Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755526AbaDNVhb (ORCPT ); Mon, 14 Apr 2014 17:37:31 -0400 Received: from mail-qg0-f50.google.com ([209.85.192.50]:45925 "EHLO mail-qg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755477AbaDNVhY (ORCPT ); Mon, 14 Apr 2014 17:37:24 -0400 From: Tejun Heo To: lizefan@huawei.com Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 06/12] cgroup: teach css_task_iter about effective csses Date: Mon, 14 Apr 2014 17:37:04 -0400 Message-Id: <1397511430-2673-7-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1397511430-2673-1-git-send-email-tj@kernel.org> References: <1397511430-2673-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, css_task_iter iterates tasks associated with a css by visiting each css_set associated with the owning cgroup and walking tasks of each of them. This works fine for !unified hierarchies as each cgroup has its own css for each associated subsystem on the hierarchy; however, on the planned unified hierarchy, a cgroup may not have csses associated and its tasks would be considered associated with the matching css of the nearest ancestor which has the subsystem enabled. This means that on the default unified hierarchy, just walking all tasks associated with a cgroup isn't enough to walk all tasks which are associated with the specified css. If any of its children doesn't have the matching css enabled, task iteration should also include all tasks from the subtree. We already added cgroup->e_csets[] to list all css_sets effectively associated with a given css and walk css_sets on that list instead to achieve such iteration. This patch updates css_task_iter iteration such that it walks css_sets on cgroup->e_csets[] instead of cgroup->cset_links if iteration is requested on an non-dummy css. Thanks to the previous iteration update, this change can be achieved with the addition of css_task_iter->ss and minimal updates to css_advance_task_iter() and css_task_iter_start(). Signed-off-by: Tejun Heo --- include/linux/cgroup.h | 2 ++ kernel/cgroup.c | 18 +++++++++++++++--- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index bee3905..18fcae3 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -842,6 +842,8 @@ css_next_descendant_post(struct cgroup_subsys_state *pos, /* A css_task_iter should be treated as an opaque object */ struct css_task_iter { + struct cgroup_subsys *ss; + struct list_head *cset_pos; struct list_head *cset_head; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index bcf390f..0318bfc 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2872,8 +2872,14 @@ static void css_advance_task_iter(struct css_task_iter *it) it->cset_pos = NULL; return; } - link = list_entry(l, struct cgrp_cset_link, cset_link); - cset = link->cset; + + if (it->ss) { + cset = container_of(l, struct css_set, + e_cset_node[it->ss->id]); + } else { + link = list_entry(l, struct cgrp_cset_link, cset_link); + cset = link->cset; + } } while (list_empty(&cset->tasks) && list_empty(&cset->mg_tasks)); it->cset_pos = l; @@ -2910,7 +2916,13 @@ void css_task_iter_start(struct cgroup_subsys_state *css, down_read(&css_set_rwsem); - it->cset_pos = &css->cgroup->cset_links; + it->ss = css->ss; + + if (it->ss) + it->cset_pos = &css->cgroup->e_csets[css->ss->id]; + else + it->cset_pos = &css->cgroup->cset_links; + it->cset_head = it->cset_pos; css_advance_task_iter(it); -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/