| [PATCH v2 4/5] don't take cgroup_mutex in destroy() [message #46035 is a reply to message #46031] |
Mon, 23 April 2012 19:37   |
Glauber Costa
Messages: 916
Registered: October 2011
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Senior Member |
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Most of the destroy functions are only doing very simple things
like freeing memory.
The ones who goes through lists and such, already use its own
locking for those.
* The cgroup itself won't go away until we free it, (after destroy)
* The parent won't go away because we hold a reference count
* There are no more tasks in the cgroup, and the cgroup is declared
dead (cgroup_is_removed() == true)
[v2: don't cgroup_lock the freezer and blkcg ]
Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Tejun Heo <tj@kernel.org>
CC: Li Zefan <lizefan@huawei.com>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Vivek Goyal <vgoyal@redhat.com>
---
kernel/cgroup.c | 9 ++++-----
1 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 932c318..976d332 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -869,13 +869,13 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode)
* agent */
synchronize_rcu();
- mutex_lock(&cgroup_mutex);
/*
* Release the subsystem state objects.
*/
for_each_subsys(cgrp->root, ss)
ss->destroy(cgrp);
+ mutex_lock(&cgroup_mutex);
cgrp->root->number_of_cgroups--;
mutex_unlock(&cgroup_mutex);
@@ -3994,13 +3994,12 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
err_destroy:
+ mutex_unlock(&cgroup_mutex);
for_each_subsys(root, ss) {
if (cgrp->subsys[ss->subsys_id])
ss->destroy(cgrp);
}
- mutex_unlock(&cgroup_mutex);
-
/* Release the reference count that we took on the superblock */
deactivate_super(sb);
@@ -4349,9 +4348,9 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
int ret = cgroup_init_idr(ss, css);
if (ret) {
dummytop->subsys[ss->subsys_id] = NULL;
+ mutex_unlock(&cgroup_mutex);
ss->destroy(dummytop);
subsys[i] = NULL;
- mutex_unlock(&cgroup_mutex);
return ret;
}
}
@@ -4447,10 +4446,10 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss)
* pointer to find their state. note that this also takes care of
* freeing the css_id.
*/
+ mutex_unlock(&cgroup_mutex);
ss->destroy(dummytop);
dummytop->subsys[ss->subsys_id] = NULL;
- mutex_unlock(&cgroup_mutex);
}
EXPORT_SYMBOL_GPL(cgroup_unload_subsys);
--
1.7.7.6
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