- 15 3月, 2010 1 次提交
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由 Martin K. Petersen 提交于
lcm() was defined to take integer-sized arguments. The supplied arguments are multiplied, however, causing us to overflow given sufficiently large input. That in turn led to incorrect optimal I/O size reporting in some cases (RAID over RAID). Switch lcm() over to unsigned long similar to gcd() and move the function from blk-settings.c to lib. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 01 3月, 2010 6 次提交
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由 Richard Kennedy 提交于
As the comment says the initial value of last_waited is never used, so there is no need to initialise it with the current jiffies. Jiffies is hot enough without accessing it for no reason. Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Richard Kennedy 提交于
Reorder cfq_rb_root to remove 8 bytes of padding on 64 bit builds. Consequently removing 56 bytes from cfq_group and 64 bytes from cfq_data. Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Shaohua Li 提交于
Currently a queue can only dispatch up to 4 requests if there are other queues. This isn't optimal, device can handle more requests, for example, AHCI can handle 31 requests. I can understand the limit is for fairness, but we could do a tweak: if the queue still has a lot of slice left, sounds we could ignore the limit. Test shows this boost my workload (two thread randread of a SSD) from 78m/s to 100m/s. Thanks for suggestions from Corrado and Vivek for the patch. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
Counters for requests "in flight" and "in driver" are used asymmetrically in cfq_may_dispatch, and have slightly different meaning. We split the rq_in_flight counter (was sync_flight) to count both sync and async requests, in order to use this one, which is more accurate in some corner cases. The rq_in_driver counter is coalesced, since individual sync/async counts are not used any more. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
CFQ currently applies the same logic of detecting seeky queues and grouping them together for rotational disks as well as SSDs. For SSDs, the time to complete a request doesn't depend on the request location, but only on the size. This patch therefore changes the criterion to group queues by request size in case of SSDs, in order to achieve better fairness. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
Current seeky detection is based on average seek lenght. This is suboptimal, since the average will not distinguish between: * a process doing medium sized seeks * a process doing some sequential requests interleaved with larger seeks and even a medium seek can take lot of time, if the requested sector happens to be behind the disk head in the rotation (50% probability). Therefore, we change the seeky queue detection to work as follows: * each request can be classified as sequential if it is very close to the current head position, i.e. it is likely in the disk cache (disks usually read more data than requested, and put it in cache for subsequent reads). Otherwise, the request is classified as seeky. * an history window of the last 32 requests is kept, storing the classification result. * A queue is marked as seeky if more than 1/8 of the last 32 requests were seeky. This patch fixes a regression reported by Yanmin, on mmap 64k random reads. Reported-by: NYanmin Zhang <yanmin_zhang@linux.intel.com> Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 26 2月, 2010 6 次提交
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由 Martin K. Petersen 提交于
Except for SCSI no device drivers distinguish between physical and hardware segment limits. Consolidate the two into a single segment limit. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
The block layer calling convention is blk_queue_<limit name>. blk_queue_max_sectors predates this practice, leading to some confusion. Rename the function to appropriately reflect that its intended use is to set max_hw_sectors. Also introduce a temporary wrapper for backwards compability. This can be removed after the merge window is closed. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
Add a BLK_ prefix to block layer constants. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
