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* | blkio: Set must_dispatch only if we decided to not dispatch the requestVivek Goyal2009-12-031-3/+3
| | | | | | | | | | | | | | | | o must_dispatch flag should be set only if we decided not to run the queue and dispatch the request. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: no dispatch limit for single queueShaohua Li2009-12-031-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 2f5cb7381b737e24c8046fd4aeab571fb71315f5, each queue can send up to 4 * 4 requests if only one queue exists. I wonder why we have such limit. Device supports tag can send more requests. For example, AHCI can send 31 requests. Test (direct aio randread) shows the limits reduce about 4% disk thoughput. On the other hand, since we send one request one time, if other queue pop when current is sending more than cfq_quantum requests, current queue will stop send requests soon after one request, so sounds there is no big latency. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | block: Allow devices to indicate whether discarded blocks are zeroedMartin K. Petersen2009-12-034-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The discard ioctl is used by mkfs utilities to clear a block device prior to putting metadata down. However, not all devices return zeroed blocks after a discard. Some drives return stale data, potentially containing old superblocks. It is therefore important to know whether discarded blocks are properly zeroed. Both ATA and SCSI drives have configuration bits that indicate whether zeroes are returned after a discard operation. Implement a block level interface that allows this information to be bubbled up the stack and queried via a new block device ioctl. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Revert "cfq: Make use of service count to estimate the rb_key offset"Jens Axboe2009-11-301-6/+2
| | | | | | | | | | | | | | | | | | | | This reverts commit 3586e917f2c7df769d173c4ec99554cb40a911e5. Corrado Zoccolo <czoccolo@gmail.com> correctly points out, that we need consistency of rb_key offset across groups. This means we cannot properly use the per-service_tree service count. Revert this change. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: fix corner cases in idling logicCorrado Zoccolo2009-11-261-10/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Idling logic was disabled in some corner cases, leading to unfair share for noidle queues. * the idle timer was not armed if there were other requests in the driver. unfortunately, those requests could come from other workloads, or queues for which we don't enable idling. So we will check only pending requests from the active queue * rq_noidle check on no-idle queue could disable the end of tree idle if the last completed request was rq_noidle. Now, we will disable that idle only if all the queues served in the no-idle tree had rq_noidle requests. Reported-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: idling on deep seeky sync queuesCorrado Zoccolo2009-11-261-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Seeky sync queues with large depth can gain unfairly big share of disk time, at the expense of other seeky queues. This patch ensures that idling will be enabled for queues with I/O depth at least 4, and small think time. The decision to enable idling is sticky, until an idle window times out without seeing a new request. The reasoning behind the decision is that, if an application is using large I/O depth, it is already optimized to make full utilization of the hardware, and therefore we reserve a slice of exclusive use for it. Reported-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: fix no-idle preemption logicCorrado Zoccolo2009-11-261-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An incoming no-idle queue should preempt the active no-idle queue only if the active queue is idling due to service tree empty. Previous code was buggy in two ways: * it relied on service_tree field to be set on the active queue, while it is not set when the code is idling for a new request * it didn't check for the service tree empty condition, so could lead to LIFO behaviour if multiple queues with depth > 1 were preempting each other on an non-NCQ device. Reported-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: fix ncq detection codeCorrado Zoccolo2009-11-261-9/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CFQ's detection of queueing devices initially assumes a queuing device and detects if the queue depth reaches a certain threshold. However, it will reconsider this choice periodically. Unfortunately, if device is considered not queuing, CFQ will force a unit queue depth for some workloads, thus defeating the detection logic. This leads to poor performance on queuing hardware, since the idle window remains enabled. Given this premise, switching to hw_tag = 0 after we have proved at least once that the device is NCQ capable is not a good choice. The new detection code starts in an indeterminate state, in which CFQ behaves as if hw_tag = 1, and then, if for a long observation period we never saw large depth, we switch to hw_tag = 0, otherwise we stick to hw_tag = 1, without reconsidering it again. