[Devel] [-mm PATCH 7/7] Memory controller OOM handling

[Balbir Singh]

Out of memory handling for containers over their limit. A task from the
container over limit is chosen using the existing OOM logic and killed.

TODO:
1. As discussed in the OLS BOF session, consider implementing a user
space policy for OOM handling.

Signed-off-by: Balbir Singh <balbir at linux.vnet.ibm.com>
---

 include/linux/memcontrol.h |    1 +
 mm/memcontrol.c            |    1 +
 mm/oom_kill.c              |   42 ++++++++++++++++++++++++++++++++++++++----
 3 files changed, 40 insertions(+), 4 deletions(-)

diff -puN include/linux/memcontrol.h~mem-control-out-of-memory include/linux/memcontrol.h
--- linux-2.6.22-rc6/include/linux/memcontrol.h~mem-control-out-of-memory	2007-07-04 15:05:34.000000000 -0700
+++ linux-2.6.22-rc6-balbir/include/linux/memcontrol.h	2007-07-04 15:05:34.000000000 -0700
@@ -33,6 +33,7 @@ extern unsigned long mem_container_isola
 					int mode, struct zone *z,
 					struct mem_container *mem_cont,
 					int active);
+extern void mem_cont_out_of_memory(struct mem_container *mem);
 
 #else /* CONFIG_CONTAINER_MEM_CONT */
 static inline void mm_init_container(struct mm_struct *mm,
diff -puN mm/memcontrol.c~mem-control-out-of-memory mm/memcontrol.c
--- linux-2.6.22-rc6/mm/memcontrol.c~mem-control-out-of-memory	2007-07-04 15:05:34.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/memcontrol.c	2007-07-04 15:05:34.000000000 -0700
@@ -240,6 +240,7 @@ int mem_container_charge(struct page *pa
 		if (res_counter_check_under_limit(&mem->res))
 			continue;
 
+		mem_cont_out_of_memory(mem);
 		goto free_mp;
 	}
 
diff -puN mm/oom_kill.c~mem-control-out-of-memory mm/oom_kill.c
--- linux-2.6.22-rc6/mm/oom_kill.c~mem-control-out-of-memory	2007-07-04 15:05:34.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/oom_kill.c	2007-07-04 15:05:34.000000000 -0700
@@ -24,6 +24,7 @@
 #include <linux/cpuset.h>
 #include <linux/module.h>
 #include <linux/notifier.h>
+#include <linux/memcontrol.h>
 
 int sysctl_panic_on_oom;
 /* #define DEBUG */
@@ -47,7 +48,8 @@ int sysctl_panic_on_oom;
  *    of least surprise ... (be careful when you change it)
  */
 
-unsigned long badness(struct task_struct *p, unsigned long uptime)
+unsigned long badness(struct task_struct *p, unsigned long uptime,
+			struct mem_container *mem)
 {
 	unsigned long points, cpu_time, run_time, s;
 	struct mm_struct *mm;
@@ -60,6 +62,13 @@ unsigned long badness(struct task_struct
 		return 0;
 	}
 
+#ifdef CONFIG_CONTAINER_MEM_CONT
+	if (mem != NULL && mm->mem_container != mem) {
+		task_unlock(p);
+		return 0;
+	}
+#endif
+
 	/*
 	 * The memory size of the process is the basis for the badness.
 	 */
@@ -204,7 +213,8 @@ static inline int constrained_alloc(stru
  *
  * (not docbooked, we don't want this one cluttering up the manual)
  */
-static struct task_struct *select_bad_process(unsigned long *ppoints)
+static struct task_struct *select_bad_process(unsigned long *ppoints,
+						struct mem_container *mem)
 {
 	struct task_struct *g, *p;
 	struct task_struct *chosen = NULL;
@@ -258,7 +268,7 @@ static struct task_struct *select_bad_pr
 		if (p->oomkilladj == OOM_DISABLE)
 			continue;
 
-		points = badness(p, uptime.tv_sec);
+		points = badness(p, uptime.tv_sec, mem);
 		if (points > *ppoints || !chosen) {
 			chosen = p;
 			*ppoints = points;
@@ -372,6 +382,30 @@ static int oom_kill_process(struct task_
 	return oom_kill_task(p);
 }
 
+#ifdef CONFIG_CONTAINER_MEM_CONT
+void mem_cont_out_of_memory(struct mem_container *mem)
+{
+	unsigned long points = 0;
+	struct task_struct *p;
+
+	container_lock();
+	rcu_read_lock();
+retry:
+	p = select_bad_process(&points, mem);
+	if (PTR_ERR(p) == -1UL)
+		goto out;
+
+	if (!p)
+		p = current;
+
+	if (oom_kill_process(p, points, "Memory container out of memory"))
+		goto retry;
+out:
+	rcu_read_unlock();
+	container_unlock();
+}
+#endif
+
 static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
 
 int register_oom_notifier(struct notifier_block *nb)
@@ -444,7 +478,7 @@ retry:
 		 * Rambo mode: Shoot down a process and hope it solves whatever
 		 * issues we may have.
 		 */
-		p = select_bad_process(&points);
+		p = select_bad_process(&points, NULL);
 
 		if (PTR_ERR(p) == -1UL)
 			goto out;
_

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
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