Messages in this thread Patch in this message | | | Date | Fri, 13 Jan 2012 19:47:31 +0800 | From | Xiao Guangrong <> | Subject | [PATCH 5/5] mm: search from free_area_cache for the bigger size |
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If the required size is bigger than cached_hole_size, we would better search from free_area_cache, it is more easier to get 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> --- arch/x86/kernel/sys_x86_64.c | 34 +++++++++++++++++----------------- mm/mmap.c | 36 +++++++++++++++++++++--------------- 2 files changed, 38 insertions(+), 32 deletions(-)
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index 0514890..ef59642 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -195,7 +195,7 @@ 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) @@ -223,25 +223,14 @@ 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; - - /* make sure it can fit in the remaining address space */ - if (addr > len) { - unsigned long tmp_addr = align_addr(addr - len, filp, - ALIGN_TOPDOWN); - - vma = find_vma(mm, tmp_addr); - if (!vma || tmp_addr + len <= vma->vm_start) - /* remember the address as a hint for next time */ - return mm->free_area_cache = tmp_addr; - } - - if (mm->mmap_base < len) - goto bottomup; + start_addr = addr = mm->free_area_cache;
- addr = mm->mmap_base-len; + if (addr < len) + goto fail;
+ addr -= len; do { addr = align_addr(addr, filp, ALIGN_TOPDOWN);
@@ -263,6 +252,17 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, addr = vma->vm_start-len; } while (len < vma->vm_start);
+fail: + /* + * if hint left us with no space for the requested + * mapping then try again: + */ + if (start_addr != mm->mmap_base) { + mm->free_area_cache = mm->mmap_base; + mm->cached_hole_size = 0; + goto try_again; + } + bottomup: /* * A failed mmap() very likely causes application failure, diff --git a/mm/mmap.c b/mm/mmap.c index 970f572..e3c4b97 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1439,7 +1439,7 @@ 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) @@ -1463,22 +1463,14 @@ 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, @@ -1498,7 +1490,21 @@ 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 -- 1.7.7.5
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