diff options
| -rw-r--r-- | mm/page_alloc.c | 51 |
1 files changed, 38 insertions, 13 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ceb45a8e1359..019af778ec55 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3677,6 +3677,39 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order, return false; } +static inline bool +check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac) +{ + /* + * It's possible that cpuset's mems_allowed and the nodemask from + * mempolicy don't intersect. This should be normally dealt with by + * policy_nodemask(), but it's possible to race with cpuset update in + * such a way the check therein was true, and then it became false + * before we got our cpuset_mems_cookie here. + * This assumes that for all allocations, ac->nodemask can come only + * from MPOL_BIND mempolicy (whose documented semantics is to be ignored + * when it does not intersect with the cpuset restrictions) or the + * caller can deal with a violated nodemask. + */ + if (cpusets_enabled() && ac->nodemask && + !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) { + ac->nodemask = NULL; + return true; + } + + /* + * When updating a task's mems_allowed or mempolicy nodemask, it is + * possible to race with parallel threads in such a way that our + * allocation can fail while the mask is being updated. If we are about + * to fail, check if the cpuset changed during allocation and if so, + * retry. + */ + if (read_mems_allowed_retry(cpuset_mems_cookie)) + return true; + + return false; +} + static inline struct page * __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct alloc_context *ac) @@ -3872,11 +3905,9 @@ retry: &compaction_retries)) goto retry; - /* - * It's possible we raced with cpuset update so the OOM would be - * premature (see below the nopage: label for full explanation). - */ - if (read_mems_allowed_retry(cpuset_mems_cookie)) + + /* Deal with possible cpuset update races before we start OOM killing */ + if (check_retry_cpuset(cpuset_mems_cookie, ac)) goto retry_cpuset; /* Reclaim has failed us, start killing things */ @@ -3897,14 +3928,8 @@ retry: } nopage: - /* - * When updating a task's mems_allowed or mempolicy nodemask, it is - * possible to race with parallel threads in such a way that our - * allocation can fail while the mask is being updated. If we are about - * to fail, check if the cpuset changed during allocation and if so, - * retry. - */ - if (read_mems_allowed_retry(cpuset_mems_cookie)) + /* Deal with possible cpuset update races before we fail */ + if (check_retry_cpuset(cpuset_mems_cookie, ac)) goto retry_cpuset; /* |