From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@fb.com>,
linux-block@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>
Cc: Omar Sandoval <osandov@fb.com>,
Bart Van Assche <bart.vanassche@sandisk.com>,
Hannes Reinecke <hare@suse.com>,
linux-kernel@vger.kernel.org, Ming Lei <ming.lei@redhat.com>
Subject: [PATCH V3 5/7] blk-mq-sched: decide how to handle flush rq via RQF_FLUSH_SEQ
Date: Thu, 2 Nov 2017 23:24:36 +0800 [thread overview]
Message-ID: <20171102152438.25324-6-ming.lei@redhat.com> (raw)
In-Reply-To: <20171102152438.25324-1-ming.lei@redhat.com>
In case of IO scheduler we always pre-allocate one driver tag before
calling blk_insert_flush(), and flush request will be marked as
RQF_FLUSH_SEQ once it is in flush machinary.
So if RQF_FLUSH_SEQ isn't set, we call blk_insert_flush() to handle
the request, otherwise the flush request is dispatched to ->dispatch
list directly.
This is a prepare patch for not preallocating driver tag on flush rq,
and don't treat flush rq as special case, just what the legacy path
did.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-mq-sched.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 7775f6b12fa9..32e4ea2d0a77 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -355,21 +355,23 @@ void blk_mq_sched_request_inserted(struct request *rq)
EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted);
static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx,
+ bool has_sched,
struct request *rq)
{
- if (rq->tag == -1) {
+ /* dispatch flush rq directly */
+ if (rq->rq_flags & RQF_FLUSH_SEQ) {
+ spin_lock(&hctx->lock);
+ list_add(&rq->queuelist, &hctx->dispatch);
+ spin_unlock(&hctx->lock);
+ return true;
+ }
+
+ if (has_sched) {
rq->rq_flags |= RQF_SORTED;
- return false;
+ WARN_ON(rq->tag != -1);
}
- /*
- * If we already have a real request tag, send directly to
- * the dispatch list.
- */
- spin_lock(&hctx->lock);
- list_add(&rq->queuelist, &hctx->dispatch);
- spin_unlock(&hctx->lock);
- return true;
+ return false;
}
/*
@@ -395,12 +397,13 @@ void blk_mq_sched_insert_request(struct request *rq, bool at_head,
struct blk_mq_ctx *ctx = rq->mq_ctx;
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
- if (rq->tag == -1 && op_is_flush(rq->cmd_flags)) {
+ /* flush rq in flush machinery need to be dispatched directly */
+ if (!(rq->rq_flags & RQF_FLUSH_SEQ) && op_is_flush(rq->cmd_flags)) {
blk_mq_sched_insert_flush(hctx, rq, can_block);
return;
}
- if (e && blk_mq_sched_bypass_insert(hctx, rq))
+ if (blk_mq_sched_bypass_insert(hctx, !!e, rq))
goto run;
if (e && e->type->ops.mq.insert_requests) {
@@ -438,7 +441,7 @@ void blk_mq_sched_insert_requests(struct request_queue *q,
list_for_each_entry_safe(rq, next, list, queuelist) {
if (WARN_ON_ONCE(rq->tag != -1)) {
list_del_init(&rq->queuelist);
- blk_mq_sched_bypass_insert(hctx, rq);
+ blk_mq_sched_bypass_insert(hctx, true, rq);
}
}
}
--
2.9.5
next prev parent reply other threads:[~2017-11-02 15:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-02 15:24 [PATCH V3 0/7] blk-mq: don't allocate driver tag beforehand for flush rq Ming Lei
2017-11-02 15:24 ` [PATCH V3 1/7] blk-mq: put the driver tag of nxt rq before first one is requeued Ming Lei
2017-11-02 15:24 ` [PATCH V3 2/7] blk-flush: don't run queue for requests of bypassing flush Ming Lei
2017-11-02 15:24 ` [PATCH V3 3/7] block: pass 'run_queue' to blk_mq_request_bypass_insert Ming Lei
2017-11-02 15:24 ` [PATCH V3 4/7] blk-flush: use blk_mq_request_bypass_insert() Ming Lei
2017-11-02 15:24 ` Ming Lei [this message]
2017-11-02 15:24 ` [PATCH V3 6/7] blk-mq: move blk_mq_put_driver_tag*() into blk-mq.h Ming Lei
2017-11-02 15:24 ` [PATCH V3 7/7] blk-mq: don't allocate driver tag beforehand for flush rq Ming Lei
2017-11-04 4:17 ` [PATCH V3 0/7] " Ming Lei
2017-11-04 14:18 ` Jens Axboe
2017-11-04 18:49 ` Jens Axboe
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