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 9D8D0C77B61 for ; Mon, 24 Apr 2023 13:22:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232031AbjDXNWt (ORCPT ); Mon, 24 Apr 2023 09:22:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232103AbjDXNWd (ORCPT ); Mon, 24 Apr 2023 09:22:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A65CA4EEB for ; Mon, 24 Apr 2023 06:22:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7B36962247 for ; Mon, 24 Apr 2023 13:22:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F976C433D2; Mon, 24 Apr 2023 13:22:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1682342539; bh=xNCN//o4SOVOA6dcoBoQB18R8W+12RFRvS4M18bmmpo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z+RS6L54k983nNhdn+Jrk0NJQi3WdDRE17SWcbQZzG7zjYVD5tgK4RG6KOxc1n4ZF mS4Nw46hGVPsQPL8JWR6rtoYRdcYsiDiKu5Brvw1jeaIP74ZbhX118CsKbeKFpXEVM IqzMj8gLLaZ4SSxDPFoVa7XSfJ5pghV/In6HSBD0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dietmar Eggemann , "Qais Yousef (Google)" , "Peter Zijlstra (Intel)" , Vincent Guittot Subject: [PATCH 5.15 51/73] sched/fair: Fixes for capacity inversion detection Date: Mon, 24 Apr 2023 15:17:05 +0200 Message-Id: <20230424131130.894767727@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230424131129.040707961@linuxfoundation.org> References: <20230424131129.040707961@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Qais Yousef commit da07d2f9c153e457e845d4dcfdd13568d71d18a4 upstream. Traversing the Perf Domains requires rcu_read_lock() to be held and is conditional on sched_energy_enabled(). Ensure right protections applied. Also skip capacity inversion detection for our own pd; which was an error. Fixes: 44c7b80bffc3 ("sched/fair: Detect capacity inversion") Reported-by: Dietmar Eggemann Signed-off-by: Qais Yousef (Google) Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Vincent Guittot Link: https://lore.kernel.org/r/20230112122708.330667-3-qyousef@layalina.io (cherry picked from commit da07d2f9c153e457e845d4dcfdd13568d71d18a4) Signed-off-by: Qais Yousef (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/sched/fair.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8649,16 +8649,23 @@ static void update_cpu_capacity(struct s * * Thermal pressure will impact all cpus in this perf domain * equally. */ - if (static_branch_unlikely(&sched_asym_cpucapacity)) { + if (sched_energy_enabled()) { unsigned long inv_cap = capacity_orig - thermal_load_avg(rq); - struct perf_domain *pd = rcu_dereference(rq->rd->pd); + struct perf_domain *pd; + rcu_read_lock(); + + pd = rcu_dereference(rq->rd->pd); rq->cpu_capacity_inverted = 0; for (; pd; pd = pd->next) { struct cpumask *pd_span = perf_domain_span(pd); unsigned long pd_cap_orig, pd_cap; + /* We can't be inverted against our own pd */ + if (cpumask_test_cpu(cpu_of(rq), pd_span)) + continue; + cpu = cpumask_any(pd_span); pd_cap_orig = arch_scale_cpu_capacity(cpu); @@ -8683,6 +8690,8 @@ static void update_cpu_capacity(struct s break; } } + + rcu_read_unlock(); } trace_sched_cpu_capacity_tp(rq);