Corrado Zoccolo cf7c25cf91 cfq-iosched: fix next_rq computation ... Cfq has a bug in computation of next_rq, that affects transition between multiple sequential request streams in a single queue (e.g.: two sequential buffered writers of the same priority), causing the alternation between the two streams for a transient period. 8,0 1 18737 0.260400660 5312 D W 141653311 + 256 8,0 1 20839 0.273239461 5400 D W 141653567 + 256 8,0 1 20841 0.276343885 5394 D W 142803919 + 256 8,0 1 20843 0.279490878 5394 D W 141668927 + 256 8,0 1 20845 0.292459993 5400 D W 142804175 + 256 8,0 1 20847 0.295537247 5400 D W 141668671 + 256 8,0 1 20849 0.298656337 5400 D W 142804431 + 256 8,0 1 20851 0.311481148 5394 D W 141668415 + 256 8,0 1 20853 0.314421305 5394 D W 142804687 + 256 8,0 1 20855 0.318960112 5400 D W 142804943 + 256 The fix makes sure that the next_rq is computed from the last dispatched request, and not affected by merging. 8,0 1 37776 4.305161306 0 D W 141738087 + 256 8,0 1 37778 4.308298091 0 D W 141738343 + 256 8,0 1 37780 4.312885190 0 D W 141738599 + 256 8,0 1 37782 4.315933291 0 D W 141738855 + 256 8,0 1 37784 4.319064459 0 D W 141739111 + 256 8,0 1 37786 4.331918431 5672 D W 142803007 + 256 8,0 1 37788 4.334930332 5672 D W 142803263 + 256 8,0 1 37790 4.337902723 5672 D W 142803519 + 256 8,0 1 37792 4.342359774 5672 D W 142803775 + 256 8,0 1 37794 4.345318286 0 D W 142804031 + 256 Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>		2009-11-08 17:16:46 +01:00
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Kconfig	Make SCSI SG v4 driver enabled by default and remove EXPERIMENTAL dependency, since udev depends on BSG	2009-08-04 22:10:17 +02:00
Kconfig.iosched	block: CFQ is more than a desktop scheduler	2009-10-03 09:40:47 +02:00
Makefile	block: remove the anticipatory IO scheduler	2009-10-03 09:37:51 +02:00
blk-barrier.c	block: allow large discard requests	2009-10-01 21:19:34 +02:00
blk-core.c	block: silently error unsupported empty barriers too	2009-10-24 14:14:31 +02:00
blk-exec.c	block: don't set REQ_NOMERGE unnecessarily	2009-04-28 07:37:33 +02:00
blk-integrity.c	block: fix improper kobject release in blk_integrity_unregister	2009-07-28 09:11:14 +02:00
blk-ioc.c	block: prevent possible io_context->refcount overflow	2009-06-10 23:07:15 +02:00
blk-iopoll.c	block: use interrupts disabled version of raise_softirq_irqoff()	2009-09-11 14:33:32 +02:00
blk-map.c	block: Use accessor functions for queue limits	2009-05-22 23:22:54 +02:00
blk-merge.c	block: Seperate read and write statistics of in_flight requests v2	2009-10-06 20:16:55 +02:00
blk-settings.c	blk-settings: fix function parameter kernel-doc notation	2009-10-12 08:20:47 +02:00
blk-softirq.c	generic-ipi: remove CSD_FLAG_WAIT	2009-02-25 14:13:44 +01:00
blk-sysfs.c	Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs	2009-10-01 21:15:46 +02:00
blk-tag.c	block: use proper BLK_RW_ASYNC in blk_queue_start_tag()	2009-10-06 20:19:02 +02:00
blk-timeout.c	block: clean up misc stuff after block layer timeout conversion	2009-04-28 07:37:34 +02:00
blk.h	block: implement mixed merge of different failfast requests	2009-09-11 14:33:30 +02:00
bsg.c	Driver-Core: extend devnode callbacks to provide permissions	2009-09-19 12:50:38 -07:00
cfq-iosched.c	cfq-iosched: fix next_rq computation	2009-11-08 17:16:46 +01:00
compat_ioctl.c	block: Topology ioctls	2009-10-03 20:52:01 +02:00
deadline-iosched.c	block: convert to pos and nr_sectors accessors	2009-05-11 09:50:54 +02:00
elevator.c	Merge branch 'for-linus' into for-2.6.33	2009-10-13 12:29:45 +02:00
genhd.c	block: Seperate read and write statistics of in_flight requests v2	2009-10-06 20:16:55 +02:00
ioctl.c	block: Topology ioctls	2009-10-03 20:52:01 +02:00
noop-iosched.c	block: get rid of elevator_t typedef	2008-12-29 08:29:50 +01:00
scsi_ioctl.c	block/scsi_ioctl.c: quiet sparse noise	2009-11-04 09:10:33 +01:00