From: Tejun Heo <tj@kernel.org>
To: lizefan@huawei.com, mhocko@suse.cz, rjw@sisk.pl
Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
fweisbec@gmail.com, Glauber Costa <glommer@parallels.com>
Subject: [PATCH 1/9 v2] cgroup: add cgroup_subsys->post_create()
Date: Wed, 7 Nov 2012 09:15:08 -0800 [thread overview]
Message-ID: <20121107171508.GF2660@mtj.dyndns.org> (raw)
In-Reply-To: <1351931915-1701-2-git-send-email-tj@kernel.org>
Currently, there's no way for a controller to find out whether a new
cgroup finished all ->create() allocatinos successfully and is
considered "live" by cgroup.
This becomes a problem later when we add generic descendants walking
to cgroup which can be used by controllers as controllers don't have a
synchronization point where it can synchronize against new cgroups
appearing in such walks.
This patch adds ->post_create(). It's called after all ->create()
succeeded and the cgroup is linked into the generic cgroup hierarchy.
This plays the counterpart of ->pre_destroy().
When used in combination with the to-be-added generic descendant
iterators, ->post_create() can be used to implement reliable state
inheritance. It will be explained with the descendant iterators.
v2: Added a paragraph about its future use w/ descendant iterators per
Michal.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@parallels.com>
---
If you can explain it better, please be my guest.
Thanks.
include/linux/cgroup.h | 1 +
kernel/cgroup.c | 12 ++++++++++--
2 files changed, 11 insertions(+), 2 deletions(-)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -438,6 +438,7 @@ int cgroup_taskset_size(struct cgroup_ta
struct cgroup_subsys {
struct cgroup_subsys_state *(*create)(struct cgroup *cgrp);
+ void (*post_create)(struct cgroup *cgrp);
void (*pre_destroy)(struct cgroup *cgrp);
void (*destroy)(struct cgroup *cgrp);
int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset);
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4060,10 +4060,15 @@ static long cgroup_create(struct cgroup
if (err < 0)
goto err_remove;
- /* each css holds a ref to the cgroup's dentry */
- for_each_subsys(root, ss)
+ for_each_subsys(root, ss) {
+ /* each css holds a ref to the cgroup's dentry */
dget(dentry);
+ /* creation succeeded, notify subsystems */
+ if (ss->post_create)
+ ss->post_create(cgrp);
+ }
+
/* The cgroup directory was pre-locked for us */
BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex));
@@ -4281,6 +4286,9 @@ static void __init cgroup_init_subsys(st
ss->active = 1;
+ if (ss->post_create)
+ ss->post_create(&ss->root->top_cgroup);
+
/* this function shouldn't be used with modular subsystems, since they
* need to register a subsys_id, among other things */
BUG_ON(ss->module);
next prev parent reply other threads:[~2012-11-07 17:15 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-03 8:38 [PATCHSET cgroup/for-3.8] cgroup_freezer: implement proper hierarchy support Tejun Heo
2012-11-03 8:38 ` [PATCH 1/9] cgroup: add cgroup_subsys->post_create() Tejun Heo
