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 7093FC4167B
	for <linux-kernel@archiver.kernel.org>; Mon, 27 Nov 2023 21:53:26 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S233260AbjK0VxR (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Mon, 27 Nov 2023 16:53:17 -0500
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43462 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S229527AbjK0VxP (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 27 Nov 2023 16:53:15 -0500
Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D788BD
        for <linux-kernel@vger.kernel.org>; Mon, 27 Nov 2023 13:53:22 -0800 (PST)
Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08F98C433C7;
        Mon, 27 Nov 2023 21:53:22 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;
        s=k20201202; t=1701122002;
        bh=HeDiF2jwasV0GP+dtz+9Y1Dd+DYvHNFxhjLYvyamAFA=;
        h=Date:From:To:Cc:Subject:References:In-Reply-To:From;
        b=OUvpcyLGrzjY+THGjy5pypahwuW47YkS6ybPWEQZEoIlIF1NahoVSiF5udEasg+4x
         ItrolP9+i5SKZUXjFtqm8o9iXMTM9rpXjqId1ZHu4o5FLXulZebxzb9Ut0/1q+ADP8
         hoNQPwBqj0qapVVahubDIoXd8zAerxRT7jvKeoOKAsgYD76EAUATrcmKyXZndsxX24
         eKF/PHLeffa+eM4jKKveodshh3xHGa02xJWcI2bp8hE9r6UBDjzye0iL5c2xvWGOj0
         z2NOQd+2gkMTgqnrXZTJQKLMhHUgaHoztyOHlfMeA713T/Gkjbg8QM/1pAC8knQO2q
         WvSPXtuSudmwg==
Received: by quaco.ghostprotocols.net (Postfix, from userid 1000)
        id 3929D40094; Mon, 27 Nov 2023 18:53:19 -0300 (-03)
Date:   Mon, 27 Nov 2023 18:53:19 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Namhyung Kim <namhyung@kernel.org>
Cc:     Ian Rogers <irogers@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Nick Terrell <terrelln@fb.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kajol Jain <kjain@linux.ibm.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        "Steinar H. Gunderson" <sesse@google.com>,
        Liam Howlett <liam.howlett@oracle.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Colin Ian King <colin.i.king@gmail.com>,
        Dmitrii Dolgov <9erthalion6@gmail.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Ming Wang <wangming01@loongson.cn>,
        James Clark <james.clark@arm.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        Leo Yan <leo.yan@linaro.org>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        German Gomez <german.gomez@arm.com>,
        Changbin Du <changbin.du@huawei.com>,
        Paolo Bonzini <pbonzini@redhat.com>, Li Dong <lidong@vivo.com>,
        Sandipan Das <sandipan.das@amd.com>,
        liuwenyu <liuwenyu7@huawei.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v4 01/53] perf comm: Use regular mutex
Message-ID: <ZWUPz6ETFEBsrDkZ@kernel.org>
References: <20231102175735.2272696-1-irogers@google.com>
 <20231102175735.2272696-2-irogers@google.com>
 <CAM9d7cgbPGzgc=QG8dStvq1iX8snGyeKTJDrg2XBjX0pCX9Qtg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CAM9d7cgbPGzgc=QG8dStvq1iX8snGyeKTJDrg2XBjX0pCX9Qtg@mail.gmail.com>
X-Url:  http://acmel.wordpress.com
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Em Sun, Nov 05, 2023 at 09:31:47AM -0800, Namhyung Kim escreveu:
> Hi Ian,
> 
> On Thu, Nov 2, 2023 at 10:58 AM Ian Rogers <irogers@google.com> wrote:
> >
> > The rwsem is only after used for writing so switch to a mutex that has
> > better error checking.
> 
> Hmm.. ok.  It doesn't make sense to use rwsem without readers.

Well, the only reader is a findnew method, that will primarily read,
but possibly write if it doesn't find it there, so converting to a
regular mutex seems sensible.

- Arnaldo
 
> > Fixes: 7a8f349e9d14 ("perf rwsem: Add debug mode that uses a mutex")
> 
> But I'm not sure this is a fix.  Other than that,

Yeah, agreed, will remove the fixes.
 
> > Signed-off-by: Ian Rogers <irogers@google.com>
> 
> Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,

- Arnaldo