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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 E2B86C3A5A3 for ; Fri, 30 Aug 2019 03:56:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0F7D20659 for ; Fri, 30 Aug 2019 03:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567137382; bh=xcQIAyQ1lp9Azi1F7v0Nnp+xnz/22i/uJok5bgvaCIw=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=U59GRKjTQiQV04BmDNg9wE+5n/h9n9hx2kapqRyziGkMU8o5ChEfdwGoJz86US6Uk mcY6IR2omYQ3jcJ48yjQFJrc9GCAWEjWZkHSqarGPAT9LH0GfBxMIjo/1lBqjGzOAX jhpDIpU3BBx/fqK6rsz7E4LT3pFyqUkYDcP20Xvo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728246AbfH3D4W (ORCPT ); Thu, 29 Aug 2019 23:56:22 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:42668 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728221AbfH3D4P (ORCPT ); Thu, 29 Aug 2019 23:56:15 -0400 Received: by mail-wr1-f67.google.com with SMTP id b16so5449799wrq.9 for ; Thu, 29 Aug 2019 20:56:14 -0700 (PDT) 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=ocQtEStflZxIuihvafAK7EGGQ6iNiCmKabe8FgYSRcU=; b=pgDyR5n0vEWcyF4mK7B7JKw1Kak17VHQbj2M3Hp3PitZ+iA4H+9RNGB3Su4xwKM8yp rbZCHB4Ul0uL2tKLqapP79SpQ7jkWzC/NnhR/QKnv1HKjlBEFizhi3RttLgk+K6ykmf7 kPbzJzfMe9rfXBT1UhoI4j6O05/3luLRnngWs2Hc+NmfIWi02eyT0JsdDBvzCnioAFHy hAZ/9QNvaxyJ1nkq320+KlNgGq+lizl0BOYrnNXluk+12xyuaJs4bg+iHALQumOAYuiR Luz/P83qlayytWmxmAtL66P/Va0YzIZbNd2uXqo8zw1tUCc9jaLZoNB6gD7yjSBoYVTM Iu8w== X-Gm-Message-State: APjAAAVxb7fc/imqHBoI5A6aN3SveMGwAekkWJxbTVNuwrmWaO11wmLS dXzamlwi9xq9IcL7X4rP4LlP4iLVdlhp1UeAZjc= X-Google-Smtp-Source: APXvYqx+KNemY0Dhr16K2V2ol6cAIcXgp6k2ocV8ZDHoGaivPd7xRhrs9zz3tkQorUlQxGLFDUQ5sTLRN0BUqS0Rvx0= X-Received: by 2002:adf:f0ce:: with SMTP id x14mr15650857wro.31.1567137373367; Thu, 29 Aug 2019 20:56:13 -0700 (PDT) MIME-Version: 1.0 References: <20190828073130.83800-1-namhyung@kernel.org> <20190828073130.83800-2-namhyung@kernel.org> <20190828144830.GQ2263813@devbig004.ftw2.facebook.com> In-Reply-To: <20190828144830.GQ2263813@devbig004.ftw2.facebook.com> From: Namhyung Kim Date: Fri, 30 Aug 2019 12:56:02 +0900 Message-ID: Subject: Re: [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event To: Tejun Heo Cc: Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , LKML , Jiri Olsa , Alexander Shishkin , Stephane Eranian , Li Zefan , Johannes Weiner , Adrian Hunter Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Tejun, On Wed, Aug 28, 2019 at 11:48 PM Tejun Heo wrote: > > Hello, Namhyung. > > On Wed, Aug 28, 2019 at 04:31:22PM +0900, Namhyung Kim wrote: > > + * struct { > > + * struct perf_event_header header; > > + * u64 ino; > > + * u64 path_len; > > + * char path[]; > > ino and path aren't great identifers for cgroups because both can get > recycled pretty quickly. Can you please take a look at > KERNFS_ROOT_SUPPORT_EXPORTOP? That's the fhandle that cgroup uses, > currently the standard ino+gen which isn't ideal but good enough. > Another benefit is that the path can also be resolved efficiently from > userspace given the handle. Thanks for the info, I'll take a look at it. Namhyung