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authorXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>2012-03-21 16:34:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-21 17:54:59 -0700
commitb69add218d32450d6604bc9080f6e33e19b06f5e (patch)
tree67c91d3534c2f7bf01b03a49be7543abe77d16a6 /arch
parent40716e29243de46720e5773797791466c28904ec (diff)
downloadlinux-b69add218d32450d6604bc9080f6e33e19b06f5e.tar.gz
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: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/mm/hugetlbpage.c18
1 files changed, 5 insertions, 13 deletions
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index c20e81c3425d..f6679a7fb8ca 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -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;
@@ -340,22 +340,14 @@ try_again:
 		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;
-			}
+			mm->free_area_cache = vma->vm_start;
+			mm->cached_hole_size = largest_hole;
 		}
 
 		/* remember the largest hole we saw so far */