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: cleanup unreachable codeCorrado Zoccolo2009-11-261-13/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cfq_should_idle returns false for no-idle queues that are not the last, so the control flow will never reach the removed code in a state that satisfies the if condition. The unreachable code was added to emulate previous cfq behaviour for non-NCQ rotational devices. My tests show that even without it, the performances and fairness are comparable with previous cfq, thanks to the fact that all seeky queues are grouped together, and that we idle at the end of the tree. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | block: add helpers to run flush_dcache_page() against a bio and a request's ↵Ilya Loginov2009-11-261-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pages Mtdblock driver doesn't call flush_dcache_page for pages in request. So, this causes problems on architectures where the icache doesn't fill from the dcache or with dcache aliases. The patch fixes this. The ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE symbol was introduced to avoid pointless empty cache-thrashing loops on architectures for which flush_dcache_page() is a no-op. Every architecture was provided with this flush pages on architectires where ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE is equal 1 or do nothing otherwise. See "fix mtd_blkdevs problem with caches on some architectures" discussion on LKML for more information. Signed-off-by: Ilya Loginov <isloginov@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Peter Horton <phorton@bitbox.co.uk> Cc: "Ed L. Cashin" <ecashin@coraid.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq: Make use of service count to estimate the rb_key offsetGui Jianfeng2009-11-261-2/+6
| | | | | | | | | | | | | | | | | | | | | | For the moment, different workload cfq queues are put into different service trees. But CFQ still uses "busy_queues" to estimate rb_key offset when inserting a cfq queue into a service tree. I think this isn't appropriate, and it should make use of service tree count to do this estimation. This patch is for for-2.6.33 branch. Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | block: jiffies fixesRandy Dunlap2009-11-113-2/+5
| | | | | | | | | | | | | | | | | | Use HZ-independent calculation of milliseconds. Add jiffies.h where it was missing since functions or macros from it are used. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | block: Expose discard granularityMartin K. Petersen2009-11-103-10/+70
| | | | | | | | | | | | | | | | | | | | While SSDs track block usage on a per-sector basis, RAID arrays often have allocation blocks that are bigger. Allow the discard granularity and alignment to be set and teach the topology stacking logic how to handle them. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: fix next_rq computationCorrado Zoccolo2009-11-081-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | block/scsi_ioctl.c: quiet sparse noiseH Hartley Sweeten2009-11-041-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Quiet sparse noise about symbol's not being declared. Symbol blk_default_cmd_filter is only used locally and should be static. The function blk_scsi_ioctl_init() is a fs_initcall and should also be static. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: get rid of the coop_preempt flagJens Axboe2009-11-041-19/+2
| | | | | | | | | | | | | | We need to rework this logic post the cooperating cfq_queue merging, for now just get rid of it and Jeff Moyer will fix the fall out. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: fix merge errorJens Axboe2009-11-031-1/+0
| | | | | | | | | | | | | | We ended up with testing the same condition twice, pretty pointless. Remove that first if. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'for-linus' into for-2.6.33Jens Axboe2009-11-032-3/+21
|\| | | | | | | | | | | | | Conflicts: block/cfq-iosched.c Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: limit coop preemptionShaohua Li2009-11-031-2/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CFQ has an optimization for cooperated applications. if several io-context have close requests, they will get boost. But the optimization get abused. Considering thread a, b, which work on one file. a reads sectors s, s+2, s+4, ...; b reads sectors s+1, s+3, s +5, ... Both a and b are sequential read, so they can open idle window. a reads a sector s and goes to idle window and wakeup b. b reads sector s+1, since in current implementation, cfq_should_preempt() thinks a and b are cooperators, b will preempt a. b then reads sector s+1 and goes to idle window and wakeup a. for the same reason, a will preempt b and reads s+2. a and b will continue the circle. The circle will be very long, and a and b will occupy whole disk queue. Other applications will nearly have no chance to run. Fix this limiting coop preempt until a queue is scheduled normally again. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: fix bad return value cfq_should_preempt()Jens Axboe2009-11-031-1/+1
