Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752114AbcDRE0C (ORCPT ); Mon, 18 Apr 2016 00:26:02 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:50755 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751930AbcDREZF (ORCPT ); Mon, 18 Apr 2016 00:25:05 -0400 From: Jens Axboe To: , , CC: , , Jens Axboe Subject: [PATCH 6/8] block: add code to track actual device queue depth Date: Sun, 17 Apr 2016 23:24:45 -0500 Message-ID: <1460953487-3430-7-git-send-email-axboe@fb.com> X-Mailer: git-send-email 2.8.0.rc4.6.g7e4ba36 In-Reply-To: <1460953487-3430-1-git-send-email-axboe@fb.com> References: <1460953487-3430-1-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=2016-04-18_04:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3069 Lines: 91 For blk-mq, ->nr_requests does track queue depth, at least at init time. But for the older queue paths, it's simply a soft setting. On top of that, it's generally larger than the hardware setting on purpose, to allow backup of requests for merging. Fill a hole in struct request with a 'queue_depth' member, that drivers can call to more closely inform the block layer of the real queue depth. Signed-off-by: Jens Axboe --- block/blk-settings.c | 12 ++++++++++++ drivers/scsi/scsi.c | 3 +++ include/linux/blkdev.h | 11 +++++++++++ 3 files changed, 26 insertions(+) diff --git a/block/blk-settings.c b/block/blk-settings.c index f679ae122843..f7e122e717e8 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -832,6 +832,18 @@ void blk_queue_flush_queueable(struct request_queue *q, bool queueable) EXPORT_SYMBOL_GPL(blk_queue_flush_queueable); /** + * blk_set_queue_depth - tell the block layer about the device queue depth + * @q: the request queue for the device + * @depth: queue depth + * + */ +void blk_set_queue_depth(struct request_queue *q, unsigned int depth) +{ + q->queue_depth = depth; +} +EXPORT_SYMBOL(blk_set_queue_depth); + +/** * blk_queue_write_cache - configure queue's write cache * @q: the request queue for the device * @wc: write back cache on or off diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 1deb6adc411f..75455d4dab68 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -621,6 +621,9 @@ int scsi_change_queue_depth(struct scsi_device *sdev, int depth) wmb(); } + if (sdev->request_queue) + blk_set_queue_depth(sdev->request_queue, depth); + return sdev->queue_depth; } EXPORT_SYMBOL(scsi_change_queue_depth); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index fc1894996b12..eee94bd6de52 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -315,6 +315,8 @@ struct request_queue { struct blk_mq_ctx __percpu *queue_ctx; unsigned int nr_queues; + unsigned int queue_depth; + /* hw dispatch queues */ struct blk_mq_hw_ctx **queue_hw_ctx; unsigned int nr_hw_queues; @@ -681,6 +683,14 @@ static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b) return false; } +static inline unsigned int blk_queue_depth(struct request_queue *q) +{ + if (q->queue_depth) + return q->queue_depth; + + return q->nr_requests; +} + /* * q->prep_rq_fn return values */ @@ -984,6 +994,7 @@ extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min); extern void blk_queue_io_min(struct request_queue *q, unsigned int min); extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt); extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt); +extern void blk_set_queue_depth(struct request_queue *q, unsigned int depth); extern void blk_set_default_limits(struct queue_limits *lim); extern void blk_set_stacking_limits(struct queue_limits *lim); extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, -- 2.8.0.rc4.6.g7e4ba36