This is mostly a followup to Michal's oom detection rework, which highlighted the need for direct compaction to provide better feedback in reclaim/compaction loop, so that it can reliably recognize when compaction cannot make further progress, and allocation should invoke OOM killer or fail. We've discussed this at LSF/MM [1] where I proposed expanding the async/sync migration mode used in compaction to more general "priorities". This patchset adds one new priority that just overrides all the heuristics and makes compaction fully scan all zones. I don't currently think that we need more fine-grained priorities, but we'll see. Other than that there's some smaller fixes and cleanups, mainly related to the THP-specific hacks. Changes since v1 RFC: * Incorporate feedback from Michal, Joonsoo, Tetsuo * Expanded cleanup of watermark checks controlling reclaim/compaction I've tested this with stress-highalloc in GFP_KERNEL order-4 and GFP_HIGHUSER_MOVABLE order-9 scenarios. There's not much report but noise, except reductions in direct reclaim. order-9: Direct pages scanned 238949 41502 Kswapd pages scanned 2069710 2229295 Kswapd pages reclaimed 1981047 2139089 Direct pages reclaimed 236534 41502 order-4: Direct pages scanned 204214 110733 Kswapd pages scanned 2125221 2179180 Kswapd pages reclaimed 2027102 2098257 Direct pages reclaimed 194942 110695 Also Patch 1 describes reductions in page migration failures. The series is based on 4.7-rc1. [1] https://lwn.net/Articles/684611/ Hugh Dickins (1): mm, compaction: don't isolate PageWriteback pages in MIGRATE_SYNC_LIGHT mode Vlastimil Babka (17): mm, page_alloc: set alloc_flags only once in slowpath mm, page_alloc: don't retry initial attempt in slowpath mm, page_alloc: restructure direct compaction handling in slowpath mm, page_alloc: make THP-specific decisions more generic mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations mm, compaction: introduce direct compaction priority mm, compaction: simplify contended compaction handling mm, compaction: make whole_zone flag ignore cached scanner positions mm, compaction: cleanup unused functions mm, compaction: add the ultimate direct compaction priority mm, compaction: more reliably increase direct compaction priority mm, compaction: use correct watermark when checking allocation success mm, compaction: create compact_gap wrapper mm, compaction: use proper alloc_flags in __compaction_suitable() mm, compaction: require only min watermarks for non-costly orders mm, vmscan: make compaction_ready() more accurate and readable mm, vmscan: use proper classzone_idx in should_continue_reclaim() include/linux/compaction.h | 101 +++++----------- include/linux/gfp.h | 14 ++- include/trace/events/compaction.h | 12 +- include/trace/events/mmflags.h | 1 + mm/compaction.c | 186 ++++++++++------------------- mm/huge_memory.c | 27 +++-- mm/internal.h | 7 +- mm/migrate.c | 2 +- mm/page_alloc.c | 241 ++++++++++++++++++-------------------- mm/vmscan.c | 80 +++++-------- tools/perf/builtin-kmem.c | 1 + 11 files changed, 271 insertions(+), 401 deletions(-) -- 2.8.3 -- 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>