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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 7F8DDC07E96 for ; Thu, 8 Jul 2021 07:23:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F66261CE2 for ; Thu, 8 Jul 2021 07:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229819AbhGHH0B (ORCPT ); Thu, 8 Jul 2021 03:26:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:33904 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229780AbhGHH0B (ORCPT ); Thu, 8 Jul 2021 03:26:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625728999; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aoZiGpC6Kf/0gFWXqlk5P9SaFK1vqVElFixbZ4rq5Zo=; b=SlC5NB+A15cqCbUwmA1YEP7ldwc0MqT3znBXrlhxo9zoiJESn8Dk9r0Yh9UQ0/QT1t/laC C+QsiQMXSRLB2u2OlunF65g3ZZpXISaOX00Fp3gv46vbrzzkCTIGde8CGO5H+cFvP+qwkg R3rjms+7pZp5EgFfAZBuLsNeahT+5bk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-524-3mKM26BrM1SyljauJIAMtQ-1; Thu, 08 Jul 2021 03:23:18 -0400 X-MC-Unique: 3mKM26BrM1SyljauJIAMtQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7775E1018721; Thu, 8 Jul 2021 07:23:17 +0000 (UTC) Received: from T590 (ovpn-12-112.pek2.redhat.com [10.72.12.112]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3612D5C1D5; Thu, 8 Jul 2021 07:23:10 +0000 (UTC) Date: Thu, 8 Jul 2021 15:23:07 +0800 From: Ming Lei To: Christoph Hellwig Cc: Jens Axboe , linux-block@vger.kernel.org, Michal =?iso-8859-1?Q?Koutn=FD?= , Dan Schatzberg Subject: Re: [PATCH 2/6] loop: conver timer for monitoring idle worker into dwork Message-ID: References: <20210705102607.127810-1-ming.lei@redhat.com> <20210705102607.127810-3-ming.lei@redhat.com> <20210706055227.GG17027@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210706055227.GG17027@lst.de> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jul 06, 2021 at 07:52:27AM +0200, Christoph Hellwig wrote: > On Mon, Jul 05, 2021 at 06:26:03PM +0800, Ming Lei wrote: > > +static void loop_free_idle_workers(struct work_struct *work) > > +{ > > + struct loop_device *lo = container_of(work, struct loop_device, > > + idle_work.work); > > + struct loop_worker *pos, *worker; > > + > > + spin_lock(&lo->lo_work_lock); > > + list_for_each_entry_safe(worker, pos, &lo->idle_worker_list, > > + idle_list) { > > + if (time_is_after_jiffies(worker->last_ran_at + > > + LOOP_IDLE_WORKER_TIMEOUT)) > > + break; > > + list_del(&worker->idle_list); > > + rb_erase(&worker->rb_node, &lo->worker_tree); > > + css_put(worker->blkcg_css); > > + kfree(worker); > > + } > > + if (!list_empty(&lo->idle_worker_list)) > > + loop_set_timer(lo); > > + spin_unlock(&lo->lo_work_lock); > > +} > > + > > + > > Double empty line. But that whole fact that the loop driver badly > reimplements work queues is just fucked up. We need to revert this > shit. Can you explain why work queues are bad for fixing this blkcg/memcg issue? Thanks, Ming