From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
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 CB12DC7EE21
	for <linux-kernel@archiver.kernel.org>; Thu,  4 May 2023 15:31:58 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S231402AbjEDPb5 (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Thu, 4 May 2023 11:31:57 -0400
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47190 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S229872AbjEDPbz (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 4 May 2023 11:31:55 -0400
Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C051D1BE4;
        Thu,  4 May 2023 08:31:54 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
        d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding:
        Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:
        Sender:Reply-To:Content-ID:Content-Description;
        bh=IIgIxNOgGajHepSM7/pf7gMv4ELrvOiprsqpPtX5j30=; b=B1XmU+s26pWozDj4BUvpHNS0Jz
        +RQJ0DU8BucpVqaYBl7JlhMjdzIigHBLi/LSa/4NxWRc6+IpkYTFATw3/8ljZerMtuCByt62ElNa3
        Z+lh5u+4c7//dpiYmUvcsgd/dQfg+N+dBkRMV2/97CuO7jtmAwfFlrXtubc9g2+SsBqxNe/gTyIeV
        tAh6xuKmmhM1kj3BlgfWzVqARuar4UnoyCi0atp6ivVK19HLgt2MSHhnAQbnKSHJE0iKxe/Gm1IUQ
        EExxjNgb4+v2c/6chk61uUE7O6DVJ71DxLpMDpdozmL/KZK2fReRB4+dOIK0InCznAUCHKLf9GJ0m
        v44CuJXA==;
Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net)
        by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux))
        id 1puav4-00AikD-4J; Thu, 04 May 2023 15:30:58 +0000
Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225])
        (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
         key-exchange X25519 server-signature RSA-PSS (4096 bits))
        (Client did not present a certificate)
        by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 643E7305ECF;
        Thu,  4 May 2023 17:30:57 +0200 (CEST)
Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000)
        id 458FD2418C43F; Thu,  4 May 2023 17:30:57 +0200 (CEST)
Date:   Thu, 4 May 2023 17:30:57 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Oleg Nesterov <oleg@redhat.com>
Cc:     Wander Lairson Costa <wander@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Brian Cain <bcain@quicinc.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Liam R. Howlett" <Liam.Howlett@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Christian Brauner <brauner@kernel.org>,
        Andrei Vagin <avagin@gmail.com>,
        Shakeel Butt <shakeelb@google.com>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:PERFORMANCE EVENTS SUBSYSTEM" 
        <linux-perf-users@vger.kernel.org>, Hu Chunyu <chuhu@redhat.com>,
        Paul McKenney <paulmck@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v7 2/3] sched/task: Add the put_task_struct_atomic_safe()
 function
Message-ID: <20230504153057.GI1744258@hirez.programming.kicks-ass.net>
References: <20230425114307.36889-1-wander@redhat.com>
 <20230425114307.36889-3-wander@redhat.com>
 <20230504084229.GI1734100@hirez.programming.kicks-ass.net>
 <20230504122945.GA28757@redhat.com>
 <20230504143303.GA1744142@hirez.programming.kicks-ass.net>
 <CAAq0SUmYrQbS1k9NNKGQP7hQRQJ308dk9NCiUimEiLeBJUavgA@mail.gmail.com>
 <20230504152306.GA1135@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20230504152306.GA1135@redhat.com>
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, May 04, 2023 at 05:23:07PM +0200, Oleg Nesterov wrote:
> On 05/04, Wander Lairson Costa wrote:
> >
> > On Thu, May 4, 2023 at 11:34 AM Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > > static inline void put_task_struct(struct task_struct *t)
> > > {
> > >         if (!refcount_dec_and_test(&t->usage))
> > >                 return;
> > >
> > >         if (IS_ENABLED(CONFIG_PREEMPT_RT) && !preemptible())
> > >                 call_rcu(&t->rcu, __put_task_struct_rcu);
> > >
> > >         __put_task_struct(t);
> > > }
> > >
> >
> > That's what v5 [1] does.
> 
> Yes, but as Sebastian explained CONFIG_PROVE_RAW_LOCK_NESTING won't like it.

This can help:

  https://lkml.kernel.org/r/168303194177.404.8610123576035502891.tip-bot2@tip-bot2