From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756401AbdKNXYF (ORCPT ); Tue, 14 Nov 2017 18:24:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:51322 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756024AbdKNXX5 (ORCPT ); Tue, 14 Nov 2017 18:23:57 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 900A4218B1 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 15:23:55 -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 6/7] blkcg: account requests instead of bios for request based request_queues Message-ID: <20171114232355.vjxlzfbqbqj5ihq4@kernel.org> References: <20171112222613.3613362-1-tj@kernel.org> <20171112222613.3613362-7-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171112222613.3613362-7-tj@kernel.org> 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 Sun, Nov 12, 2017 at 02:26:12PM -0800, Tejun Heo wrote: > blkcg accounting is currently bio based, which is silly for request > based request_queues. This is silly as the number of bios doesn't > have much to do with the actual number of IOs issued to the underlying > device (can be significantly higher or lower) and may change depending > on the implementation details on how the bios are issued (e.g. from > the recent split-bios-while-issuing change). > > request based request_queues have QUEUE_FLAG_IO_STAT set by default > which controls the gendisk accounting. Do cgroup accounting for those > request_queues together with gendisk accounting on request completion. > > This makes cgroup accounting consistent with gendisk accounting and > what's happening on the system. > > Signed-off-by: Tejun Heo > --- > block/blk-core.c | 3 +++ > include/linux/blk-cgroup.h | 18 +++++++++++++++++- > 2 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 048be4a..ad23b96 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -2429,6 +2429,7 @@ void blk_account_io_completion(struct request *req, unsigned int bytes) > cpu = part_stat_lock(); > part = req->part; > part_stat_add(cpu, part, sectors[rw], bytes >> 9); > + blkcg_account_io_completion(req, bytes); > part_stat_unlock(); > } > } > @@ -2454,6 +2455,8 @@ void blk_account_io_done(struct request *req) > part_round_stats(req->q, cpu, part); > part_dec_in_flight(req->q, part, rw); > > + blkcg_account_io_done(req); > + > hd_struct_put(part); > part_stat_unlock(); > } > diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h > index 96eed0f..f2f9691 100644 > --- a/include/linux/blk-cgroup.h > +++ b/include/linux/blk-cgroup.h > @@ -715,7 +715,8 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q, > > throtl = blk_throtl_bio(q, blkg, bio); > > - if (!throtl) { > + /* if @q does io stat, blkcg stats are updated together with them */ > + if (!blk_queue_io_stat(q) && !throtl) { Reviewed-by: Shaohua Li One nitpick, can we use q->request_fn to determine request based queue? I think that is more reliable and usual way for this. Thanks, Shaohua > blkg_rwstat_add(&blkg->stat_bytes, bio->bi_opf, > bio->bi_iter.bi_size); > blkg_rwstat_add(&blkg->stat_ios, bio->bi_opf, 1); > @@ -764,6 +765,17 @@ static inline void blk_rq_disassociate_blkg(struct request *rq) > rq->blkg = NULL; > } > > +static inline void blkcg_account_io_completion(struct request *rq, > + unsigned int bytes) > +{ > + blkg_rwstat_add(&rq->blkg->stat_bytes, rq_data_dir(rq), bytes); > +} > + > +static inline void blkcg_account_io_done(struct request *rq) > +{ > + blkg_rwstat_add(&rq->blkg->stat_ios, rq_data_dir(rq), 1); > +} > + > #else /* CONFIG_BLK_CGROUP */ > > struct blkcg { > @@ -823,6 +835,10 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q, > static inline void blk_rq_associate_blkg(struct request *rq, struct blkcg *blkcg) { } > static inline void blk_rq_disassociate_blkg(struct request *rq) { } > > +static inline void blkcg_account_io_completion(struct request *rq, > + unsigned int bytes) { } > +static inline void blkcg_account_io_done(struct request *rq) { } > + > #define blk_queue_for_each_rl(rl, q) \ > for ((rl) = &(q)->root_rl; (rl); (rl) = NULL) > > -- > 2.9.5 >