On 09/22/2016 04:52 PM, Michal Hocko wrote:
> On Thu 22-09-16 16:08:21, Michal Hocko wrote:
>> On Thu 22-09-16 14:51:48, Vlastimil Babka wrote:
>> > >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.
>>
>> OK, this is an improvement. I am just thinking that we might want to
>> pull
>> if (order && compaction_made_progress(compact_result))
>> compaction_retries++;
>>
>> into should_compact_retry as well. I've had it there originally because
>> it was in line with no_progress_loops but now that we have compaction
>> priorities it would fit into retry logic better. As a plus it would
>> count only those compaction rounds where we we didn't have to rely on
> did that should be
>
>> the compaction retry logic. What do you think?
In that case I would also add this for consistency?
----8<----
>From a7921e57ba1189b9c08fc4879358a908c390e47c Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@xxxxxxx>
Date: Thu, 22 Sep 2016 17:02:37 +0200
Subject: [PATCH] mm, page_alloc: pull no_progress_loops update to
should_reclaim_retry()
The should_reclaim_retry() makes decisions based on no_progress_loops, so it
makes sense to also update the counter there. It will be also consistent with
should_compact_retry() and compaction_retries. No functional change.
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
---
mm/page_alloc.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 582820080601..a01359ab3ed6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3401,16 +3401,26 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
static inline bool
should_reclaim_retry(gfp_t gfp_mask, unsigned order,
struct alloc_context *ac, int alloc_flags,
- bool did_some_progress, int no_progress_loops)
+ bool did_some_progress, int *no_progress_loops)
{
struct zone *zone;
struct zoneref *z;
/*
+ * Costly allocations might have made a progress but this doesn't mean
+ * their order will become available due to high fragmentation so
+ * always increment the no progress counter for them
+ */
+ if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
+ no_progress_loops = 0;
+ else
+ no_progress_loops++;
+
+ /*
* Make sure we converge to OOM if we cannot make any progress
* several times in the row.
*/
- if (no_progress_loops > MAX_RECLAIM_RETRIES)
+ if (*no_progress_loops > MAX_RECLAIM_RETRIES)
return false;
/*
@@ -3425,7 +3435,7 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
unsigned long reclaimable;
available = reclaimable = zone_reclaimable_pages(zone);
- available -= DIV_ROUND_UP(no_progress_loops * available,
+ available -= DIV_ROUND_UP((*no_progress_loops) * available,
MAX_RECLAIM_RETRIES);
available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
@@ -3641,18 +3651,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT))
goto nopage;
- /*
- * Costly allocations might have made a progress but this doesn't mean
- * their order will become available due to high fragmentation so
- * always increment the no progress counter for them
- */
- if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
- no_progress_loops = 0;
- else
- no_progress_loops++;
-
if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
- did_some_progress > 0, no_progress_loops))
+ did_some_progress > 0, &no_progress_loops))
goto retry;
/*
--
2.10.0
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