2012-11-05 13:42 ` Glauber Costa
2012-11-05 18:02 ` [RFC] cgroup: deprecate clone_children Tejun Heo
2012-11-05 19:17 ` Serge Hallyn
2012-11-05 19:26 ` Tejun Heo
2012-11-07 15:25 ` [PATCH 1/9] cgroup: add cgroup_subsys->post_create() Michal Hocko
2012-11-07 17:02 ` Tejun Heo
2012-11-07 17:15 ` Tejun Heo [this message]
2012-11-07 17:40 ` [PATCH 1/9 v2] " Michal Hocko
2012-11-08 2:59 ` Kamezawa Hiroyuki
2012-11-08 19:07 ` [PATCH 1/9 v3] " Tejun Heo
2012-11-09 9:09 ` Li Zefan
2012-11-09 9:09 ` Li Zefan
2012-11-09 11:09 ` Daniel Wagner
2012-11-09 17:22 ` Tejun Heo
2012-11-10 1:35 ` Glauber Costa
2012-11-12 13:04 ` Daniel Wagner
2012-11-03 8:38 ` [PATCH 2/9] cgroup: Use rculist ops for cgroup->children Tejun Heo
2012-11-07 15:30 ` Michal Hocko
2012-11-08 3:01 ` Kamezawa Hiroyuki
2012-11-09 9:10 ` Li Zefan
2012-11-03 8:38 ` [PATCH 3/9] cgroup: implement generic child / descendant walk macros Tejun Heo
2012-11-06 20:31 ` Tejun Heo
2012-11-07 15:38 ` Michal Hocko
2012-11-07 16:54 ` Michal Hocko
2012-11-07 17:01 ` Tejun Heo
2012-11-07 17:49 ` Michal Hocko
2012-11-08 3:21 ` Kamezawa Hiroyuki
2012-11-08 9:50 ` Michal Hocko
2012-11-08 17:15 ` Tejun Heo
2012-11-08 17:59 ` [PATCH 3/9 v2] " Tejun Heo
2012-11-09 9:13 ` Li Zefan
2012-11-03 8:38 ` [PATCH 4/9] cgroup_freezer: trivial cleanups Tejun Heo
2012-11-08 3:24 ` Kamezawa Hiroyuki
2012-11-08 9:53 ` Michal Hocko
2012-11-03 8:38 ` [PATCH 5/9] cgroup_freezer: prepare freezer_change_state() for full hierarchy support Tejun Heo
2012-11-08 4:25 ` Kamezawa Hiroyuki
2012-11-08 9:56 ` Michal Hocko
2012-11-03 8:38 ` [PATCH 6/9] cgroup_freezer: make freezer->state mask of flags Tejun Heo
2012-11-08 4:37 ` Kamezawa Hiroyuki
2012-11-08 4:42 ` Tejun Heo
2012-11-08 5:00 ` Kamezawa Hiroyuki
2012-11-08 14:38 ` Tejun Heo
2012-11-08 10:39 ` Michal Hocko
2012-11-08 14:39 ` Tejun Heo
2012-11-08 14:47 ` Michal Hocko
2012-11-03 8:38 ` [PATCH 7/9] cgroup_freezer: introduce CGROUP_FREEZING_[SELF|PARENT] Tejun Heo
2012-11-08 4:42 ` Kamezawa Hiroyuki
2012-11-08 4:45 ` Tejun Heo
2012-11-08 4:56 ` Kamezawa Hiroyuki
2012-11-08 14:41 ` Tejun Heo
2012-11-08 12:47 ` Michal Hocko
2012-11-08 14:42 ` Tejun Heo
2012-11-03 8:38 ` [PATCH 8/9] cgroup_freezer: add ->post_create() and ->pre_destroy() and track online state Tejun Heo
2012-11-08 4:48 ` Kamezawa Hiroyuki
2012-11-08 15:41 ` Tejun Heo
2012-11-08 13:23 ` Michal Hocko
2012-11-08 17:17 ` Tejun Heo
2012-11-03 8:38 ` [PATCH 9/9] cgroup_freezer: implement proper hierarchy support Tejun Heo
2012-11-07 11:00 ` Michal Hocko
2012-11-07 16:31 ` Tejun Heo
2012-11-07 16:39 ` [PATCH 9/9 v2] " Tejun Heo
2012-11-08 14:08 ` Michal Hocko
2012-11-08 14:18 ` Tejun Heo
2012-11-08 15:20 ` Michal Hocko
2012-11-08 15:29 ` Tejun Heo
2012-11-08 15:57 ` Michal Hocko
2012-11-08 17:57 ` [PATCH 9/9 v3] " Tejun Heo
2012-11-08 18:02 ` Michal Hocko
2012-11-08 18:04 ` Tejun Heo
2012-11-08 18:08 ` Michal Hocko
2012-11-08 18:01 ` [PATCHSET cgroup/for-3.8] " Tejun Heo
2012-11-09 17:15 ` Tejun Heo
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