From patchwork Thu Jan 12 16:14:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Valentin Schneider X-Patchwork-Id: 42525 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:4e01:0:0:0:0:0 with SMTP id p1csp3972035wrt; Thu, 12 Jan 2023 08:20:29 -0800 (PST) X-Google-Smtp-Source: AMrXdXuanjQoaatumTVN3zxYlXwnMcJYpVv3d66+WVQDLuC0/T76PQ36umPiWAGJiAkHDvfjBKG3 X-Received: by 2002:a17:907:c606:b0:84d:456f:91b7 with SMTP id ud6-20020a170907c60600b0084d456f91b7mr15662881ejc.43.1673540429706; Thu, 12 Jan 2023 08:20:29 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1673540429; cv=none; d=google.com; s=arc-20160816; b=sWAzCYe1G2Z2828SdbafgOIHYyFJUtZTMwfw1AH1oAd9DwwCuBzfRJUAaNBwFUp3Hx QAji7q+k9bJTEnUr4Lo13f+HmoLzhzoivB+6rpal/xxCe27438wQ+s1Tc/ojTFIVHH89 HuFef9u6Z9qksngQThzkqxZdC+ssbXvDs7WQVcsXVJUHPCSfC+wW3H3BNSbmiX7FS9Gr BbRhBBD/dpu0W13GQohBpB+SJ5KH7U7wZhqUhel07b5nm6ouDd3gh8z/Qz6Dcj/8HG+s 2mNPnxntNXe4a48LIx0/t+wnqvqg49XjJcL5Cz/T12PSM6PK41U6Pl0tqKPNZs9wqUZK aRhg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=ZaDHq41SfAlEO/FEWzBquw15t81pf5rbinRD53jl+xU=; b=kM7qgrJTRJLjioEWYJN9xfO2mC8aAFbDUOkcjnh12qtD4jvTweApzjPkpUMuucS18h 0NX/0kepH8VEFrADwvbTBbJWtu1dKnEVq3luh3yC5/pnToObCDtjvkblZXRPUz60lgLw YwXaplPJ0NEhWJc5yPbmGVGAllE5drBGhQpq12MtHOmZHwhDWzlrqHkStvNkbszFBxdQ L4D0wZKXK22owPJr5fao4XOQJZRtwag0cGAqLPJrDkj13EWvpqGBgyBVv9dsH9jZetyP JB2CbIfHsEnumfRBMwIx79EHvNw2nYfpDjFFkDEjeiy0csbtsg+1KZvwQei+9ivszV44 NANg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=bNIoAgAB; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id ho38-20020a1709070ea600b0084ce55f4b7csi21541089ejc.470.2023.01.12.08.20.06; Thu, 12 Jan 2023 08:20:29 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=bNIoAgAB; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231881AbjALQTl (ORCPT + 99 others); Thu, 12 Jan 2023 11:19:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236750AbjALQSi (ORCPT ); Thu, 12 Jan 2023 11:18:38 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B26B71CFF7 for ; Thu, 12 Jan 2023 08:14:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673540083; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZaDHq41SfAlEO/FEWzBquw15t81pf5rbinRD53jl+xU=; b=bNIoAgABqYHJs4fZK8qt/4ZS9cuc5gZnqU1dzQHJMw96b+MoGCxkg5968Zk5/mqZLFAXt0 pRREWdQmsNtHtWUoaV3Al8j8JjXQzVyT49pLn2S/57h6A2wIBwRduCz1YuWD6RySxr1HzQ k8VEHh19E1U+bHa6xtlQOgvjW0L5Evo= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-13--Cy6S057Or-Z-MOjx798qg-1; Thu, 12 Jan 2023 11:14:39 -0500 X-MC-Unique: -Cy6S057Or-Z-MOjx798qg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 219541C087A3; Thu, 12 Jan 2023 16:14:39 +0000 (UTC) Received: from vschneid.remote.csb (unknown [10.33.36.188]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C3A502166B26; Thu, 12 Jan 2023 16:14:37 +0000 (UTC) From: Valentin Schneider To: linux-kernel@vger.kernel.org Cc: Lai Jiangshan , Tejun Heo , Lai Jiangshan , Peter Zijlstra , Frederic Weisbecker , Juri Lelli , Phil Auld , Marcelo Tosatti Subject: [PATCH v8 1/5] workqueue: Protects wq_unbound_cpumask with wq_pool_attach_mutex Date: Thu, 12 Jan 2023 16:14:27 +0000 Message-Id: <20230112161431.860196-2-vschneid@redhat.com> In-Reply-To: <20230112161431.860196-1-vschneid@redhat.com> References: <20230112161431.860196-1-vschneid@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1754834329360339542?= X-GMAIL-MSGID: =?utf-8?q?1754834329360339542?