[RFC v8 PATCH 4/5] mm: unmap VM_HUGETLB mappings with optimized path
From: Yang Shi <hidden>
Date: 2018-08-15 18:50:47
Also in:
lkml
Subsystem:
memory management, memory mapping, the rest · Maintainers:
Andrew Morton, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
When unmapping VM_HUGETLB mappings, vm flags need to be updated. Since the vmas have been detached, so it sounds safe to update vm flags with read mmap_sem. Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <redacted> Signed-off-by: Yang Shi <redacted> --- mm/mmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index e92f680..3b9f734 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -2812,7 +2812,6 @@ static int do_munmap_zap_rlock(struct mm_struct *mm, unsigned long start, /* * Unmapping vmas, which have: - * VM_HUGETLB or * VM_PFNMAP or * uprobes * need get done with write mmap_sem held since they may update
@@ -2821,7 +2820,7 @@ static int do_munmap_zap_rlock(struct mm_struct *mm, unsigned long start, for (vma = start_vma; vma && vma->vm_start < end; vma = vma->vm_next) { if ((vma->vm_file && has_uprobes(vma, vma->vm_start, vma->vm_end)) || - (vma->vm_flags & (VM_HUGETLB | VM_PFNMAP))) + (vma->vm_flags & VM_PFNMAP)) goto regular_path; }
--
1.8.3.1