blk_queue_max_hw_sectors is no longer called by any subsystem and can be removed. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
Clarify blk_queue_max_sectors and update documentation. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Gui Jianfeng 提交于
There's no need to take css reference here, for the caller has already called rcu_read_lock() to prevent cgroup from being removed. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Reviewed-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 23 2月, 2010 2 次提交
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由 Akinobu Mita 提交于
Now that the bio list management stuff is generic, convert generic_make_request to use bio lists instead of its own private bio list implementation. Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
This reverts commit fb1e7538. "Benjamin S." <sbenni@gmx.de> reports that the patch in question causes a big drop in sequential throughput for him, dropping from 200MB/sec down to only 70MB/sec. Needs to be investigated more fully, for now lets just revert the offending commit. Conflicts: include/linux/blkdev.h Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 22 2月, 2010 1 次提交
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由 Richard Kennedy 提交于
This removes 8 bytes of padding from struct cfq_queue on 64 bit builds, shrinking it's size to 256 bytes, so fitting into 1 fewer cachelines and allowing 1 more object/slab in it's kmem_cache. Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk> Reviewed-by: NJeff Moyer <jmoyer@redhat.com> ---- patch against 2.6.33-rc8 tested on x86_64 AMDX2 Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 05 2月, 2010 1 次提交
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由 Shaohua Li 提交于
Currently we split seeky coop queues after 1s, which is too big. Below patch marks seeky coop queue split_coop flag after one slice. After that, if new requests come in, the queues will be splitted. Patch is suggested by Corrado. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Reviewed-by: NCorrado Zoccolo <czoccolo@gmail.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 03 2月, 2010 1 次提交
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由 Vivek Goyal 提交于
Few weeks back, Shaohua Li had posted similar patch. I am reposting it with more test results. This patch does two things. - Do not idle on async queues. - It also changes the write queue depth CFQ drives (cfq_may_dispatch()). Currently, we seem to driving queue depth of 1 always for WRITES. This is true even if there is only one write queue in the system and all the logic of infinite queue depth in case of single busy queue as well as slowly increasing queue depth based on last delayed sync request does not seem to be kicking in at all. This patch will allow deeper WRITE queue depths (subjected to the other WRITE queue depth contstraints like cfq_quantum and last delayed sync request). Shaohua Li had reported getting more out of his SSD. For me, I have got one Lun exported from an HP EVA and when pure buffered writes are on, I can get more out of the system. Following are test results of pure buffered writes (with end_fsync=1) with vanilla and patched kernel. These results are average of 3 sets of run with increasing number of threads. AVERAGE[bufwfs][vanilla] ------- job Set NR ReadBW(KB/s) MaxClat(us) WriteBW(KB/s) MaxClat(us) --- --- -- ------------ ----------- ------------- ----------- bufwfs 3 1 0 0 95349 474141 bufwfs 3 2 0 0 100282 806926 bufwfs 3 4 0 0 109989 2.7301e+06 bufwfs 3 8 0 0 116642 3762231 bufwfs 3 16 0 0 118230 6902970 AVERAGE[bufwfs] [patched kernel] ------- bufwfs 3 1 0 0 270722 404352 bufwfs 3 2 0 0 206770 1.06552e+06 bufwfs 3 4 0 0 195277 1.62283e+06 bufwfs 3 8 0 0 260960 2.62979e+06 bufwfs 3 16 0 0 299260 1.70731e+06 I also ran buffered writes along with some sequential reads and some buffered reads going on in the system on a SATA disk because the potential risk could be that we should not be driving queue depth higher in presence of sync IO going to keep the max clat low. With some random and sequential reads going on in the system on one SATA disk I did not see any significant increase in max clat. So it looks like other WRITE queue depth control logic is doing its job. Here are the