From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754904Ab1AVBSH (ORCPT ); Fri, 21 Jan 2011 20:18:07 -0500 Received: from hera.kernel.org ([140.211.167.34]:45839 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754844Ab1AVBSD (ORCPT ); Fri, 21 Jan 2011 20:18:03 -0500 From: Jens Axboe To: jaxboe@fusionio.com, linux-kernel@vger.kernel.org Cc: hch@infradead.org Subject: [PATCH 06/10] block: kill request allocation batching Date: Sat, 22 Jan 2011 01:17:25 +0000 Message-Id: <1295659049-2688-7-git-send-email-jaxboe@fusionio.com> X-Mailer: git-send-email 1.7.3.5 In-Reply-To: <1295659049-2688-1-git-send-email-jaxboe@fusionio.com> References: <1295659049-2688-1-git-send-email-jaxboe@fusionio.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Sat, 22 Jan 2011 01:17:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Jens Axboe --- block/blk-core.c | 81 ++--------------------------------------------- block/blk-settings.c | 1 - block/blk.h | 6 --- include/linux/blkdev.h | 1 - 4 files changed, 4 insertions(+), 85 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 7ab6620..54b5987 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -593,40 +593,6 @@ blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask) return rq; } -/* - * ioc_batching returns true if the ioc is a valid batching request and - * should be given priority access to a request. - */ -static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) -{ - if (!ioc) - return 0; - - /* - * Make sure the process is able to allocate at least 1 request - * even if the batch times out, otherwise we could theoretically - * lose wakeups. - */ - return ioc->nr_batch_requests == q->nr_batching || - (ioc->nr_batch_requests > 0 - && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); -} - -/* - * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This - * will cause the process to be a "batcher" on all queues in the system. This - * is the behaviour we want though - once it gets a wakeup it should be given - * a nice run. - */ -static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) -{ - if (!ioc || ioc_batching(q, ioc)) - return; - - ioc->nr_batch_requests = q->nr_batching; - ioc->last_waited = jiffies; -} - static void __freed_request(struct request_queue *q, int sync) { struct request_list *rl = &q->rq; @@ -670,7 +636,6 @@ static struct request *get_request(struct request_queue *q, int rw_flags, { struct request *rq = NULL; struct request_list *rl = &q->rq; - struct io_context *ioc = NULL; const bool is_sync = rw_is_sync(rw_flags) != 0; int may_queue, priv; @@ -679,30 +644,11 @@ static struct request *get_request(struct request_queue *q, int rw_flags, goto rq_starved; if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { - if (rl->count[is_sync]+1 >= q->nr_requests) { - ioc = current_io_context(GFP_ATOMIC, q->node); - /* - * The queue will fill after this allocation, so set - * it as full, and mark this process as "batching". - * This process will be allowed to complete a batch of - * requests, others will be blocked. - */ - if (!blk_queue_full(q, is_sync)) { - ioc_set_batching(q, ioc); - blk_set_queue_full(q, is_sync); - } else { - if (may_queue != ELV_MQUEUE_MUST - && !ioc_batching(q, ioc)) { - /* - * The queue is full and the allocating - * process is not a "batcher", and not - * exempted by the IO scheduler - */ - goto out; - } - } - } blk_set_queue_congested(q, is_sync); + + if (rl->count[is_sync]+1 >= q->nr_requests) + if (may_queue != ELV_MQUEUE_MUST) + goto out; } /* @@ -750,15 +696,6 @@ rq_starved: goto out; } - /* - * ioc may be NULL here, and ioc_batching will be false. That's - * OK, if the queue is under the request limit then requests need - * not count toward the nr_batch_requests limit. There will always - * be some limit enforced by BLK_BATCH_TIME. - */ - if (ioc_batching(q, ioc)) - ioc->nr_batch_requests--; - trace_block_getrq(q, bio, rw_flags & 1); out: return rq; @@ -779,7 +716,6 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags, rq = get_request(q, rw_flags, bio, GFP_NOIO); while (!rq) { DEFINE_WAIT(wait); - struct io_context *ioc; struct request_list *rl = &q->rq; prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, @@ -790,15 +726,6 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags, spin_unlock_irq(q->queue_lock); io_schedule(); - /* - * After sleeping, we become a "batching" process and - * will be able to allocate at least one request, and - * up to a big batch of them for a small period time. - * See ioc_batching, ioc_set_batching - */ - ioc = current_io_context(GFP_NOIO, q->node); - ioc_set_batching(q, ioc); - spin_lock_irq(q->queue_lock); finish_wait(&rl->wait[is_sync], &wait); diff --git a/block/blk-settings.c b/block/blk-settings.c index c8d6892..35420f2 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -162,7 +162,6 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) q->make_request_fn = mfn; blk_queue_dma_alignment(q, 511); blk_queue_congestion_threshold(q); - q->nr_batching = BLK_BATCH_REQ; blk_set_default_limits(&q->limits); blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS); diff --git a/block/blk.h b/block/blk.h index 2c3d2e7..6db2e75 100644 --- a/block/blk.h +++ b/block/blk.h @@ -1,12 +1,6 @@ #ifndef BLK_INTERNAL_H #define BLK_INTERNAL_H -/* Amount of time in which a process may batch requests */ -#define BLK_BATCH_TIME (HZ/50UL) - -/* Number of requests a "batching" process may submit */ -#define BLK_BATCH_REQ 32 - extern struct kmem_cache *blk_requestq_cachep; extern struct kobj_type blk_queue_ktype; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index dfb6ffd..ebaf9d6 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -326,7 +326,6 @@ struct request_queue unsigned long nr_requests; /* Max # of requests */ unsigned int nr_congestion_on; unsigned int nr_congestion_off; - unsigned int nr_batching; void *dma_drain_buffer; unsigned int dma_drain_size; -- 1.7.3.2.146.gca209