[RFC][PATCH 6/6] fix oom under hierarchy

From: KAMEZAWA Hiroyuki
Date: Tue Dec 09 2008 - 06:13:31 EST


From: KAMEZAWA Hiroyki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

Current memcg's code other than memcontrol.c cannot handle hierarchy
in correct way.
In following,
/opt/cgroup/01 limit=1G
/opt/cgroup/01/A limit = unlimited
/opt/cgroup/01/B limit = unlimited

searching tasks under '01' and cannot find bad process in 01/A and 01/B

After this.
- OOM Killer check hierarchy and can Kill badprocess under hierarchy.

Changelog:
- adjusted to the base kernel.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

---
include/linux/memcontrol.h | 6 +++-
mm/memcontrol.c | 57 ++++++++++++++++++++++++++++++++++++++++++---
mm/oom_kill.c | 2 -
3 files changed, 59 insertions(+), 6 deletions(-)

Index: mmotm-2.6.28-Dec08/mm/memcontrol.c
===================================================================
--- mmotm-2.6.28-Dec08.orig/mm/memcontrol.c
+++ mmotm-2.6.28-Dec08/mm/memcontrol.c
@@ -403,12 +403,36 @@ void mem_cgroup_move_lists(struct page *
mem_cgroup_add_lru_list(page, to);
}

-int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
+static int mm_under_cgroup(struct mm_struct *mm, struct mem_cgroup *mcg)
+{
+ struct cgroup *cg, *check;
+ int ret = 0;
+
+ if (!mm)
+ return 0;
+
+ rcu_read_lock();
+
+ cg = task_cgroup(rcu_dereference(mm->owner), mem_cgroup_subsys_id);
+ check = mcg->css.cgroup;
+
+ if (!mcg->use_hierarchy)
+ ret = (cg == check);
+ else
+ ret = cgroup_is_ancestor(cg, check);
+ rcu_read_unlock();
+
+ return ret;
+}
+
+
+int task_in_mem_cgroup(struct task_struct *task,
+ struct mem_cgroup *mem)
{
int ret;

task_lock(task);
- ret = task->mm && mm_match_cgroup(task->mm, mem);
+ ret = mm_under_cgroup(task->mm, mem);
task_unlock(task);
return ret;
}
@@ -662,6 +686,33 @@ static int mem_cgroup_hierarchical_recla
return ret;
}

+void update_oom_jiffies(struct mem_cgroup *mem)
+{
+ struct cgroup *cgroup, *rootcg;
+ struct mem_cgroup *tmp;
+ int rootid, nextid, depth, found;
+
+ if (!mem->use_hierarchy) {
+ mem->last_oom_jiffies = jiffies;
+ return;
+ }
+ rootcg = mem->css.cgroup;
+ rootid = cgroup_id(rootcg);
+ depth = cgroup_depth(rootcg);
+ nextid = 0;
+ rcu_read_lock();
+ while (1) {
+ cgroup = cgroup_get_next(nextid, rootid, depth, &found);
+
+ if (!cgroup)
+ break;
+ tmp = mem_cgroup_from_cont(cgroup);
+ tmp->last_oom_jiffies = jiffies;
+ nextid = found + 1;
+ }
+ rcu_read_unlock();
+}
+
bool mem_cgroup_oom_called(struct task_struct *task)
{
bool ret = false;
@@ -764,7 +815,7 @@ static int __mem_cgroup_try_charge(struc
mutex_lock(&memcg_tasklist);
mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
mutex_unlock(&memcg_tasklist);
- mem_over_limit->last_oom_jiffies = jiffies;
+ update_oom_jiffies(mem_over_limit);
}
goto nomem;
}
Index: mmotm-2.6.28-Dec08/mm/oom_kill.c
===================================================================
--- mmotm-2.6.28-Dec08.orig/mm/oom_kill.c
+++ mmotm-2.6.28-Dec08/mm/oom_kill.c
@@ -279,7 +279,7 @@ static struct task_struct *select_bad_pr
*
* Call with tasklist_lock read-locked.
*/
-static void dump_tasks(const struct mem_cgroup *mem)
+static void dump_tasks(struct mem_cgroup *mem)
{
struct task_struct *g, *p;

Index: mmotm-2.6.28-Dec08/include/linux/memcontrol.h
===================================================================
--- mmotm-2.6.28-Dec08.orig/include/linux/memcontrol.h
+++ mmotm-2.6.28-Dec08/include/linux/memcontrol.h
@@ -65,7 +65,9 @@ extern unsigned long mem_cgroup_isolate_
struct mem_cgroup *mem_cont,
int active, int file);
extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
-int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
+
+int task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *mem);
+

extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);

@@ -191,7 +193,7 @@ static inline int mm_match_cgroup(struct
}

static inline int task_in_mem_cgroup(struct task_struct *task,
- const struct mem_cgroup *mem)
+ struct mem_cgroup *mem)
{
return 1;
}

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