- 25 9月, 2014 1 次提交
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由 Tejun Heo 提交于
This reverts commit 0a30288d, which was a temporary fix for SCSI blk-mq stall issue. The following patches will fix the issue properly by introducing atomic mode to percpu_ref. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de>
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- 24 9月, 2014 1 次提交
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由 Tejun Heo 提交于
blk-mq uses percpu_ref for its usage counter which tracks the number of in-flight commands and used to synchronously drain the queue on freeze. percpu_ref shutdown takes measureable wallclock time as it involves a sched RCU grace period. This means that draining a blk-mq takes measureable wallclock time. One would think that this shouldn't matter as queue shutdown should be a rare event which takes place asynchronously w.r.t. userland. Unfortunately, SCSI probing involves synchronously setting up and then tearing down a lot of request_queues back-to-back for non-existent LUNs. This means that SCSI probing may take more than ten seconds when scsi-mq is used. This will be properly fixed by implementing a mechanism to keep q->mq_usage_counter in atomic mode till genhd registration; however, that involves rather big updates to percpu_ref which is difficult to apply late in the devel cycle (v3.17-rc6 at the moment). As a stop-gap measure till the proper fix can be implemented in the next cycle, this patch introduces __percpu_ref_kill_expedited() and makes blk_mq_freeze_queue() use it. This is heavy-handed but should work for testing the experimental SCSI blk-mq implementation. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-by: NChristoph Hellwig <hch@infradead.org> Link: http://lkml.kernel.org/g/20140919113815.GA10791@lst.de Fixes: add703fd ("blk-mq: use percpu_ref for mq usage count") Cc: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Tested-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 23 9月, 2014 5 次提交
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由 Jens Axboe 提交于
When requests are retried due to hw or sw resource shortages, we often stop the associated hardware queue. So ensure that we restart the queues when running the requeue work, otherwise the queue run will be a no-op. Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Jens Axboe 提交于
__blk_mq_alloc_rq_maps() can be invoked multiple times, if we scale back the queue depth if we are low on memory. So don't clear set->tags when we fail, this is handled directly in the parent function, blk_mq_alloc_tag_set(). Reported-by: NRobert Elliott <Elliott@hp.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Christoph Hellwig 提交于
We should not insert requests into the flush state machine from blk_mq_insert_request. All incoming flush requests come through blk_{m,s}q_make_request and are handled there, while blk_execute_rq_nowait should only be called for BLOCK_PC requests. All other callers deal with requests that already went through the flush statemchine and shouldn't be reinserted into it. Reported-by: NRobert Elliott <Elliott@hp.com> Debugged-by: NMing Lei <ming.lei@canonical.com> Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 David Hildenbrand 提交于
This patch should fix the bug reported in https://lkml.org/lkml/2014/9/11/249. We have to initialize at least the atomic_flags and the cmd_flags when allocating storage for the requests. Otherwise blk_mq_timeout_check() might dereference uninitialized pointers when racing with the creation of a request. Also move the reset of cmd_flags for the initializing code to the point where a request is freed. So we will never end up with pending flush request indicators that might trigger dereferences of invalid pointers in blk_mq_timeout_check(). Cc: stable@vger.kernel.org Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com> Reported-by: NPaulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> Tested-by: NPaulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Jens Axboe 提交于
When we start the request, we set the deadline and flip the bits marking the request as started and non-complete. However, it's important that the deadline store is ordered before flipping the bits, otherwise we could have a small window where the request is marked started but with an invalid deadline. This can confuse the timeout handling. Suggested-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 10 9月, 2014 1 次提交
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由 Jens Axboe 提交于
If we are running in a kdump environment, resources are scarce. For some SCSI setups with a huge set of shared tags, we run out of memory allocating what the drivers is asking for. So implement a scale back logic to reduce the tag depth for those cases, allowing the driver to successfully load. We should extend this to detect low memory situations, and implement a sane fallback for those (1 queue, 64 tags, or something like that). Tested-by: NRobert Elliott <elliott@hp.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 08 9月, 2014 1 次提交
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由 Tejun Heo 提交于