| | | | | | | | | | | | | | | | Commit a6151c3a5c8e1ff5a28450bc8d6a99a2a0add0a7 inadvertently reversed a preempt condition check, potentially causing a performance regression. Make the meta check correct again. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * block: silently error unsupported empty barriers tooMark McLoughlin2009-10-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With 2.6.32-rc5 in a KVM guest using dm and virtio_blk, we see the following errors: end_request: I/O error, dev vda, sector 0 end_request: I/O error, dev vda, sector 0 The errors go away if dm stops submitting empty barriers, by reverting: commit 52b1fd5a27c625c78373e024bf570af3c9d44a79 Author: Mikulas Patocka <mpatocka@redhat.com> dm: send empty barriers to targets in dm_flush We should silently error all barriers, even empty barriers, on devices like virtio_blk which don't support them. See also: https://bugzilla.redhat.com/514901 Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Mikulas Patocka <mpatocka@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'cfq-2.6.33' into for-2.6.33Jens Axboe2009-11-031-52/+321
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| * | cfq-iosched: fix style issue in cfq_get_avg_queues()Jens Axboe2009-10-281-2/+2
| | | | | | | | | | | | | | | | | | Line breaks and bad brace placement. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: fairness for sync no-idle queuesCorrado Zoccolo2009-10-281-32/+168
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently no-idle queues in cfq are not serviced fairly: even if they can only dispatch a small number of requests at a time, they have to compete with idling queues to be serviced, experiencing large latencies. We should notice, instead, that no-idle queues are the ones that would benefit most from having low latency, in fact they are any of: * processes with large think times (e.g. interactive ones like file managers) * seeky (e.g. programs faulting in their code at startup) * or marked as no-idle from upper levels, to improve latencies of those requests. This patch improves the fairness and latency for those queues, by: * separating sync idle, sync no-idle and async queues in separate service_trees, for each priority * service all no-idle queues together * and idling when the last no-idle queue has been serviced, to anticipate for more no-idle work * the timeslices allotted for idle and no-idle service_trees are computed proportionally to the number of processes in each set. Servicing all no-idle queues together should have a performance boost for NCQ-capable drives, without compromising fairness. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: enable idling for last queue on priority classCorrado Zoccolo2009-10-281-3/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cfq can disable idling for queues in various circumstances. When workloads of different priorities are competing, if the higher priority queue has idling disabled, lower priority queues may steal its disk share. For example, in a scenario with an RT process performing seeky reads vs a BE process performing sequential reads, on an NCQ enabled hardware, with low_latency unset, the RT process will dispatch only the few pending requests every full slice of service for the BE process. The patch solves this issue by always performing idle on the last queue at a given priority class > idle. If the same process, or one that can pre-empt it (so at the same priority or higher), submits a new request within the idle window, the lower priority queue won't dispatch, saving the disk bandwidth for higher priority ones. Note: this doesn't touch the non_rotational + NCQ case (no hardware to test if this is a benefit in that case). Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: reimplement priorities using different service treesCorrado Zoccolo2009-10-281-34/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | We use different service trees for different priority classes. This allows a simplification in the service tree insertion code, that no longer has to consider priority while walking the tree. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: preparation to handle multiple service treesCorrado Zoccolo2009-10-281-11/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We embed a pointer to the service tree in each queue, to handle multiple service trees easily. Service trees are enriched with a counter. cfq_add_rq_rb is invoked after putting the rq in the fifo, to ensure that all fields in rq are properly initialized. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: adapt slice to number of processes doing I/OCorrado Zoccolo2009-10-281-2/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the number of processes performing I/O concurrently increases, a fixed time slice per process will cause large latencies. This patch, if low_latency mode is enabled, will scale the time slice assigned to each process according to a 300ms target latency. In order to keep fairness among processes: * The number of active processes is computed using a special form of running average, that quickly follows sudden increases (to keep latency low), and decrease slowly (to have fairness in spite of rapid decreases of this value). To safeguard sequential bandwidth, we impose a minimum time slice (computed using 2*cfq_slice_idle as base, adjusted according to priority and async-ness). Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | | cfq-iosched: simplify prio-unboost codeCorrado Zoccolo2009-11-021-5/+3