results. AVERAGE[brr, bsr, bufw together] [vanilla] ------- job Set NR ReadBW(KB/s) MaxClat(us) WriteBW(KB/s) MaxClat(us) --- --- -- ------------ ----------- ------------- ----------- brr 3 1 850 546345 0 0 bsr 3 1 14650 729543 0 0 bufw 3 1 0 0 23908 8274517 brr 3 2 981.333 579395 0 0 bsr 3 2 14149.7 1175689 0 0 bufw 3 2 0 0 21921 1.28108e+07 brr 3 4 898.333 1.75527e+06 0 0 bsr 3 4 12230.7 1.40072e+06 0 0 bufw 3 4 0 0 19722.3 2.4901e+07 brr 3 8 900 3160594 0 0 bsr 3 8 9282.33 1.91314e+06 0 0 bufw 3 8 0 0 18789.3 23890622 AVERAGE[brr, bsr, bufw mixed] [patched kernel] ------- job Set NR ReadBW(KB/s) MaxClat(us) WriteBW(KB/s) MaxClat(us) --- --- -- ------------ ----------- ------------- ----------- brr 3 1 837 417973 0 0 bsr 3 1 14357.7 591275 0 0 bufw 3 1 0 0 24869.7 8910662 brr 3 2 1038.33 543434 0 0 bsr 3 2 13351.3 1205858 0 0 bufw 3 2 0 0 18626.3 13280370 brr 3 4 913 1.86861e+06 0 0 bsr 3 4 12652.3 1430974 0 0 bufw 3 4 0 0 15343.3 2.81305e+07 brr 3 8 890 2.92695e+06 0 0 bsr 3 8 9635.33 1.90244e+06 0 0 bufw 3 8 0 0 17200.3 24424392 So looks like it might make sense to include this patch. Thanks Vivek Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 01 2月, 2010 1 次提交
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由 Gui Jianfeng 提交于
I triggered a lockdep warning as following. ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.33-rc2 #1 ------------------------------------------------------- test_io_control/7357 is trying to acquire lock: (blkio_list_lock){+.+...}, at: [<c053a990>] blkiocg_weight_write+0x82/0x9e but task is already holding lock: (&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&(&blkcg->lock)->rlock){......}: [<c04583b7>] validate_chain+0x8bc/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a [<c053a4e1>] blkiocg_add_blkio_group+0x1a/0x6d [<c053cac7>] cfq_get_queue+0x225/0x3de [<c053eec2>] cfq_set_request+0x217/0x42d [<c052c8a6>] elv_set_request+0x17/0x26 [<c0532a0f>] get_request+0x203/0x2c5 [<c0532ae9>] get_request_wait+0x18/0x10e [<c0533470>] __make_request+0x2ba/0x375 [<c0531985>] generic_make_request+0x28d/0x30f [<c0532da7>] submit_bio+0x8a/0x8f [<c04d827a>] submit_bh+0xf0/0x10f [<c04d91d2>] ll_rw_block+0xc0/0xf9 [<f86e9705>] ext3_find_entry+0x319/0x544 [ext3] [<f86eae58>] ext3_lookup+0x2c/0xb9 [ext3] [<c04c3e1b>] do_lookup+0xd3/0x172 [<c04c56c8>] link_path_walk+0x5fb/0x95c [<c04c5a65>] path_walk+0x3c/0x81 [<c04c5b63>] do_path_lookup+0x21/0x8a [<c04c66cc>] do_filp_open+0xf0/0x978 [<c04c0c7e>] open_exec+0x1b/0xb7 [<c04c1436>] do_execve+0xbb/0x266 [<c04081a9>] sys_execve+0x24/0x4a [<c04028a2>] ptregs_execve+0x12/0x18 -> #1 (&(&q->__queue_lock)->rlock){..-.-.}: [<c04583b7>] validate_chain+0x8bc/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a [<c053dd2a>] cfq_unlink_blkio_group+0x17/0x41 [<c053a6eb>] blkiocg_destroy+0x72/0xc7 [<c0467df0>] cgroup_diput+0x4a/0xb2 [<c04ca473>] dentry_iput+0x93/0xb7 [<c04ca4b3>] d_kill+0x1c/0x36 [<c04cb5c5>] dput+0xf5/0xfe [<c04c6084>] do_rmdir+0x95/0xbe [<c04c60ec>] sys_rmdir+0x10/0x12 [<c04027cc>] sysenter_do_call+0x12/0x32 -> #0 (blkio_list_lock){+.+...}: [<c0458117>] validate_chain+0x61c/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c06929fd>] _raw_spin_lock+0x1e/0x4e [<c053a990>] blkiocg_weight_write+0x82/0x9e [<c0467f1e>] cgroup_file_write+0xc6/0x1c0 [<c04bd2f3>] vfs_write+0x8c/0x116 [<c04bd7c6>] sys_write+0x3b/0x60 [<c04027cc>] sysenter_do_call+0x12/0x32 other info that might help us debug this: 1 lock held by test_io_control/7357: #0: (&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e stack backtrace: Pid: 7357, comm: test_io_control Not tainted 2.6.33-rc2 #1 Call Trace: [<c045754f>] print_circular_bug+0x91/0x9d [<c0458117>] validate_chain+0x61c/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c053a990>] ? blkiocg_weight_write+0x82/0x9e [<c06929fd>] _raw_spin_lock+0x1e/0x4e [<c053a990>] ? blkiocg_weight_write+0x82/0x9e [<c053a990>] blkiocg_weight_write+0x82/0x9e [<c0467f1e>] cgroup_file_write+0xc6/0x1c0 [<c0454df5>] ? trace_hardirqs_off+0xb/0xd [<c044d93a>] ? cpu_clock+0x2e/0x44 [<c050e6ec>] ? security_file_permission+0xf/0x11 [<c04bcdda>] ? rw_verify_area+0x8a/0xad [<c0467e58>] ? cgroup_file_write+0x0/0x1c0 [<c04bd2f3>] vfs_write+0x8c/0x116 [<c04bd7c6>] sys_write+0x3b/0x60 [<c04027cc>] sysenter_do_call+0x12/0x32 To prevent deadlock, we should take locks as following sequence: blkio_list_lock -> queue_lock -> blkcg_lock. The following patch should fix this bug. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 29 1月, 2010 1 次提交
