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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 C5D57C4360F for ; Fri, 5 Apr 2019 12:53:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 95A4620700 for ; Fri, 5 Apr 2019 12:53:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731102AbfDEMxV (ORCPT ); Fri, 5 Apr 2019 08:53:21 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:45713 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726027AbfDEMxU (ORCPT ); Fri, 5 Apr 2019 08:53:20 -0400 Received: by mail-wr1-f65.google.com with SMTP id s15so7825249wra.12 for ; Fri, 05 Apr 2019 05:53:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=OqoLdziHSEu6DYBl2hUx025VWynIi2G0T48ShRGwesw=; b=WqnimKmFKSb4Dg5m2oqUjrPBqi559oV/nI25Ij/wzxyqLJsP3EHFxK8xnMuaKh6HOL 8qAdxptjK3ANqAlVHwB0WZSKF7sFrZa6wLodYNoik6+hJZBoykHZiUS/CRUHvIetdjN+ CxfQiv0hcSEAxynKc7JX+uPbyUm+oIP5jT2EPJibDy7EhhZCZrpdeqHQKeu+nSVPYOLY PbajHOWxkwTxGTiueIZ0PYSOAeYGRgxLqQtItY73HtNw1Z+v3YAGsg6hgoPTIxBsWruL F4N/VVgVA46RInwDf9atHRNne5ZdEAKTEfwLsxdnrv7B6y8Y8bwIdhcwViNSV/NOkiAJ oWlw== X-Gm-Message-State: APjAAAUWs4LdxeKWC+Emvxs/elyG0Vpg8x8BzJqI5PPoRSQongidWHI8 oGGpo0BRCqrlJCw0MlpZwXtP9g== X-Google-Smtp-Source: APXvYqwLojOCdHMClFxB4bA1tXEx+ELpPs4ctGTf3RHk8QEzmT3WB/dknuj6SYr8D2R0EJJ4EpvGNA== X-Received: by 2002:adf:e443:: with SMTP id t3mr7153324wrm.257.1554468799264; Fri, 05 Apr 2019 05:53:19 -0700 (PDT) Received: from localhost.localdomain ([151.29.174.33]) by smtp.gmail.com with ESMTPSA id t15sm2715103wmt.2.2019.04.05.05.53.17 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 05 Apr 2019 05:53:18 -0700 (PDT) Date: Fri, 5 Apr 2019 14:53:15 +0200 From: Juri Lelli To: Peter Zijlstra Cc: mingo@redhat.com, rostedt@goodmis.org, tj@kernel.org, linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it, claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it, bristot@redhat.com, mathieu.poirier@linaro.org, lizefan@huawei.com, cgroups@vger.kernel.org Subject: Re: [PATCH v7 4/7] sched/core: Prevent race condition between cpuset and __sched_setscheduler() Message-ID: <20190405125315.GC5453@localhost.localdomain> References: <20190403084650.4414-1-juri.lelli@redhat.com> <20190403084650.4414-5-juri.lelli@redhat.com> <20190405123645.GT12232@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190405123645.GT12232@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 05/04/19 14:36, Peter Zijlstra wrote: > On Wed, Apr 03, 2019 at 10:46:47AM +0200, Juri Lelli wrote: > > +static inline void cpuset_read_only_lock(unsigned long *flags) > > +{ > > + local_irq_save(*flags); > > + preempt_disable(); > > +} > > + > > +static inline void cpuset_read_only_unlock(unsigned long *flags) > > +{ > > + local_irq_restore(*flags); > > + preempt_enable(); > > +} > > You can ditch the preempt stuff. IRQs disabled already very much implies > !preemptible. OK. Thanks, - Juri