|/ / | | | | | | | | | | | | Eliminate redundant checks. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: improve hw_tag detectionShaohua Li2009-10-271-0/+12
| | | | | | | | | | | | | | | | | | | | If active queue hasn't enough requests and idle window opens, cfq will not dispatch sufficient requests to hardware. In such situation, current code will zero hw_tag. But this is because cfq doesn't dispatch enough requests instead of hardware queue doesn't work. Don't zero hw_tag in such case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq: break apart merged cfqqs if they stop cooperatingJeff Moyer2009-10-261-3/+76
| | | | | | | | | | | | | | | | | | cfq_queues are merged if they are issuing requests within the mean seek distance of one another. This patch detects when the coopearting stops and breaks the queues back up. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq: change the meaning of the cfqq_coop flagJeff Moyer2009-10-261-14/+6
| | | | | | | | | | | | | | | | | | | | | | | | The flag used to indicate that a cfqq was allowed to jump ahead in the scheduling order due to submitting a request close to the queue that just executed. Since closely cooperating queues are now merged, the flag holds little meaning. Change it to indicate that multiple queues were merged. This will later be used to allow the breaking up of merged queues when they are no longer cooperating. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq: merge cooperating cfq_queuesJeff Moyer2009-10-261-2/+87
| | | | | | | | | | | | | | | | | | | | | | | | When cooperating cfq_queues are detected currently, they are allowed to skip ahead in the scheduling order. It is much more efficient to automatically share the cfq_queue data structure between cooperating processes. Performance of the read-test2 benchmark (which is written to emulate the dump(8) utility) went from 12MB/s to 90MB/s on my SATA disk. NFS servers with multiple nfsd threads also saw performance increases. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq: calculate the seek_mean per cfq_queue not per cfq_io_contextJeff Moyer2009-10-261-35/+33
| | | | | | | | | | | | | | | | | | | | async cfq_queue's are already shared between processes within the same priority, and forthcoming patches will change the mapping of cic to sync cfq_queue from 1:1 to 1:N. So, calculate the seekiness of a process based on the cfq_queue instead of the cfq_io_context. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'for-linus' into for-2.6.33Jens Axboe2009-10-137-136/+153
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| * blk-settings: fix function parameter kernel-doc notationRandy Dunlap2009-10-121-1/+1
| | | | | | | | | | | | | | Fix kernel-doc notation in blk-settings.c::blk_queue_max_discard_sectors(). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * elv_iosched_store(): fix strstrip() misuseKOSAKI Motohiro2009-10-091-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | elv_iosched_store() ignore the return value of strstrip(). It makes small inconsistent behavior. This patch fixes it. <before> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler bash: echo: write error: Invalid argument <after> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler noop [anticipatory] deadline cfq Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: avoid probable slice overrun when idlingCorrado Zoccolo2009-10-081-0/+9
| | | | | | | | | | | | | | | | | | | | | | If the average think time is larger than the remaining time slice for any given queue, don't allow it to idle. A succesful idle also means that we need to dispatch and complete a request, so if we don't even have time left for the idle process, we would overrun the slice in any case. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: apply bool value where we return 0/1Jens Axboe2009-10-071-37/+31
| | | | | | | | | | | | | | | | Saves 16 bytes of text, woohoo. But the more important point is that it makes the code more readable when returning bool for 0/1 cases. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: fix think time allowed for seekersCorrado Zoccolo2009-10-071-1/+4
| | | | | | | | | | | | | | | | | | CFQ enables idle only for processes that think less than the allowed idle time. Since idle time is lower for seeky queues, we should use the correct value in the comparison. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: fix the slice residual signJens Axboe2009-10-061-1/+7