Percpu allocator now supports allocation mask. Add @gfp to percpu_ref_init() so that !GFP_KERNEL allocation masks can be used with percpu_refs too. This patch doesn't make any functional difference. v2: blk-mq conversion was missing. Updated. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Kent Overstreet <koverstreet@google.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Cc: Jens Axboe <axboe@kernel.dk>
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- 04 9月, 2014 1 次提交
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由 Robert Elliott 提交于
In blk-mq.c blk_mq_alloc_tag_set, if: set->tags = kmalloc_node() succeeds, but one of the blk_mq_init_rq_map() calls fails, goto out_unwind; needs to free set->tags so the caller is not obligated to do so. None of the current callers (null_blk, virtio_blk, virtio_blk, or the forthcoming scsi-mq) do so. set->tags needs to be set to NULL after doing so, so other tag cleanup logic doesn't try to free a stale pointer later. Also set it to NULL in blk_mq_free_tag_set. Tested with error injection on the forthcoming scsi-mq + hpsa combination. Signed-off-by: NRobert Elliott <elliott@hp.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 23 8月, 2014 1 次提交
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由 Tony Battersby 提交于
This patch fixes code such as the following with scsi-mq enabled: rq = blk_get_request(...); blk_rq_set_block_pc(rq); rq->cmd = my_cmd_buffer; /* separate CDB buffer */ blk_execute_rq_nowait(...); Code like this appears in e.g. sg_start_req() in drivers/scsi/sg.c (for large CDBs only). Without this patch, scsi_mq_prep_fn() will set rq->cmd back to rq->__cmd, causing the wrong CDB to be sent to the device. Signed-off-by: NTony Battersby <tonyb@cybernetics.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 22 8月, 2014 3 次提交
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由 Tejun Heo 提交于
While converting to percpu_ref for freezing, add703fd ("blk-mq: use percpu_ref for mq usage count") incorrectly made blk_mq_freeze_queue() misbehave when freezing is nested due to percpu_ref_kill() being invoked on an already killed ref. Fix it by making blk_mq_freeze_queue() kill and kick the queue only for the outermost freeze attempt. All the nested ones can simply wait for the ref to reach zero. While at it, remove unnecessary @wake initialization from blk_mq_unfreeze_queue(). Signed-off-by: NTejun Heo <tj@kernel.org> Reported-by: NMing Lei <ming.lei@canonical.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Jens Axboe 提交于
Just grammar or spelling errors, nothing major. Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Jens Axboe 提交于
blk-mq uses BLK_MQ_F_SHOULD_MERGE, as set by the driver at init time, to determine whether it should merge IO or not. However, this could also be disabled by the admin, if merging is switched off through sysfs. So check the general queue state as well before attempting to merge IO. Reported-by: NRob Elliott <Elliott@hp.com> Tested-by: NRob Elliott <Elliott@hp.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 16 8月, 2014 1 次提交
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由 Ming Lei 提交于
Before doing queue release, the queue has been freezed already by blk_cleanup_queue(), so needn't to freeze queue for deleting tag set. This patch fixes the WARNING of "percpu_ref_kill() called more than once!" which is triggered during unloading block driver. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: NMing Lei <ming.lei@canonical.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 02 7月, 2014 5 次提交
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由 Tejun Heo 提交于
Currently, blk-mq uses a percpu_counter to keep track of how many usages are in flight. The percpu_counter is drained while freezing to ensure that no usage is left in-flight after freezing is complete. blk_mq_queue_enter/exit() and blk_mq_[un]freeze_queue() implement this per-cpu gating mechanism. This type of code has relatively high chance of subtle bugs which are extremely difficult to trigger and it's way too hairy to be open coded in blk-mq. percpu_ref can serve the same purpose after the recent changes. This patch replaces the open-coded per-cpu usage counting and draining mechanism with percpu_ref. blk_mq_queue_enter() performs tryget_live on the ref and exit() performs put. blk_mq_freeze_queue() kills the ref and waits until the reference count reaches zero. blk_mq_unfreeze_queue() revives the ref and wakes up the waiters. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Cc: Kent Overstreet <kmo@daterainc.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Tejun Heo 提交于
Keeping __blk_mq_drain_queue() as a separate function doesn't buy us anything and it's gonna be further simplified. Let's flatten it into its caller. This patch doesn't make any functional change. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Tejun Heo 提交于
