hugetlbfs: fix hugetlb_get_unmapped_area()

Use/update cached_hole_size and free_area_cache properly to speedup
finding of a free region.

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 4 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 1e85a7ac021..b7bc7868c7b 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -154,10 +154,12 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
                         return addr;
         }
 
-        start_addr = mm->free_area_cache;
-
-        if (len <= mm->cached_hole_size)
+        if (len > mm->cached_hole_size)
+                start_addr = mm->free_area_cache;
+        else {
                 start_addr = TASK_UNMAPPED_BASE;
+                mm->cached_hole_size = 0;
+        }
 
 full_search:
         addr = ALIGN(start_addr, huge_page_size(h));
@@ -171,13 +173,18 @@ full_search:
                          */
                         if (start_addr != TASK_UNMAPPED_BASE) {
                                 start_addr = TASK_UNMAPPED_BASE;
+                                mm->cached_hole_size = 0;
                                 goto full_search;
                         }
                         return -ENOMEM;
                 }
 
-                if (!vma || addr + len <= vma->vm_start)
+                if (!vma || addr + len <= vma->vm_start) {
+                        mm->free_area_cache = addr + len;
                         return addr;
+                }
+                if (addr + mm->cached_hole_size < vma->vm_start)
+                        mm->cached_hole_size = vma->vm_start - addr;
                 addr = ALIGN(vma->vm_end, huge_page_size(h));
         }
 }