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=-16.7 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT, 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 3EF84C43444 for ; Thu, 10 Jan 2019 22:08:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0D40D218AE for ; Thu, 10 Jan 2019 22:08:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="srgGXbB+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728910AbfAJWIL (ORCPT ); Thu, 10 Jan 2019 17:08:11 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:44209 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728807AbfAJWIK (ORCPT ); Thu, 10 Jan 2019 17:08:10 -0500 Received: by mail-pg1-f195.google.com with SMTP id t13so5382804pgr.11 for ; Thu, 10 Jan 2019 14:08:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+OULLMuerNEP0alqy6OmnDEtcrB759rW8C6mN7L4vig=; b=srgGXbB+MDNra9yHvnpA7JnWGI1yejRbQpFLJdis5RB26UjMRqie4R/aLpnklNN0sS 5MS4o1NN5rAT8Ib1XEseXKu47U1MW3+j8Nkeaj9RrKK9MxEaoeMMi7fVSpRYgDcAjikr RiGmbTb0KnMwV26nPA14fjRBZePi7eM3fcfGCU4Dmom9T1iiwNS+gg622NARdbtZlrdy xTwWjl+Z+99ssFmmYZqRPn7SNQYWzW6GoP30dPpVQv/zuXIAg8wvN0SWhp7AX1FS6eZF oHZ75LY1xssaHYs2FxZ7UEZi6KubW8MBt6CheGcaSE3XdXz9IntU59HFtunkyEXA2Hwk 9keA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=+OULLMuerNEP0alqy6OmnDEtcrB759rW8C6mN7L4vig=; b=B51nfefLwmiMuSm57k9MOFhDhRapKnOgF0L1X2Wxq2+fdLNQV+W2TluC/26mycTLux 45BEDMiIYlorq/de1T2nGTgmweFK+vMiVyh8Lp5atK66KNEOWSC/wS1MI0yl+JOGC9re mnpc7TmQlPAXxNMw02hhrbo5l66YrlQPNh9XsrQQi3i3rrwx0hiXKQ7Laf397N09JAEo gA8TRtSTP5D632WlvwKsbN71hdZ2sEMRxdS2o8WCqcXp0R1eYjGAykzsGS2+rUj3TI4o y5JwLgSMPFWWhWfRChUBvn2cyPg+dX6643f4aEuR0i2e6mPjfmFetNRRNNFN873Lj832 Wg/g== X-Gm-Message-State: AJcUukcEOnqKyanfdIASXyqGg+Aw4MDulEAEubhrJCESlzS8t17kFV7A j29cDzKXXJ08FrOsEGq8Pulwug== X-Google-Smtp-Source: ALg8bN60+69qoUR4ahkci/QfrF0Ij7K44dZKkAyRXtZKwR23+ut1vvrrUADTQ2Xl1Peh8ZO+UT3bSQ== X-Received: by 2002:a63:7e5b:: with SMTP id o27mr10907220pgn.214.1547158088900; Thu, 10 Jan 2019 14:08:08 -0800 (PST) Received: from surenb0.mtv.corp.google.com ([2620:0:1000:1612:3320:4357:47df:276b]) by smtp.googlemail.com with ESMTPSA id p7sm152958019pfj.72.2019.01.10.14.08.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Jan 2019 14:08:08 -0800 (PST) From: Suren Baghdasaryan To: gregkh@linuxfoundation.org Cc: tj@kernel.org, lizefan@huawei.com, hannes@cmpxchg.org, axboe@kernel.dk, dennis@kernel.org, dennisszhou@gmail.com, mingo@redhat.com, peterz@infradead.org, akpm@linux-foundation.org, corbet@lwn.net, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, Suren Baghdasaryan Subject: [PATCH v2 2/5] kernel: cgroup: add poll file operation Date: Thu, 10 Jan 2019 14:07:15 -0800 Message-Id: <20190110220718.261134-3-surenb@google.com> X-Mailer: git-send-email 2.20.1.97.g81188d93c3-goog In-Reply-To: <20190110220718.261134-1-surenb@google.com> References: <20190110220718.261134-1-surenb@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johannes Weiner Cgroup has a standardized poll/notification mechanism for waking all pollers on all fds when a filesystem node changes. To allow polling for custom events, add a .poll callback that can override the default. This is in preparation for pollable cgroup pressure files which have per-fd trigger configurations. Signed-off-by: Johannes Weiner Signed-off-by: Suren Baghdasaryan --- include/linux/cgroup-defs.h | 4 ++++ kernel/cgroup/cgroup.c | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 5e1694fe035b..6f9ea8601421 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -32,6 +32,7 @@ struct kernfs_node; struct kernfs_ops; struct kernfs_open_file; struct seq_file; +struct poll_table_struct; #define MAX_CGROUP_TYPE_NAMELEN 32 #define MAX_CGROUP_ROOT_NAMELEN 64 @@ -573,6 +574,9 @@ struct cftype { ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off); + __poll_t (*poll)(struct kernfs_open_file *of, + struct poll_table_struct *pt); + #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lock_class_key lockdep_key; #endif diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 7a8429f8e280..3f533f95acdc 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3499,6 +3499,16 @@ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf, return ret ?: nbytes; } +static __poll_t cgroup_file_poll(struct kernfs_open_file *of, poll_table *pt) +{ + struct cftype *cft = of->kn->priv; + + if (cft->poll) + return cft->poll(of, pt); + + return kernfs_generic_poll(of, pt); +} + static void *cgroup_seqfile_start(struct seq_file *seq, loff_t *ppos) { return seq_cft(seq)->seq_start(seq, ppos); @@ -3537,6 +3547,7 @@ static struct kernfs_ops cgroup_kf_single_ops = { .open = cgroup_file_open, .release = cgroup_file_release, .write = cgroup_file_write, + .poll = cgroup_file_poll, .seq_show = cgroup_seqfile_show, }; @@ -3545,6 +3556,7 @@ static struct kernfs_ops cgroup_kf_ops = { .open = cgroup_file_open, .release = cgroup_file_release, .write = cgroup_file_write, + .poll = cgroup_file_poll, .seq_start = cgroup_seqfile_start, .seq_next = cgroup_seqfile_next, .seq_stop = cgroup_seqfile_stop, -- 2.20.1.97.g81188d93c3-goog