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| author | Paolo Bonzini <pbonzini@redhat.com> | 2014-11-07 23:03:59 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-11-11 11:04:47 -0700 |
| commit | 398205b8391b208f0034a392242867b28ad8af3d (patch) | |
| tree | 2b7ce3ddc4029a15f7efbe4bb1e5711b9607dfc3 /block | |
| parent | 9c6ac78eb3521c5937b2dd8a7d1b300f41092f45 (diff) | |
| download | linux-398205b8391b208f0034a392242867b28ad8af3d.tar.gz linux-398205b8391b208f0034a392242867b28ad8af3d.tar.bz2 linux-398205b8391b208f0034a392242867b28ad8af3d.zip | |
blk_mq: call preempt_disable/enable in blk_mq_run_hw_queue, and only if needed
preempt_disable/enable surrounds every call to blk_mq_run_hw_queue,
except the one in blk-flush.c. In fact that one is always asynchronous,
and it does not need smp_processor_id().
We can do the same for all other calls, avoiding preempt_disable when
async is true. This avoids peppering blk-mq.c with preemption-disabled
regions.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Clark Williams <williams@redhat.com>
Tested-by: Clark Williams <williams@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index b355b5957cd7..8b309e81ed0f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -801,9 +801,18 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state))) return; - if (!async && cpumask_test_cpu(smp_processor_id(), hctx->cpumask)) - __blk_mq_run_hw_queue(hctx); - else if (hctx->queue->nr_hw_queues == 1) + if (!async) { + preempt_disable(); + if (cpumask_test_cpu(smp_processor_id(), hctx->cpumask)) { + __blk_mq_run_hw_queue(hctx); + preempt_enable(); + return; + } + + preempt_enable(); + } + + if (hctx->queue->nr_hw_queues == 1) kblockd_schedule_delayed_work(&hctx->run_work, 0); else { unsigned int cpu; @@ -824,9 +833,7 @@ void blk_mq_run_queues(struct request_queue *q, bool async) test_bit(BLK_MQ_S_STOPPED, &hctx->state)) continue; - preempt_disable(); blk_mq_run_hw_queue(hctx, async); - preempt_enable(); } } EXPORT_SYMBOL(blk_mq_run_queues); @@ -853,9 +860,7 @@ void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) { clear_bit(BLK_MQ_S_STOPPED, &hctx->state); - preempt_disable(); blk_mq_run_hw_queue(hctx, false); - preempt_enable(); } EXPORT_SYMBOL(blk_mq_start_hw_queue); @@ -880,9 +885,7 @@ void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) continue; clear_bit(BLK_MQ_S_STOPPED, &hctx->state); - preempt_disable(); blk_mq_run_hw_queue(hctx, async); - preempt_enable(); } } EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); |