From b716ad953a2bc4a543143c1d9836b7007a4b182f Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Wed, 21 Mar 2012 16:33:56 -0700 Subject: 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 Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Michal Hocko Cc: Hillf Danton Cc: Andrea Arcangeli Cc: KAMEZAWA Hiroyuki Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index 4f31764d838f..9e0c0de2e7e3 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 -- cgit v1.2.3-55-g7522