When increasing the compaction priority, also reset retries. Otherwise we can consume all retries on the lower priorities. Also pull the retries increment into should_compact_retry() so it counts only the rounds where we actually rely on it.
Suggested-by: Michal Hocko <[email protected]> Signed-off-by: Vlastimil Babka <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Joonsoo Kim <[email protected]> Cc: David Rientjes <[email protected]> Cc: Rik van Riel <[email protected]> --- Please squash into mm-compaction-more-reliably-increase-direct-compaction-priority.patch mm/page_alloc.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5155485057cb..0fd29731ab35 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; int min_priority; @@ -3170,6 +3170,9 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, if (!order) return false; + if (compaction_made_progress(compact_result)) + (*compaction_retries)++; + /* * compaction considers all the zone as desperately out of memory * so it doesn't really make much sense to retry except when the @@ -3197,18 +3200,19 @@ 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: min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; if (*compact_priority > min_priority) { (*compact_priority)--; + *compaction_retries = 0; return true; } return false; @@ -3227,7 +3231,7 @@ 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; @@ -3635,9 +3639,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, if (page) goto got_pg; - if (order && compaction_made_progress(compact_result)) - compaction_retries++; - /* Do not loop if specifically requested */ if (gfp_mask & __GFP_NORETRY) goto nopage; @@ -3672,7 +3673,7 @@ __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
