On 04/05/2016 01:25 PM, Michal Hocko wrote:
From: Michal Hocko <mhocko@xxxxxxxx> try_to_compact_pages can currently return COMPACT_SKIPPED even when the compaction is defered for some zone just because zone DMA is skipped in 99% of cases due to watermark checks. This makes COMPACT_DEFERRED basically unusable for the page allocator as a feedback mechanism. Make sure we distinguish those two states properly and switch their ordering in the enum. This would mean that the COMPACT_SKIPPED will be returned only when all eligible zones are skipped. This shouldn't introduce any functional change.
Hmm, really? __alloc_pages_direct_compact() does distinguish COMPACT_DEFERRED, and sets *deferred compaction, so ultimately this is some change for THP allocations?
Also there's no mention of COMPACT_INACTIVE in the changelog (which indeed isn't functional change, but might surprise somebody).
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Patch itself is OK. Acked-by: Vlastimil Babka <vbabka@xxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>