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Commit b69add21 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Linus Torvalds
Browse files

hugetlb: remove prev_vma from hugetlb_get_unmapped_area_topdown() 



After looking up the vma which covers or follows the cached search
address, the following condition is always true:

	!prev_vma || (addr >= prev_vma->vm_end)

so we can stop checking the previous VMA altogether.

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 40716e29

arch/x86/mm/hugetlbpage.c

+5 −13
Original line number Diff line number Diff line
@@ -308,7 +308,7 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 
{

	struct hstate *h = hstate_file(file);

	struct mm_struct *mm = current->mm;

	struct vm_area_struct *vma, *prev_vma;

	struct vm_area_struct *vma;

	unsigned long base = mm->mmap_base;

	unsigned long addr = addr0;

	unsigned long largest_hole = mm->cached_hole_size;
@@ -340,23 +340,15 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 
		if (!vma)

			return addr;



		/*

		 * new region fits between prev_vma->vm_end and

		 * vma->vm_start, use it:

		 */

		prev_vma = vma->vm_prev;

		if (addr + len <= vma->vm_start &&

		            (!prev_vma || (addr >= prev_vma->vm_end))) {

		if (addr + len <= vma->vm_start) {

			/* remember the address as a hint for next time */

		        mm->cached_hole_size = largest_hole;

		        return (mm->free_area_cache = addr);

		} else {

		} else if (mm->free_area_cache == vma->vm_end) {

			/* pull free_area_cache down to the first hole */

		        if (mm->free_area_cache == vma->vm_end) {

			mm->free_area_cache = vma->vm_start;

			mm->cached_hole_size = largest_hole;

		}

		}



		/* remember the largest hole we saw so far */

		if (addr + largest_hole < vma->vm_start)