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Date: Wed, 4 Nov 2009 17:09:44 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To: "linux-mm@...ck.org" <linux-mm@...ck.org>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
cl@...ux-foundation.org, rientjes@...gle.com
Subject: [BUGFIX][PATCH] oom-kill: fix NUMA consraint check with nodemask
If clarification is not enough, let me know.
Thank you for all your review in RFC version.
Thanks,
-Kame
==
From: KAMEZAWA Hiroyuki <kamezawa.hioryu@...fujitsu.com>
Fixing node-oriented allocation handling in oom-kill.c
I myself think this as bugfix not as enhancement.
In these days, things are changed as
- alloc_pages() eats nodemask as its arguments, __alloc_pages_nodemask().
- mempolicy don't maintain its own private zonelists.
(And cpuset doesn't use nodemask for __alloc_pages_nodemask())
So, current oom-killer's check function is wrong.
This patch does
- check nodemask, if nodemask && nodemask != node_states[N_HIGH_MEMORY]
this is never be CONSTRAINT_NONE. We assume this from mempolicy.
- Scan all zonelist under nodemask, if it hits cpuset's wall
this faiulre is from cpuset.
And
- modifies the caller of out_of_memory not to call oom if __GFP_THISNODE.
This doesn't change "current" behavior.
If callers use __GFP_THISNODE, it should handle "page allocation failure"
by itself.
Changelog: 2009/11/04
- cut out as bug-fix for passing nodemask.
- added GFP_THISNODE sanity check.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@...fujitsu.com>
---
drivers/char/sysrq.c | 2 +-
mm/oom_kill.c | 38 ++++++++++++++++++++++++++------------
mm/page_alloc.c | 10 ++++++++--
3 files changed, 35 insertions(+), 15 deletions(-)
Index: mmotm-2.6.32-Nov2/drivers/char/sysrq.c
===================================================================
--- mmotm-2.6.32-Nov2.orig/drivers/char/sysrq.c
+++ mmotm-2.6.32-Nov2/drivers/char/sysrq.c
@@ -339,7 +339,7 @@ static struct sysrq_key_op sysrq_term_op
static void moom_callback(struct work_struct *ignored)
{
- out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0);
+ out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL);
}
static DECLARE_WORK(moom_work, moom_callback);
Index: mmotm-2.6.32-Nov2/mm/oom_kill.c
===================================================================
--- mmotm-2.6.32-Nov2.orig/mm/oom_kill.c
+++ mmotm-2.6.32-Nov2/mm/oom_kill.c
@@ -196,27 +196,40 @@ unsigned long badness(struct task_struct
/*
* Determine the type of allocation constraint.
*/
+#ifdef CONFIG_NUMA
static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist,
- gfp_t gfp_mask)
+ gfp_t gfp_mask, nodemask_t *nodemask)
{
-#ifdef CONFIG_NUMA
struct zone *zone;
struct zoneref *z;
enum zone_type high_zoneidx = gfp_zone(gfp_mask);
- nodemask_t nodes = node_states[N_HIGH_MEMORY];
+ int ret = CONSTRAINT_NONE;
- for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
- if (cpuset_zone_allowed_softwall(zone, gfp_mask))
- node_clear(zone_to_nid(zone), nodes);
- else
+ /*
+ * The nodemask here is a nodemask passed to alloc_pages(). Now,
+ * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy
+ * feature. Then, only mempolicy use this nodemask.
+ */
+ if (nodemask && nodes_equal(*nodemask, node_states[N_HIGH_MEMORY]))
+ ret = CONSTRAINT_MEMORY_POLICY;
+
+ /* Check this allocation failure is caused by cpuset's wall function */
+ for_each_zone_zonelist_nodemask(zone, z, zonelist,
+ high_zoneidx, nodemask)
+ if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
return CONSTRAINT_CPUSET;
- if (!nodes_empty(nodes))
- return CONSTRAINT_MEMORY_POLICY;
-#endif
+ /* __GFP_THISNODE never calls OOM.*/
+ return ret;
+}
+#else
+static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist,
+ gfp_t gfp_mask, nodemask_t *nodemask)
+{
return CONSTRAINT_NONE;
}
+#endif
/*
* Simple selection loop. We chose the process with the highest
@@ -603,7 +616,8 @@ rest_and_return:
* OR try to be smart about which process to kill. Note that we
* don't have to be perfect here, we just have to be good.
*/
-void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
+void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
+ int order, nodemask_t *nodemask)
{
unsigned long freed = 0;
enum oom_constraint constraint;
@@ -622,7 +636,7 @@ void out_of_memory(struct zonelist *zone
* Check if there were limitations on the allocation (only relevant for
* NUMA) that may require different handling.
*/
- constraint = constrained_alloc(zonelist, gfp_mask);
+ constraint = constrained_alloc(zonelist, gfp_mask, nodemask);
read_lock(&tasklist_lock);
switch (constraint) {
Index: mmotm-2.6.32-Nov2/mm/page_alloc.c
===================================================================
--- mmotm-2.6.32-Nov2.orig/mm/page_alloc.c
+++ mmotm-2.6.32-Nov2/mm/page_alloc.c
@@ -1667,9 +1667,15 @@ __alloc_pages_may_oom(gfp_t gfp_mask, un
/* The OOM killer will not help higher order allocs */
if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_NOFAIL))
goto out;
-
+ /*
+ * In usual, GFP_THISNODE contains __GFP_NORETRY and we never hit this.
+ * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
+ * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
+ */
+ if (gfp_mask & __GFP_THISNODE)
+ goto out;
/* Exhausted what can be done so it's blamo time */
- out_of_memory(zonelist, gfp_mask, order);
+ out_of_memory(zonelist, gfp_mask, order, nodemask);
out:
clear_zonelist_oom(zonelist, gfp_mask);
--
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