From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760262AbcLUJ7P (ORCPT ); Wed, 21 Dec 2016 04:59:15 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:36804 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756942AbcLUJ7L (ORCPT ); Wed, 21 Dec 2016 04:59:11 -0500 Date: Wed, 21 Dec 2016 10:59:22 +0100 From: Greg KH To: Tejun Heo Cc: lizefan@huawei.com, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCHSET] kernfs, cgroup: reimplement "cgroup.procs" reading for v2 Message-ID: <20161221095922.GF27395@kroah.com> References: <20161220161222.15234-1-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161220161222.15234-1-tj@kernel.org> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 20, 2016 at 11:12:17AM -0500, Tejun Heo wrote: > On cgroup v1, the pid listings in "cgroup.procs" and "tasks" are > sorted which adds a lot of complications and overhead. v2 doesn't > have such requirement and has been intentionally using a modified > sorting order so that the output doesn't look sorted to users. > > This patchset re-implements "cgroup.procs" reading for v2 which simply > keeps a css_task_iter open while the file is being read. Keeping the > iterator open makes it unnecessary to skip to the right position on > each read segment and associated errors - e.g. incorrectly skipping > over pids because earlier pids disappeared between the reads. > > Using persistent iterator across multiple read calls requires > ->release() callback to clean it up. kernfs operations > ->open/release() are added and piped through cftype. > > This patchset contains the following five patches. > > 0001-kernfs-make-kernfs_open_file-mmapped-a-bitfield.patch > 0002-kernfs-add-kernfs_ops-open-release-callbacks.patch > 0003-cgroup-add-cftype-open-release-callbacks.patch > 0004-cgroup-reimplement-reading-cgroup.procs-on-cgroup-v2.patch > 0005-cgroup-remove-cgroup_pid_fry-and-friends.patch > > 0001 is a misc kernfs patch and 0002 adds ->open/release() to kernfs. > 0003 pipes ->open/release() through cftype. 0004 implements the new > cgroup.procs for v2 and 0005 removes the now unused sort order frying > logic. > > Greg, would it be okay to route the kernfs patches through > cgroup/for-4.11? No objection from me at all: Acked-by: Greg Kroah-Hartman