From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751855AbbJJDbn (ORCPT ); Fri, 9 Oct 2015 23:31:43 -0400 Received: from mail-io0-f179.google.com ([209.85.223.179]:34142 "EHLO mail-io0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751788AbbJJDbj (ORCPT ); Fri, 9 Oct 2015 23:31:39 -0400 From: Tejun Heo To: lizefan@huawei.com, hannes@cmpxchg.org Cc: cgroups@vger.kernel.org, cyphar@cyphar.com, linux-kernel@vger.kernel.org, kernel-team@fb.com, Tejun Heo Subject: [PATCH 08/14] cgroup: keep css_set and task lists in chronological order Date: Fri, 9 Oct 2015 23:29:35 -0400 Message-Id: <1444447781-16182-9-git-send-email-tj@kernel.org> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1444447781-16182-1-git-send-email-tj@kernel.org> References: <1444447781-16182-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org css task iteration will be updated to not leak cgroup internal locking to iterator users. In preparation, update css_set and task lists to be in chronological order. For tasks, as migration path is already using list_splice_tail_init(), only cgroup_enable_task_cg_lists() and cgroup_post_fork() need updating. For css_sets, link_css_set() is the only place which needs to be updated. Signed-off-by: Tejun Heo --- kernel/cgroup.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index b8da97a..5cb28d2 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -913,12 +913,11 @@ static void link_css_set(struct list_head *tmp_links, struct css_set *cset, link->cset = cset; link->cgrp = cgrp; - list_move(&link->cset_link, &cgrp->cset_links); - /* - * Always add links to the tail of the list so that the list - * is sorted by order of hierarchy creation + * Always add links to the tail of the lists so that the lists are + * in choronological order. */ + list_move_tail(&link->cset_link, &cgrp->cset_links); list_add_tail(&link->cgrp_link, &cset->cgrp_links); cgroup_get(cgrp); @@ -1778,7 +1777,7 @@ static void cgroup_enable_task_cg_lists(void) if (!css_set_populated(cset)) css_set_update_populated(cset, true); - list_add(&p->cg_list, &cset->tasks); + list_add_tail(&p->cg_list, &cset->tasks); get_css_set(cset); } spin_unlock_irq(&p->sighand->siglock); @@ -5478,7 +5477,7 @@ void cgroup_post_fork(struct task_struct *child, cset = task_css_set(current); if (list_empty(&child->cg_list)) { rcu_assign_pointer(child->cgroups, cset); - list_add(&child->cg_list, &cset->tasks); + list_add_tail(&child->cg_list, &cset->tasks); get_css_set(cset); } up_write(&css_set_rwsem); -- 2.4.3