= From: Lai Jiangshan When unbind_workers() reads wq_unbound_cpumask to set the affinity of freshly-unbound kworkers, it only holds wq_pool_attach_mutex. This isn't sufficient as wq_unbound_cpumask is only protected by wq_pool_mutex. Make wq_unbound_cpumask protected with wq_pool_attach_mutex and also remove the need of temporary saved_cpumask. Fixes: 10a5a651e3af ("workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs") Reported-by: Valentin Schneider Signed-off-by: Lai Jiangshan --- kernel/workqueue.c | 41 ++++++++++++++++------------------------- 1 file changed, 16 insertions(+), 25 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 07895deca2711..76ea87b0251ce 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -326,7 +326,7 @@ static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait); static LIST_HEAD(workqueues); /* PR: list of all workqueues */ static bool workqueue_freezing; /* PL: have wqs started freezing? */ -/* PL: allowable cpus for unbound wqs and work items */ +/* PL&A: allowable cpus for unbound wqs and work items */ static cpumask_var_t wq_unbound_cpumask; /* CPU where unbound work was last round robin scheduled from this CPU */ @@ -3952,7 +3952,8 @@ static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx) /* allocate the attrs and pwqs for later installation */ static struct apply_wqattrs_ctx * apply_wqattrs_prepare(struct workqueue_struct *wq, - const struct workqueue_attrs *attrs) + const struct workqueue_attrs *attrs, + const cpumask_var_t unbound_cpumask) { struct apply_wqattrs_ctx *ctx; struct workqueue_attrs *new_attrs, *tmp_attrs; @@ -3968,14 +3969,15 @@ apply_wqattrs_prepare(struct workqueue_struct *wq, goto out_free; /* - * Calculate the attrs of the default pwq. + * Calculate the attrs of the default pwq with unbound_cpumask + * which is wq_unbound_cpumask or to set to wq_unbound_cpumask. * If the user configured cpumask doesn't overlap with the * wq_unbound_cpumask, we fallback to the wq_unbound_cpumask. */ copy_workqueue_attrs(new_attrs, attrs); - cpumask_and(new_attrs->cpumask, new_attrs->cpumask, wq_unbound_cpumask); + cpumask_and(new_attrs->cpumask, new_attrs->cpumask, unbound_cpumask); if (unlikely(cpumask_empty(new_attrs->cpumask))) - cpumask_copy(new_attrs->cpumask, wq_unbound_cpumask); + cpumask_copy(new_attrs->cpumask, unbound_cpumask); /* * We may create multiple pwqs with differing cpumasks. Make a @@ -4072,7 +4074,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, wq->flags &= ~__WQ_ORDERED; } - ctx = apply_wqattrs_prepare(wq, attrs); + ctx = apply_wqattrs_prepare(wq, attrs, wq_unbound_cpumask); if (!ctx) return -ENOMEM; @@ -5334,7 +5336,7 @@ void thaw_workqueues(void) } #endif /* CONFIG_FREEZER */ -static int workqueue_apply_unbound_cpumask(void) +static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask) { LIST_HEAD(ctxs); int ret = 0; @@ -5350,7 +5352,7 @@ static int workqueue_apply_unbound_cpumask(void) if (wq->flags & __WQ_ORDERED) continue; - ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs); + ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask); if (!ctx) { ret = -ENOMEM; break; @@ -5365,6 +5367,11 @@ static int workqueue_apply_unbound_cpumask(void) apply_wqattrs_cleanup(ctx); } + if (!ret) { + mutex_lock(&wq_pool_attach_mutex); + cpumask_copy(wq_unbound_cpumask, unbound_cpumask); + mutex_unlock(&wq_pool_attach_mutex); + } return ret; } @@ -5383,7 +5390,6 @@ static int workqueue_apply_unbound_cpumask(void) int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) { int ret = -EINVAL; - cpumask_var_t saved_cpumask; /* * Not excluding isolated cpus on purpose. @@ -5397,23 +5403,8 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) goto out_unlock; } - if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) { - ret = -ENOMEM; - goto out_unlock; - } - - /* save the old wq_unbound_cpumask. */ - cpumask_copy(saved_cpumask, wq_unbound_cpumask); - - /* update wq_unbound_cpumask at first and apply it to wqs. */ - cpumask_copy(wq_unbound_cpumask, cpumask); - ret = workqueue_apply_unbound_cpumask(); - - /* restore the wq_unbound_cpumask when failed. */ - if (ret < 0) - cpumask_copy(wq_unbound_cpumask, saved_cpumask); + ret = workqueue_apply_unbound_cpumask(cpumask); - free_cpumask_var(saved_cpumask); out_unlock: apply_wqattrs_unlock(); }