Re: [PATCH 2/6] mm: compaction: Acquire the zone->lru_lock as late as possible

2012-09-20 Thread Rik van Riel
On 09/20/2012 10:04 AM, Mel Gorman wrote: Compactions migrate scanner acquires the zone->lru_lock when scanning a range of pages looking for LRU pages to acquire. It does this even if there are no LRU pages in the range. If multiple processes are compacting then this can cause severe locking cont

[PATCH 2/6] mm: compaction: Acquire the zone->lru_lock as late as possible

2012-09-20 Thread Mel Gorman
Compactions migrate scanner acquires the zone->lru_lock when scanning a range of pages looking for LRU pages to acquire. It does this even if there are no LRU pages in the range. If multiple processes are compacting then this can cause severe locking contention. To make matters worse commit b2eef8c