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Thu, 10 Sep 2020 22:41:53 -0400 X-MC-Unique: ar5BfwrINFOV6Zibr0MI1g-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E48181882FB6; Fri, 11 Sep 2020 02:41:51 +0000 (UTC) Received: from localhost (ovpn-13-69.pek2.redhat.com [10.72.13.69]) by smtp.corp.redhat.com (Postfix) with ESMTP id F1B6F60BF4; Fri, 11 Sep 2020 02:41:47 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Christoph Hellwig , Keith Busch Subject: [PATCH V5 3/4] blk-mq: add tagset quiesce interface Date: Fri, 11 Sep 2020 10:41:16 +0800 Message-Id: <20200911024117.62480-4-ming.lei@redhat.com> In-Reply-To: <20200911024117.62480-1-ming.lei@redhat.com> References: <20200911024117.62480-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200910_224155_716926_E2A880A4 X-CRM114-Status: GOOD ( 19.87 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sagi Grimberg , Johannes Thumshirn , Ming Lei , Hannes Reinecke , Chao Leng , Bart Van Assche Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org drivers that have shared tagsets may need to quiesce potentially a lot of request queues that all share a single tagset (e.g. nvme). Add an interface to quiesce all the queues on a given tagset. This interface is useful because it can speedup the quiesce by doing it in parallel. For tagsets that have BLK_MQ_F_BLOCKING set, we kill request queue's dispatch percpu-refcount such that all of them wait for the counter becoming zero. For tagsets that don't have BLK_MQ_F_BLOCKING set, we simply call a single synchronize_rcu as this is sufficient. This patch is against Sagi's original post. Signed-off-by: Ming Lei Cc: Sagi Grimberg Cc: Bart Van Assche Cc: Johannes Thumshirn Cc: Chao Leng Reviewed-by: Hannes Reinecke --- block/blk-mq.c | 59 +++++++++++++++++++++++++++++++++++------- include/linux/blk-mq.h | 2 ++ 2 files changed, 51 insertions(+), 10 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index df0fa3640649..ccb500e38008 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -214,16 +214,7 @@ void blk_mq_quiesce_queue_nowait(struct request_queue *q) } EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); -/** - * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished - * @q: request queue. - * - * Note: this function does not prevent that the struct request end_io() - * callback function is invoked. Once this function is returned, we make - * sure no dispatch can happen until the queue is unquiesced via - * blk_mq_unquiesce_queue(). - */ -void blk_mq_quiesce_queue(struct request_queue *q) +static void __blk_mq_quiesce_queue(struct request_queue *q, bool wait) { bool blocking = !!(q->tag_set->flags & BLK_MQ_F_BLOCKING); bool was_quiesced =__blk_mq_quiesce_queue_nowait(q); @@ -231,6 +222,9 @@ void blk_mq_quiesce_queue(struct request_queue *q) if (!was_quiesced && blocking) percpu_ref_kill(&q->dispatch_counter); + if (!wait) + return; + /* * In case of F_BLOCKING, if driver unquiesces its queue being * quiesced, it can cause bigger trouble, and we simply return & @@ -244,6 +238,20 @@ void blk_mq_quiesce_queue(struct request_queue *q) else synchronize_rcu(); } + +/* + * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished + * @q: request queue. + * + * Note: this function does not prevent that the struct request end_io() + * callback function is invoked. Once this function is returned, we make + * sure no dispatch can happen until the queue is unquiesced via + * blk_mq_unquiesce_queue(). + */ +void blk_mq_quiesce_queue(struct request_queue *q) +{ + __blk_mq_quiesce_queue(q, true); +} EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); /* @@ -265,6 +273,37 @@ void blk_mq_unquiesce_queue(struct request_queue *q) } EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); +void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set) +{ + struct request_queue *q; + + mutex_lock(&set->tag_list_lock); + list_for_each_entry(q, &set->tag_list, tag_set_list) + __blk_mq_quiesce_queue(q, false); + + /* wait until all queues' quiesce is done */ + if (set->flags & BLK_MQ_F_BLOCKING) { + list_for_each_entry(q, &set->tag_list, tag_set_list) + wait_event(q->mq_quiesce_wq, + percpu_ref_is_zero(&q->dispatch_counter)); + } else { + synchronize_rcu(); + } + mutex_unlock(&set->tag_list_lock); +} +EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset); + +void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set) +{ + struct request_queue *q; + + mutex_lock(&set->tag_list_lock); + list_for_each_entry(q, &set->tag_list, tag_set_list) + blk_mq_unquiesce_queue(q); + mutex_unlock(&set->tag_list_lock); +} +EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset); + void blk_mq_wake_waiters(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index df642055f02c..90da3582b91d 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -519,6 +519,8 @@ int blk_mq_map_queues(struct blk_mq_queue_map *qmap); void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues); void blk_mq_quiesce_queue_nowait(struct request_queue *q); +void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set); +void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set); unsigned int blk_mq_rq_cpu(struct request *rq); -- 2.25.2 _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme