aboutsummaryrefslogtreecommitdiffstats
path: root/block
Commit message (Collapse)AuthorAgeFilesLines
...
| * | | block: fix a typo in the blk-cgroup.h fileJie Liu2011-10-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | byptes -> bytes. Signed-off-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: fix request_queue lifetime handling by making blk_queue_cleanup() ↵Tejun Heo2011-10-195-29/+87
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | properly shutdown request_queue is refcounted but actually depdends on lifetime management from the queue owner - on blk_cleanup_queue(), block layer expects that there's no request passing through request_queue and no new one will. This is fundamentally broken. The queue owner (e.g. SCSI layer) doesn't have a way to know whether there are other active users before calling blk_cleanup_queue() and other users (e.g. bsg) don't have any guarantee that the queue is and would stay valid while it's holding a reference. With delay added in blk_queue_bio() before queue_lock is grabbed, the following oops can be easily triggered when a device is removed with in-flight IOs. sd 0:0:1:0: [sdb] Stopping disk ata1.01: disabled general protection fault: 0000 [#1] PREEMPT SMP CPU 2 Modules linked in: Pid: 648, comm: test_rawio Not tainted 3.1.0-rc3-work+ #56 Bochs Bochs RIP: 0010:[<ffffffff8137d651>] [<ffffffff8137d651>] elv_rqhash_find+0x61/0x100 ... Process test_rawio (pid: 648, threadinfo ffff880019efa000, task ffff880019ef8a80) ... Call Trace: [<ffffffff8137d774>] elv_merge+0x84/0xe0 [<ffffffff81385b54>] blk_queue_bio+0xf4/0x400 [<ffffffff813838ea>] generic_make_request+0xca/0x100 [<ffffffff81383994>] submit_bio+0x74/0x100 [<ffffffff811c53ec>] dio_bio_submit+0xbc/0xc0 [<ffffffff811c610e>] __blockdev_direct_IO+0x92e/0xb40 [<ffffffff811c39f7>] blkdev_direct_IO+0x57/0x60 [<ffffffff8113b1c5>] generic_file_aio_read+0x6d5/0x760 [<ffffffff8118c1ca>] do_sync_read+0xda/0x120 [<ffffffff8118ce55>] vfs_read+0xc5/0x180 [<ffffffff8118cfaa>] sys_pread64+0x9a/0xb0 [<ffffffff81afaf6b>] system_call_fastpath+0x16/0x1b This happens because blk_queue_cleanup() destroys the queue and elevator whether IOs are in progress or not and DEAD tests are sprinkled in the request processing path without proper synchronization. Similar problem exists for blk-throtl. On queue cleanup, blk-throtl is shutdown whether it has requests in it or not. Depending on timing, it either oopses or throttled bios are lost putting tasks which are waiting for bio completion into eternal D state. The way it should work is having the usual clear distinction between shutdown and release. Shutdown drains all currently pending requests, marks the queue dead, and performs partial teardown of the now unnecessary part of the queue. Even after shutdown is complete, reference holders are still allowed to issue requests to the queue although they will be immmediately failed. The rest of teardown happens on release. This patch makes the following changes to make blk_queue_cleanup() behave as proper shutdown. * QUEUE_FLAG_DEAD is now set while holding both q->exit_mutex and queue_lock. * Unsynchronized DEAD check in generic_make_request_checks() removed. This couldn't make any meaningful difference as the queue could die after the check. * blk_drain_queue() updated such that it can drain all requests and is now called during cleanup. * blk_throtl updated such that it checks DEAD on grabbing queue_lock, drains all throttled bios during cleanup and free td when queue is released. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: drop @tsk from attempt_plug_merge() and explain sync rulesTejun Heo2011-10-191-7/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | attempt_plug_merge() accesses elevator without holding queue_lock and may call into ->elevator_bio_merge_fn(). The elvator is guaranteed to be valid because it's accessed iff the plugged list has requests and elevator is never exited with live requests, so as long as the elevator method can deal with unlocked access, this is safe. Explain the sync rules around attempt_plug_merge() and drop the unnecessary @tsk parameter. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: make get_request[_wait]() fail if queue is deadTejun Heo2011-10-191-16/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently get_request[_wait]() allocates request whether queue is dead or not. This patch makes get_request[_wait]() return NULL if @q is dead. blk_queue_bio() is updated to fail the submitted bio if request allocation fails. While at it, add docbook comments for get_request[_wait](). Note that the current code has rather unclear (there are spurious DEAD tests scattered around) assumption that the owner of a queue guarantees that no request travels block layer if the queue is dead and this patch in itself doesn't change much; however, this will allow fixing the broken assumption in the next patch. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: reorganize throtl_get_tg() and blk_throtl_bio()Tejun Heo2011-10-193-41/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_throtl_bio() and throtl_get_tg() have rather unusual interface. * throtl_get_tg() returns pointer to a valid tg or ERR_PTR(-ENODEV), and drops queue_lock in the latter case. Different locking context depending on return value is error-prone and DEAD state is scheduled to be protected by queue_lock anyway. Move DEAD check inside queue_lock and return valid tg or NULL. * blk_throtl_bio() indicates return status both with its return value and in/out param **@bio. The former is used to indicate whether queue is found to be dead during throtl processing. The latter whether the bio is throttled. There's no point in returning DEAD check result from blk_throtl_bio(). The queue can die after blk_throtl_bio() is finished but before make_request_fn() grabs queue lock. Make it take *@bio instead and return boolean result indicating whether the request is throttled or not. This patch doesn't cause any visible functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: reorganize queue drainingTejun Heo2011-10-193-26/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reorganize queue draining related code in preparation of queue exit changes. * Factor out actual draining from elv_quiesce_start() to blk_drain_queue(). * Make elv_quiesce_start/end() responsible for their own locking. * Replace open-coded ELVSWITCH clearing in elevator_switch() with elv_quiesce_end(). This patch doesn't cause any visible functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: drop unnecessary blk_get/put_queue() in scsi_cmd_ioctl() and blk_get_tg()Tejun Heo2011-10-192-9/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_get/put_queue() in scsi_cmd_ioctl() and throtl_get_tg() are completely bogus. The caller must have a reference to the queue on entry and taking an extra reference doesn't change anything. For scsi_cmd_ioctl(), the only effect is that it ends up checking QUEUE_FLAG_DEAD on entry; however, this is bogus as queue can die right after blk_get_queue(). Dead queue should be and is handled in request issue path (it's somewhat broken now but that's a separate problem and doesn't affect this one much). throtl_get_tg() incorrectly assumes that q is rcu freed. Also, it doesn't check return value of blk_get_queue(). If the queue is already dead, it ends up doing an extra put. Drop them. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: pass around REQ_* flags instead of broken down booleans during ↵Tejun Heo2011-10-191-19/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | request alloc/free blk_alloc_request() and freed_request() take different combinations of REQ_* @flags, @priv and @is_sync when @flags is superset of the latter two. Make them take @flags only. This cleans up the code a bit and will ease updating allocation related REQ_* flags. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: move blk_throtl prototypes to block/blk.hTejun Heo2011-10-192-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_throtl interface is block internal and there's no reason to have them in linux/blkdev.h. Move them to block/blk.h. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: fix genhd refcounting in blkio_policy_parse_and_set()Tejun Heo2011-10-191-33/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blkio_policy_parse_and_set() calls blkio_check_dev_num() to check whether the given dev_t is valid. blkio_check_dev_num() uses get_gendisk() for verification but never puts the returned genhd leaking the reference. This patch collapses blkio_check_dev_num() into its caller and updates it such that the genhd is put before returning. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: make gendisk hold a reference to its queueTejun Heo2011-10-191-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following command sequence triggers an oops. # mount /dev/sdb1 /mnt # echo 1 > /sys/class/scsi_device/0\:0\:1\:0/device/delete # umount /mnt general protection fault: 0000 [#1] PREEMPT SMP CPU 2 Modules linked in: Pid: 791, comm: umount Not tainted 3.1.0-rc3-work+ #8 Bochs Bochs RIP: 0010:[<ffffffff810d0879>] [<ffffffff810d0879>] __lock_acquire+0x389/0x1d60 ... Call Trace: [<ffffffff810d2845>] lock_acquire+0x95/0x140 [<ffffffff81aed87b>] _raw_spin_lock+0x3b/0x50 [<ffffffff811573bc>] bdi_lock_two+0x5c/0x70 [<ffffffff811c2f6c>] bdev_inode_switch_bdi+0x4c/0xf0 [<ffffffff811c3fcb>] __blkdev_put+0x11b/0x1d0 [<ffffffff811c4010>] __blkdev_put+0x160/0x1d0 [<ffffffff811c40df>] blkdev_put+0x5f/0x190 [<ffffffff8118f18d>] kill_block_super+0x4d/0x80 [<ffffffff8118f4a5>] deactivate_locked_super+0x45/0x70 [<ffffffff8119003a>] deactivate_super+0x4a/0x70 [<ffffffff811ac4ad>] mntput_no_expire+0xed/0x130 [<ffffffff811acf2e>] sys_umount+0x7e/0x3a0 [<ffffffff81aeeeab>] system_call_fastpath+0x16/0x1b This is because bdev holds on to disk but disk doesn't pin the associated queue. If a SCSI device is removed while the device is still open, the sdev puts the base reference to the queue on release. When the bdev is finally released, the associated queue is already gone along with the bdi and bdev_inode_switch_bdi() ends up dereferencing already freed bdi. Even if it were not for this bug, disk not holding onto the associated queue is very unusual and error-prone. Fix it by making add_disk() take an extra reference to its queue and put it on disk_release() and ensuring that disk and its fops owner are put in that order after all accesses to the disk and queue are complete. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | Merge branch 'v3.1-rc10' into for-3.2/coreJens Axboe2011-10-1912-54/+413