blk_mq freezing is entangled with generic bypassing which bypasses blkcg and io scheduler and lets IO requests fall through the block layer to the drivers in FIFO order. This allows forward progress on IOs with the advanced features disabled so that those features can be configured or altered without worrying about stalling IO which may lead to deadlock through memory allocation. However, generic bypassing doesn't quite fit blk-mq. blk-mq currently doesn't make use of blkcg or ioscheds and it maps bypssing to freezing, which blocks request processing and drains all the in-flight ones. This causes problems as bypassing assumes that request processing is online. blk-mq works around this by conditionally allowing request processing for the problem case - during queue initialization. Another weirdity is that except for during queue cleanup, bypassing started on the generic side prevents blk-mq from processing new requests but doesn't drain the in-flight ones. This shouldn't break anything but again highlights that something isn't quite right here. The root cause is conflating blk-mq freezing and generic bypassing which are two different mechanisms. The only intersecting purpose that they serve is during queue cleanup. Let's properly separate blk-mq freezing from generic bypassing and simply use it where necessary. * request_queue->mq_freeze_depth is added and blk_mq_[un]freeze_queue() now operate on this counter instead of ->bypass_depth. The replacement for QUEUE_FLAG_BYPASS isn't added but the counter is tested directly. This will be further updated by later changes. * blk_mq_drain_queue() is dropped and "__" prefix is dropped from blk_mq_freeze_queue(). Queue cleanup path now calls blk_mq_freeze_queue() directly. * blk_queue_enter()'s fast path condition is simplified to simply check @q->mq_freeze_depth. Previously, the condition was !blk_queue_dying(q) && (!blk_queue_bypass(q) || !blk_queue_init_done(q)) mq_freeze_depth is incremented right after dying is set and blk_queue_init_done() exception isn't necessary as blk-mq doesn't start frozen, which only leaves the blk_queue_bypass() test which can be replaced by @q->mq_freeze_depth test. This change simplifies the code and reduces confusion in the area. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Tejun Heo 提交于
Currently, both blk_queue_bypass_start() and blk_mq_freeze_queue() skip queue draining if bypass_depth was already above zero. The assumption is that the one which bumped the bypass_depth should have performed draining already; however, there's nothing which prevents a new instance of bypassing/freezing from starting before the previous one finishes draining. The current code may allow the later bypassing/freezing instances to complete while there still are in-flight requests which haven't finished draining. Fix it by draining regardless of bypass_depth. We still skip draining from blk_queue_bypass_start() while the queue is initializing to avoid introducing excessive delays during boot. INIT_DONE setting is moved above the initial blk_queue_bypass_end() so that bypassing attempts can't slip inbetween. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Tejun Heo 提交于
blk-mq uses a percpu_counter to keep track of how many usages are in flight. The percpu_counter is drained while freezing to ensure that no usage is left in-flight after freezing is complete. blk_mq_queue_enter/exit() and blk_mq_[un]freeze_queue() implement this per-cpu gating mechanism; unfortunately, it contains a subtle bug - smp_wmb() in blk_mq_queue_enter() doesn't prevent prevent the cpu from fetching @q->bypass_depth before incrementing @q->mq_usage_counter and if freezing happens inbetween the caller can slip through and freezing can be complete while there are active users. Use smp_mb() instead so that bypass_depth and mq_usage_counter modifications and tests are properly interlocked. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 25 6月, 2014 1 次提交
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由 Jens Axboe 提交于
Currently it calls __blk_mq_run_hw_queue(), which depends on the CPU placement being correct. This means it's not possible to call blk_mq_start_hw_queues(q) from a context that is correct for all queues, leading to triggering the WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)); in __blk_mq_run_hw_queue(). Reported-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 14 6月, 2014 2 次提交
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由 Christoph Hellwig 提交于
Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Christoph Hellwig 提交于
If we need to drain a queue we need to run all queues, even if they are marked stopped to make sure the driver has a chance to error out on all queued requests. This fixes surprise removal with scsi-mq. Reported-by: NBart Van Assche <bvanassche@acm.org> Tested-by: NBart Van Assche <bvanassche@acm.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 10 6月, 2014 1 次提交
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由 Ming Lei 提交于
This way will become consistent with non-mq case, also avoid to update rq->deadline twice for mq. The comment said: "We do this early, to ensure we are on the right CPU.", but no percpu stuff is used in blk_add_timer(), so it isn't necessary. Even when inserting from plug list, there is no such guarantee at all. Signed-off-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 09 6月, 2014 1 次提交
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由 Jens Axboe 提交于
The blk-mq core only initializes this if io stats are enabled, since blk-mq only reads the field in that case. But drivers could potentially use it internally, so ensure that we always set it to the current time when the request is allocated. Reported-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 07 6月, 2014 2 次提交
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由 Jens Axboe 提交于
