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 10FA3C433FE for ; Wed, 5 Oct 2022 16:14:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230252AbiJEQO0 (ORCPT ); Wed, 5 Oct 2022 12:14:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230022AbiJEQOX (ORCPT ); Wed, 5 Oct 2022 12:14:23 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CD207D1F9 for ; Wed, 5 Oct 2022 09:14:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664986461; 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=h8IFjZlZP/WQ78LWaXxVDrINKc4I9eLwNoWa4oc+Q8U=; b=DyN9n4amuGT4SbRZHy63sTzrZV3t14BxLnzqrjoAEBkkNrzSwQH0Rt6MQQfyzXFcwLWVK/ Ap2AjdHIokk10UsEqKEG1j7SOsxVlSqMCqjSgLnTpE+hHKPOzpsPb7HVBtuJYv90/bSg3I 600OQaz+iNhKPZ/1e3ndKTjvQ/dRoyI= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-160-IuDgR_6KOx2u3HHPpUeJmw-1; Wed, 05 Oct 2022 12:14:20 -0400 X-MC-Unique: IuDgR_6KOx2u3HHPpUeJmw-1 Received: by mail-wr1-f71.google.com with SMTP id i1-20020adfa501000000b0022cd1e1137bso5379761wrb.0 for ; Wed, 05 Oct 2022 09:14:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=h8IFjZlZP/WQ78LWaXxVDrINKc4I9eLwNoWa4oc+Q8U=; b=uRvw93Tf5uun378viRQdJpeM30MATDD3Oji0bdO96/1xaSce/t8tawa1VtyrY0BkEO cBtMsQcRJSIe0201H8G4b3TOMg5aI86Yg6UyqP5RUy0zHOIJ4z21M2+CEfJO1VRB3rJ5 WPqbuzKs25aSZxYyi2Vy6F1mWSROmPqO8QKXg1mkEhYHQjKEFufzHIDS5ytM70vScWUu 9uT5AUSyM196wFqVXqdiKcYVC0ltI+sPO+D1UMDlNxZjYIgk0RV4hgH+cMURKyqEHgJy NeeNZkeqfySjGGJDVgG+QH6pXGkPCskmeoHVTeuhpRG5g1zlutyKFXoGfWVl/n1VdItq 97iA== X-Gm-Message-State: ACrzQf1cR3L/q/V8FQHd9IqWDzETeFoiv3Ul43wL1X56wVd2uZ7qJcuc KNl6J25DQH5rPgtqmBpn9ef2DT/Bs0s0/4jwWFTTbn3bhzUQvLkQKmsP28mLYFLpfLRTOlSOGoV 5Rxc+5D83jpQn3Xo2xWjiTEwf X-Received: by 2002:a5d:5c08:0:b0:228:e139:43f3 with SMTP id cc8-20020a5d5c08000000b00228e13943f3mr351004wrb.396.1664986459307; Wed, 05 Oct 2022 09:14:19 -0700 (PDT) X-Google-Smtp-Source: AMsMyM7Ap+AkZUjQNOKuWLZsMO3FeanzD7owNw3uY2MOnJOOwA7JRKE7kP4/gxls+InRnf/RmtkN5A== X-Received: by 2002:a5d:5c08:0:b0:228:e139:43f3 with SMTP id cc8-20020a5d5c08000000b00228e13943f3mr350996wrb.396.1664986459141; Wed, 05 Oct 2022 09:14:19 -0700 (PDT) Received: from vschneid.remote.csb ([149.71.65.94]) by smtp.gmail.com with ESMTPSA id l128-20020a1c2586000000b003bd44dc524csm2324923wml.34.2022.10.05.09.14.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Oct 2022 09:14:18 -0700 (PDT) From: Valentin Schneider To: Hillf Danton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lai Jiangshan , Peter Zijlstra , Frederic Weisbecker , Marcelo Tosatti Subject: Re: [PATCH v4 4/4] workqueue: Unbind workers before sending them to exit() In-Reply-To: <20221005145022.1695-1-hdanton@sina.com> References: <20221004150521.822266-1-vschneid@redhat.com> <20221005010832.1934-1-hdanton@sina.com> <20221005145022.1695-1-hdanton@sina.com> Date: Wed, 05 Oct 2022 17:14:17 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/10/22 22:50, Hillf Danton wrote: > On 05 Oct 2022 12:13:17 +0100 Valentin Schneider > > Bound kworkers can be destroyed by the idle timer on a housekeeping CPU. > > Diff is only for thoughts. > > +++ b/kernel/workqueue.c > @@ -1985,6 +1985,7 @@ fail: > static void destroy_worker(struct worker *worker) > { > struct worker_pool *pool = worker->pool; > + int cpu = smp_processor_id(); > > lockdep_assert_held(&pool->lock); > > @@ -1999,6 +2000,12 @@ static void destroy_worker(struct worker > > list_del_init(&worker->entry); > worker->flags |= WORKER_DIE; > + > + if (!(pool->flags & POOL_DISASSOCIATED) && pool->cpu != cpu) { > + /* send worker to die on a housekeeping cpu */ > + cpumask_clear(&worker->task->cpus_mask); > + cpumask_set_cpu(cpu, &worker->task->cpus_mask); > + } > wake_up_process(worker->task); > } > The proper interface to play with that cpumask is set_cpus_allowed_ptr(), which requires a sleepable context, hence the whole series.