From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15AC2C77B78 for ; Thu, 4 May 2023 15:09:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231274AbjEDPJl (ORCPT ); Thu, 4 May 2023 11:09:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231402AbjEDPJ3 (ORCPT ); Thu, 4 May 2023 11:09:29 -0400 Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com [IPv6:2607:f8b0:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEB234209 for ; Thu, 4 May 2023 08:08:59 -0700 (PDT) Received: by mail-pf1-x42c.google.com with SMTP id d2e1a72fcca58-64382139ebaso462285b3a.2 for ; Thu, 04 May 2023 08:08:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1683212939; x=1685804939; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=OFa1D5Tpf/QrQJM5h3CrUwGz4UKarPH+tDSx3KZiqW0=; b=DNqvvH4fVrTxxmy3uWocPqMrVQzGrvn1bKV/DBRhuLaJP6xVuRfHqmbHfrevd1owR/ jiCrzjiOJ6WKw3SidjtKGTAo3Kw6pc6zVNOe6oEJ3Q7NwivVlUyL5fyWvqWOdTYm67kg bB8EjQA5ooh95ZqFlEOhksFT0f1AAMr4Zq0N5VHLOQUfiSYQ2Jc4c9mMxf5zpl9GlztJ 79At54zrwpPkmPzu2hgVlWkTkzYQtfrDyMp6XW8rtYcSI5MAQsYKVXYMVqd667juw5MI 6RoawcuDBmVVXahW627FRVPS71JWh8CGrpk9MFh7Dh0Tq7PtZCP2VYWXY72KPg5byozj 1LIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683212939; x=1685804939; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=OFa1D5Tpf/QrQJM5h3CrUwGz4UKarPH+tDSx3KZiqW0=; b=WWfzSUDrg6YGTpE1r3hn8/hqkUexPrC6T/skn2u93cx5xZWNwV0aQCOH1DUcLQ1w4E jKcDUFbQYfeyUq/iwYhH8glGB89D8kMVMN9QjIvdnWtmAlVbOv0wEM1W/sA+cz0CuBEt 58TJSSg5/cMzoZYU7MMVQBhcCOJ82PO/cCmSd0hBfNomeH91YTiLLjzc8kAVjU0i7gv4 16/IM1tay3BMzx6KxPXHSKtCw8B9B8+P6DfhfU4CmlRbbyltiVK+ZHQMJGQ4Uhiar1d0 0LW9l/EyTC4J6GKxadGgVkipZxRXpqclCfz8HZblLRVIxU3T+UANYMoXqDJXYRSvJjNL 3WHg== X-Gm-Message-State: AC+VfDxr5UtheSNeqNeLhFY2mQ1If6oLuRKn60Ve8zVtnt3b14ogDSbJ ddDt2cnpJW2QOkxCBwgOruVFDQ== X-Google-Smtp-Source: ACHHUZ7b8yMStegf41qN6JKvTRQVyQ3nCGCRxb9QEu/dI4w/6IChTI343PJi8jI6S37UwLLoQfMuuQ== X-Received: by 2002:a05:6a00:23d1:b0:63d:311a:a16b with SMTP id g17-20020a056a0023d100b0063d311aa16bmr2998351pfc.23.1683212939365; Thu, 04 May 2023 08:08:59 -0700 (PDT) Received: from [10.255.14.217] ([139.177.225.234]) by smtp.gmail.com with ESMTPSA id u21-20020aa78495000000b0063d24fcc2besm1753144pfn.125.2023.05.04.08.08.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 04 May 2023 08:08:58 -0700 (PDT) Message-ID: Date: Thu, 4 May 2023 23:08:53 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [External] Re: [PATCH v2] blk-throttle: Fix io statistics for cgroup v1 To: Andrea Righi Cc: tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230401094708.77631-1-hanjinke.666@bytedance.com> From: hanjinke In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Sorry for delay（Chinese Labor Day holiday). 在 2023/4/29 上午3:05, Andrea Righi 写道: > On Sat, Apr 01, 2023 at 05:47:08PM +0800, Jinke Han wrote: >> From: Jinke Han >> >> After commit f382fb0bcef4 ("block: remove legacy IO schedulers"), >> blkio.throttle.io_serviced and blkio.throttle.io_service_bytes become >> the only stable io stats interface of cgroup v1, and these statistics >> are done in the blk-throttle code. But the current code only counts the >> bios that are actually throttled. When the user does not add the throttle >> limit, the io stats for cgroup v1 has nothing. I fix it according to the >> statistical method of v2, and made it count all ios accurately. >> >> Fixes: a7b36ee6ba29 ("block: move blk-throtl fast path inline") >> Signed-off-by: Jinke Han > > Thanks for fixing this! > > The code looks correct to me, but this seems to report io statistics > only if at least one throttling limit is defined. IIRC with cgroup v1 it > was possible to see the io statistics inside a cgroup also with no > throttling limits configured. > > Basically to restore the old behavior we would need to drop the > cgroup_subsys_on_dfl() check, something like the following (on top of > your patch). > > But I'm not sure if we're breaking other behaviors in this way... > opinions? > > block/blk-cgroup.c | 3 --- > block/blk-throttle.h | 12 +++++------- > 2 files changed, 5 insertions(+), 10 deletions(-) > > diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c > index 79138bfc6001..43af86db7cf3 100644 > --- a/block/blk-cgroup.c > +++ b/block/blk-cgroup.c > @@ -2045,9 +2045,6 @@ void blk_cgroup_bio_start(struct bio *bio) > struct blkg_iostat_set *bis; > unsigned long flags; > > - if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) > - return; > - > /* Root-level stats are sourced from system-wide IO stats */ > if (!cgroup_parent(blkcg->css.cgroup)) > return; > diff --git a/block/blk-throttle.h b/block/blk-throttle.h > index d1ccbfe9f797..bcb40ee2eeba 100644 > --- a/block/blk-throttle.h > +++ b/block/blk-throttle.h > @@ -185,14 +185,12 @@ static inline bool blk_should_throtl(struct bio *bio) > struct throtl_grp *tg = blkg_to_tg(bio->bi_blkg); > int rw = bio_data_dir(bio); > > - if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) { > - if (!bio_flagged(bio, BIO_CGROUP_ACCT)) { > - bio_set_flag(bio, BIO_CGROUP_ACCT); > - blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf, > - bio->bi_iter.bi_size); > - } > - blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1); > + if (!bio_flagged(bio, BIO_CGROUP_ACCT)) { > + bio_set_flag(bio, BIO_CGROUP_ACCT); > + blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf, > + bio->bi_iter.bi_size); > } > + blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1); It seems that statistics have been carried out in both v1 and v2，we can get the statistics of v2 from io.stat, is it necessary to count v2 here?