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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 AD3F3C433DB for ; Fri, 22 Jan 2021 14:14:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A64E23A54 for ; Fri, 22 Jan 2021 14:14:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728274AbhAVOOg (ORCPT ); Fri, 22 Jan 2021 09:14:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728329AbhAVOIr (ORCPT ); Fri, 22 Jan 2021 09:08:47 -0500 Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9813C0613D6 for ; Fri, 22 Jan 2021 06:08:06 -0800 (PST) Received: by mail-qt1-x835.google.com with SMTP id l23so1642222qtq.13 for ; Fri, 22 Jan 2021 06:08:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=TERIPq8AnRP0+heC8JP6C1Hqcc4LMIy29lTpckheB7I=; b=g8GUkZ7waXCLdvp9NP/6HED27xxvBUYuul5TF2IOCO3fvEztrPYrkLqiQiLAY4KJ2u 0EfIuhIMqfkFkVsTTpkaNh4yl6rY/OYNJz7ggobBFo4x2D8RKDAvs3qkpQjekX1xU+lN f7q3pJfwJMPYu+x41OqiHrZB2gv+oZahg8GYw3eDQBcmpiydQKKrznQdWWFo5IMT6O8T vN2s6zh5zu+EWg+C8ka02G7jVaX7MAu5g9VfoBKNkRMvZpFodzJR3NPYL3prcyhLv3AJ IfdSE3/6KDxxtNd7osLUqcrmA5LbY4YBlotYJwFVZHXkPRqhyIe9TLbIgH1FvtBtbgzg 8c2A== 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; bh=TERIPq8AnRP0+heC8JP6C1Hqcc4LMIy29lTpckheB7I=; b=qNULxTTVj31taex8np1eIdn2m5X9etecqCV2T/EwxUhYYroSqP/yfM9DjxBBfwp0LE jtB4BZNvosPUxpgGwB5m2aYZ0KsE2j4cuktEZcD1/vaOxMZ3z1GjkEEU0CXwynODlqdV ZEq+IrpREQ1r8epYLOOzBzYhBRwFK5rN4Wheje8TC1H9zo3X9jbQQ7GkqsbGmaZiqVxM 0L8ZAJ/7C7sVOJknE9R4ve9C152dXGdyfI0slRahCQvFlK9LAP1ADGMRKwkTEZDCIDCH kGQAavVuCha9M8pWiPyrtEBBXHpPX/41JNLt/yZfAtBJMMiJNekm2Idg1crGd8IHLy6c 804A== X-Gm-Message-State: AOAM53318RTo2vIG46Gledn7BHS3uBAgASx3WBrABwT5sx376MmZxfji fFXwt7+yP6xWIkHNOF2PhWPVfJRs5j+HR0uao64qP8PGyDYfE4CJ X-Google-Smtp-Source: ABdhPJzfvNjSEdtB3qItEhSxC0TUC7ROqxEUGjpCv/54F1yC2Oyrq0eA6BZz2oWGvWwfGQ/EMnQcXvem42bP95QxqkI= X-Received: by 2002:ac8:dc5:: with SMTP id t5mr4562036qti.246.1611324486158; Fri, 22 Jan 2021 06:08:06 -0800 (PST) MIME-Version: 1.0 References: <20201217170009.GA29186@192.168.3.9> In-Reply-To: From: Weiping Zhang Date: Fri, 22 Jan 2021 22:07:50 +0800 Message-ID: Subject: Re: [RFC PATCH v2] taskstats: add /proc/taskstats to fetch pid/tgid status To: sblbir@amazon.com, davem@davemloft.net, bsingharora@gmail.com, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Balbir Singh, Could you help review this patch, thanks On Mon, Dec 28, 2020 at 10:10 PM Weiping Zhang wrote: > > Hi David, > > Could you help review this patch ? > > thanks > > On Fri, Dec 18, 2020 at 1:24 AM Weiping Zhang > wrote: > > > > If a program needs monitor lots of process's status, it needs two > > syscalls for every process. The first one is telling kernel which > > pid/tgid should be monitored by send a command(write socket) to kernel. > > The second one is read the statistics by read socket. This patch add > > a new interface /proc/taskstats to reduce two syscalls to one ioctl. > > The user just set the target pid/tgid to the struct taskstats.ac_pid, > > then kernel will collect statistics for that pid/tgid. > > > > Signed-off-by: Weiping Zhang > > --- > > Changes since v1: > > * use /proc/taskstats instead of /dev/taskstats > > > > include/uapi/linux/taskstats.h | 5 +++ > > kernel/taskstats.c | 73 +++++++++++++++++++++++++++++++++- > > 2 files changed, 77 insertions(+), 1 deletion(-) > > > > diff --git a/include/uapi/linux/taskstats.h