From 486fce1ea442ab921b6564bc7a64ae189e6f4c69 Mon Sep 17 00:00:00 2001
From: Balbir Singh <balbir@linux.vnet.ibm.com>
Date: Thu, 2 Apr 2009 16:57:39 -0700
Subject: [PATCH] --- yaml --- r: 139664 b: refs/heads/master c:
 e222432bfa7dcf6ec008622a978c9f284ed5e3a9 h: refs/heads/master v: v3

---
 [refs]                           |  2 +-
 trunk/include/linux/memcontrol.h |  7 ++++
 trunk/mm/memcontrol.c            | 69 ++++++++++++++++++++++++++++++++
 trunk/mm/oom_kill.c              |  1 +
 4 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 4b702e94525d..f9fd24491436 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0b7f569e45bb6be142d87017030669a6a7d327a1
+refs/heads/master: e222432bfa7dcf6ec008622a978c9f284ed5e3a9
diff --git a/trunk/include/linux/memcontrol.h b/trunk/include/linux/memcontrol.h
index 326f45c86530..7aba9f264622 100644
--- a/trunk/include/linux/memcontrol.h
+++ b/trunk/include/linux/memcontrol.h
@@ -104,6 +104,8 @@ struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
 						      struct zone *zone);
 struct zone_reclaim_stat*
 mem_cgroup_get_reclaim_stat_from_page(struct page *page);
+extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
+					struct task_struct *p);
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 extern int do_swap_account;
@@ -270,6 +272,11 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
 	return NULL;
 }
 
+static inline void
+mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
+{
+}
+
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff --git a/trunk/mm/memcontrol.c b/trunk/mm/memcontrol.c
index 025f8abfae2d..2bdb6149faeb 100644
--- a/trunk/mm/memcontrol.c
+++ b/trunk/mm/memcontrol.c
@@ -27,6 +27,7 @@
 #include <linux/backing-dev.h>
 #include <linux/bit_spinlock.h>
 #include <linux/rcupdate.h>
+#include <linux/limits.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
@@ -721,6 +722,74 @@ static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
 	(*val)++;
 	return 0;
 }
+
+/**
+ * mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode.
+ * @memcg: The memory cgroup that went over limit
+ * @p: Task that is going to be killed
+ *
+ * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
+ * enabled
+ */
+void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
+{
+	struct cgroup *task_cgrp;
+	struct cgroup *mem_cgrp;
+	/*
+	 * Need a buffer in BSS, can't rely on allocations. The code relies
+	 * on the assumption that OOM is serialized for memory controller.
+	 * If this assumption is broken, revisit this code.
+	 */
+	static char memcg_name[PATH_MAX];
+	int ret;
+
+	if (!memcg)
+		return;
+
+
+	rcu_read_lock();
+
+	mem_cgrp = memcg->css.cgroup;
+	task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
+
+	ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
+	if (ret < 0) {
+		/*
+		 * Unfortunately, we are unable to convert to a useful name
+		 * But we'll still print out the usage information
+		 */
+		rcu_read_unlock();
+		goto done;
+	}
+	rcu_read_unlock();
+
+	printk(KERN_INFO "Task in %s killed", memcg_name);
+
+	rcu_read_lock();
+	ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
+	if (ret < 0) {
+		rcu_read_unlock();
+		goto done;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * Continues from above, so we don't need an KERN_ level
+	 */
+	printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
+done:
+
+	printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
+		res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
+		res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
+		res_counter_read_u64(&memcg->res, RES_FAILCNT));
+	printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
+		"failcnt %llu\n",
+		res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
+		res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
+		res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
+}
+
 /*
  * This function returns the number of memcg under hierarchy tree. Returns
  * 1(self count) if no children.
diff --git a/trunk/mm/oom_kill.c b/trunk/mm/oom_kill.c
index d3b9bac085b5..2f3166e308d9 100644
--- a/trunk/mm/oom_kill.c
+++ b/trunk/mm/oom_kill.c
@@ -394,6 +394,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
 		cpuset_print_task_mems_allowed(current);
 		task_unlock(current);
 		dump_stack();
+		mem_cgroup_print_oom_info(mem, current);
 		show_mem();
 		if (sysctl_oom_dump_tasks)
 			dump_tasks(mem);