From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756673AbdKNXRw (ORCPT ); Tue, 14 Nov 2017 18:17:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:50434 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755415AbdKNXRq (ORCPT ); Tue, 14 Nov 2017 18:17:46 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48A0321872 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=shli@kernel.org Date: Tue, 14 Nov 2017 15:17:43 -0800 From: Shaohua Li To: Tejun Heo Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, kernel-team@fb.com, lizefan@huawei.com, hannes@cmpxchg.org, cgroups@vger.kernel.org, guro@fb.com Subject: Re: [PATCH v2 3/7] blkcg: associate a request with its blkcg_gq instead of request_list Message-ID: <20171114231743.2eprnbfmgesqc42c@kernel.org> References: <20171112222613.3613362-1-tj@kernel.org> <20171112222613.3613362-4-tj@kernel.org> <20171113201523.GM983427@devbig577.frc2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171113201523.GM983427@devbig577.frc2.facebook.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 13, 2017 at 12:15:23PM -0800, Tejun Heo wrote: > From c856a199ec70e4022e997609f1b17b9106408777 Mon Sep 17 00:00:00 2001 > From: Tejun Heo > Date: Mon, 13 Nov 2017 12:11:57 -0800 > > On the legacy request_queue, each blkcg_gq has a dedicated > request_list that requests for the cgroup are allocated from. Each > request points to the originating request_list and cgroup membership > can be determined by examining which cgroup the associated > request_list belongs to. > > This doesn't work for blk-mq which doesn't use request_list. Let's > associate each request with the blkcg_gq directly. Except for minor > wrapper changes, this doesn't affect the legacy request_queue and will > allow blk-mq to track each request's cgroup association. > > v2: Build fix for !CONFIG_BLK_CGROUP. > > Signed-off-by: Tejun Heo > --- > block/blk-mq.c | 2 +- > include/linux/blk-cgroup.h | 7 +++++-- > include/linux/blkdev.h | 2 +- > 3 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 98a1860..af958c4 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -306,7 +306,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, > rq->part = NULL; > rq->start_time = jiffies; > #ifdef CONFIG_BLK_CGROUP > - rq->rl = NULL; > + rq->blkg = NULL; > set_start_time_ns(rq); > rq->io_start_time_ns = 0; > #endif > diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h > index c0d4736..47db75a 100644 > --- a/include/linux/blk-cgroup.h > +++ b/include/linux/blk-cgroup.h > @@ -463,7 +463,7 @@ static inline void blk_put_rl(struct request_list *rl) > */ > static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) > { > - rq->rl = rl; > + rq->blkg = rl->blkg; > } After patch 5, we don't really need the blk_put_rl, blk_get_rl, blk_rq_set_rl functions. I'd like to delete them and only keep blk_rq_rl. The name blk_rq_set_rl is confusing too. Thanks, Shaohua > /** > @@ -474,7 +474,10 @@ static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) > */ > static inline struct request_list *blk_rq_rl(struct request *rq) > { > - return rq->rl; > + if (!rq->blkg->parent) > + return &rq->q->root_rl; > + else > + return &rq->blkg->rl; > } > > struct request_list *__blk_queue_next_rl(struct request_list *rl, > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index 8da6637..6ec1067 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -206,7 +206,7 @@ struct request { > unsigned long start_time; > struct blk_issue_stat issue_stat; > #ifdef CONFIG_BLK_CGROUP > - struct request_list *rl; /* rl this rq is alloced from */ > + struct blkcg_gq *blkg; /* blkg of this rq */ > unsigned long long start_time_ns; > unsigned long long io_start_time_ns; /* when passed to hardware */ > #endif > -- > 2.9.5 >