Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754388AbZDUNcY (ORCPT ); Tue, 21 Apr 2009 09:32:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751124AbZDUNcO (ORCPT ); Tue, 21 Apr 2009 09:32:14 -0400 Received: from mx2.redhat.com ([66.187.237.31]:53127 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750874AbZDUNcO (ORCPT ); Tue, 21 Apr 2009 09:32:14 -0400 Message-ID: <49EDCAD6.9000807@redhat.com> Date: Tue, 21 Apr 2009 15:32:06 +0200 From: Jerome Marchand User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Jens Axboe CC: linux-kernel@vger.kernel.org, Nikanth Karthikesan Subject: [PATCH v3] block: simplify I/O stat accounting References: <49E72F19.1030400@redhat.com> <49E8662D.5010607@redhat.com> <20090417113756.GU4593@kernel.dk> <20090417115449.GV4593@kernel.dk> <49E87502.3050806@redhat.com> <20090417123025.GW4593@kernel.dk> In-Reply-To: <20090417123025.GW4593@kernel.dk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4325 Lines: 135 This simplifies I/O stat accounting switching code and separates it completely from I/O scheduler switch code. Requests are accounted according to the state of their request queue at the time of the request allocation. There is no need anymore to flush the request queue when switching I/O accounting state. Signed-off-by: Jerome Marchand --- block/blk-core.c | 6 ++++-- block/blk-merge.c | 5 ++++- block/blk-sysfs.c | 4 ---- block/blk.h | 7 +------ include/linux/blkdev.h | 3 +++ 5 files changed, 12 insertions(+), 13 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 07ab754..2998fe3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -643,7 +643,7 @@ static inline void blk_free_request(struct request_queue *q, struct request *rq) } static struct request * -blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask) +blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask) { struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); @@ -652,7 +652,7 @@ blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask) blk_rq_init(q, rq); - rq->cmd_flags = rw | REQ_ALLOCED; + rq->cmd_flags = flags | REQ_ALLOCED; if (priv) { if (unlikely(elv_set_request(q, rq, gfp_mask))) { @@ -792,6 +792,8 @@ static struct request *get_request(struct request_queue *q, int rw_flags, if (priv) rl->elvpriv++; + if (blk_queue_io_stat(q)) + rw_flags |= REQ_IO_STAT; spin_unlock_irq(q->queue_lock); rq = blk_alloc_request(q, rw_flags, priv, gfp_mask); diff --git a/block/blk-merge.c b/block/blk-merge.c index 63760ca..23d2a6f 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -402,7 +402,10 @@ static int attempt_merge(struct request_queue *q, struct request *req, elv_merge_requests(q, req, next); - blk_account_io_merge(req); + /* + * 'next' is going away, so update stats accordingly + */ + blk_account_io_merge(next); req->ioprio = ioprio_best(req->ioprio, next->ioprio); if (blk_rq_cpu_valid(next)) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index cac4e9f..3ff9bba 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -209,14 +209,10 @@ static ssize_t queue_iostats_store(struct request_queue *q, const char *page, ssize_t ret = queue_var_store(&stats, page, count); spin_lock_irq(q->queue_lock); - elv_quiesce_start(q); - if (stats) queue_flag_set(QUEUE_FLAG_IO_STAT, q); else queue_flag_clear(QUEUE_FLAG_IO_STAT, q); - - elv_quiesce_end(q); spin_unlock_irq(q->queue_lock); return ret; diff --git a/block/blk.h b/block/blk.h index 5dfc412..79c85f7 100644 --- a/block/blk.h +++ b/block/blk.h @@ -114,12 +114,7 @@ static inline int blk_cpu_to_group(int cpu) static inline int blk_do_io_stat(struct request *rq) { - struct gendisk *disk = rq->rq_disk; - - if (!disk || !disk->queue) - return 0; - - return blk_queue_io_stat(disk->queue) && (rq->cmd_flags & REQ_ELVPRIV); + return rq->rq_disk && blk_rq_io_stat(rq); } #endif diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index ba54c83..2755d5c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -118,6 +118,7 @@ enum rq_flag_bits { __REQ_COPY_USER, /* contains copies of user pages */ __REQ_INTEGRITY, /* integrity metadata has been remapped */ __REQ_NOIDLE, /* Don't anticipate more IO after this one */ + __REQ_IO_STAT, /* account I/O stat */ __REQ_NR_BITS, /* stops here */ }; @@ -145,6 +146,7 @@ enum rq_flag_bits { #define REQ_COPY_USER (1 << __REQ_COPY_USER) #define REQ_INTEGRITY (1 << __REQ_INTEGRITY) #define REQ_NOIDLE (1 << __REQ_NOIDLE) +#define REQ_IO_STAT (1 << __REQ_IO_STAT) #define BLK_MAX_CDB 16 @@ -598,6 +600,7 @@ enum { blk_failfast_transport(rq) || \ blk_failfast_driver(rq)) #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED) +#define blk_rq_io_stat(rq) ((rq)->cmd_flags & REQ_IO_STAT) #define blk_account_rq(rq) (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq))) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/