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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 6D58BC4360F for ; Fri, 5 Apr 2019 12:37:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 30ECD21738 for ; Fri, 5 Apr 2019 12:37:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="If2bqmPe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730554AbfDEMhI (ORCPT ); Fri, 5 Apr 2019 08:37:08 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:45646 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726027AbfDEMhH (ORCPT ); Fri, 5 Apr 2019 08:37:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=cqaSZ+K93rrnDdKM+dpoAtz2NJApotYf4sBHoFtFOEs=; b=If2bqmPeef2+ZfqZ/OBWdNmNX 5LsA+suau83D/ZuXavzMK+mtpt8cnUFbn2nWPdNBQOipjVijtMH2QRXZ6cAL/OlcNzD+JB2WK5cQ4 f5Ga3ImjSTnFJy092oTPV38iIfSAoKU6ySsfaFXFYTBf8Zdn36Bag2/s26NCXIijvMUPwelTTb9pf zkjAPVYlRTzoWfzqb2I1EaQFKstTt1+EtKV+aWmzP0nhPHD8/4IyNe0e39wLtp8qzdODH7HdJW0Kf LgjuPvIrla1dECa+JnPdJJ5XySqeZbolgyljSs4xhcwUJBx57juwcDHpojhxnSdOmEXDNI3KRdm9N NogZ3aKZg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hCO5Q-0002ln-DE; Fri, 05 Apr 2019 12:36:48 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D9E0D23954638; Fri, 5 Apr 2019 14:36:45 +0200 (CEST) Date: Fri, 5 Apr 2019 14:36:45 +0200 From: Peter Zijlstra To: Juri Lelli 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: <20190405123645.GT12232@hirez.programming.kicks-ass.net> References: <20190403084650.4414-1-juri.lelli@redhat.com> <20190403084650.4414-5-juri.lelli@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190403084650.4414-5-juri.lelli@redhat.com> 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 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.