| |\ \ \ | | |/ / | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: block/blk-core.c include/linux/blkdev.h Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block/blk-sysfs.c: fix kerneldoc referencesAndrew Morton2011-09-211-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kerneldoc for blk_release_queue() is referring to blk_cleanup_queue(). Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: document blk-plugSuresh Jayaraman2011-09-211-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Thus spake Andrew Morton: "And I have the usual maintainability whine. If someone comes up to vmscan.c and sees it calling blk_start_plug(), how are they supposed to work out why that call is there? They go look at the blk_start_plug() definition and it is undocumented. I think we can do better than this?" Adapted from the LWN article - http://lwn.net/Articles/438256/ by Jens Axboe and from an earlier attempt by Shaohua Li to document blk-plug. [akpm@linux-foundation.org: grammatical and spelling tweaks] Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: refactor generic_make_requestChristoph Hellwig2011-09-151-46/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move all the checks performed on a bio into a new helper, and call it as soon as bio is submitted even if it is a re-submission from ->make_request. We explicitly mark the new helper as beeing non-inlined as the stack usage for printing the block device name in the failure case is quite high and this a patch where we have to be extremely conservative about stack usage. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: remove support for bio remapping from ->make_requestChristoph Hellwig2011-09-121-91/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is very little benefit in allowing to let a ->make_request instance update the bios device and sector and loop around it in __generic_make_request when we can archive the same through calling generic_make_request from the driver and letting the loop in generic_make_request handle it. Note that various drivers got the return value from ->make_request and returned non-zero values for errors. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * | | block: rename __make_request() to blk_queue_bio()Jens Axboe2011-09-121-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | Now that it's exported, lets put it in a more sane namespace. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * | | block: export __make_requestChristoph Hellwig2011-09-121-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid the hacks need for request based device mappers currently by simply exporting the symbol instead of trying to get it through the back door. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * | | elevator: use ELV_NAME_MAX instead of magic number 16 for chosen_elevatorWang Sheng-Hui2011-09-121-1/+1
| | |/ | |/| | | | | | | | | | | | | | | | | | | We have ELV_NAME_MAX defined to 16, and hence we should use it instead of the magic nubmer 16 for elevator's name string. Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | | Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds2011-10-281-0/+71
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (204 commits) [SCSI] qla4xxx: export address/port of connection (fix udev disk names) [SCSI] ipr: Fix BUG on adapter dump timeout [SCSI] megaraid_sas: Fix instance access in megasas_reset_timer [SCSI] hpsa: change confusing message to be more clear [SCSI] iscsi class: fix vlan configuration [SCSI] qla4xxx: fix data alignment and use nl helpers [SCSI] iscsi class: fix link local mispelling [SCSI] iscsi class: Replace iscsi_get_next_target_id with IDA [SCSI] aacraid: use lower snprintf() limit [SCSI] lpfc 8.3.27: Change driver version to 8.3.27 [SCSI] lpfc 8.3.27: T10 additions for SLI4 [SCSI] lpfc 8.3.27: Fix queue allocation failure recovery [SCSI] lpfc 8.3.27: Change algorithm for getting physical port name [SCSI] lpfc 8.3.27: Changed worst case mailbox timeout [SCSI] lpfc 8.3.27: Miscellanous logic and interface fixes [SCSI] megaraid_sas: Changelog and version update [SCSI] megaraid_sas: Add driver workaround for PERC5/1068 kdump kernel panic [SCSI] megaraid_sas: Add multiple MSI-X vector/multiple reply queue support [SCSI] megaraid_sas: Add support for MegaRAID 9360/9380 12GB/s controllers [SCSI] megaraid_sas: Clear FUSION_IN_RESET before enabling interrupts ...
