diff mbox series

[RFC,v9,3/4] mm: unmap VM_HUGETLB mappings with optimized path

Message ID 1536699493-69195-4-git-send-email-yang.shi@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series mm: zap pages with read mmap_sem in munmap for large mapping | expand

Commit Message

Yang Shi Sept. 11, 2018, 8:58 p.m. UTC 
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 <vbabka@suse.cz>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
 mm/mmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/mm/mmap.c b/mm/mmap.c
index 937d2f2..086f8b5 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2812,12 +2812,12 @@  static int do_munmap_zap_rlock(struct mm_struct *mm, unsigned long start,
 	}
 
 	/*
-	 * Unmapping vmas, which have VM_HUGETLB or VM_PFNMAP
+	 * Unmapping vmas, which have VM_PFNMAP
 	 * need get done with write mmap_sem held since they may update
 	 * vm_flags. Deal with such mappings with regular do_munmap() call.
 	 */
 	for (vma = start_vma; vma && vma->vm_start < end; vma = vma->vm_next) {
-		if (vma->vm_flags & (VM_HUGETLB | VM_PFNMAP))
+		if (vma->vm_flags & VM_PFNMAP)
 			goto regular_path;
 	}