30:34 +02:00
Kconfig.iosched
Makefile
noop-iosched.c
partition-generic.c	block: add partition resize function to blkpg ioctl	2012-08-01 12:24:18 +02:00
scsi_ioctl.c	scsi: Silence unnecessary warnings about ioctl to partition	2012-06-15 12:52:46 +02:00