aboutsummaryrefslogtreecommitdiff
path: root/kernel/audit.c
diff options
context:
space:
mode:
authorMing Lei2017-10-14 17:22:29 +0800
committerJens Axboe2017-11-01 08:20:02 -0600
commitde1482974080ec9ef414bf048b2646b246b63f6e (patch)
tree3ecdc2b581a83848c43205c2fd9b6e97a6808f6a /kernel/audit.c
parent63ba8e31c3ac6393b07c6e18538814a730478766 (diff)
blk-mq: introduce .get_budget and .put_budget in blk_mq_ops
For SCSI devices, there is often a per-request-queue depth, which needs to be respected before queuing one request. Currently blk-mq always dequeues the request first, then calls .queue_rq() to dispatch the request to lld. One obvious issue with this approach is that I/O merging may not be successful, because when the per-request-queue depth can't be respected, .queue_rq() has to return BLK_STS_RESOURCE, and then this request has to stay in hctx->dispatch list. This means it never gets a chance to be merged with other IO. This patch introduces .get_budget and .put_budget callback in blk_mq_ops, then we can try to get reserved budget first before dequeuing request. If the budget for queueing I/O can't be satisfied, we don't need to dequeue request at all. Hence the request can be left in the IO scheduler queue, for more merging opportunities. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel/audit.c')
0 files changed, 0 insertions, 0 deletions