From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754503Ab2KHEm5 (ORCPT ); Wed, 7 Nov 2012 23:42:57 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:42193 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753397Ab2KHEmz (ORCPT ); Wed, 7 Nov 2012 23:42:55 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.8.4 Message-ID: <509B382E.4030707@jp.fujitsu.com> Date: Thu, 08 Nov 2012 13:42:22 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:16.0) Gecko/20121026 Thunderbird/16.0.2 MIME-Version: 1.0 To: Tejun Heo CC: lizefan@huawei.com, mhocko@suse.cz, rjw@sisk.pl, linux-pm@vger.kernel.org, fweisbec@gmail.com, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH 7/9] cgroup_freezer: introduce CGROUP_FREEZING_[SELF|PARENT] References: <1351931915-1701-1-git-send-email-tj@kernel.org> <1351931915-1701-8-git-send-email-tj@kernel.org> In-Reply-To: <1351931915-1701-8-git-send-email-tj@kernel.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2012/11/03 17:38), Tejun Heo wrote: > Introduce FREEZING_SELF and FREEZING_PARENT and make FREEZING OR of > the two flags. This is to prepare for full hierarchy support. > > freezer_apply_date() is updated such that it can handle setting and > clearing of both flags. The two flags are also exposed to userland > via read-only files self_freezing and parent_freezing. > > Other than the added cgroupfs files, this patch doesn't introduce any > behavior change. > > Signed-off-by: Tejun Heo What is the purpose of FREEZING_SELG/PARENT, having 2 flags and make it visible to users ? Thanks, -Kame > --- > kernel/cgroup_freezer.c | 55 ++++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 47 insertions(+), 8 deletions(-) > > diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c > index e76aa9f..b8ad93c 100644 > --- a/kernel/cgroup_freezer.c > +++ b/kernel/cgroup_freezer.c > @@ -23,8 +23,12 @@ > #include > > enum freezer_state_flags { > - CGROUP_FREEZING = (1 << 1), /* this freezer is freezing */ > + CGROUP_FREEZING_SELF = (1 << 1), /* this freezer is freezing */ > + CGROUP_FREEZING_PARENT = (1 << 2), /* the parent freezer is freezing */ > CGROUP_FROZEN = (1 << 3), /* this and its descendants frozen */ > + > + /* mask for all FREEZING flags */ > + CGROUP_FREEZING = CGROUP_FREEZING_SELF | CGROUP_FREEZING_PARENT, > }; > > struct freezer { > @@ -245,8 +249,13 @@ static void unfreeze_cgroup(struct freezer *freezer) > * freezer_apply_state - apply state change to a single cgroup_freezer > * @freezer: freezer to apply state change to > * @freeze: whether to freeze or unfreeze > + * @state: CGROUP_FREEZING_* flag to set or clear > + * > + * Set or clear @state on @cgroup according to @freeze, and perform > + * freezing or thawing as necessary. > */ > -static void freezer_apply_state(struct freezer *freezer, bool freeze) > +static void freezer_apply_state(struct freezer *freezer, bool freeze, > + unsigned int state) > { > /* also synchronizes against task migration, see freezer_attach() */ > lockdep_assert_held(&freezer->lock); > @@ -254,13 +263,19 @@ static void freezer_apply_state(struct freezer *freezer, bool freeze) > if (freeze) { > if (!(freezer->state & CGROUP_FREEZING)) > atomic_inc(&system_freezing_cnt); > - freezer->state |= CGROUP_FREEZING; > + freezer->state |= state; > freeze_cgroup(freezer); > } else { > - if (freezer->state & CGROUP_FREEZING) > - atomic_dec(&system_freezing_cnt); > - freezer->state &= ~(CGROUP_FREEZING | CGROUP_FROZEN); > - unfreeze_cgroup(freezer); > + bool was_freezing = freezer->state & CGROUP_FREEZING; > + > + freezer->state &= ~state; > + > + if (!(freezer->state & CGROUP_FREEZING)) { > + if (was_freezing) > + atomic_dec(&system_freezing_cnt); > + freezer->state &= ~CGROUP_FROZEN; > + unfreeze_cgroup(freezer); > + } > } > } > > @@ -275,7 +290,7 @@ static void freezer_change_state(struct freezer *freezer, bool freeze) > { > /* update @freezer */ > spin_lock_irq(&freezer->lock); > - freezer_apply_state(freezer, freeze); > + freezer_apply_state(freezer, freeze, CGROUP_FREEZING_SELF); > spin_unlock_irq(&freezer->lock); > } > > @@ -295,6 +310,20 @@ static int freezer_write(struct cgroup *cgroup, struct cftype *cft, > return 0; > } > > +static u64 freezer_self_freezing_read(struct cgroup *cgroup, struct cftype *cft) > +{ > + struct freezer *freezer = cgroup_freezer(cgroup); > + > + return (bool)(freezer->state & CGROUP_FREEZING_SELF); > +} > + > +static u64 freezer_parent_freezing_read(struct cgroup *cgroup, struct cftype *cft) > +{ > + struct freezer *freezer = cgroup_freezer(cgroup); > + > + return (bool)(freezer->state & CGROUP_FREEZING_PARENT); > +} > + > static struct cftype files[] = { > { > .name = "state", > @@ -302,6 +331,16 @@ static struct cftype files[] = { > .read_seq_string = freezer_read, > .write_string = freezer_write, > }, > + { > + .name = "self_freezing", > + .flags = CFTYPE_NOT_ON_ROOT, > + .read_u64 = freezer_self_freezing_read, > + }, > + { > + .name = "parent_freezing", > + .flags = CFTYPE_NOT_ON_ROOT, > + .read_u64 = freezer_parent_freezing_read, > + }, > { } /* terminate */ > }; > >