Changes since v1: - add/remove comments per Michal Hocko and Hillf Danton - move no_zone: label in patch 3 so we don't miss part of ac initialization This is v2 of my attempt to fix the recent report based on LTP cpuset stress test [1]. The intention is to go to stable 4.9 LTSS with this, as triggering repeated OOMs is not nice. That's why the patches try to be not too intrusive. Unfortunately why investigating I found that modifying the testcase to use per-VMA policies instead of per-task policies will bring the OOM's back, but that seems to be much older and harder to fix problem. I have posted a RFC [2] but I believe that fixing the recent regressions has a higher priority. Longer-term we might try to think how to fix the cpuset mess in a better and less error prone way. I was for example very surprised to learn, that cpuset updates change not only task->mems_allowed, but also nodemask of mempolicies. Until now I expected the parameter to alloc_pages_nodemask() to be stable. I wonder why do we then treat cpusets specially in get_page_from_freelist() and distinguish HARDWALL etc, when there's unconditional intersection between mempolicy and cpuset. I would expect the nodemask adjustment for saving overhead in g_p_f(), but that clearly doesn't happen in the current form. So we have both crazy complexity and overhead, AFAICS. [1] https://lkml.kernel.org/r/CAFpQJXUq-JuEP=QPidy4p_=FN0rkH5Z-kfB4qBvsf6jMS87Edg@xxxxxxxxxxxxxx [2] https://lkml.kernel.org/r/7c459f26-13a6-a817-e508-b65b903a8378@xxxxxxx Vlastimil Babka (4): mm, page_alloc: fix check for NULL preferred_zone mm, page_alloc: fix fast-path race with cpuset update or removal mm, page_alloc: move cpuset seqcount checking to slowpath mm, page_alloc: fix premature OOM when racing with cpuset mems update include/linux/mmzone.h | 6 ++++- mm/page_alloc.c | 68 ++++++++++++++++++++++++++++++++++---------------- 2 files changed, 52 insertions(+), 22 deletions(-) -- 2.11.0 -- 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>