[RFC][-mm][PATCH 5/6] oom-killer: check last total_vm expansion

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

At considering oom-kill algorithm, we can't avoid to take runtime
into account. But this can adds too big bonus to slow-memory-leaker.
For adding penalty to slow-memory-leaker, we record jiffies of
the last mm->hiwater_vm expansion. That catches processes which leak
memory periodically.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
 include/linux/mm_types.h |    2 ++
 include/linux/sched.h    |    4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

Index: mmotm-2.6.32-Nov2/include/linux/mm_types.h
===================================================================
--- mmotm-2.6.32-Nov2.orig/include/linux/mm_types.h
+++ mmotm-2.6.32-Nov2/include/linux/mm_types.h
@@ -291,6 +291,8 @@ struct mm_struct {
 #endif
 	/* For OOM, fork-bomb detector */
 	unsigned long bomb_score;
+	/* set to jiffies at total_vm is finally expanded (see sched.h) */
+	unsigned long last_vm_expansion;
 };
 
 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
Index: mmotm-2.6.32-Nov2/include/linux/sched.h
===================================================================
--- mmotm-2.6.32-Nov2.orig/include/linux/sched.h
+++ mmotm-2.6.32-Nov2/include/linux/sched.h
@@ -422,8 +422,10 @@ extern void arch_unmap_area_topdown(stru
 		(mm)->hiwater_rss = _rss;		\
 } while (0)
 #define update_hiwater_vm(mm)	do {			\
-	if ((mm)->hiwater_vm < (mm)->total_vm)		\
+	if ((mm)->hiwater_vm < (mm)->total_vm) {	\
 		(mm)->hiwater_vm = (mm)->total_vm;	\
+		(mm)->last_vm_expansion = jiffies;	\
+	}\
 } while (0)
 
 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)

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