On 17.08.2016 00:56, Vlastimil Babka wrote:
Again, migration failures are there but not so many, and failures to isolate freepages stand out. I assume it's because the kernel build workload and not the btrfs balance one. I think the patches in mmotm could make compaction try harder and use more appropriate watermarks, but it's not guaranteed that will help. The free scanner seems to become more and more a fundamental problem. And I really wonder how did all those unmovable pageblocks happen. AFAICS zoneinfo shows that most of memory is occupied by file lru pages. These should be movable.
Is it the pressure on the page cache? Don't forget that I write to some disk drives (recently, 2) at media speed with dd if=/dev/zero bs=4M of=/dev/SDX.
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