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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 CDAC6C43603 for ; Fri, 20 Dec 2019 15:23:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A140021D7E for ; Fri, 20 Dec 2019 15:23:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576855410; bh=Xngl0akcA9oyoBaD+j4NC9ZhmSFN/lCnqu5mH8MwMww=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=nRMsYMyyJmvKx/m/dQIgz1N2NgAdsLWf5Jb2AyTeyMT+uYS6q1ZTn0E1RGwwO2t5m q38zAvW3tmmJo+88hm5AImqcivCs6vkegPmwPqqxtHTHNc1ohR46y464ImvSndJOhj e5TDDgMHsah8uX2H4N6Go9u6Kl0QPgCW+vG+Jqk4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727541AbfLTPX3 (ORCPT ); Fri, 20 Dec 2019 10:23:29 -0500 Received: from mail-qv1-f68.google.com ([209.85.219.68]:38500 "EHLO mail-qv1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727233AbfLTPX3 (ORCPT ); Fri, 20 Dec 2019 10:23:29 -0500 Received: by mail-qv1-f68.google.com with SMTP id t6so3749339qvs.5; Fri, 20 Dec 2019 07:23:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=2dn9cCazElcEyS2nqL7r4gWAf9lvaYb6Vn/YiRslYl4=; b=dGqWkP7rNkkQ7wUNrXT5Y+51zZH0VVkgByyhw1p3XDzd8Hm6ZI/KbJ15sYaaKz40mK m14HPSZLBB8qG6man7ts9USB8X02PwIELsvF+5HE7dyPBIQEYANf400GS5D45CGtOwGd UoUgAvbZgoFH9qNxz1fAu4gPXznAN221WPoStJYmjwGiZts7nmHEeS4QP/bfEgD3WXxI W0coGzcwpxRTNR5W+wa4L+N6p1VkOWbvkAG28QfMLLeqIxFKEsP6elr6fsdzJRtTLtnK Y0Yv9GoWMDoQ5a2sEI99k0ieykriHKFoOw1e0zMDDEd5yHCZgMD0jZzoP+5USz+bgVgm uc0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=2dn9cCazElcEyS2nqL7r4gWAf9lvaYb6Vn/YiRslYl4=; b=s8Nvstzdyxh1Gf1YqUtPWUHIe1z+fTMnvr7S0cGW+ndzuybLHSWqttGwyfPqO50YdM bEapaEUXRIJ9CDR/KfvPbTy+9nthgJIBA1FvFWBovbs+UWL0qwr6cxWIkAEqZ+YYJrVK 15oubOVFoPcQRjbbTpAhHhkg0uWCuZkT7LwWwNZoJELxjmwhK5L7cJq8LAWq0aVdMCLY 5UrTxHknoVALpcw6bIxOMb/eybPK8v3khw0dvzXsVdaQdkc8IWLqwV7eaqNFwr4xnfw0 fiPoqXWINfCInPttoXOJARDPwUGRvNI32pXKGWYQcZlwT1+CK5UePyqmIeWaALlEEryi EB3A== X-Gm-Message-State: APjAAAWVgTILhUKsjGCDT/87bafybIxFlIf1vuyt18kinLwqWocPlPjO 0Hc0ko9A9ejfN+G30p/6EYo= X-Google-Smtp-Source: APXvYqzDPIlFhFSz/g8F5LJ6vpVFsAu6aHjc9thDeArzy5CSpzV1/fm1bZ/GTXvelMJtI2ygX+dpKw== X-Received: by 2002:a0c:aa8a:: with SMTP id f10mr13041213qvb.200.1576855408130; Fri, 20 Dec 2019 07:23:28 -0800 (PST) Received: from localhost ([2620:10d:c091:480::11e7]) by smtp.gmail.com with ESMTPSA id n19sm2941698qkn.52.2019.12.20.07.23.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Dec 2019 07:23:27 -0800 (PST) Date: Fri, 20 Dec 2019 07:23:24 -0800 From: Tejun Heo To: Namhyung Kim Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Jiri Olsa , Alexander Shishkin , Mark Rutland , Stephane Eranian , LKML , linux-perf-users@vger.kernel.org, Li Zefan , Johannes Weiner Subject: Re: [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature Message-ID: <20191220152324.GG2914998@devbig004.ftw2.facebook.com> References: <20191220043253.3278951-1-namhyung@kernel.org> <20191220043253.3278951-3-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191220043253.3278951-3-namhyung@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 20, 2019 at 01:32:46PM +0900, Namhyung Kim wrote: > The PERF_SAMPLE_CGROUP bit is to save (perf_event) cgroup information > in the sample. It will add a 64-bit id to identify current cgroup and > it's the file handle in the cgroup file system. Userspace should use > this information with PERF_RECORD_CGROUP event to match which cgroup > it belongs. You don't need PERF_RECORD_CGROUP for that. Something like the following should work. struct { struct file_handle fh; char stor[MAX_HANDLE_SZ]; } fh_store; struct file_handle *fh = &fh_store; fh->handle_type = 0xfe; // FILEID_KERNFS fh->handle_bytes = sizeof(u64); *(u64 *)fh->f_handle = cgrp_id; mnt_fd = open('/sys/fs/cgroup', O_RDONLY); fd = open_by_handle_at(mnt_fd, fh, O_RDONLY); snprintf(proc_path, PATH_MAX, "/proc/self/fd/%d", fd); readlink(proc_path, cgrp_path, PATH_MAX); -- tejun