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=-23.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 7D64BC11F67 for ; Tue, 29 Jun 2021 15:51:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6203E61D74 for ; Tue, 29 Jun 2021 15:51:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233986AbhF2Pxs (ORCPT ); Tue, 29 Jun 2021 11:53:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233946AbhF2Pxq (ORCPT ); Tue, 29 Jun 2021 11:53:46 -0400 Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [IPv6:2a00:1450:4864:20::330]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72206C061766 for ; Tue, 29 Jun 2021 08:51:19 -0700 (PDT) Received: by mail-wm1-x330.google.com with SMTP id p10-20020a05600c430ab02901df57d735f7so2150731wme.3 for ; Tue, 29 Jun 2021 08:51:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=YTv8Tc7EKr0PzcUpaPHiI9onaP3uWQq/Vd6rHddjRjA=; b=RpQi7APS9B63UyQUVEGrgotj4uE3OjXtjczk1Upg5oxT7JKfJMno+mHnV+MalqI3Qo GYXTFCyoIrrMFemKL9Of3cMnUD7vSoS/jOxxzgrzHUZ9wNRvC2KpPk8r8LUJHNyXiXJ2 S3uws8//rDJ37Pq84hbZUQGdJyBuTZ0SPU/z4lyzyhsYk3Sb7JWQH0+uhFxoBLNkbbTf NqDfBYnDxCNQGLJ8BqcY77lEzJesKtF5Pkxb4ZlqgABxuv++R0KEDgAz5/4wplsAS8Yr AvDzpqUs+L/XdEDHDWnCJvp13ygyv3+czc6Vn4T7r1ogehNgQJDBSY1grOFw5aaT3BpW H/Pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=YTv8Tc7EKr0PzcUpaPHiI9onaP3uWQq/Vd6rHddjRjA=; b=e5dRkODjnvPZVQxj0Y6KnRhFsSB1vw4lSf6UyqX/7b2avKxCHERircJ2vChjQwjxzs 7F8LHFRF67s2OX0NkdanZRf27f5HDHt2cIgTAVdYb2x0KH4GgbDKn0WQleYNSF/mkzoR QLhedm4D6Isih/RQqsxel060x66fe4NAwwRhf/AsRMLDaTOghztqs8CktuvcRULnufw7 4iXhBblNicwGvUwe1L9y0WjKEHpm0EKieVA+LDDeRLZwxlsXRYA+gCd+x9YLkHnR4o41 9Gzmr/QzluHYT6qAyQHsDjgzchcJJlBwXFXV0Md2MfAPqo7v+TP6EsYWQbuCxCh7Orda CrwA== X-Gm-Message-State: AOAM5336hnrbzEuvUiw0+XjJ8iq5tzr2uBoo+rtWnE9c0TDfdFZ/hyfB ENHct+xuYSVplABbM6s52TehRTYvdxmlIHq4OUTecw== X-Google-Smtp-Source: ABdhPJw8XUZzoWPvrqaUFAXIvzoEdZQ2ZXFbuXzyHrBdIsWVcJzLAxRh2/KSxO31vl7wC9wtAPJ+xkBsZZU06Qmeww4= X-Received: by 2002:a05:600c:a01:: with SMTP id z1mr33659683wmp.77.1624981877946; Tue, 29 Jun 2021 08:51:17 -0700 (PDT) MIME-Version: 1.0 References: <20210625071826.608504-1-namhyung@kernel.org> <20210625071826.608504-3-namhyung@kernel.org> In-Reply-To: <20210625071826.608504-3-namhyung@kernel.org> From: Ian Rogers Date: Tue, 29 Jun 2021 08:51:05 -0700 Message-ID: Subject: Re: [PATCH 2/4] perf tools: Add cgroup_is_v2() helper To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Jiri Olsa , Ingo Molnar , Peter Zijlstra , LKML , Andi Kleen , Stephane Eranian , Song Liu Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 25, 2021 at 12:18 AM Namhyung Kim wrote: > > The cgroup_is_v2() is to check if the given subsystem is mounted on > cgroup v2 or not. It'll be used by BPF cgroup code later. > > Signed-off-by: Namhyung Kim > --- > tools/perf/util/cgroup.c | 19 +++++++++++++++++++ > tools/perf/util/cgroup.h | 2 ++ > 2 files changed, 21 insertions(+) > > diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c > index ef18c988c681..e819a4f30fc2 100644 > --- a/tools/perf/util/cgroup.c > +++ b/tools/perf/util/cgroup.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -70,6 +71,24 @@ int read_cgroup_id(struct cgroup *cgrp) > } > #endif /* HAVE_FILE_HANDLE */ > > +#ifndef CGROUP2_SUPER_MAGIC > +#define CGROUP2_SUPER_MAGIC 0x63677270 > +#endif > + > +int cgroup_is_v2(const char *subsys) > +{ > + char mnt[PATH_MAX + 1]; > + struct statfs stbuf; > + > + if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, subsys)) > + return -1; > + > + if (statfs(mnt, &stbuf) < 0) > + return -1; > + > + return (stbuf.f_type == CGROUP2_SUPER_MAGIC); > +} > + > static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str) > { > struct evsel *counter; > diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h > index 707adbe25123..1549ec2fd348 100644 > --- a/tools/perf/util/cgroup.h > +++ b/tools/perf/util/cgroup.h > @@ -47,4 +47,6 @@ int read_cgroup_id(struct cgroup *cgrp) > } > #endif /* HAVE_FILE_HANDLE */ > > +int cgroup_is_v2(const char *subsys); > + I think this is okay. It may make sense to have this in tools/lib/api/fs/fs.h, for example fs__valid_mount is already checking magic numbers. Perhaps we can avoid a statfs call, but it'd need some reorganization of the fs.h code. Acked-by: Ian Rogers Thanks, Ian > #endif /* __CGROUP_H__ */ > -- > 2.32.0.93.g670b81a890-goog >