From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750884AbVJSMfq (ORCPT ); Wed, 19 Oct 2005 08:35:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750888AbVJSMfn (ORCPT ); Wed, 19 Oct 2005 08:35:43 -0400 Received: from zproxy.gmail.com ([64.233.162.206]:484 "EHLO zproxy.gmail.com") by vger.kernel.org with ESMTP id S1750866AbVJSMfZ (ORCPT ); Wed, 19 Oct 2005 08:35:25 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:from:to:cc:user-agent:content-type:references:in-reply-to:subject:message-id:date; b=TM+HGNqIlU/agnVMk0anuUlwPeitKSOtXPonZmfSnuj+CNttL9thOVDPHFRYatbye3YUWd5C6Qr7aLUz45/kB82KkjD++GHe3icBid9gKi585pD0hPo7vQ/iFyZP+nGkA/T8SzBmwgXwpKXUBSksxDuUraV0jfiLOtXFGcc+aRQ= From: Tejun Heo To: axboe@suse.de Cc: linux-kernel@vger.kernel.org User-Agent: lksp 0.3 Content-Type: text/plain; charset=US-ASCII References: <20051019123429.450E4424@htj.dyndns.org> In-Reply-To: <20051019123429.450E4424@htj.dyndns.org> Subject: Re: [PATCH linux-2.6-block:master 03/05] blk: move last_merge handling into generic elevator code Message-ID: <20051019123429.2FBB370A@htj.dyndns.org> Date: Wed, 19 Oct 2005 21:35:19 +0900 (KST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 03_blk_generic-last_merge-handling.patch Currently, both generic elevator code and specific ioscheds participate in the management and usage of last_merge. This and the following patches move last_merge handling into generic elevator code. Signed-off-by: Tejun Heo elevator.c | 43 ++++++++++++++++++------------------------- 1 file changed, 18 insertions(+), 25 deletions(-) Index: blk-fixes/drivers/block/elevator.c =================================================================== --- blk-fixes.orig/drivers/block/elevator.c 2005-10-19 21:34:02.000000000 +0900 +++ blk-fixes/drivers/block/elevator.c 2005-10-19 21:34:02.000000000 +0900 @@ -88,15 +88,6 @@ inline int elv_try_merge(struct request } EXPORT_SYMBOL(elv_try_merge); -inline int elv_try_last_merge(request_queue_t *q, struct bio *bio) -{ - if (q->last_merge) - return elv_try_merge(q->last_merge, bio); - - return ELEVATOR_NO_MERGE; -} -EXPORT_SYMBOL(elv_try_last_merge); - static struct elevator_type *elevator_find(const char *name) { struct elevator_type *e = NULL; @@ -244,6 +235,9 @@ void elv_dispatch_insert(request_queue_t unsigned max_back; struct list_head *entry; + if (q->last_merge == rq) + q->last_merge = NULL; + if (!sort) { /* Specific elevator is performing sort. Step away. */ q->last_sector = rq_last_sector(rq); @@ -278,6 +272,15 @@ void elv_dispatch_insert(request_queue_t int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) { elevator_t *e = q->elevator; + int ret; + + if (q->last_merge) { + ret = elv_try_merge(q->last_merge, bio); + if (ret != ELEVATOR_NO_MERGE) { + *req = q->last_merge; + return ret; + } + } if (e->ops->elevator_merge_fn) return e->ops->elevator_merge_fn(q, req, bio); @@ -291,6 +294,8 @@ void elv_merged_request(request_queue_t if (e->ops->elevator_merged_fn) e->ops->elevator_merged_fn(q, rq); + + q->last_merge = rq; } void elv_merge_requests(request_queue_t *q, struct request *rq, @@ -298,11 +303,10 @@ void elv_merge_requests(request_queue_t { elevator_t *e = q->elevator; - if (q->last_merge == next) - q->last_merge = NULL; - if (e->ops->elevator_merge_req_fn) e->ops->elevator_merge_req_fn(q, rq, next); + + q->last_merge = rq; } void elv_requeue_request(request_queue_t *q, struct request *rq) @@ -397,6 +401,8 @@ void __elv_add_request(request_queue_t * BUG_ON(!blk_fs_request(rq)); rq->flags |= REQ_SORTED; q->elevator->ops->elevator_add_req_fn(q, rq); + if (q->last_merge == NULL && rq_mergeable(rq)) + q->last_merge = rq; break; default: @@ -475,9 +481,6 @@ struct request *elv_next_request(request rq->flags |= REQ_STARTED; } - if (rq == q->last_merge) - q->last_merge = NULL; - if (!q->boundary_rq || q->boundary_rq == rq) { q->last_sector = rq_last_sector(rq); q->boundary_rq = NULL; @@ -531,16 +534,6 @@ void elv_dequeue_request(request_queue_t */ if (blk_account_rq(rq)) q->in_flight++; - - /* - * the main clearing point for q->last_merge is on retrieval of - * request by driver (it calls elv_next_request()), but it _can_ - * also happen here if a request is added to the queue but later - * deleted without ever being given to driver (merged with another - * request). - */ - if (rq == q->last_merge) - q->last_merge = NULL; } int elv_queue_empty(request_queue_t *q)