From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759567AbeAIQa0 (ORCPT + 1 other); Tue, 9 Jan 2018 11:30:26 -0500 Received: from mail-qt0-f194.google.com ([209.85.216.194]:35290 "EHLO mail-qt0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759557AbeAIQaU (ORCPT ); Tue, 9 Jan 2018 11:30:20 -0500 X-Google-Smtp-Source: ACJfBouwsSJ6F3XSx659RPfEgddpO+otS17wi5eUU0f56z+2O7Q4i9fgKgTGRPboIHMCs3w+iRh7xA== From: Tejun Heo To: jack@suse.cz, axboe@kernel.dk, clm@fb.com, jbacik@fb.com Cc: kernel-team@fb.com, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, peterz@infradead.org, jianchao.w.wang@oracle.com, Bart.VanAssche@wdc.com, linux-block@vger.kernel.org, Tejun Heo Subject: [PATCH 6/8] blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mq Date: Tue, 9 Jan 2018 08:29:51 -0800 Message-Id: <20180109162953.1211451-7-tj@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20180109162953.1211451-1-tj@kernel.org> References: <20180109162953.1211451-1-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: After the recent updates to use generation number and state based synchronization, blk-mq no longer depends on REQ_ATOM_COMPLETE except to avoid firing the same timeout multiple times. Remove all REQ_ATOM_COMPLETE usages and use a new rq_flags flag RQF_MQ_TIMEOUT_EXPIRED to avoid firing the same timeout multiple times. This removes atomic bitops from hot paths too. v2: Removed blk_clear_rq_complete() from blk_mq_rq_timed_out(). v3: Added RQF_MQ_TIMEOUT_EXPIRED flag. Signed-off-by: Tejun Heo Cc: "jianchao.wang" --- block/blk-mq.c | 15 +++++++-------- block/blk-timeout.c | 1 + include/linux/blkdev.h | 2 ++ 3 files changed, 10 insertions(+), 8 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index b419746..3f297f0 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -634,8 +634,7 @@ void blk_mq_complete_request(struct request *rq) * hctx_lock() covers both issue and completion paths. */ hctx_lock(hctx, &srcu_idx); - if (blk_mq_rq_aborted_gstate(rq) != rq->gstate && - !blk_mark_rq_complete(rq)) + if (blk_mq_rq_aborted_gstate(rq) != rq->gstate) __blk_mq_complete_request(rq); hctx_unlock(hctx, srcu_idx); } @@ -685,8 +684,6 @@ void blk_mq_start_request(struct request *rq) preempt_enable(); set_bit(REQ_ATOM_STARTED, &rq->atomic_flags); - if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) - clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); if (q->dma_drain_size && blk_rq_bytes(rq)) { /* @@ -837,6 +834,8 @@ static void blk_mq_rq_timed_out(struct request *req, bool reserved) if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags)) return; + req->rq_flags |= RQF_MQ_TIMEOUT_EXPIRED; + if (ops->timeout) ret = ops->timeout(req, reserved); @@ -852,7 +851,6 @@ static void blk_mq_rq_timed_out(struct request *req, bool reserved) */ blk_mq_rq_update_aborted_gstate(req, 0); blk_add_timer(req); - blk_clear_rq_complete(req); break; case BLK_EH_NOT_HANDLED: break; @@ -871,7 +869,8 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, might_sleep(); - if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) + if ((rq->rq_flags & RQF_MQ_TIMEOUT_EXPIRED) || + !test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) return; /* read coherent snapshots of @rq->state_gen and @rq->deadline */ @@ -906,8 +905,8 @@ static void blk_mq_terminate_expired(struct blk_mq_hw_ctx *hctx, * now guaranteed to see @rq->aborted_gstate and yield. If * @rq->aborted_gstate still matches @rq->gstate, @rq is ours. */ - if (READ_ONCE(rq->gstate) == rq->aborted_gstate && - !blk_mark_rq_complete(rq)) + if (!(rq->rq_flags & RQF_MQ_TIMEOUT_EXPIRED) && + READ_ONCE(rq->gstate) == rq->aborted_gstate) blk_mq_rq_timed_out(rq, reserved); } diff --git a/block/blk-timeout.c b/block/blk-timeout.c index 4f04cd1..ebe9996 100644 --- a/block/blk-timeout.c +++ b/block/blk-timeout.c @@ -214,6 +214,7 @@ void blk_add_timer(struct request *req) req->timeout = q->rq_timeout; req->deadline = jiffies + req->timeout; + req->rq_flags &= ~RQF_MQ_TIMEOUT_EXPIRED; /* * Only the non-mq case needs to add the request to a protected list. diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index ae563d0..007a7cf 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -125,6 +125,8 @@ typedef __u32 __bitwise req_flags_t; #define RQF_SPECIAL_PAYLOAD ((__force req_flags_t)(1 << 18)) /* The per-zone write lock is held for this request */ #define RQF_ZONE_WRITE_LOCKED ((__force req_flags_t)(1 << 19)) +/* timeout is expired */ +#define RQF_MQ_TIMEOUT_EXPIRED ((__force req_flags_t)(1 << 20)) /* flags that prevent us from merging requests: */ #define RQF_NOMERGE_FLAGS \ -- 2.9.5