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Date: Fri, 21 Nov 2008 19:01:52 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Cc: Li Zefan <lizf@...fujitsu.com>,
"linux-mm@...ck.org" <linux-mm@...ck.org>,
"balbir@...ux.vnet.ibm.com" <balbir@...ux.vnet.ibm.com>,
"nishimura@....nes.nec.co.jp" <nishimura@....nes.nec.co.jp>,
pbadari@...ibm.com, jblunck@...e.de, taka@...inux.co.jp,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
npiggin@...e.de
Subject: [PATCH 1/2] memcg: avoid unnecessary system-wide-oom-killer
Current mmtom has new oom function as pagefault_out_of_memory().
It's added for select bad process rathar than killing current.
When memcg hit limit and calls OOM at page_fault, this handler
called and system-wide-oom handling happens.
(means kernel panics if panic_on_oom is true....)
For avoiding overkill, check memcg's recent behavior before
starting system-wide-oom.
And this patch also fixes to guarantee "don't accnout against
process with TIF_MEMDIE". This is necessary for smooth OOM.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
---
include/linux/memcontrol.h | 6 ++++++
mm/memcontrol.c | 33 +++++++++++++++++++++++++++++----
mm/oom_kill.c | 8 ++++++++
3 files changed, 43 insertions(+), 4 deletions(-)
Index: mmotm-2.6.28-Nov20/include/linux/memcontrol.h
===================================================================
--- mmotm-2.6.28-Nov20.orig/include/linux/memcontrol.h
+++ mmotm-2.6.28-Nov20/include/linux/memcontrol.h
@@ -95,6 +95,8 @@ static inline bool mem_cgroup_disabled(v
return false;
}
+extern bool mem_cgroup_oom_called(struct task_struct *task);
+
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
struct mem_cgroup;
@@ -227,6 +229,10 @@ static inline bool mem_cgroup_disabled(v
{
return true;
}
+static inline bool mem_cgroup_oom_called(struct task_struct *task);
+{
+ return false;
+}
#endif /* CONFIG_CGROUP_MEM_CONT */
#endif /* _LINUX_MEMCONTROL_H */
Index: mmotm-2.6.28-Nov20/mm/oom_kill.c
===================================================================
--- mmotm-2.6.28-Nov20.orig/mm/oom_kill.c
+++ mmotm-2.6.28-Nov20/mm/oom_kill.c
@@ -560,6 +560,13 @@ void pagefault_out_of_memory(void)
/* Got some memory back in the last second. */
return;
+ /*
+ * If this is from memcg, oom-killer is already invoked.
+ * and not worth to go system-wide-oom.
+ */
+ if (mem_cgroup_oom_called(current))
+ goto rest_and_return;
+
if (sysctl_panic_on_oom)
panic("out of memory from page fault. panic_on_oom is selected.\n");
@@ -571,6 +578,7 @@ void pagefault_out_of_memory(void)
* Give "p" a good chance of killing itself before we
* retry to allocate memory.
*/
+rest_and_return:
if (!test_thread_flag(TIF_MEMDIE))
schedule_timeout_uninterruptible(1);
}
Index: mmotm-2.6.28-Nov20/mm/memcontrol.c
===================================================================
--- mmotm-2.6.28-Nov20.orig/mm/memcontrol.c
+++ mmotm-2.6.28-Nov20/mm/memcontrol.c
@@ -153,7 +153,7 @@ struct mem_cgroup {
* Should the accounting and control be hierarchical, per subtree?
*/
bool use_hierarchy;
-
+ unsigned long last_oom_jiffies;
int obsolete;
atomic_t refcnt;
/*
@@ -618,6 +618,22 @@ static int mem_cgroup_hierarchical_recla
return ret;
}
+bool mem_cgroup_oom_called(struct task_struct *task)
+{
+ bool ret = false;
+ struct mem_cgroup *mem;
+ struct mm_struct *mm;
+
+ rcu_read_lock();
+ mm = task->mm;
+ if (!mm)
+ mm = &init_mm;
+ mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
+ ret = true;
+ rcu_read_unlock();
+ return ret;
+}
/*
* Unlike exported interface, "oom" parameter is added. if oom==true,
* oom-killer can be invoked.
@@ -629,6 +645,13 @@ static int __mem_cgroup_try_charge(struc
struct mem_cgroup *mem, *mem_over_limit;
int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct res_counter *fail_res;
+
+ if (unlikely(test_thread_flag(TIF_MEMDIE))) {
+ /* Don't account this! */
+ *memcg = NULL;
+ return 0;
+ }
+
/*
* We always charge the cgroup the mm_struct belongs to.
* The mm_struct's mem_cgroup changes on task migration if the
@@ -699,8 +722,10 @@ static int __mem_cgroup_try_charge(struc
continue;
if (!nr_retries--) {
- if (oom)
+ if (oom) {
mem_cgroup_out_of_memory(mem, gfp_mask);
+ mem->last_oom_jiffies = jiffies;
+ }
goto nomem;
}
}
@@ -837,7 +862,7 @@ static int mem_cgroup_move_parent(struct
ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
- if (ret)
+ if (ret || !parent)
return ret;
if (!get_page_unless_zero(page))
@@ -888,7 +913,7 @@ static int mem_cgroup_charge_common(stru
mem = memcg;
ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
- if (ret)
+ if (ret || !mem)
return ret;
__mem_cgroup_commit_charge(mem, pc, ctype);
--
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