X-Git-Url: http://git.cascardo.info/?a=blobdiff_plain;f=mm%2Fhuge_memory.c;h=74c78aa8bc2fa68454928b09f34a7b97f3419e05;hb=9a2ad529ed26c4dd81368d0bc87fc77db1febb35;hp=f8ffd9412ec502d10f2c103554ffe333306e2e3f;hpb=87d7bcee4f5973a593b0d50134364cfe5652ff33;p=cascardo%2Flinux.git

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f8ffd9412ec5..74c78aa8bc2f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1096,7 +1096,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	unsigned long mmun_end;		/* For mmu_notifiers */
 
 	ptl = pmd_lockptr(mm, pmd);
-	VM_BUG_ON(!vma->anon_vma);
+	VM_BUG_ON_VMA(!vma->anon_vma, vma);
 	haddr = address & HPAGE_PMD_MASK;
 	if (is_huge_zero_pmd(orig_pmd))
 		goto alloc;
@@ -2048,7 +2048,7 @@ int __khugepaged_enter(struct mm_struct *mm)
 		return -ENOMEM;
 
 	/* __khugepaged_exit() must not run from under us */
-	VM_BUG_ON(khugepaged_test_exit(mm));
+	VM_BUG_ON_MM(khugepaged_test_exit(mm), mm);
 	if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
 		free_mm_slot(mm_slot);
 		return 0;
@@ -2083,7 +2083,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
 	if (vma->vm_ops)
 		/* khugepaged not yet working on file or special mappings */
 		return 0;
-	VM_BUG_ON(vma->vm_flags & VM_NO_THP);
+	VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma);
 	hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
 	hend = vma->vm_end & HPAGE_PMD_MASK;
 	if (hstart < hend)
@@ -2322,23 +2322,17 @@ static struct page
 		       int node)
 {
 	VM_BUG_ON_PAGE(*hpage, *hpage);
+
 	/*
-	 * Allocate the page while the vma is still valid and under
-	 * the mmap_sem read mode so there is no memory allocation
-	 * later when we take the mmap_sem in write mode. This is more
-	 * friendly behavior (OTOH it may actually hide bugs) to
-	 * filesystems in userland with daemons allocating memory in
-	 * the userland I/O paths.  Allocating memory with the
-	 * mmap_sem in read mode is good idea also to allow greater
-	 * scalability.
+	 * Before allocating the hugepage, release the mmap_sem read lock.
+	 * The allocation can take potentially a long time if it involves
+	 * sync compaction, and we do not need to hold the mmap_sem during
+	 * that. We will recheck the vma after taking it again in write mode.
 	 */
+	up_read(&mm->mmap_sem);
+
 	*hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask(
 		khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER);
-	/*
-	 * After allocating the hugepage, release the mmap_sem read lock in
-	 * preparation for taking it in write mode.
-	 */
-	up_read(&mm->mmap_sem);
 	if (unlikely(!*hpage)) {
 		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
 		*hpage = ERR_PTR(-ENOMEM);
@@ -2412,7 +2406,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
 		return false;
 	if (is_vma_temporary_stack(vma))
 		return false;
-	VM_BUG_ON(vma->vm_flags & VM_NO_THP);
+	VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma);
 	return true;
 }