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由 Alan D. Brunelle 提交于
Updated 'nomerges' tunable to accept a value of '2' - indicating that _no_ merges at all are to be attempted (not even the simple one-hit cache). The following table illustrates the additional benefit - 5 minute runs of a random I/O load were applied to a dozen devices on a 16-way x86_64 system. nomerges Throughput %System Improvement (tput / %sys) -------- ------------ ----------- ------------------------- 0 12.45 MB/sec 0.669365609 1 12.50 MB/sec 0.641519199 0.40% / 2.71% 2 12.52 MB/sec 0.639849750 0.56% / 2.96% Signed-off-by: NAlan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 11 1月, 2010 6 次提交
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由 Divyesh Shah 提交于
In cfq_should_preempt(), we currently allow some cases where a non-RT request can preempt an ongoing RT cfqq timeslice. This should not happen. Examples include: o A sync_noidle wl type non-RT request pre-empting a sync_noidle wl type cfqq on which we are idling. o Once we have per-cgroup async queues, a non-RT sync request pre-empting a RT async cfqq. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
All callers of the stacking functions use 512-byte sector units rather than byte offsets. Simplify the code so the stacking functions take sectors when specifying data offsets. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Kirill Afonshin 提交于
It isn't used anymore, since AS was deleted. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
DM does not want to know about partition offsets. Add a partition-aware wrapper that DM can use when stacking block devices. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Acked-by: NMike Snitzer <snitzer@redhat.com> Reviewed-by: NAlasdair G Kergon <agk@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
Discard alignment reporting for partitions was incorrect. Update to match the algorithm used elsewhere. The alignment can be negative (misaligned). Fix format string accordingly. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
The top device misalignment flag would not be set if the added bottom device was already misaligned as opposed to causing a stacking failure. Also massage the reporting so that an error is only returned if adding the bottom device caused the misalignment. I.e. don't return an error if the top is already flagged as misaligned. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 29 12月, 2009 2 次提交
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由 OGAWA Hirofumi 提交于
Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Martin K. Petersen 提交于
queue_sector_alignment_offset returned the wrong value which caused partitions to report an incorrect alignment_offset. Since offset alignment calculation is needed several places it has been split into a separate helper function. The topology stacking function has been updated accordingly. Furthermore, comments have been added to clarify how the stacking function works. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Tested-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 28 12月, 2009 1 次提交
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由 Shaohua Li 提交于
seek_mean could be very big sometimes, using it as close criteria is meaningless as this doen't improve any performance. So if it's big, let's fallback to default value. Reviewed-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Shaohua Li<shaohua.li@intel.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 21 12月, 2009 1 次提交
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由 Martin K. Petersen 提交于
The stacking code incorrectly scaled up the data offset in some cases causing misaligned devices to report alignment. Rewrite the stacking algorithm to remedy this and apply the same alignment principles to the discard handling. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 18 12月, 2009 3 次提交
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由 Vivek Goyal 提交于
