Both Joonsoo Kim and Minchan Kim have reported premature OOM kills on a 32-bit platform. The common element is a zone-constrained high-order allocation failing. Two factors appear to be at fault -- pgdat being considered unreclaimable prematurely and insufficient rotation of the active list. Unfortunately to date I have been unable to reproduce this with a variety of stress workloads on a 2G 32-bit KVM instance. It's not clear why as the steps are similar to what was described. It means I've been unable to determine if this series addresses the problem or not. I'm hoping they can test and report back before these are merged to mmotm. What I have checked is that a basic parallel DD workload completed successfully on the same machine I used for the node-lru performance tests. I'll leave the other tests running just in case anything interesting falls out. The series is in three basic parts; Patch 1 does not account for skipped pages as scanned. This avoids the pgdat being prematurely marked unreclaimable Patches 2-4 add per-zone stats back in. The actual stats patch is different to Minchan's as the original patch did not account for unevictable LRU which would corrupt counters. The second two patches remove approximations based on pgdat statistics. It's effectively a revert of "mm, vmstat: remove zone and node double accounting by approximating retries" but different LRU stats are used. This is better than a full revert or a reworking of the series as it preserves history of why the zone stats are necessary. If this work out, we may have to leave the double accounting in place for now until an alternative cheap solution presents itself. Patch 5 rotates inactive/active lists for lowmem allocations. This is also quite different to Minchan's patch as the original patch did not account for memcg and would rotate if *any* eligible zone needed rotation which may rotate excessively. The new patch considers the ratio for all eligible zones which is more in line with node-lru in general. include/linux/mm_inline.h | 19 ++------------- include/linux/mmzone.h | 7 ++++++ include/linux/swap.h | 1 + mm/compaction.c | 20 +--------------- mm/migrate.c | 2 ++ mm/page-writeback.c | 17 +++++++------- mm/page_alloc.c | 59 ++++++++++++++++------------------------------ mm/vmscan.c | 60 ++++++++++++++++++++++++++++++++++++++++++----- mm/vmstat.c | 6 +++++ 9 files changed, 102 insertions(+), 89 deletions(-) -- 2.6.4 -- 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>