| * | [SCSI] genhd: add a new attribute "alias" in gendiskNao Nishijima2011-08-291-0/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch allows the user to set an "alias" of the disk via sysfs interface. This patch only adds a new attribute "alias" in gendisk structure. To show the alias instead of the device name in kernel messages, we need to revise printk messages and use alias_name() in them. Example: (current) printk("disk name is %s\n", disk->disk_name); (new) printk("disk name is %s\n", alias_name(disk)); Users can use alphabets, numbers, '-' and '_' in "alias" attribute. A disk can have an "alias" which length is up to 255 bytes. This attribute is write-once. Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Suggested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Nao Nishijima <nao.nishijima.xt@hitachi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* | | block: Free queue resources at blk_release_queue()Hannes Reinecke2011-09-282-7/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A kernel crash is observed when a mounted ext3/ext4 filesystem is physically removed. The problem is that blk_cleanup_queue() frees up some resources eg by calling elevator_exit(), which are not checked for in normal operation. So we should rather move these calls to the destructor function blk_release_queue() as at that point all remaining references are gone. However, in doing so we have to ensure that any externally supplied queue_lock is disconnected as the driver might free up the lock after the call of blk_cleanup_queue(), Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | blk-cgroup: be able to remove the record of unplugged deviceWanlong Gao2011-09-211-21/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The bug is we're not able to remove the device from blkio cgroup's per-device control files if it gets unplugged. To reproduce the bug: # mount -t cgroup -o blkio xxx /cgroup # cd /cgroup # echo "8:0 1000" > blkio.throttle.read_bps_device # unplug the device # cat blkio.throttle.read_bps_device 8:0 1000 # echo "8:0 0" > blkio.throttle.read_bps_device -bash: echo: write error: No such device After patching, the device removal will succeed. Thanks for the comments of Paul, Zefan, and Vivek. Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <paul@paulmenage.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | block: Don't check QUEUE_FLAG_SAME_COMP in __blk_complete_requestTao Ma2011-09-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In __blk_complete_request, we check both QUEUE_FLAG_SAME_COMP and req->cpu to decide whether we should use req->cpu. Actually the user can also select the complete cpu by either setting BIO_CPU_AFFINE or by calling bio_set_completion_cpu. Current solution makes these 2 ways don't work any more. So we'd better just check req->cpu. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | block: simplify force plug flush code a little bitShaohua Li2011-08-241-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cleaning up the code a little bit. attempt_plug_merge() traverses the plug list anyway, we can do the request counting there, so stack size is reduced a little bit. The motivation here is I suspect if we should count the requests for each queue (task could handle multiple disks in the meantime), but my test doesn't show it's worthy doing. If somebody proves we should do it, below change will make that more easier. Signed-off-by: Shaohua Li <shli@kernel.org> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | | block: change force plug flush call orderShaohua Li2011-08-241-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Do blk_flush_plug_list() first and then add new request aDo blk_flush_plug_list() first and then add new request aDo blk_flush_plug_list() first and then add new request at the tail. New request can't be merged to existing requests, but later new requests might be merged with this new one. If blk_flush_plug_list() is done later, the merge doesn't happen. Believe it or not, this fixes a 10% regression running sysbench workload. Signed-off-by: Shaohua Li <shli@kernel.org> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | | block: Fix queue_flag update when rq_affinity goes from 2 to 1Eric Seppanen2011-08-241-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 5757a6d76cdf added the QUEUE_FLAG_SAME_FORCE flag, but fails to clear that flag when the current state is '2' (SAME_COMP + SAME_FORCE) and the new state is '1' (SAME_COMP). Acked-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Eric Seppanen <eric@purestorage.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | | block: separate priority boosting from REQ_METAChristoph Hellwig2011-08-231-10/+10
|/ / | | | | | | | | | | | | | | | | | | | | | | Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule, and lave REQ_META purely for marking requests as metadata in blktrace. All existing callers of REQ_META except for XFS are updated to also set REQ_PRIO for now. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds2011-08-1910-14/+371
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/linux-block: (23 commits) Revert "cfq: Remove special treatment for metadata rqs." block: fix flush machinery for stacking drivers with differring flush flags block: improve rq_affinity placement blktrace: add FLUSH/FUA support Move some REQ flags to the common bio/request area allow blk_flush_policy to return REQ_FSEQ_DATA independent of *FLUSH xen/blkback: Make description more obvious. cfq-iosched: Add documentation about idling block: Make rq_affinity = 1 work as expected block: swim3: fix unterminated of_device_id table block/genhd.c: remove useless cast in diskstats_show() drivers/cdrom/cdrom.c: relax check on dvd manufacturer value drivers/block/drbd/drbd_nl.c: use bitmap_parse instead of __bitmap_parse bsg-lib: add module.h include cfq-iosched: Reduce linked group count upon group destruction blk-throttle: correctly determine sync bio loop: fix deadlock when sysfs and LOOP_CLR_FD race against each other loop: add BLK_DEV_LOOP_MIN_COUNT=%i to allow distros 0 pre-allocated loop devices loop: add management interface for on-demand device allocation loop: replace linked list of allocated devices with an idr index ...
| * Revert "cfq: Remove special treatment for metadata rqs."Jens Axboe2011-08-191-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a kernel build regression since 3.1-rc1, which is about 10% regression. The kernel source is in an ext3 filesystem. Alex Shi bisect it to commit: commit a07405b7802691d29ab3b23bdc76ee6d006aad0b Author: Justin TerAvest <teravest@google.com> Date: Sun Jul 10 22:09:19 2011 +0200 cfq: Remove special treatment for metadata rqs. Apparently this is caused by lack metadata preemption, where ext3/ext4 do use READ_META. I didn't see a way to fix the issue, so suggest reverting the patch. This reverts commit a07405b7802691d29ab3b23bdc76ee6d006aad0b. Reported-by: Alex Shi<alex.shi@intel.com> Reported-by: Shaohua Li<shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: fix flush machinery for stacking drivers with differring flush flagsJeff Moyer2011-08-153-6/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit ae1b1539622fb46e51b4d13b3f9e5f4c713f86ae, block: reimplement FLUSH/FUA to support merge, introduced a performance regression when running any sort of fsyncing workload using dm-multipath and certain storage (in our case, an HP EVA). The test I ran was fs_mark, and it dropped from ~800 files/sec on ext4 to ~100 files/sec. It turns out that dm-multipath always advertised flush+fua support, and passed commands on down the stack, where those flags used to get stripped off. The above commit changed that behavior: static inline struct request *__elv_next_request(struct request_queue *q) { struct request *rq; while (1) { - while (!list_empty(&q->queue_head)) { + if (!list_empty(&q->queue_head)) { rq = list_entry_rq(q->queue_head.next); - if (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) || - (rq->cmd_flags & REQ_FLUSH_SEQ)) - return rq; - rq = blk_do_flush(q, rq); - if (rq) - return rq; + return rq; } Note that previously, a command would come in here, have REQ_FLUSH|REQ_FUA set, and then get handed off to blk_do_flush: struct request *blk_do_flush(struct request_queue *q, struct request *rq) { unsigned int fflags = q->flush_flags; /* may change, cache it */ bool has_flush = fflags & REQ_FLUSH, has_fua = fflags & REQ_FUA; bool do_preflush = has_flush && (rq->cmd_flags & REQ_FLUSH); bool do_postflush = has_flush && !has_fua && (rq->cmd_flags & REQ_FUA); unsigned skip = 0; ... if (blk_rq_sectors(rq) && !do_preflush && !do_postflush) { rq->cmd_flags &= ~REQ_FLUSH; if (!has_fua) rq->cmd_flags &= ~REQ_FUA; return rq; } So, the flush machinery was bypassed in such cases (q->flush_flags == 0 && rq->cmd_flags & (REQ_FLUSH|REQ_FUA)). Now, however, we don't get into the flush machinery at all. Instead, __elv_next_request just hands a request with flush and fua bits set to the scsi_request_fn, even if the underlying request_queue does not support flush or fua. The agreed upon approach is to fix the flush machinery to allow stacking. While this isn't used in practice (since there is only one request-based dm target, and that target will now reflect the flush flags of the underlying device), it does future-proof the solution, and make it function as designed. In order to make this work, I had to add a field to the struct request, inside the flush structure (to store the original req->end_io). Shaohua had suggested overloading the union with rb_node and completion_data, but the completion data is used by device mapper and can also be used by other drivers. So, I didn't see a way around the additional field. I tested this patch on an HP EVA with both ext4 and xfs, and it recovers the lost performance. Comments and other testers, as always, are appreciated. Cheers, Jeff Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: improve rq_affinity placementShaohua Li2011-08-111-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch reverts commit 35ae66e0a09ab70ed(block: Make rq_affinity = 1 work as expected). The purpose is to avoid an unnecessary IPI. Let's take an example. My test box has cpu 0-7, one socket. Say request is added from CPU 1, blk_complete_request() occurs at CPU 7. Without the reverted patch, softirq will be done at CPU 7. With it, an IPI will be directed to CPU 0, and softirq will be done at CPU 0. In this case, doing softirq at CPU 0 and CPU 7 have no difference from cache sharing point view and we can avoid an ipi if doing it in CPU 7. An immediate concern is this is just like QUEUE_FLAG_SAME_FORCE, but actually not. blk_complete_request() is running in interrupt handler, and currently I/O controller doesn't support multiple interrupts (I checked several LSI cards and AHCI), so only one CPU can run blk_complete_request(). This is still quite different as QUEUE_FLAG_SAME_FORCE. Since only one CPU runs softirq, the only difference with below patch is softirq not always runs at the first CPU of a group. