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=-0.7 required=3.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,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 1061FC433ED for ; Sat, 3 Apr 2021 02:09:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 395C761154 for ; Sat, 3 Apr 2021 02:09:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 395C761154 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 93B628D0003; Fri, 2 Apr 2021 22:09:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 912318D0001; Fri, 2 Apr 2021 22:09:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B71F8D0003; Fri, 2 Apr 2021 22:09:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0061.hostedemail.com [216.40.44.61]) by kanga.kvack.org (Postfix) with ESMTP id 5DF778D0001 for ; Fri, 2 Apr 2021 22:09:23 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 120E6805E542 for ; Sat, 3 Apr 2021 02:09:23 +0000 (UTC) X-FDA: 77989423806.23.8B56E1E Received: from mail3-167.sinamail.sina.com.cn (mail3-167.sinamail.sina.com.cn [202.108.3.167]) by imf22.hostedemail.com (Postfix) with SMTP id 7BD12C0001EE for ; Sat, 3 Apr 2021 02:09:19 +0000 (UTC) Received: from unknown (HELO localhost.localdomain)([114.244.161.230]) by sina.com (172.16.97.32) with ESMTP id 6067CE4800010316; Sat, 3 Apr 2021 10:09:17 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 565308628876 From: Hillf Danton To: Dan Schatzberg Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/3] loop: Use worker per cgroup instead of kworker Date: Sat, 3 Apr 2021 10:09:02 +0800 Message-Id: <20210403020902.1384-1-hdanton@sina.com> In-Reply-To: <20210402191638.3249835-2-schatzberg.dan@gmail.com> References: <20210402191638.3249835-1-schatzberg.dan@gmail.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 7BD12C0001EE X-Stat-Signature: rqkai4r9qwmcxda4b3ewcf6bsiik6xnh X-Rspamd-Server: rspam02 Received-SPF: none (sina.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=mail3-167.sinamail.sina.com.cn; client-ip=202.108.3.167 X-HE-DKIM-Result: none/none X-HE-Tag: 1617415759-626352 Content-Transfer-Encoding: quoted-printable 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: On Fri, 2 Apr 2021 12:16:32 Dan Schatzberg wrote: > +queue_work: > + if (worker) { > + /* > + * We need to remove from the idle list here while > + * holding the lock so that the idle timer doesn't > + * free the worker > + */ > + if (!list_empty(&worker->idle_list)) > + list_del_init(&worker->idle_list); Nit, only queue work if the worker is inactive - otherwise it is taking care of the cmd_list. > + work =3D &worker->work; > + cmd_list =3D &worker->cmd_list; > + } else { > + work =3D &lo->rootcg_work; > + cmd_list =3D &lo->rootcg_cmd_list; > + } > + list_add_tail(&cmd->list_entry, cmd_list); > + queue_work(lo->workqueue, work); > + spin_unlock_irq(&lo->lo_work_lock); > } [...] > + /* > + * We only add to the idle list if there are no pending cmds > + * *and* the worker will not run again which ensures that it > + * is safe to free any worker on the idle list > + */ > + if (worker && !work_pending(&worker->work)) { The empty cmd_list is a good enough reason for worker to become idle. > + worker->last_ran_at =3D jiffies; > + list_add_tail(&worker->idle_list, &lo->idle_worker_list); > + loop_set_timer(lo); > + } > + spin_unlock_irq(&lo->lo_work_lock); > + current->flags =3D orig_flags; > +}