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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C74CFC352A2 for ; Thu, 6 Feb 2020 15:46:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8BEC621741 for ; Thu, 6 Feb 2020 15:46:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="0gXevC6a" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8BEC621741 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=cmpxchg.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0B8526B0003; Thu, 6 Feb 2020 10:46:28 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 069906B0006; Thu, 6 Feb 2020 10:46:28 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E73156B0007; Thu, 6 Feb 2020 10:46:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0241.hostedemail.com [216.40.44.241]) by kanga.kvack.org (Postfix) with ESMTP id CDCB96B0003 for ; Thu, 6 Feb 2020 10:46:27 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 7F815181AEF00 for ; Thu, 6 Feb 2020 15:46:27 +0000 (UTC) X-FDA: 76460129214.20.heart10_8f9a336dadf42 X-HE-Tag: heart10_8f9a336dadf42 X-Filterd-Recvd-Size: 5713 Received: from mail-qk1-f194.google.com (mail-qk1-f194.google.com [209.85.222.194]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Thu, 6 Feb 2020 15:46:26 +0000 (UTC) Received: by mail-qk1-f194.google.com with SMTP id x82so5946420qkb.8 for ; Thu, 06 Feb 2020 07:46:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=kRRvyBPWT8Es74STxomqTpDHCa76gQjLB2CCJUssayM=; b=0gXevC6aEU0IZUlb9/scF02jWHTiU00qYk9LUijF/5hdiUCvqa3NevcaCnTmUvmIZJ CYl8Ti03GJNi5pVRpJqPN5HOA8djad0yBQW9pK1tLsRFlhHCIXSm+pLiNRbNLQAJyYBb 8hB7k5FpnOV9OvPz6HvFNMEhfAGLY8OO2Tbooi/mlTZ1d0gBgQ7mhUyPkm0pn09Lr09x dhaCfJ5w00U3iDJU2nz/apuWVj+wqT0tTZZjH+MAiTH97+aChNnm99JtRN1E3cl5C62J uG+Z9gfVIqQMx3/mFI+VdLgQ+QdjDNLLJ5HtIe8hotQ+LY7VXECCoCGTXi7SuNk1OtnH 8ujQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=kRRvyBPWT8Es74STxomqTpDHCa76gQjLB2CCJUssayM=; b=DvAhlwnTH+H4HVzwVWDOnAiuoe/7Un7vfg+axovqlxDQVdO/+EbGA8YdfIp1LALTcz bquFKWBkSnE4IX7jzmIdC5tqnOX8C2WIrqQSWOXoMklj6CNgQ4PVRaDRhbKymDwZLWMB 9HnqERPiz5FyD2+lRxlqjg/HLVYtOyW6sA83WVk7lobeZtgwdxZWnc0yOM185M4QkE7B Xopoj0TKYIdicwBO6fRD2NuZN3DXxbwYebFCSV+HGSlOJQ6K+tUdGwGoHB195mfPBv/9 ielGC/n+0CKqzow/4UDO1Da4ze8UBFd0o7vKoUsQJQnRfoj12kI0KZpzOG8kaGoEFfGD WGKg== X-Gm-Message-State: APjAAAXAQtoLatdKXr+8VzTi1Q0VDCBXtGjLz7kbwqVkr1/lCDCj/nzn ciYPyMzJfPErk2tWB+/3XbeHrg== X-Google-Smtp-Source: APXvYqyMsmQpyg9uEjfMfe0RGA/Dtl5TtuYO75M1CcYm9p74JGnF1dhnxvivzvRQG/vj+RNZiyRUkw== X-Received: by 2002:a05:620a:1112:: with SMTP id o18mr3046650qkk.126.1581003985950; Thu, 06 Feb 2020 07:46:25 -0800 (PST) Received: from localhost (pool-108-27-252-85.nycmny.fios.verizon.net. [108.27.252.85]) by smtp.gmail.com with ESMTPSA id t7sm1574736qkm.136.2020.02.06.07.46.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Feb 2020 07:46:25 -0800 (PST) Date: Thu, 6 Feb 2020 10:46:24 -0500 From: Johannes Weiner To: Dan Schatzberg Cc: Jens Axboe , Tejun Heo , Li Zefan , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , "open list:BLOCK LAYER" , open list , "open list:CONTROL GROUP (CGROUP)" , "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" Subject: Re: [PATCH 2/2] loop: charge i/o per cgroup Message-ID: <20200206154624.GB24735@cmpxchg.org> References: <20200205223348.880610-1-dschatzberg@fb.com> <20200205223348.880610-3-dschatzberg@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200205223348.880610-3-dschatzberg@fb.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hello Dan, On Wed, Feb 05, 2020 at 02:33:48PM -0800, Dan Schatzberg wrote: > @@ -1925,14 +1990,13 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, > } > > /* always use the first bio's css */ > + cmd->blk_css = NULL; > #ifdef CONFIG_BLK_CGROUP > - if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) { > - cmd->css = &bio_blkcg(rq->bio)->css; > - css_get(cmd->css); > - } else > + if (rq->bio && rq->bio->bi_blkg) > + cmd->blk_css = &bio_blkcg(rq->bio)->css; > #endif > - cmd->css = NULL; > - kthread_queue_work(&lo->worker, &cmd->work); > + > + loop_queue_work(lo, cmd); > > return BLK_STS_OK; > } > @@ -1942,6 +2006,9 @@ static void loop_handle_cmd(struct loop_cmd *cmd) > struct request *rq = blk_mq_rq_from_pdu(cmd); > const bool write = op_is_write(req_op(rq)); > struct loop_device *lo = rq->q->queuedata; > +#ifdef CONFIG_MEMCG > + struct cgroup_subsys_state *mem_css; > +#endif > int ret = 0; > > if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { > @@ -1949,8 +2016,24 @@ static void loop_handle_cmd(struct loop_cmd *cmd) > goto failed; > } > > + if (cmd->blk_css) { > +#ifdef CONFIG_MEMCG > + mem_css = cgroup_get_e_css(cmd->blk_css->cgroup, > + &memory_cgrp_subsys); > + memalloc_use_memcg(mem_cgroup_from_css(mem_css)); > +#endif > + kthread_associate_blkcg(cmd->blk_css); > + } > + > ret = do_req_filebacked(lo, rq); > - failed: > + > + if (cmd->blk_css) { > + kthread_associate_blkcg(NULL); > +#ifdef CONFIG_MEMCG > + memalloc_unuse_memcg(); > +#endif cgroup_get_e_css() acquires a reference, it looks like you're missing a css_put() here. I also wonder why you look up blk_css and mem_css in separate places. Since you already renamed cmd->css to cmd->blk_css, can you also add cmd->mem_css and pair up their lookup and refcounting? This should make loop_handle_cmd() a bit more straight-forward: if (cmd->blk_css) kthread_associate_blkcg(cmd->blk_css); if (cmd->mem_css) memalloc_use_memcg(mem_cgroup_from_css(mem_css)); ret = do_req_filebacked(lo, rq); memalloc_unuse_memcg(); kthread_associate_blkcg(NULL); All these functions have dummy implementations for !CONFIG_BLK_CGROUP, !CONFIG_MEMCG etc., so it shouldn't require any additional ifdefs.