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * allow blk_flush_policy to return REQ_FSEQ_DATA independent of *FLUSHJeff Moyer2011-08-091-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_insert_flush has the following check: /* * If there's data but flush is not necessary, the request can be * processed directly without going through flush machinery. Queue * for normal execution. */ if ((policy & REQ_FSEQ_DATA) && !(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) { list_add_tail(&rq->queuelist, &q->queue_head); return; } However, blk_flush_policy will not return with policy set to only REQ_FSEQ_DATA: static unsigned int blk_flush_policy(unsigned int fflags, struct request *rq) { unsigned int policy = 0; if (fflags & REQ_FLUSH) { if (rq->cmd_flags & REQ_FLUSH) policy |= REQ_FSEQ_PREFLUSH; if (blk_rq_sectors(rq)) policy |= REQ_FSEQ_DATA; if (!(fflags & REQ_FUA) && (rq->cmd_flags & REQ_FUA)) policy |= REQ_FSEQ_POSTFLUSH; } return policy; } Notice that REQ_FSEQ_DATA is only set if REQ_FLUSH is set. Fix this mismatch by moving the setting of REQ_FSEQ_DATA outside of the REQ_FLUSH check. Tejun notes: Hmmm... yes, this can become a correctness issue if (and only if) blk_queue_flush() is called to change q->flush_flags while requests are in-flight; otherwise, requests wouldn't reach the function at all. Also, I think it would be a generally good idea to always set FSEQ_DATA if the request has data. Cheers, Jeff Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: Make rq_affinity = 1 work as expectedTao Ma2011-08-051-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 5757a6d76c introduced a new rq_affinity = 2 so as to make the request completed in the __make_request cpu. But it makes the old rq_affinity = 1 not work any more. The root cause is that if the 'cpu' and 'req->cpu' is in the same group and cpu != req->cpu, ccpu will be the same as group_cpu, so the completion will be excuted in the 'cpu' not 'group_cpu'. This patch fix problem by simpling removing group_cpu and the codes are more explicit now. If ccpu == cpu, we complete in cpu, otherwise we raise_blk_irq to ccpu. Cc: Christoph Hellwig <hch@infradead.org> Cc: Roland Dreier <roland@purestorage.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Reviewed-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block/genhd.c: remove useless cast in diskstats_show()Herbert Poetzl2011-08-021-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the (unsigned long long) cast in diskstats_show() and adjusts the seq_printf() format string to 'unsigned long' diskstats_show() uses part_stat_read() to get the stats, which either accesses the specified field in the struct disk_stats directly (non SMP) or sums up the per CPU values in a variable of the same type as the field, so in any case the result will have the same type and range as the specified field which for all disk_stats entries is unsigned long Also, for unsigned long ranges the output of %lu should be identical to the one of %llu, so no change in the actual proc entry contents. Signed-off-by: Herbert Poetzl <herbert@13thfloor.at> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * bsg-lib: add module.h includeJens Axboe2011-08-021-0/+1
| | | | | | | | | | | | | | | | | | | | Due to conflicts with the moduleh tree in linux-next, we run into an include file mess. We really need export.h in that tree, but if we add module.h locally then the issue is easier to resolve. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * cfq-iosched: Reduce linked group count upon group destructionVivek Goyal2011-08-021-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | FQ keeps track of number of groups which are linked on blkcg->blkg_list. This is useful to avoid races between queue exit and cgroup exit code paths. So if at the request queue exit time linked group count is not zero, that means there are some group out there which is yet to be deleted under rcu read period and queue exit code should wait for on rcu period. In my previous patch I forgot to decrease the number of group count. So in current form, we nr_blkcg_linked_grps is always non-zero and we will always wait one rcu period (if BLK_CGROUP=y). The side effect of this is that it can increase boot time. I am surprised, nobody complained so far. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * blk-throttle: correctly determine sync bioShaohua Li2011-08-011-2/+2
