On 09/21/2016 07:13 PM, Michal Hocko wrote:
> On Tue 06-09-16 15:52:56, Vlastimil Babka wrote:
> [...]
>> @@ -3204,6 +3199,15 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
>> if (compaction_retries <= max_retries)
>> return true;
>>
>> + /*
>> + * Make sure there is at least one attempt at the highest priority
>> + * if we exhausted all retries at the lower priorities
>> + */
>> +check_priority:
>> + if (*compact_priority > MIN_COMPACT_PRIORITY) {
>> + (*compact_priority)--;
>> + return true;
>
> Don't we want to reset compaction_retries here? Otherwise we can consume
> all retries on the lower priorities.
Good point, patch-fix below.
> Other than that it looks good to me. With that you can add
> Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Thanks!
>> + }
>> return false;
>> }
>> #else
>
----8<----
>From 465e1bd61b7a6d6901a44f09b1a76514dbc220fa Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@xxxxxxx>
Date: Thu, 22 Sep 2016 13:54:32 +0200
Subject: [PATCH] mm, compaction: more reliably increase direct compaction
priority-fix
When increasing the compaction priority, also reset retries. Otherwise we can
consume all retries on the lower priorities.
Suggested-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
---
mm/page_alloc.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f8bed910e3cf..82fdb690ac62 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3162,7 +3162,7 @@ static inline bool
should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
enum compact_result compact_result,
enum compact_priority *compact_priority,
- int compaction_retries)
+ int *compaction_retries)
{
int max_retries = MAX_COMPACT_RETRIES;
@@ -3196,16 +3196,17 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
*/
if (order > PAGE_ALLOC_COSTLY_ORDER)
max_retries /= 4;
- if (compaction_retries <= max_retries)
+ if (*compaction_retries <= max_retries)
return true;
/*
- * Make sure there is at least one attempt at the highest priority
- * if we exhausted all retries at the lower priorities
+ * Make sure there are attempts at the highest priority if we exhausted
+ * all retries or failed at the lower priorities.
*/
check_priority:
if (*compact_priority > MIN_COMPACT_PRIORITY) {
(*compact_priority)--;
+ *compaction_retries = 0;
return true;
}
return false;
@@ -3224,7 +3225,7 @@ static inline bool
should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
enum compact_result compact_result,
enum compact_priority *compact_priority,
- int compaction_retries)
+ int *compaction_retries)
{
struct zone *zone;
struct zoneref *z;
@@ -3663,7 +3664,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
if (did_some_progress > 0 &&
should_compact_retry(ac, order, alloc_flags,
compact_result, &compact_priority,
- compaction_retries))
+ &compaction_retries))
goto retry;
/* Reclaim has failed us, start killing things */
--
2.10.0
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