Messages in this thread Patch in this message | | | Date | Wed, 7 Mar 2012 14:01:01 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 2/5] hugetlb: drop prev_vma in hugetlb_get_unmapped_area_topdown |
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On Fri, 13 Jan 2012 19:44:53 +0800 Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> wrote:
> Afte call find_vma_prev(mm, addr, &prev_vma), following condition is always > true: > !prev_vma || (addr >= prev_vma->vm_end) > it can be happily drop prev_vma and use find_vma instead of find_vma_prev
I had to rework this patch due to 097d59106a8e4b ("vm: avoid using find_vma_prev() unnecessarily") in mainline. Can you please check my handiwork?
From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Subject: hugetlb: drop prev_vma in hugetlb_get_unmapped_area_topdown()
After the call find_vma_prev(mm, addr, &prev_vma), the following condition is always true:
!prev_vma || (addr >= prev_vma->vm_end)
it can happily drop prev_vma and use find_vma() instead of find_vma_prev().
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> ---
arch/x86/mm/hugetlbpage.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-)
diff -puN arch/x86/mm/hugetlbpage.c~hugetlb-drop-prev_vma-in-hugetlb_get_unmapped_area_topdown arch/x86/mm/hugetlbpage.c --- a/arch/x86/mm/hugetlbpage.c~hugetlb-drop-prev_vma-in-hugetlb_get_unmapped_area_topdown +++ a/arch/x86/mm/hugetlbpage.c @@ -308,7 +308,7 @@ static unsigned long hugetlb_get_unmappe { 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, addr = addr0; unsigned long largest_hole = mm->cached_hole_size; int first_time = 1; @@ -334,25 +334,16 @@ try_again: * i.e. return with success: */ vma = find_vma(mm, addr); - 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 (vma) + prev_vma = vma->vm_prev; + if (!vma || 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 */ _
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