Just move down outside_reserve check and don't check vma_need_reservation() when outside_resever is true. It is slightly optimized implementation. This makes code more readable. Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0f56bbf..03ab285 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2576,7 +2576,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, struct page *old_page, *new_page; int outside_reserve = 0; long chg; - bool use_reserve; + bool use_reserve = false; unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ @@ -2591,6 +2591,11 @@ retry_avoidcopy: return 0; } + page_cache_get(old_page); + + /* Drop page table lock as buddy allocator may be called */ + spin_unlock(ptl); + /* * If the process that created a MAP_PRIVATE mapping is about to * perform a COW due to a shared page count, attempt to satisfy @@ -2604,19 +2609,17 @@ retry_avoidcopy: old_page != pagecache_page) outside_reserve = 1; - page_cache_get(old_page); - - /* Drop page table lock as buddy allocator may be called */ - spin_unlock(ptl); - chg = vma_needs_reservation(h, vma, address); - if (chg < 0) { - page_cache_release(old_page); + if (!outside_reserve) { + chg = vma_needs_reservation(h, vma, address); + if (chg < 0) { + page_cache_release(old_page); - /* Caller expects lock to be held */ - spin_lock(ptl); - return VM_FAULT_OOM; + /* Caller expects lock to be held */ + spin_lock(ptl); + return VM_FAULT_OOM; + } + use_reserve = !chg; } - use_reserve = !chg && !outside_reserve; new_page = alloc_huge_page(vma, address, use_reserve); -- 1.7.9.5 -- 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>