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authorXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>2012-03-21 16:33:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-21 17:54:56 -0700
commitb716ad953a2bc4a543143c1d9836b7007a4b182f (patch)
tree99791c6c857b1ff7b922eaa0163ec3c912549009 /mm/mmap.c
parentf44d21985eb6af7361d3785e26923355172147bd (diff)
mm: search from free_area_cache for the bigger size
If the required size is bigger than cached_hole_size it is better to search from free_area_cache - it is easier to get a free region, specifically for the 64 bit process whose address space is large enough Do it just as hugetlb_get_unmapped_area_topdown() in arch/x86/mm/hugetlbpage.c 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> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c36
1 files changed, 21 insertions, 15 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 4f31764d838..9e0c0de2e7e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1442,7 +1442,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
- unsigned long addr = addr0;
+ unsigned long addr = addr0, start_addr;
/* requested length too big for entire address space */
if (len > TASK_SIZE)
@@ -1466,22 +1466,14 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
mm->free_area_cache = mm->mmap_base;
}
+try_again:
/* either no address requested or can't fit in requested address hole */
- addr = mm->free_area_cache;
+ start_addr = addr = mm->free_area_cache;
- /* make sure it can fit in the remaining address space */
- if (addr > len) {
- vma = find_vma(mm, addr-len);
- if (!vma || addr <= vma->vm_start)
- /* remember the address as a hint for next time */
- return (mm->free_area_cache = addr-len);
- }
-
- if (mm->mmap_base < len)
- goto bottomup;
-
- addr = mm->mmap_base-len;
+ if (addr < len)
+ goto fail;
+ addr -= len;
do {
/*
* Lookup failure means no vma is above this address,
@@ -1501,7 +1493,21 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
addr = vma->vm_start-len;
} while (len < vma->vm_start);
-bottomup:
+fail:
+ /*
+ * if hint left us with no space for the requested
+ * mapping then try again:
+ *
+ * Note: this is different with the case of bottomup
+ * which does the fully line-search, but we use find_vma
+ * here that causes some holes skipped.
+ */
+ if (start_addr != mm->mmap_base) {
+ mm->free_area_cache = mm->mmap_base;
+ mm->cached_hole_size = 0;
+ goto try_again;
+ }
+
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario