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* 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 Moal2019-09-063-3/+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 Moal2019-09-061-7/+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 Moal2019-09-063-11/+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 Moal2019-09-063-19/+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 Moal2019-09-062-15/+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 Heo2019-08-291-0/+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 Heo2019-08-291-0/+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 Heo2019-08-294-0/+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 Heo2019-08-292-2/+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 Heo2019-08-292-5/+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 Heo2019-08-295-15/+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 Heo2019-08-293-0/+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 Heo2019-08-291-19/+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 Heo2019-08-291-1/+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 Heo2019-08-294-9/+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 Lei2019-08-051-7/+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 Kulkarni2019-08-052-0/+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 Assche2019-08-051-1/+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>
* block: Improve physical block alignment of split biosBart Van Assche2019-08-051-4/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Consider the following example: * The logical block size is 4 KB. * The physical block size is 8 KB. * max_sectors equals (16 KB >> 9) sectors. * A non-aligned 4 KB and an aligned 64 KB bio are merged into a single non-aligned 68 KB bio. The current behavior is to split such a bio into (16 KB + 16 KB + 16 KB + 16 KB + 4 KB). The start of none of these five bio's is aligned to a physical block boundary. This patch ensures that such a bio is split into four aligned and one non-aligned bio instead of being split into five non-aligned bios. This improves performance because most block devices can handle aligned requests faster than non-aligned requests. Since the physical block size is larger than or equal to the logical block size, this patch preserves the guarantee that the returned value is a multiple of the logical block size. 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: Simplify blk_bio_segment_split()Bart Van Assche2019-08-051-35/+33
| | | | | | | | | | | | Move the max_sectors check into bvec_split_segs() such that a single call to that function can do all the necessary checks. This patch optimizes the fast path further, namely if a bvec fits in a page. Cc: Christoph Hellwig <hch@lst.de> 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: Simplify bvec_split_segs()Bart Van Assche2019-08-051-9/+7
| | | | | | | | | | | | | Simplify this function by by removing two if-tests. Other than requiring that the @sectors pointer is not NULL, this patch does not change the behavior of bvec_split_segs(). Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: Christoph Hellwig <hch@lst.de> 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: Document the bio splitting functionsBart Van Assche2019-08-052-2/+45
| | | | | | | | | | | | Since what the bio splitting functions do is nontrivial, document these functions. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> 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: Declare several function pointer arguments 'const'Bart Van Assche2019-08-051-3/+4
| | | | | | | | | | | | | Make it clear to the compiler and also to humans that the functions that query request queue properties do not modify any member of the request_queue data structure. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> 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>
* blk-mq: remove blk_mq_complete_request_syncMing Lei2019-08-051-7/+0
| | | | | | | | | | | | | | blk_mq_tagset_wait_completed_request() has been applied for waiting for completed request's fn, so not necessary to use blk_mq_complete_request_sync() any more. Cc: Max Gurtovoy <maxg@mellanox.com> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Keith Busch <keith.busch@intel.com> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: introduce blk_mq_tagset_wait_completed_request()Ming Lei2019-08-051-0/+32
| | | | | | | | | | | | | | | | | | | | | | blk-mq may schedule to call queue's complete function on remote CPU via IPI, but doesn't provide any way to synchronize the request's complete fn. The current queue freeze interface can't provide the synchonization because aborted requests stay at blk-mq queues during EH. In some driver's EH(such as NVMe), hardware queue's resource may be freed & re-allocated. If the completed request's complete fn is run finally after the hardware queue's resource is released, kernel crash will be triggered. Prepare for fixing this kind of issue by introducing blk_mq_tagset_wait_completed_request(). Cc: Max Gurtovoy <maxg@mellanox.com> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Keith Busch <keith.busch@intel.com> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: introduce blk_mq_request_completed()Ming Lei2019-08-051-0/+6
| | | | | | | | | | | | | | | NVMe needs this function to decide if one request to be aborted has been completed in normal IO path already. So introduce it. Cc: Max Gurtovoy <maxg@mellanox.com> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Keith Busch <keith.busch@intel.com> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge tag 'for-linus-20190726-2' of git://git.kernel.dk/linux-blockLinus Torvalds2019-07-271-1/+2
|\ | | | | | | | | | | | | | | Pull block DMA segment fix from Jens Axboe: "Here's the virtual boundary segment size fix" * tag 'for-linus-20190726-2' of git://git.kernel.dk/linux-block: block: fix max segment size handling in blk_queue_virt_boundary
| * block: fix max segment size handling in blk_queue_virt_boundaryChristoph Hellwig2019-07-261-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | We should only set the max segment size to unlimited if we actually have a virt boundary. Otherwise we accidentally clear that limit when called from the SCSI midlayer, which always calls blk_queue_virt_boundary, even if that mask is 0. Fixes: 7ad388d8e4c7 ("scsi: core: add a host / host template field for the virt boundary") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | Merge tag 'for-linus-20190726' of git://git.kernel.dk/linux-blockLinus Torvalds2019-07-267-45/+62
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block fixes from Jens Axboe: - Several io_uring fixes/improvements: - Blocking fix for O_DIRECT (me) - Latter page slowness for registered buffers (me) - Fix poll hang under certain conditions (me) - Defer sequence check fix for wrapped rings (Zhengyuan) - Mismatch in async inc/dec accounting (Zhengyuan) - Memory ordering issue that could cause stall (Zhengyuan) - Track sequential defer in bytes, not pages (Zhengyuan) - NVMe pull request from Christoph - Set of hang fixes for wbt (Josef) - Redundant error message kill for libahci (Ding) - Remove unused blk_mq_sched_started_request() and related ops (Marcos) - drbd dynamic alloc shash descriptor to reduce stack use (Arnd) - blkcg ->pd_stat() non-debug print (Tejun) - bcache memory leak fix (Wei) - Comment fix (Akinobu) - BFQ perf regression fix (Paolo) * tag 'for-linus-20190726' of git://git.kernel.dk/linux-block: (24 commits) io_uring: ensure ->list is initialized for poll commands Revert "nvme-pci: don't create a read hctx mapping without read queues" nvme: fix multipath crash when ANA is deactivated nvme: fix memory leak caused by incorrect subsystem free nvme: ignore subnqn for ADATA SX6000LNP drbd: dynamically allocate shash descriptor block: blk-mq: Remove blk_mq_sched_started_request and started_request bcache: fix possible memory leak in bch_cached_dev_run() io_uring: track io length in async_list based on bytes io_uring: don't use iov_iter_advance() for fixed buffers block: properly handle IOCB_NOWAIT for async O_DIRECT IO blk-mq: allow REQ_NOWAIT to return an error inline io_uring: add a memory barrier before atomic_read rq-qos: use a mb for got_token rq-qos: set ourself TASK_UNINTERRUPTIBLE after we schedule rq-qos: don't reset has_sleepers on spurious wakeups rq-qos: fix missed wake-ups in rq_qos_throttle wait: add wq_has_single_sleeper helper block, bfq: check also in-flight I/O in dispatch plugging block: fix sysfs module parameters directory path in comment ...
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