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authorBalbir Singh <balbir@linux.vnet.ibm.com>2008-04-29 01:00:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:10 -0700
commitcf475ad28ac35cc9ba612d67158f29b73b38b05d (patch)
tree2c7cd568d00357bd42643ea602884e731cc24f26 /kernel/cgroup.c
parent29486df325e1fe6e1764afcb19e3370804c2b002 (diff)
cgroups: add an owner to the mm_struct
Remove the mem_cgroup member from mm_struct and instead adds an owner. This approach was suggested by Paul Menage. The advantage of this approach is that, once the mm->owner is known, using the subsystem id, the cgroup can be determined. It also allows several control groups that are virtually grouped by mm_struct, to exist independent of the memory controller i.e., without adding mem_cgroup's for each controller, to mm_struct. A new config option CONFIG_MM_OWNER is added and the memory resource controller selects this config option. This patch also adds cgroup callbacks to notify subsystems when mm->owner changes. The mm_cgroup_changed callback is called with the task_lock() of the new task held and is called just prior to changing the mm->owner. I am indebted to Paul Menage for the several reviews of this patchset and helping me make it lighter and simpler. This patch was tested on a powerpc box, it was compiled with both the MM_OWNER config turned on and off. After the thread group leader exits, it's moved to init_css_state by cgroup_exit(), thus all future charges from runnings threads would be redirected to the init_css_set's subsystem. Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Hirokazu Takahashi <taka@valinux.co.jp> Cc: David Rientjes <rientjes@google.com>, Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index abc433772e5..b9d467d83fc 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -119,6 +119,7 @@ static int root_count;
* be called.
*/
static int need_forkexit_callback;
+static int need_mm_owner_callback __read_mostly;
/* convenient tests for these bits */
inline int cgroup_is_removed(const struct cgroup *cgrp)
@@ -2498,6 +2499,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id];
need_forkexit_callback |= ss->fork || ss->exit;
+ need_mm_owner_callback |= !!ss->mm_owner_changed;
/* At system boot, before all subsystems have been
* registered, no tasks have been forked, so we don't
@@ -2748,6 +2750,34 @@ void cgroup_fork_callbacks(struct task_struct *child)
}
}
+#ifdef CONFIG_MM_OWNER
+/**
+ * cgroup_mm_owner_callbacks - run callbacks when the mm->owner changes
+ * @p: the new owner
+ *
+ * Called on every change to mm->owner. mm_init_owner() does not
+ * invoke this routine, since it assigns the mm->owner the first time
+ * and does not change it.
+ */
+void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
+{
+ struct cgroup *oldcgrp, *newcgrp;
+
+ if (need_mm_owner_callback) {
+ int i;
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+ struct cgroup_subsys *ss = subsys[i];
+ oldcgrp = task_cgroup(old, ss->subsys_id);
+ newcgrp = task_cgroup(new, ss->subsys_id);
+ if (oldcgrp == newcgrp)
+ continue;
+ if (ss->mm_owner_changed)
+ ss->mm_owner_changed(ss, oldcgrp, newcgrp);
+ }
+ }
+}
+#endif /* CONFIG_MM_OWNER */
+
/**
* cgroup_post_fork - called on a new task after adding it to the task list
* @child: the task in question