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| * | block: also check RQF_STATS in blk_mq_need_time_stamp()Hou Tao2019-09-151-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | In __blk_mq_end_request() if block stats needs update, we should ensure now is valid instead of 0 even when iostat is disabled. Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: make rq sector size accessible for block statsHou Tao2019-09-152-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently rq->data_len will be decreased by partial completion or zeroed by completion, so when blk_stat_add() is invoked, data_len will be zero and there will never be samples in poll_cb because blk_mq_poll_stats_bkt() will return -1 if data_len is zero. We could move blk_stat_add() back to __blk_mq_complete_request(), but that would make the effort of trying to call ktime_get_ns() once in vain. Instead we can reuse throtl_size field, and use it for both block stats and block throttle, and adjust the logic in blk_mq_poll_stats_bkt() accordingly. Fixes: 4bc6339a583c ("block: move blk_stat_add() to __blk_mq_end_request()") Tested-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | bfq: Fix bfq linkage errorPavel Begunkov2019-09-141-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 795fe54c2a828099e ("bfq: Add per-device weight"), bfq uses blkg_conf_prep() and blkg_conf_finish(), which are not exported. So, it causes linkage error if bfq compiled as a module. Fixes: 795fe54c2a828099e ("bfq: Add per-device weight") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: fix race between switching elevator and removing queuesMing Lei2019-09-121-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cecf5d87ff20 ("block: split .sysfs_lock into two locks") starts to release & actuire sysfs_lock again during switching elevator. So it isn't enough to prevent switching elevator from happening by simply clearing QUEUE_FLAG_REGISTERED with holding sysfs_lock, because in-progress switch still can move on after re-acquiring the lock, meantime the flag of QUEUE_FLAG_REGISTERED won't get checked. Fixes this issue by checking 'q->elevator' directly & locklessly after q->kobj is removed in blk_unregister_queue(), this way is safe because q->elevator can't be changed at that time. Fixes: cecf5d87ff20 ("block: split .sysfs_lock into two locks") Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: bypass blk_set_runtime_active for uninitialized q->devStanley Chu2019-09-121-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some devices may skip blk_pm_runtime_init() and have null pointer in its request_queue->dev. For example, SCSI devices of UFS Well-Known LUNs. Currently the null pointer is checked by the user of blk_set_runtime_active(), i.e., scsi_dev_type_resume(). It is better to check it by blk_set_runtime_active() itself instead of by its users. Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | iocost_monitor: Report debtTejun Heo2019-09-101-3/+3
| | | | | | | | | | | | | | | | | | | | | Report debt and rename del_ms row to delay for consistency. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-iocost: Don't let merges push vtime into the futureTejun Heo2019-09-101-7/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merges have the same problem that forced-bios had which is fixed by the previous patch. The cost of a merge is calculated at the time of issue and force-advances vtime into the future. Until global vtime catches up, how the cgroup's hweight changes in the meantime doesn't matter and it often leads to situations where the cost is calculated at one hweight and paid at a very different one. See the previous patch for more details. Fix it by never advancing vtime into the future for merges. If budget is available, vtime is advanced. Otherwise, the cost is charged as debt. This brings merge cost handling in line with issue cost handling in ioc_rqos_throttle(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-iocost: Account force-charged overage in absolute vtimeTejun Heo2019-09-101-7/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, when a bio needs to be force-charged and there isn't enough budget, vtime is simply pushed into the future. This means that the cost of the whole bio is scaled using the current hweight and then charged immediately. Until the global vtime advances beyond this future vtime, the cgroup won't be allowed to issue normal IOs. This is incorrect and can lead to, for example, exploding vrate or extended stalls if vrate range is constrained. Consider the following scenario. 1. A cgroup with a very low hweight runs out of budget. 2. A storm of swap-out happens on it. All of them are scaled according to the current low hweight and charged to vtime pushing it to a far future. 3. All other cgroups go idle and now the above cgroup has access to the whole device. However, because vtime is already wound using the past low hweight, what its current hweight is doesn't matter until global vtime catches up to the local vtime. 4. As a result, either vrate gets ramped up extremely or the IOs stall while the underlying device is idle. This is because the hweight the overage is calculated at is different from the hweight that it's being paid at. Fix it by remembering the overage in absoulte vtime and continuously paying with the actual budget according to the current hweight at each period. Note that non-forced bios which wait already remembers the cost in absolute vtime. This brings forced-bio accounting in line. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-iocost: Fix incorrect operation order during iocg freeTejun Heo2019-09-101-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ioc_pd_free() first cancels the hrtimers and then deactivates the iocg. However, the iocg timer can run inbetween and reschedule the hrtimers which will end up running after the iocg is freed leading to crashes like the following. general protection fault: 0000 [#1] SMP ... RIP: 0010:iocg_kick_delay+0xbe/0x1b0 RSP: 0018:ffffc90003598ea0 EFLAGS: 00010046 RAX: 1cee00fd69512b54 RBX: ffff8881bba48400 RCX: 00000000000003e8 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8881bba48400 RBP: 0000000000004e20 R08: 0000000000000002 R09: 00000000000003e8 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90003598ef0 R13: 00979f3810ad461f R14: ffff8881bba4b400 R15: 25439f950d26e1d1 FS: 0000000000000000(0000) GS:ffff88885f800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f64328c7e40 CR3: 0000000002409005 CR4: 00000000003606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> iocg_delay_timer_fn+0x3d/0x60 __hrtimer_run_queues+0xfe/0x270 hrtimer_interrupt+0xf4/0x210 smp_apic_timer_interrupt+0x5e/0x120 apic_timer_interrupt+0xf/0x20 </IRQ> Fix it by canceling hrtimers after deactivating the iocg. Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Reported-by: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | bfq: Add per-device weightFam Zheng2019-09-062-11/+87
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds to BFQ the missing per-device weight interfaces: blkio.bfq.weight_device on legacy and io.bfq.weight on unified. The implementation pretty closely resembles what we had in CFQ and the parsing code is basically reused. Tests ===== Using two cgroups and three block devices, having weights setup as: Cgroup test1 test2 ============================================ default 100 500 sda 500 100 sdb default default sdc 200 200 cgroup v1 runs -------------- sda.test1.out: READ: bw=913MiB/s sda.test2.out: READ: bw=183MiB/s sdb.test1.out: READ: bw=213MiB/s sdb.test2.out: READ: bw=1054MiB/s sdc.test1.out: READ: bw=650MiB/s sdc.test2.out: READ: bw=650MiB/s cgroup v2 runs -------------- sda.test1.out: READ: bw=915MiB/s sda.test2.out: READ: bw=184MiB/s sdb.test1.out: READ: bw=216MiB/s sdb.test2.out: READ: bw=1069MiB/s sdc.test1.out: READ: bw=621MiB/s sdc.test2.out: READ: bw=622MiB/s Signed-off-by: Fam Zheng <zhengfeiran@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | bfq: Extract bfq_group_set_weight from bfq_io_set_weight_legacyFam Zheng2019-09-061-28/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | This function will be useful when we update weight from the soon-coming per-device interface. Signed-off-by: Fam Zheng <zhengfeiran@bytedance.com> Reviewed-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | bfq: Fix the missing barrier in __bfq_entity_update_weight_prioFam Zheng2019-09-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The comment of bfq_group_set_weight says the reading of prio_changed should happen before the reading of weight, but a memory barrier is missing here. Add it now, to match the smp_wmb() there. Signed-off-by: Fam Zheng <zhengfeiran@bytedance.com> Reviewed-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: fix elevator_get_by_features()Jens Axboe2019-09-061-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | The lookup logic is broken - 'e' will never be NULL, even if the list is empty. Maintain lookup hit in a separate variable instead. Fixes: a0958ba7fcdc ("block: Improve default elevator selection") Reported-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Delay default elevator initializationDamien Le Moal2019-09-053-3/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When elevator_init_mq() is called from blk_mq_init_allocated_queue(), the only information known about the device is the number of hardware queues as the block device scan by the device driver is not completed yet for most drivers. The device type and elevator required features are not set yet, preventing to correctly select the default elevator most suitable for the device. This currently affects all multi-queue zoned block devices which default to the "none" elevator instead of the required "mq-deadline" elevator. These drives currently include host-managed SMR disks connected to a smartpqi HBA and null_blk block devices with zoned mode enabled. Upcoming NVMe Zoned Namespace devices will also be affected. Fix this by adding the boolean elevator_init argument to blk_mq_init_allocated_queue() to control the execution of elevator_init_mq(). Two cases exist: 1) elevator_init = false is used for calls to blk_mq_init_allocated_queue() within blk_mq_init_queue(). In this case, a call to elevator_init_mq() is added to __device_add_disk(), resulting in the delayed initialization of the queue elevator after the device driver finished probing the device information. This effectively allows elevator_init_mq() access to more information about the device. 2) elevator_init = true preserves the current behavior of initializing the elevator directly from blk_mq_init_allocated_queue(). This case is used for the special request based DM devices where the device gendisk is created before the queue initialization and device information (e.g. queue limits) is already known when the queue initialization is executed. Additionally, to make sure that the elevator initialization is never done while requests are in-flight (there should be none when the device driver calls device_add_disk()), freeze and quiesce the device request queue before calling blk_mq_init_sched() in elevator_init_mq(). Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Improve default elevator selectionDamien Le Moal2019-09-051-7/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For block devices that do not specify required features, preserve the current default elevator selection (mq-deadline for single queue devices, none for multi-queue devices). However, for devices specifying required features (e.g. zoned block devices ELEVATOR_F_ZBD_SEQ_WRITE feature), select the first available elevator providing the required features. In all cases, default to "none" if no elevator is available or if the initialization of the default elevator fails. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Introduce elevator featuresDamien Le Moal2019-09-053-11/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce the definition of elevator features through the elevator_features flags in the elevator_type structure. Each flag can represent a feature supported by an elevator. The first feature defined by this patch is support for zoned block device sequential write constraint with the flag ELEVATOR_F_ZBD_SEQ_WRITE, which is implemented by the mq-deadline elevator using zone write locking. Other possible features are IO priorities, write hints, latency targets or single-LUN dual-actuator disks (for which the elevator could maintain one LBA ordered list per actuator). The required_elevator_features field is also added to the request_queue structure to allow a device driver to specify elevator feature flags that an elevator must support for the correct operation of the device (e.g. device drivers for zoned block devices can have the ELEVATOR_F_ZBD_SEQ_WRITE flag as a required feature). The helper function blk_queue_required_elevator_features() is defined for setting this new field. With these two new fields in place, the elevator functions elevator_match() and elevator_find() are modified to allow a user to set only an elevator with a set of features that satisfies the device required features. Elevators not matching the device requirements are not shown in the device sysfs queue/scheduler file to prevent their use. The "none" elevator can always be selected as before. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Change elevator_init_mq() to always succeedDamien Le Moal2019-09-053-19/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the default elevator chosen is mq-deadline, elevator_init_mq() may return an error if mq-deadline initialization fails, leading to blk_mq_init_allocated_queue() returning an error, which in turn will cause the block device initialization to fail and the device not being exposed. Instead of taking such extreme measure, handle mq-deadline initialization failures in the same manner as when mq-deadline is not available (no module to load), that is, default to the "none" scheduler. With this change, elevator_init_mq() return type can be changed to void. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Cleanup elevator_init_mq() useDamien Le Moal2019-09-052-15/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of checking a queue tag_set BLK_MQ_F_NO_SCHED flag before calling elevator_init_mq() to make sure that the queue supports IO scheduling, use the elevator.c function elv_support_iosched() in elevator_init_mq(). This does not introduce any functional change but ensure that elevator_init_mq() does the right thing based on the queue settings. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: elevator.c: Remove now unused elevator= argumentMarcos Paulo de Souza2019-09-031-14/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the inclusion of blk-mq, elevator argument was not being considered anymore, and it's utility died long with the legacy IO path, now removed too. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com> Fold with doc removal patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: mq-deadline: Fix queue restart handlingDamien Le Moal2019-09-031-10/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 7211aef86f79 ("block: mq-deadline: Fix write completion handling") added a call to blk_mq_sched_mark_restart_hctx() in dd_dispatch_request() to make sure that write request dispatching does not stall when all target zones are locked. This fix left a subtle race when a write completion happens during a dispatch execution on another CPU: CPU 0: Dispatch CPU1: write completion dd_dispatch_request() lock(&dd->lock); ... lock(&dd->zone_lock); dd_finish_request() rq = find request lock(&dd->zone_lock); unlock(&dd->zone_lock); zone write unlock unlock(&dd->zone_lock); ... __blk_mq_free_request check restart flag (not set) -> queue not run ... if (!rq && have writes) blk_mq_sched_mark_restart_hctx() unlock(&dd->lock) Since the dispatch context finishes after the write request completion handling, marking the queue as needing a restart is not seen from __blk_mq_free_request() and blk_mq_sched_restart() not executed leading to the dispatch stall under 100% write workloads. Fix this by moving the call to blk_mq_sched_mark_restart_hctx() from dd_dispatch_request() into dd_finish_request() under the zone lock to ensure full mutual exclusion between write request dispatch selection and zone unlock on write request completion. Fixes: 7211aef86f79 ("block: mq-deadline: Fix write completion handling") Cc: stable@vger.kernel.org Reported-by: Hans Holmberg <Hans.Holmberg@wdc.com> Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: add missing NULL check in ioc_cpd_alloc()Tejun Heo2019-08-301-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | ioc_cpd_alloc() forgot to check NULL return from kzalloc(). Add it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: fix missing free on error path of blk_iocost_init()Tejun Heo2019-08-291-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_iocost_init() forgot to free its percpu stat on the error path. Fix it. Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Reported-by: Hillf Danton <hdanton@sina.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: add tools/cgroup/iocost_coef_gen.pyTejun Heo2019-08-281-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | Add a script which can be used to generate device-specific iocost linear model coefficients. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: add tools/cgroup/iocost_monitor.pyTejun Heo2019-08-281-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of mucking with debugfs and ->pd_stat(), add drgn based monitoring script. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: implement blk-iocostTejun Heo2019-08-284-0/+2385
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset implements IO cost model based work-conserving proportional controller. While io.latency provides the capability to comprehensively prioritize and protect IOs depending on the cgroups, its protection is binary - the lowest latency target cgroup which is suffering is protected at the cost of all others. In many use cases including stacking multiple workload containers in a single system, it's necessary to distribute IO capacity with better granularity. One challenge of controlling IO resources is the lack of trivially observable cost metric. The most common metrics - bandwidth and iops - can be off by orders of magnitude depending on the device type and IO pattern. However, the cost isn't a complete mystery. Given several key attributes, we can make fairly reliable predictions on how expensive a given stream of IOs would be, at least compared to other IO patterns. The function which determines the cost of a given IO is the IO cost model for the device. This controller distributes IO capacity based on the costs estimated by such model. The more accurate the cost model the better but the controller adapts based on IO completion latency and as long as the relative costs across differents IO patterns are consistent and sensible, it'll adapt to the actual performance of the device. Currently, the only implemented cost model is a simple linear one with a few sets of default parameters for different classes of device. This covers most common devices reasonably well. All the infrastructure to tune and add different cost models is already in place and a later patch will also allow using bpf progs for cost models. Please see the top comment in blk-iocost.c and documentation for more details. v2: Rebased on top of RQ_ALLOC_TIME changes and folded in Rik's fix for a divide-by-zero bug in current_hweight() triggered by zero inuse_sum. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Andy Newell <newella@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-mq: add optional request->alloc_time_nsTejun Heo2019-08-282-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are currently two start time timestamps - start_time_ns and io_start_time_ns. The former marks the request allocation and and the second issue-to-device time. The planned io.weight controller needs to measure the total time bios take to execute after it leaves rq_qos including the time spent waiting for request to become available, which can easily dominate on saturated devices. This patch adds request->alloc_time_ns which records when the request allocation attempt started. As it isn't used for the usual stats, make it optional behind CONFIG_BLK_RQ_ALLOC_TIME and QUEUE_FLAG_RQ_ALLOC_TIME so that it can be compiled out when there are no users and it's active only on queues which need it even when compiled in. v2: s/pre_start_time/alloc_time/ and add CONFIG_BLK_RQ_ALLOC_TIME gating as suggested by Jens. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: s/RQ_QOS_CGROUP/RQ_QOS_LATENCY/Tejun Heo2019-08-282-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | io.weight is gonna be another rq_qos cgroup mechanism. Let's rename RQ_QOS_CGROUP which is being used by io.latency to RQ_QOS_LATENCY in preparation. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block/rq_qos: implement rq_qos_ops->queue_depth_changed()Tejun Heo2019-08-285-15/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wbt already gets queue depth changed notification through wbt_set_queue_depth(). Generalize it into rq_qos_ops->queue_depth_changed() so that other rq_qos policies can easily hook into the events too. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block/rq_qos: add rq_qos_merge()Tejun Heo2019-08-283-0/+22
| | | | | | | | | | | | | | | | | | | | | Add a merge hook for rq_qos. This will be used by io.weight. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: separate blkcg_conf_get_disk() out of blkg_conf_prep()Tejun Heo2019-08-281-19/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | Separate out blkcg_conf_get_disk() so that it can be used by blkcg policy interface file input parsers before the policy is actually enabled. This doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: make ->cpd_init_fn() optionalTejun Heo2019-08-281-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | For policies which can do enough initialization from ->cpd_alloc_fn(), make ->cpd_init_fn() optional. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn()Tejun Heo2019-08-284-9/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of @node, pass in @q and @blkcg so that the alloc function has more context. This doesn't cause any behavior change and will be used by io.weight implementation. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: split .sysfs_lock into two locksMing Lei2019-08-275-33/+83
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernfs built-in lock of 'kn->count' is held in sysfs .show/.store path. Meantime, inside block's .show/.store callback, q->sysfs_lock is required. However, when mq & iosched kobjects are removed via blk_mq_unregister_dev() & elv_unregister_queue(), q->sysfs_lock is held too. This way causes AB-BA lock because the kernfs built-in lock of 'kn-count' is required inside kobject_del() too, see the lockdep warning[1]. On the other hand, it isn't necessary to acquire q->sysfs_lock for both blk_mq_unregister_dev() & elv_unregister_queue() because clearing REGISTERED flag prevents storing to 'queue/scheduler' from being happened. Also sysfs write(store) is exclusive, so no necessary to hold the lock for elv_unregister_queue() when it is called in switching elevator path. So split .sysfs_lock into two: one is still named as .sysfs_lock for covering sync .store, the other one is named as .sysfs_dir_lock for covering kobjects and related status change. sysfs itself can handle the race between add/remove kobjects and showing/storing attributes under kobjects. For switching scheduler via storing to 'queue/scheduler', we use the queue flag of QUEUE_FLAG_REGISTERED with .sysfs_lock for avoiding the race, then we can avoid to hold .sysfs_lock during removing/adding kobjects. [1] lockdep warning ====================================================== WARNING: possible circular locking dependency detected 5.3.0-rc3-00044-g73277fc75ea0 #1380 Not tainted ------------------------------------------------------ rmmod/777 is trying to acquire lock: 00000000ac50e981 (kn->count#202){++++}, at: kernfs_remove_by_name_ns+0x59/0x72 but task is already holding lock: 00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10b which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&q->sysfs_lock){+.+.}: __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 __mutex_lock+0x14a/0xa9b blk_mq_hw_sysfs_show+0x63/0xb6 sysfs_kf_seq_show+0x11f/0x196 seq_read+0x2cd/0x5f2 vfs_read+0xc7/0x18c ksys_read+0xc4/0x13e do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (kn->count#202){++++}: check_prev_add+0x5d2/0xc45 validate_chain+0xed3/0xf94 __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 __kernfs_remove+0x237/0x40b kernfs_remove_by_name_ns+0x59/0x72 remove_files+0x61/0x96 sysfs_remove_group+0x81/0xa4 sysfs_remove_groups+0x3b/0x44 kobject_del+0x44/0x94 blk_mq_unregister_dev+0x83/0xdd blk_unregister_queue+0xa0/0x10b del_gendisk+0x259/0x3fa null_del_dev+0x8b/0x1c3 [null_blk] null_exit+0x5c/0x95 [null_blk] __se_sys_delete_module+0x204/0x337 do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->sysfs_lock); lock(kn->count#202); lock(&q->sysfs_lock); lock(kn->count#202); *** DEADLOCK *** 2 locks held by rmmod/777: #0: 00000000e69bd9de (&lock){+.