b/include/uapi/linux/taskstats.h > > index ccbd08709321..077eab84c77e 100644 > > --- a/include/uapi/linux/taskstats.h > > +++ b/include/uapi/linux/taskstats.h > > @@ -214,6 +214,11 @@ enum { > > > > #define TASKSTATS_CMD_ATTR_MAX (__TASKSTATS_CMD_ATTR_MAX - 1) > > > > +/* ioctl command */ > > +#define TASKSTATS_IOC_ATTR_PID _IO('T', TASKSTATS_CMD_ATTR_PID) > > +#define TASKSTATS_IOC_ATTR_TGID _IO('T', TASKSTATS_CMD_ATTR_TGID) > > + > > + > > /* NETLINK_GENERIC related info */ > > > > #define TASKSTATS_GENL_NAME "TASKSTATS" > > diff --git a/kernel/taskstats.c b/kernel/taskstats.c > > index a2802b6ff4bb..c0f9e2f2308b 100644 > > --- a/kernel/taskstats.c > > +++ b/kernel/taskstats.c > > @@ -21,6 +21,8 @@ > > #include > > #include > > #include > > +#include > > +#include > > > > /* > > * Maximum length of a cpumask that can be specified in > > @@ -28,6 +30,10 @@ > > */ > > #define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS) > > > > +#ifdef CONFIG_PROC_FS > > +#define PROC_TASKSTATS "taskstats" > > +#endif > > + > > static DEFINE_PER_CPU(__u32, taskstats_seqnum); > > static int family_registered; > > struct kmem_cache *taskstats_cache; > > @@ -666,6 +672,60 @@ static struct genl_family family __ro_after_init = { > > .n_ops = ARRAY_SIZE(taskstats_ops), > > }; > > > > +#ifdef CONFIG_PROC_FS > > +static long taskstats_ioctl_pid_tgid(unsigned long arg, bool tgid) > > +{ > > + struct taskstats kstat; > > + struct taskstats *ustat = (struct taskstats *)arg; > > + u32 id; > > + unsigned long offset = offsetof(struct taskstats, ac_pid); > > + long ret; > > + > > + /* userspace set monitored pid/tgid to the field "ac_pid" */ > > + if (unlikely(copy_from_user(&id, (void *)(arg + offset), sizeof(u32)))) > > + return -EFAULT; > > + > > + if (tgid) > > + ret = fill_stats_for_tgid(id, &kstat); > > + else > > + ret = fill_stats_for_pid(id, &kstat); > > + if (ret < 0) > > + return ret; > > + > > + if (unlikely(copy_to_user(ustat, &kstat, sizeof(struct taskstats)))) > > + return -EFAULT; > > + > > + return 0; > > +} > > + > > +static long taskstats_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > > +{ > > + long ret; > > + > > + switch (cmd) { > > + case TASKSTATS_IOC_ATTR_PID: > > + ret = taskstats_ioctl_pid_tgid(arg, false); > > + break; > > + case TASKSTATS_IOC_ATTR_TGID: > > + ret = taskstats_ioctl_pid_tgid(arg, true); > > + break; > > + default: > > + ret = -EINVAL; > > + break; > > + } > > + > > + return ret; > > +} > > + > > +static const struct proc_ops taskstats_proc_ops = { > > + .proc_ioctl = taskstats_ioctl, > > +#ifdef CONFIG_COMPAT > > + .proc_compat_ioctl = taskstats_ioctl, > > +#endif > > +}; > > +#endif > > + > > + > > /* Needed early in initialization */ > > void __init taskstats_init_early(void) > > { > > @@ -682,9 +742,20 @@ static int __init taskstats_init(void) > > { > > int rc; > > > > +#ifdef CONFIG_PROC_FS > > + if (!proc_create(PROC_TASKSTATS, 0, NULL, &taskstats_proc_ops)) { > > + pr_err("failed to create /proc/%s\n", PROC_TASKSTATS); > > + return -1; > > + } > > +#endif > > + > > rc = genl_register_family(&family); > > - if (rc) > > + if (rc) { > > +#ifdef CONFIG_PROC_FS > > + remove_proc_entry(PROC_TASKSTATS, NULL); > > +#endif > > return rc; > > + } > > > > family_registered = 1; > > pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION); > > -- > > 2.17.2 > >