From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Gushchin Subject: [RFC 1/4] cgroup: keep track of number of descent cgroups Date: Wed, 2 Aug 2017 17:55:29 +0100 Message-ID: <20170802165532.22277-2-guro@fb.com> References: <20170802165532.22277-1-guro@fb.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=6EmvzNCsS9/6ea7/tFUD3Q4dX1LSDMfpazxXxF4fIDk=; b=CBsmW1SuAUf90KXInBRm9EygfGTLNQxUgzVt0PVnEkC4tnVlKyPozQ2uQtY2f4FDiQvM whW3h3Du5LHqsqtXwesfaQQm8n7jaA5Az3RjI1jfftxPj1zJSo8S40nn5/M6nbXOr3+W CFqTprvNfcHwkGzhmopxUCXt2DAe3J3RwwU= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector1-fb-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=6EmvzNCsS9/6ea7/tFUD3Q4dX1LSDMfpazxXxF4fIDk=; b=KbBmeK/rhGuIF8TYLD+2swWTXp51lLk3gEz8ShzOj5hxzRsxLrX6IVYyH7IvaKevPpP976cqNJZlu2mQGPWRTogfWg7YRd4u7QgLb6rHTzBn6Gk0ZpsYLgD7OXw7pcEffmlH/w+qAw045CxJWNRBjOVtZAW2X0B58DkO+emon9k= In-Reply-To: <20170802165532.22277-1-guro@fb.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: cgroups@vger.kernel.org Cc: Roman Gushchin , Tejun Heo , Zefan Li , Waiman Long , Johannes Weiner , kernel-team@fb.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Keep track of the number of online and dying descent cgroups. This data will be used later to add an ability to control cgroup hierarchy (limit the depth and the number of descent cgroups) and display hierarchy stats. Signed-off-by: Roman Gushchin Suggested-by: Tejun Heo Cc: Tejun Heo Cc: Zefan Li Cc: Waiman Long Cc: Johannes Weiner Cc: kernel-team@fb.com Cc: cgroups@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- include/linux/cgroup-defs.h | 8 ++++++++ kernel/cgroup/cgroup.c | 19 +++++++++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 9d741959f218..58b4c425a155 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -274,6 +274,14 @@ struct cgroup { int level; /* + * Keep track of total numbers of visible and dying descent cgroups. + * Dying cgroups are cgroups which were deleted by a user, + * but are still existing because someone else is holding a reference. + */ + int nr_descendants; + int nr_dying_descendants; + + /* * Each non-empty css_set associated with this cgroup contributes * one to nr_populated_csets. The counter is zero iff this cgroup * doesn't have any tasks. diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 85f6a112344b..cfdbb1e780de 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4408,9 +4408,15 @@ static void css_release_work_fn(struct work_struct *work) if (ss->css_released) ss->css_released(css); } else { + struct cgroup *tcgrp; + /* cgroup release path */ trace_cgroup_release(cgrp); + for (tcgrp = cgroup_parent(cgrp); tcgrp; + tcgrp = cgroup_parent(tcgrp)) + tcgrp->nr_dying_descendants--; + cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id); cgrp->id = -1; @@ -4609,9 +4615,13 @@ static struct cgroup *cgroup_create(struct cgroup *parent) cgrp->root = root; cgrp->level = level; - for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) + for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) { cgrp->ancestor_ids[tcgrp->level] = tcgrp->id; + if (tcgrp != cgrp) + tcgrp->nr_descendants++; + } + if (notify_on_release(parent)) set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); @@ -4817,7 +4827,7 @@ static void kill_css(struct cgroup_subsys_state *css) static int cgroup_destroy_locked(struct cgroup *cgrp) __releases(&cgroup_mutex) __acquires(&cgroup_mutex) { - struct cgroup *parent = cgroup_parent(cgrp); + struct cgroup *tcgrp, *parent = cgroup_parent(cgrp); struct cgroup_subsys_state *css; struct cgrp_cset_link *link; int ssid; @@ -4865,6 +4875,11 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) if (parent && cgroup_is_threaded(cgrp)) parent->nr_threaded_children--; + for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) { + tcgrp->nr_descendants--; + tcgrp->nr_dying_descendants++; + } + cgroup1_check_for_release(cgroup_parent(cgrp)); /* put the base reference */ -- 2.13.3