| | | | | | | | | | | | | | | | | | | | We should subtract the slice residual from the rb tree key, since a negative residual count indicates that the cfqq overran its slice the last time. Hence we want to add the overrun time, to position it a bit further away in the service tree. Reported-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: abstract out the 'may this cfqq dispatch' logicJens Axboe2009-10-061-54/+67
| | | | | | | | | | | | | | Makes the whole thing easier to read, cfq_dispatch_requests() was a bit messy before. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * block: use proper BLK_RW_ASYNC in blk_queue_start_tag()Jens Axboe2009-10-061-1/+1
| | | | | | | | | | | | Makes it easier to read than the 0. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * block: Seperate read and write statistics of in_flight requests v2Nikanth Karthikesan2009-10-063-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit a9327cac440be4d8333bba975cbbf76045096275 added seperate read and write statistics of in_flight requests. And exported the number of read and write requests in progress seperately through sysfs. But Corrado Zoccolo <czoccolo@gmail.com> reported getting strange output from "iostat -kx 2". Global values for service time and utilization were garbage. For interval values, utilization was always 100%, and service time is higher than normal. So this was reverted by commit 0f78ab9899e9d6acb09d5465def618704255963b The problem was in part_round_stats_single(), I missed the following: if (now == part->stamp) return; - if (part->in_flight) { + if (part_in_flight(part)) { __part_stat_add(cpu, part, time_in_queue, part_in_flight(part) * (now - part->stamp)); __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); With this chunk included, the reported regression gets fixed. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> -- Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * block: get rid of kblock_schedule_delayed_work()Jens Axboe2009-10-052-21/+11
| | | | | | | | | | | | | | | | | | | | It was briefly introduced to allow CFQ to to delayed scheduling, but we ended up removing that feature again. So lets kill the function and export, and just switch CFQ back to the normal work schedule since it is now passing in a '0' delay from all call sites. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: fix possible problem with jiffies wraparoundCorrado Zoccolo2009-10-051-3/+6
| | | | | | | | | | | | | | | | | | | | | | The RR service tree is indexed by a key that is relative to current jiffies. This can cause problems on jiffies wraparound. The patch fixes it using time_before comparison, and changing the add_front path to use a relative number, too. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: fix issue with rq-rq merging and fifo list orderingJens Axboe2009-10-051-8/+7
| | | | | | | | | | | | | | | | | | | | cfq uses rq->start_time as the fifo indicator, but that field may get modified prior to cfq doing it's fifo list adjustment when a request gets merged with another request. This can cause the fifo list to become unordered. Reported-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'master' into for-2.6.33Jens Axboe2009-10-056-26/+87
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| * Revert "Seperate read and write statistics of in_flight requests"Jens Axboe2009-10-043-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit a9327cac440be4d8333bba975cbbf76045096275. Corrado Zoccolo <czoccolo@gmail.com> reports: "with 2.6.32-rc1 I started getting the following strange output from "iostat -kx 2": Linux 2.6.31bisect (et2) 04/10/2009 _i686_ (2 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 10,70 0,00 3,16 15,75 0,00 70,38 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 18,22 0,00 0,67 0,01 14,77 0,02 43,94 0,01 10,53 39043915,03 2629219,87 sdb 60,89 9,68 50,79 3,04 1724,43 50,52 65,95 0,70 13,06 488437,47 2629219,87 avg-cpu: %user %nice %system %iowait %steal %idle 2,72 0,00 0,74 0,00 0,00 96,53 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 avg-cpu: %user %nice %system %iowait %steal %idle 6,68 0,00 0,99 0,00 0,00 92,33 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 avg-cpu: %user %nice %system %iowait %steal %idle 4,40 0,00 0,73 1,47 0,00 93,40 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 4,00 0,00 3,00 0,00 28,00 18,67 0,06 19,50 333,33 100,00 Global values for service time and utilization are garbage. For interval values, utilization is always 100%, and service time is higher than normal. I bisected it down to: [a9327cac440be4d8333bba975cbbf76045096275] Seperate read and write statistics of in_flight requests and verified that reverting just that commit indeed solves the issue on 2.6.32-rc1." So until this is debugged, revert the bad commit. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * cfq-iosched: don't delay async queue if it hasn't dispatched at allJens Axboe2009-10-041-9/+2
| | | | | | | | | | | | | | | | | | We cannot delay for the first dispatch of the async queue if it hasn't dispatched at all, since that could present a local user DoS attack vector using an app that just did slow timed sync reads while filling memory. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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