Now, we have prepared to have an infrastructure in order to remove a this awkward mutex which serialize all faulting tasks, so remove it.
Signed-off-by: Joonsoo Kim <iamjoonsoo....@lge.com> diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0501fe5..f2c3a51 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2504,9 +2504,7 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, /* * Hugetlb_cow() should be called with page lock of the original hugepage held. - * Called with hugetlb_instantiation_mutex held and pte_page locked so we - * cannot race with other handlers or page migration. - * Keep the pte_same checks anyway to make transition from the mutex easier. + * Called with pte_page locked so we cannot race with page migration. */ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t pte, @@ -2844,7 +2842,6 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, int ret; struct page *page = NULL; struct page *pagecache_page = NULL; - static DEFINE_MUTEX(hugetlb_instantiation_mutex); struct hstate *h = hstate_vma(vma); address &= huge_page_mask(h); @@ -2864,17 +2861,9 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (!ptep) return VM_FAULT_OOM; - /* - * Serialize hugepage allocation and instantiation, so that we don't - * get spurious allocation failures if two CPUs race to instantiate - * the same page in the page cache. - */ - mutex_lock(&hugetlb_instantiation_mutex); entry = huge_ptep_get(ptep); - if (huge_pte_none(entry)) { - ret = hugetlb_no_page(mm, vma, address, ptep, flags); - goto out_mutex; - } + if (huge_pte_none(entry)) + return hugetlb_no_page(mm, vma, address, ptep, flags); ret = 0; @@ -2887,10 +2876,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, * consumed. */ if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { - if (vma_needs_reservation(h, vma, address) < 0) { - ret = VM_FAULT_OOM; - goto out_mutex; - } + if (vma_needs_reservation(h, vma, address) < 0) + return VM_FAULT_OOM; if (!(vma->vm_flags & VM_MAYSHARE)) pagecache_page = hugetlbfs_pagecache_page(h, @@ -2939,9 +2926,6 @@ out_page_table_lock: unlock_page(page); put_page(page); -out_mutex: - mutex_unlock(&hugetlb_instantiation_mutex); - return ret; } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/