+.}, at: null_exit+0x2e/0x95 [null_blk] #1: 00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10b stack backtrace: CPU: 0 PID: 777 Comm: rmmod Not tainted 5.3.0-rc3-00044-g73277fc75ea0 #1380 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180724_192412-buildhw-07.phx4 Call Trace: dump_stack+0x9a/0xe6 check_noncircular+0x207/0x251 ? print_circular_bug+0x32a/0x32a ? find_usage_backwards+0x84/0xb0 check_prev_add+0x5d2/0xc45 validate_chain+0xed3/0xf94 ? check_prev_add+0xc45/0xc45 ? mark_lock+0x11b/0x804 ? check_usage_forwards+0x1ca/0x1ca __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 ? kernfs_remove_by_name_ns+0x59/0x72 __kernfs_remove+0x237/0x40b ? kernfs_remove_by_name_ns+0x59/0x72 ? kernfs_next_descendant_post+0x7d/0x7d ? strlen+0x10/0x23 ? strcmp+0x22/0x44 kernfs_remove_by_name_ns+0x59/0x72 remove_files+0x61/0x96 sysfs_remove_group+0x81/0xa4 sysfs_remove_groups+0x3b/0x44 kobject_del+0x44/0x94 blk_mq_unregister_dev+0x83/0xdd blk_unregister_queue+0xa0/0x10b del_gendisk+0x259/0x3fa ? disk_events_poll_msecs_store+0x12b/0x12b ? check_flags+0x1ea/0x204 ? mark_held_locks+0x1f/0x7a null_del_dev+0x8b/0x1c3 [null_blk] null_exit+0x5c/0x95 [null_blk] __se_sys_delete_module+0x204/0x337 ? free_module+0x39f/0x39f ? blkcg_maybe_throttle_current+0x8a/0x718 ? rwlock_bug+0x62/0x62 ? __blkcg_punt_bio_submit+0xd0/0xd0 ? trace_hardirqs_on_thunk+0x1a/0x20 ? mark_held_locks+0x1f/0x7a ? do_syscall_64+0x4c/0x295 do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fb696cdbe6b Code: 73 01 c3 48 8b 0d 1d 20 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 008 RSP: 002b:00007ffec9588788 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559e589137c0 RCX: 00007fb696cdbe6b RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559e58913828 RBP: 0000000000000000 R08: 00007ffec9587701 R09: 0000000000000000 R10: 00007fb696d4eae0 R11: 0000000000000206 R12: 00007ffec95889b0 R13: 00007ffec95896b3 R14: 0000559e58913260 R15: 0000559e589137c0 Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: add helper for checking if queue is registeredMing Lei2019-08-273-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are 4 users which check if queue is registered, so add one helper to check it. Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-mq: don't hold q->sysfs_lock in blk_mq_map_swqueueMing Lei2019-08-271-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_mq_map_swqueue() is called from blk_mq_init_allocated_queue() and blk_mq_update_nr_hw_queues(). For the former caller, the kobject isn't exposed to userspace yet. For the latter caller, hctx sysfs entries and debugfs are un-registered before updating nr_hw_queues. On the other hand, commit 2f8f1336a48b ("blk-mq: always free hctx after request queue is freed") moves freeing hctx into queue's release handler, so there won't be race with queue release path too. So don't hold q->sysfs_lock in blk_mq_map_swqueue(). Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: don't hold q->sysfs_lock in elevator_init_mqMing Lei2019-08-271-9/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original comment says: q->sysfs_lock must be held to provide mutual exclusion between elevator_switch() and here. Which is simply wrong. elevator_init_mq() is only called from blk_mq_init_allocated_queue, which is always called before the request queue is registered via blk_register_queue(), for dm-rq or normal rq based driver. However, queue's kobject is only exposed and added to sysfs in blk_register_queue(). So there isn't such race between elevator_switch() and elevator_init_mq(). So avoid to hold q->sysfs_lock in elevator_init_mq(). Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Remove blk_mq_register_dev()Bart Van Assche2019-08-271-11/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function has no callers. Hence remove it. Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: move same page handling from __bio_add_pc_page to the callersChristoph Hellwig2019-08-221-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | Hiding page refcount manipulation inside a low-level bio helper is somewhat awkward. Instead return the same page information to the callers, where it fits in much better. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: create a bio_try_merge_pc_page helperChristoph Hellwig2019-08-221-24/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Passsthrough bio handling should be the same as normal bio handling, except that we need to take hardware limitations into account. Thus use the common try_merge implementation after checking the hardware limits. This changes behavior in that we now also check segment and dma boundary settings for same page merges, which is a little more work but has no effect as those need to be larger than the page size. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: improve the gap check in __bio_add_pc_pageChristoph Hellwig2019-08-221-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we can add more data into an existing segment we do not create a gap per definition, so move the check for a gap after the attempt to merge into the segment. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: sed-opal: Removed duplicate OPAL_METHOD_LENGTH definitionRevanth Rajashekar2019-08-201-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original commit adding the sed-opal library by mistake added two definitions of OPAL_METHOD_LENGTH, remove one of them. Signed-off-by: Revanth Rajashekar <revanth.rajashekar@intel.com> Reviewed-by: Scott Bauer <sbauer@plzdonthack.me> Reviewed-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: sed-opal: Remove always false conditional statementRevanth Rajashekar2019-08-201-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the function 'response_parse', num_entries will never be 0 as slen is checked for 0. Hence, the condition 'if (num_entries == 0)' can never be true. Signed-off-by: Revanth Rajashekar <revanth.rajashekar@intel.com> Reviewed-by: Scott Bauer <sbauer@plzdonthack.me> Reviewed-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: sed-opal: Add/remove spacesRevanth Rajashekar2019-08-202-6/+42
| | | | | | | | | | | | | | | | | | | | | Signed-off-by: Revanth Rajashekar <revanth.rajashekar@intel.com> Reviewed-by: Scott Bauer <sbauer@plzdonthack.me> Reviewed-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: remove struct request_queue queue_headJunxiao Bi2019-08-191-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dispatch list is not used any more, as the legacy block IO stack has been removed. Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: annotate refault stalls from IO submissionJohannes Weiner2019-08-142-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | psi tracks the time tasks wait for refaulting pages to become uptodate, but it does not track the time spent submitting the IO. The submission part can be significant if backing storage is contended or when cgroup throttling (io.latency) is in effect - a lot of time is spent in submit_bio(). In that case, we underreport memory pressure. Annotate submit_bio() to account submission time as memory stall when the bio is reading userspace workingset pages. Tested-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-mq: Fix memory leak in blk_mq_init_allocated_queue error handlingzhengbin2019-08-121-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | If blk_mq_init_allocated_queue->elevator_init_mq fails, need to release the previously requested resources. Fixes: d34849913819 ("blk-mq-sched: allow setting of default IO scheduler") Signed-off-by: zhengbin <zhengbin13@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: stop exporting bio_map_kernHans Holmberg2019-08-061-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that there no module users left of bio_map_kern, stop exporting the symbol. Reviewed-by: Javier González <javier@javigon.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hans Holmberg <hans@owltronix.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-mq: balance mapping between present CPUs and queuesMing Lei2019-08-041-7/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Spread queues among present CPUs first, then building mapping on other non-present CPUs. So we can minimize count of dead queues which are mapped by un-present CPUs only. Then bad IO performance can be avoided by unbalanced mapping between present CPUs and queues. The similar policy has been applied on Managed IRQ affinity. Cc: Yi Zhang <yi.zhang@redhat.com> Reported-by: Yi Zhang <yi.zhang@redhat.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-zoned: implement REQ_OP_ZONE_RESET_ALLChaitanya Kulkarni2019-08-042-0/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This implements REQ_OP_ZONE_RESET_ALL as a special case of the block device zone reset operations where we just simply issue bio with the newly introduced req op. We issue this req op when the number of sectors is equal to the device's partition's number of sectors and device has no partitions. We also add support so that blk_op_str() can print the new reset-all zone operation. This patch also adds a generic make request check for newly introduced REQ_OP_ZONE_RESET_ALL req_opf. We simply return error when queue is zoned and reset-all flag is not set for REQ_OP_ZONE_RESET_ALL. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Fix a comment in blk_cleanup_queue()Bart Van Assche2019-08-041-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change a reference to the legacy block layer into a reference to blk-mq. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: James Smart <james.smart@broadcom.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Dongli Zhang <dongli.zhang@oracle.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-06 01:45:31 +0000