o CFQ now internally divides cfq queues in therr workload categories. sync-idle, sync-noidle and async. Which workload to run depends primarily on rb_key offset across three service trees. Which is a combination of mulitiple things including what time queue got queued on the service tree. There is one exception though. That is if we switched the prio class, say we served some RT tasks and again started serving BE class, then with-in BE class we always started with sync-noidle workload irrespective of rb_key offset in service trees. This can provide better latencies for sync-noidle workload in the presence of RT tasks. o This patch gets rid of that exception and which workload to run with-in class always depends on lowest rb_key across service trees. The reason being that now we have multiple BE class groups and if we always switch to sync-noidle workload with-in group, we can potentially starve a sync-idle workload with-in group. Same is true for async workload which will be in root group. Also the workload-switching with-in group will become very unpredictable as it now depends whether some RT workload was running in the system or not. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Acked-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Vivek Goyal 提交于
o Currently code does not seem to be using cfqd->nr_groups. Get rid of it. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Vivek Goyal 提交于
o allow_merge() already checks if submitting task is pointing to same cfqq as rq has been queued in. If everything is fine, we should not be having a task in one cgroup and having a pointer to cfqq in other cgroup. Well I guess in some situations it can happen and that is, when a random IO queue has been moved into root cgroup for group_isolation=0. In this case, tasks's cgroup/group is different from where actually cfqq is, but this is intentional and in this case merging should be allowed. The second situation is where due to close cooperator patches, multiple processes can be sharing a cfqq. If everything implemented right, we should not end up in a situation where tasks from different processes in different groups are sharing the same cfqq as we allow merging of cooperating queues only if they are in same group. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 16 12月, 2009 1 次提交
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由 Jens Axboe 提交于
Commit 86b37281 adds a check for misaligned stacking offsets, but it's buggy since the defaults are 0. Hence all dm devices that pass in a non-zero starting offset will be marked as misaligned amd dm will complain. A real fix is coming, in the mean time disable the discard granularity check so that users don't worry about dm reporting about misaligned devices. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 15 12月, 2009 1 次提交
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由 Gui Jianfeng 提交于
When a group is resumed, if it doesn't have workload slice left, we should set workload_expires as expired. Otherwise, we might start from where we left in previous group by error. Thanks the idea from Corrado. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 11 12月, 2009 1 次提交
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由 Vivek Goyal 提交于
I think my previous patch introduced a bug which can lead to CFQ hitting BUG_ON(). The offending commit in for-2.6.33 branch is. commit 7667aa06 Author: Vivek Goyal <vgoyal@redhat.com> Date: Tue Dec 8 17:52:58 2009 -0500 cfq-iosched: Take care of corner cases of group losing share due to deletion While doing some stress testing on my box, I enountered following. login: [ 3165.148841] BUG: scheduling while atomic: swapper/0/0x10000100 [ 3165.149821] Modules linked in: cfq_iosched dm_multipath qla2xxx igb scsi_transport_fc dm_snapshot [last unloaded: scsi_wait_scan] [ 3165.149821] Pid: 0, comm: swapper Not tainted 2.6.32-block-for-33-merged-new #3 [ 3165.149821] Call Trace: [ 3165.149821] <IRQ> [<ffffffff8103fab8>] __schedule_bug+0x5c/0x60 [ 3165.149821] [<ffffffff8103afd7>] ? __wake_up+0x44/0x4d [ 3165.149821] [<ffffffff8153a979>] schedule+0xe3/0x7bc [ 3165.149821] [<ffffffff8103a796>] ? cpumask_next+0x1d/0x1f [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff810422d8>] __cond_resched+0x2a/0x35 [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff8153b1ee>] _cond_resched+0x2c/0x37 [ 