From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752829AbcLES1g (ORCPT ); Mon, 5 Dec 2016 13:27:36 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:40660 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752779AbcLES1b (ORCPT ); Mon, 5 Dec 2016 13:27:31 -0500 From: Jens Axboe To: , , CC: , Jens Axboe Subject: [PATCH 7/7] block: drop irq+lock when flushing queue plugs Date: Mon, 5 Dec 2016 11:27:06 -0700 Message-ID: <1480962426-15767-8-git-send-email-axboe@fb.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1480962426-15767-1-git-send-email-axboe@fb.com> References: <1480962426-15767-1-git-send-email-axboe@fb.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [192.168.54.13] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-12-05_14:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Not convinced this is a faster approach, and it does look IRQs off longer than otherwise. With mq+scheduling, it's a problem since it forces us to offload the queue running. If we get rid of it, we can run the queue without the queue lock held. Signed-off-by: Jens Axboe --- block/blk-core.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 8be12ba91f8e..2c61d2020c3f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -3204,18 +3204,21 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) * plugger did not intend it. */ static void queue_unplugged(struct request_queue *q, unsigned int depth, - bool from_schedule) + bool from_schedule, unsigned long flags) __releases(q->queue_lock) { trace_block_unplug(q, depth, !from_schedule); - if (q->mq_ops) - blk_mq_run_hw_queues(q, true); - else if (from_schedule) - blk_run_queue_async(q); - else - __blk_run_queue(q); - spin_unlock(q->queue_lock); + if (q->mq_ops) { + spin_unlock_irqrestore(q->queue_lock, flags); + blk_mq_run_hw_queues(q, from_schedule); + } else { + if (from_schedule) + blk_run_queue_async(q); + else + __blk_run_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); + } } static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) @@ -3283,11 +3286,6 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) q = NULL; depth = 0; - /* - * Save and disable interrupts here, to avoid doing it for every - * queue lock we have to take. - */ - local_irq_save(flags); while (!list_empty(&list)) { rq = list_entry_rq(list.next); list_del_init(&rq->queuelist); @@ -3297,10 +3295,10 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) * This drops the queue lock */ if (q) - queue_unplugged(q, depth, from_schedule); + queue_unplugged(q, depth, from_schedule, flags); q = rq->q; depth = 0; - spin_lock(q->queue_lock); + spin_lock_irqsave(q->queue_lock, flags); } /* @@ -3329,9 +3327,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) * This drops the queue lock */ if (q) - queue_unplugged(q, depth, from_schedule); - - local_irq_restore(flags); + queue_unplugged(q, depth, from_schedule, flags); } void blk_finish_plug(struct blk_plug *plug) -- 2.7.4