| | | | | | | | | | | | | | | | read request is always sync. Using rw_is_sync() to determine if a bio is sync. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: add bsg helper libraryMike Christie2011-07-313-0/+308
| | | | | | | | | | | | | | | | | | | | | | | | | | This moves the FC classes bsg code to the block layer and makes it a lib so that other classes like iscsi and SAS can use it. It is helpful because working with the request queue, bios, creating scatterlists, etc are a pain that the LLD does not have to worry about with normal IOs and should not have to worry about for bsg requests. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | fault-injection: add ability to export fault_attr in arbitrary directoryAkinobu Mita2011-08-032-3/+8
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | init_fault_attr_dentries() is used to export fault_attr via debugfs. But it can only export it in debugfs root directory. Per Forlin is working on mmc_fail_request which adds support to inject data errors after a completed host transfer in MMC subsystem. The fault_attr for mmc_fail_request should be defined per mmc host and export it in debugfs directory per mmc host like /sys/kernel/debug/mmc0/mmc_fail_request. init_fault_attr_dentries() doesn't help for mmc_fail_request. So this introduces fault_create_debugfs_attr() which is able to create a directory in the arbitrary directory and replace init_fault_attr_dentries(). [akpm@linux-foundation.org: extraneous semicolon, per Randy] Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Tested-by: Per Forlin <per.forlin@linaro.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fail_make_request: cleanup should_fail_requestAkinobu Mita2011-07-261-14/+12
| | | | | | | | | | | This changes should_fail_request() to more usable wrapper function of should_fail(). It can avoid putting #ifdef CONFIG_FAIL_MAKE_REQUEST in the middle of a function. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* block: fix warning with calling smp_processor_id() in preemptible sectionJens Axboe2011-07-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | After commit 5757a6d7 introduced an unsafe calling of smp_processor_id(), with preempt debuggin turned on we spew a lot of: BUG: using smp_processor_id() in preemptible [00000000] code: kjournald/514 caller is __make_request+0x1b8/0x308 [<c0019f44>] (unwind_backtrace+0x0/0xe8) from [<c024b4cc>] (debug_smp_processor_id+0xbc/0xf0) [<c024b4cc>] (debug_smp_processor_id+0xbc/0xf0) from [<c0223d14>] (__make_request+0x1b8/0x308) [<c0223d14>] (__make_request+0x1b8/0x308) from [<c02215ac>] (generic_make_request+0x4dc/0x558) [<c02215ac>] (generic_make_request+0x4dc/0x558) from [<c022173c>] (submit_bio+0x114/0x138) [<c022173c>] (submit_bio+0x114/0x138) from [<c011f504>] (submit_bh+0x148/0x16c) [<c011f504>] (submit_bh+0x148/0x16c) from [<c0121ed8>] (__sync_dirty_buffer+0x88/0xd8) [<c0121ed8>] (__sync_dirty_buffer+0x88/0xd8) from [<c01aff78>] (journal_commit_transaction+0x1198/0x1688) [<c01aff78>] (journal_commit_transaction+0x1198/0x1688) from [<c01b4034>] (kjournald+0xb4/0x224) [<c01b4034>] (kjournald+0xb4/0x224) from [<c0069ea0>] (kthread+0x8c/0x94) [<c0069ea0>] (kthread+0x8c/0x94) from [<c00137f8>] (kernel_thread_exit+0x0/0x8) Fix this by just using raw_smp_processor_id(), it's just a hint after all. There's no pinning of the CPU or accessing per-cpu structures involved. Reported-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Merge branch 'for-3.1/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds2011-07-251-9/+9
|\ | | | | | | | | | | | | | | | | | | * 'for-3.1/drivers' of git://git.kernel.dk/linux-block: cciss: do not attempt to read from a write-only register xen/blkback: Add module alias for autoloading xen/blkback: Don't let in-flight requests defer pending ones. bsg: fix address space warning from sparse bsg: remove unnecessary conditional expressions bsg: fix bsg_poll() to return POLLOUT properly
| * bsg: fix address space warning from sparseNamhyung Kim2011-06-201-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | copy_from/to_user() and blk_rq_map_user() want __user pointer. This patch fixes following warnings from sparse: CHECK block/bsg.c block/bsg.c:185:38: warning: incorrect type in argument 2 (different address spaces) block/bsg.c:185:38: expected void const [noderef] <asn:1>*from block/bsg.c:185:38: got void *<noident> block/bsg.c:295:58: warning: incorrect type in argument 4 (different address spaces) block/bsg.c:295:58: expected void [noderef] <asn:1>*<noident> block/bsg.c:295:58: got void *[assigned] dxferp block/bsg.c:311:52: warning: incorrect type in argument 4 (different address spaces) block/bsg.c:311:52: expected void [noderef] <asn:1>*<noident> block/bsg.c:311:52: got void *[assigned] dxferp block/bsg.c:448:37: warning: incorrect type in argument 1 (different address spaces) block/bsg.c:448:37: expected void [noderef] <asn:1>*dst block/bsg.c:448:37: got void *<noident> Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * bsg: remove unnecessary conditional expressionsNamhyung Kim2011-06-201-2/+2
| | | | | | | | | | | | | | | | | | | | Second condition in OR always implies first condition is false thus bytes_read in the second is not needed. The same goes to bytes_written. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * bsg: fix bsg_poll() to return POLLOUT properlyNamhyung Kim2011-06-201-1/+1
| | | | | | | | | | | | | | | | | | POLLOUT should be returned only if bd->queued_cmds < bd->max_queue so that bsg_alloc_command() can proceed. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | Merge branch 'for-3.1/core' of git://git.kernel.dk/linux-blockLinus Torvalds2011-07-2511-148/+145
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-3.1/core' of git://git.kernel.dk/linux-block: (24 commits) block: strict rq_affinity backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu block: fix patch import error in max_discard_sectors check block: reorder request_queue to remove 64 bit alignment padding CFQ: add think time check for group CFQ: add think time check for service tree CFQ: move think time check variables to a separate struct fixlet: Remove fs_excl from struct task. cfq: Remove special treatment for metadata rqs. block: document blk_plug list access block: avoid building too big plug list compat_ioctl: fix make headers_check regression block: eliminate potential for infinite loop in blkdev_issue_discard compat_ioctl: fix warning caused by qemu block: flush MEDIA_CHANGE from drivers on close(2) blk-throttle: Make total_nr_queued unsigned block: Add __attribute__((format(printf...) and fix fallout fs/partitions/check.c: make local symbols static block:remove some spare spaces in genhd.c block:fix the comment error in blkdev.h ...
| * | block: strict rq_affinityDan Williams2011-07-233-12/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some systems benefit from completions always being steered to the strict requester cpu rather than the looser "per-socket" steering that blk_cpu_to_group() attempts by default. This is because the first CPU in the group mask ends up being completely overloaded with work, while the others (including the original submitter) has power left to spare. Allow the strict mode to be set by writing '2' to the sysfs control file. This is identical to the scheme used for the nomerges file, where '2' is a more aggressive setting than just being turned on. echo 2 > /sys/block/<bdev>/queue/rq_affinity Cc: Christoph Hellwig <hch@infradead.org> Cc: Roland Dreier <roland@purestorage.com> Tested-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * | block: fix patch import error in max_discard_sectors checkJens Axboe2011-07-231-1/+1
| | | | | | | | | | | | | | | | | | | | | A '!' snuck in before the unlikely, rendering it useless. Reported-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * | CFQ: add think time check for groupShaohua Li2011-07-121-2/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently when the last queue of a group has no request, we don't expire the queue to hope request from the group comes soon, so the group doesn't miss its share. But if the think time is big, the assumption isn't correct and we just waste bandwidth. In such case, we don't do idle. [global] runtime=30 direct=1 [test1] cgroup=test1 cgroup_weight=1000 rw=randread ioengine=libaio size=500m runtime=30 directory=/mnt filename=file1 thinktime=9000 [test2] cgroup=test2 cgroup_weight=1000 rw=randread ioengine=libaio size=500m runtime=30 directory=/mnt filename=file2 patched base test1 64k 39k test2 548k 540k total 604k 578k group1 gets much better throughput because it waits less time. To check if the patch changes behavior of queue without think time. I also tried to give test1 2ms think time or no think time. The test result is stable. The thoughput doesn't change with/without the patch. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
generated by cgit v1.1 at 2024-05-19 07:03:42 +0000