Commit b4cefb36 authored Oct 26, 2018 by Yang Shi Committed by Linus Torvalds Oct 26, 2018

mm: unmap VM_HUGETLB mappings with optimized path

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.

Link: http://lkml.kernel.org/r/1537376621-51150-3-git-send-email-yang.shi@linux.alibaba.com


Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent dd2283f2

mm/mmap.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -2777,7 +2777,7 @@ static int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
	* update vm_flags.		* update vm_flags.
	*/		*/
	if (downgrade &&		if (downgrade &&
	(tmp->vm_flags & (VM_HUGETLB \| VM_PFNMAP)))		(tmp->vm_flags & VM_PFNMAP))
	downgrade = false;		downgrade = false;

	tmp = tmp->vm_next;		tmp = tmp->vm_next;

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