It'll be used in blk_mq_start_request() to set a potential timeout for the request, so clear it to zero at alloc time to ensure that we know if someone has set it or not. Fixes random early timeouts on NVMe testing. Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Keith Busch 提交于
If the queue is going away, don't let new allocs or queueing happen on it. Go through the normal wait process, and exit with ENODEV in that case. Signed-off-by: NKeith Busch <keith.busch@intel.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 06 6月, 2014 1 次提交
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由 Jens Axboe 提交于
For some scsi-mq cases, the tag map can be huge. So increase the max number of tags we support. Additionally, don't fail with EINVAL if a user requests too many tags. Warn that the tag depth has been adjusted down, and store the new value inside the tag_set passed in. Signed-off-by: NJens Axboe <axboe@fb.com>
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- 05 6月, 2014 1 次提交
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由 Jens Axboe 提交于
We currently pass in the hardware queue, and get the tags from there. But from scsi-mq, with a shared tag space, it's a lot more convenient to pass in the blk_mq_tags instead as the hardware queue isn't always directly available. So instead of having to re-map to a given hardware queue from rq->mq_ctx, just pass in the tags structure. Signed-off-by: NJens Axboe <axboe@fb.com>
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- 04 6月, 2014 5 次提交
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由 Jens Axboe 提交于
When the code was collapsed to avoid duplication, the recent patch for ensuring that a queue is idled before free was dropped, which was added by commit 19c5d84f. Add back the blk_mq_tag_idle(), to ensure we don't leak a reference to an active queue when it is freed. Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Jens Axboe 提交于
blk_mq_map_request() can return NULL if we fail entering the queue (dying, or removed), in which case it has already ended IO on the bio. So nothing more to do, except just return. Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Ming Lei 提交于
'struct blk_mq_ctx' is __percpu, so add the annotation and fix the sparse warning reported from Fengguang: [block:for-linus 2/3] block/blk-mq.h:75:16: sparse: incorrect type in initializer (different address spaces) Reported-by: Nkbuild test robot <fengguang.wu@intel.com> Signed-off-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Ming Lei 提交于
blk_mq_put_ctx() has to be called before io_schedule() in bt_get(). This patch fixes the problem by taking similar approach from percpu_ida allocation for the situation. Signed-off-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Ming Lei 提交于
The blk-mq tag code need these helpers. Signed-off-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 31 5月, 2014 2 次提交
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由 Jens Axboe 提交于
We have callers outside of the blk-mq proper (like timeouts) that want to call __blk_mq_complete_request(), so rename the function and put the decision code for whether to use ->softirq_done_fn or blk_mq_endio() into __blk_mq_complete_request(). This also makes the interface more logical again. blk_mq_complete_request() attempts to atomically mark the request completed, and calls __blk_mq_complete_request() if successful. __blk_mq_complete_request() then just ends the request. Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Jens Axboe 提交于
Commit 07068d5b added a direct-to-hw-queue mode, but this mode needs to remember to add the request timeout handler as well. Without it, we don't track timeouts for these requests. Signed-off-by: NJens Axboe <axboe@fb.com>
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- 30 5月, 2014 3 次提交
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由 Jens Axboe 提交于
Currently blk-mq registers all the hardware queues in sysfs, regardless of whether it uses them (e.g. they have CPU mappings) or not. The unused hardware queues lack the cpux/ directories, and the other sysfs entries (like active, pending, etc) are all zeroes. Change this so that sysfs correctly reflects the current mappings of the hardware queues. Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Shaohua Li 提交于
flush request is special, which borrows the tag from the parent request. Hence blk_mq_tag_to_rq needs special handling to return the flush request from the tag. Signed-off-by: NShaohua Li <shli@fusionio.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Jens Axboe 提交于
We currently clear a lot more than we need to, so make that a bit more clever. Make some of the init dependent on features, like only setting start_time if we are going to use it. Signed-off-by: NJens Axboe <axboe@fb.com>
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- 29 5月, 2014 1 次提交
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由 Jens Axboe 提交于
If devices are not SG starved, we waste a lot of time potentially collapsing SG segments. Enough that 1.5% of the CPU time goes to this, at only 400K IOPS. Add a queue flag, QUEUE_FLAG_NO_SG_MERGE, which just returns the number of vectors in a bio instead of looping over all segments and checking for collapsible ones. Add a BLK_MQ_F_SG_MERGE flag so that drivers can opt-in on the sg merging, if they so desire. Signed-off-by: NJens Axboe <axboe@fb.com>
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