Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=4fca88c87b7969c698912e2de9b1b31088c777cb
Commit: 4fca88c87b7969c698912e2de9b1b31088c777cb
Parent: d2ceb9b7ddedbb2e8e590bc6ce33c854043016f9
Author: KAMEZAWA Hiroyuki <[EMAIL PROTECTED]>
AuthorDate: Thu Feb 7 00:14:27 2008 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu Feb 7 08:42:20 2008 -0800
memory cgroup enhancements: add- pre_destroy() handler
Add a handler "pre_destroy" to cgroup_subsys. It is called before
cgroup_rmdir() checks all subsys's refcnt.
I think this is useful for subsys which have some extra refs even if there
are no tasks in cgroup. By adding pre_destroy(), the kernel keeps the rule
"destroy() against subsystem is called only when refcnt=0." and allows css
ref to be used by other objects than tasks.
Signed-off-by: KAMEZAWA Hiroyuki <[EMAIL PROTECTED]>
Cc: "Eric W. Biederman" <[EMAIL PROTECTED]>
Cc: Balbir Singh <[EMAIL PROTECTED]>
Cc: David Rientjes <[EMAIL PROTECTED]>
Cc: Herbert Poetzl <[EMAIL PROTECTED]>
Cc: Kirill Korotaev <[EMAIL PROTECTED]>
Cc: Nick Piggin <[EMAIL PROTECTED]>
Cc: Paul Menage <[EMAIL PROTECTED]>
Cc: Pavel Emelianov <[EMAIL PROTECTED]>
Cc: Peter Zijlstra <[EMAIL PROTECTED]>
Cc: Vaidyanathan Srinivasan <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
include/linux/cgroup.h | 1 +
kernel/cgroup.c | 22 ++++++++++++++++++++++
2 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 8747932..d8e9222 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -233,6 +233,7 @@ int cgroup_is_descendant(const struct cgroup *cont);
struct cgroup_subsys {
struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
struct cgroup *cont);
+ void (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
int (*can_attach)(struct cgroup_subsys *ss,
struct cgroup *cont, struct task_struct *tsk);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 4d67a39..4e8b16a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -586,6 +586,21 @@ static struct inode *cgroup_new_inode(mode_t mode, struct
super_block *sb)
return inode;
}
+/*
+ * Call subsys's pre_destroy handler.
+ * This is called before css refcnt check.
+ */
+
+static void cgroup_call_pre_destroy(struct cgroup *cgrp)
+{
+ struct cgroup_subsys *ss;
+ for_each_subsys(cgrp->root, ss)
+ if (ss->pre_destroy && cgrp->subsys[ss->subsys_id])
+ ss->pre_destroy(ss, cgrp);
+ return;
+}
+
+
static void cgroup_diput(struct dentry *dentry, struct inode *inode)
{
/* is dentry a directory ? if so, kfree() associated cgroup */
@@ -2160,6 +2175,13 @@ static int cgroup_rmdir(struct inode *unused_dir, struct
dentry *dentry)
parent = cgrp->parent;
root = cgrp->root;
sb = root->sb;
+ /*
+ * Call pre_destroy handlers of subsys
+ */
+ cgroup_call_pre_destroy(cgrp);
+ /*
+ * Notify subsyses that rmdir() request comes.
+ */
if (cgroup_has_css_refs(cgrp)) {
mutex_unlock(&cgroup_mutex);
-
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