3165.149821] [<ffffffff8100e2db>] is_valid_bugaddr+0x16/0x2f [ 3165.149821] [<ffffffff811e4161>] report_bug+0x18/0xac [ 3165.149821] [<ffffffff8100f1fc>] die+0x39/0x63 [ 3165.149821] [<ffffffff8153cde1>] do_trap+0x11a/0x129 [ 3165.149821] [<ffffffff8100d470>] do_invalid_op+0x96/0x9f [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff81034b4d>] ? enqueue_task+0x5c/0x67 [ 3165.149821] [<ffffffff8103ae83>] ? task_rq_unlock+0x11/0x13 [ 3165.149821] [<ffffffff81041aae>] ? try_to_wake_up+0x292/0x2a4 [ 3165.149821] [<ffffffff8100c935>] invalid_op+0x15/0x20 [ 3165.149821] [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e [cfq_iosched] [ 3165.149821] [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f [ 3165.149821] [<ffffffff811d8c2a>] blk_peek_request+0x191/0x1a7 [ 3165.149821] [<ffffffff811e5b8d>] ? kobject_get+0x1a/0x21 [ 3165.149821] [<ffffffff812c8d4c>] scsi_request_fn+0x82/0x3df [ 3165.149821] [<ffffffff8110b2de>] ? bio_fs_destructor+0x15/0x17 [ 3165.149821] [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f [ 3165.149821] [<ffffffff811d931f>] __blk_run_queue+0x42/0x71 [ 3165.149821] [<ffffffff811d9403>] blk_run_queue+0x26/0x3a [ 3165.149821] [<ffffffff812c8761>] scsi_run_queue+0x2de/0x375 [ 3165.149821] [<ffffffff812b60ac>] ? put_device+0x17/0x19 [ 3165.149821] [<ffffffff812c92d7>] scsi_next_command+0x3b/0x4b [ 3165.149821] [<ffffffff812c9b9f>] scsi_io_completion+0x1c9/0x3f5 [ 3165.149821] [<ffffffff812c3c36>] scsi_finish_command+0xb5/0xbe I think I have hit following BUG_ON() in cfq_dispatch_request(). BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); Please find attached the patch to fix it. I have done some stress testing with it and have not seen it happening again. o We should wait on a queue even after slice expiry only if it is empty. If queue is not empty then continue to expire it. o If we decide to keep the queue then make cfqq=NULL. Otherwise select_queue() will return a valid cfqq and cfq_dispatch_request() can hit following BUG_ON(). BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)) Reviewed-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 10 12月, 2009 2 次提交
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由 Gui Jianfeng 提交于
Remove wait_request flag when idle time is being deleted, otherwise it'll hit this path every time when a request is enqueued. Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Corrado Zoccolo 提交于
Added a comment to explain the initialization of last_delayed_sync. Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 09 12月, 2009 2 次提交
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由 Vivek Goyal 提交于
If there is a sequential reader running in a group, we wait for next request to come in that group after slice expiry and once new request is in, we expire the queue. Otherwise we delete the group from service tree and group looses its fair share. So far I was marking a queue as wait_busy if it had consumed its slice and it was last queue in the group. But this condition did not cover following two cases. 1.If a request completed and slice has not expired yet. Next request comes in and is dispatched to disk. Now select_queue() hits and slice has expired. This group will be deleted. Because request is still in the disk, this queue will never get a chance to wait_busy. 2.If request completed and slice has not expired yet. Before next request comes in (delay due to think time), select_queue() hits and expires the queue hence group. This queue never got a chance to wait busy. Gui was hitting the boundary condition 1 and not getting fairness numbers proportional to weight. This patch puts the checks for above two conditions and improves the fairness numbers for sequential workload on rotational media. Check in select_queue() takes care of case 1 and additional check in should_wait_busy() takes care of case 2. Reported-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Vivek Goyal 提交于
o Get rid of wait_busy_done flag. This flag only tells we were doing wait busy on a queue and that queue got request so expire it. That information can easily be obtained by (cfq_cfqq_wait_busy() && queue_is_not_empty). So remove this flag and keep code simple. Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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