Re: + mm-vmalloc-use-well-defined-find_last_bit-func.patch addedto -mm tree

From: Zhang Yanfei
Date: Wed Aug 07 2013 - 20:54:58 EST


Hi Andrew,

ä 2013/8/8 5:05, akpm@xxxxxxxxxxxxxxxxxxxx åé:
> Subject: + mm-vmalloc-use-well-defined-find_last_bit-func.patch added to -mm tree
> To: iamjoonsoo.kim@xxxxxxx,hannes@xxxxxxxxxxx,liwanp@xxxxxxxxxxxxxxxxxx,zhangyanfei@xxxxxxxxxxxxxx
> From: akpm@xxxxxxxxxxxxxxxxxxxx
> Date: Wed, 07 Aug 2013 14:05:29 -0700
>
>
> The patch titled
> Subject: mm, vmalloc: use well-defined find_last_bit() func
> has been added to the -mm tree. Its filename is
> mm-vmalloc-use-well-defined-find_last_bit-func.patch
>
> This patch should soon appear at
> http://ozlabs.org/~akpm/mmots/broken-out/mm-vmalloc-use-well-defined-find_last_bit-func.patch
> and later at
> http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmalloc-use-well-defined-find_last_bit-func.patch
>
> Before you just go and hit "reply", please:
> a) Consider who else should be cc'ed
> b) Prefer to cc a suitable mailing list as well
> c) Ideally: find the original patch on the mailing list and do a
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>
> *** Remember to use Documentation/SubmitChecklist when testing your code ***
>
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
>
> ------------------------------------------------------
> From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Subject: mm, vmalloc: use well-defined find_last_bit() func
>
> Our intention in here is to find last_bit within the region to flush.
> There is well-defined function, find_last_bit() for this purpose and its
> performance may be slightly better than current implementation. So change
> it.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Reviewed-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Acked-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>

s/zhangyanfei@xxxxxxxxxxxxxx/zhangyanfei@xxxxxxxxxxxxxx/g

> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
>
> mm/vmalloc.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff -puN mm/vmalloc.c~mm-vmalloc-use-well-defined-find_last_bit-func mm/vmalloc.c
> --- a/mm/vmalloc.c~mm-vmalloc-use-well-defined-find_last_bit-func
> +++ a/mm/vmalloc.c
> @@ -1016,15 +1016,16 @@ void vm_unmap_aliases(void)
>
> rcu_read_lock();
> list_for_each_entry_rcu(vb, &vbq->free, free_list) {
> - int i;
> + int i, j;
>
> spin_lock(&vb->lock);
> i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS);
> - while (i < VMAP_BBMAP_BITS) {
> + if (i < VMAP_BBMAP_BITS) {
> unsigned long s, e;
> - int j;
> - j = find_next_zero_bit(vb->dirty_map,
> - VMAP_BBMAP_BITS, i);
> +
> + j = find_last_bit(vb->dirty_map,
> + VMAP_BBMAP_BITS);
> + j = j + 1; /* need exclusive index */
>
> s = vb->va->va_start + (i << PAGE_SHIFT);
> e = vb->va->va_start + (j << PAGE_SHIFT);
> @@ -1034,10 +1035,6 @@ void vm_unmap_aliases(void)
> start = s;
> if (e > end)
> end = e;
> -
> - i = j;
> - i = find_next_bit(vb->dirty_map,
> - VMAP_BBMAP_BITS, i);
> }
> spin_unlock(&vb->lock);
> }
> _
>
> Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
>
> mm-hugetlb-move-up-the-code-which-check-availability-of-free-huge-page.patch
> mm-hugetlb-trivial-commenting-fix.patch
> mm-hugetlb-clean-up-alloc_huge_page.patch
> mm-hugetlb-fix-and-clean-up-node-iteration-code-to-alloc-or-free.patch
> mm-hugetlb-remove-redundant-list_empty-check-in-gather_surplus_pages.patch
> mm-hugetlb-do-not-use-a-page-in-page-cache-for-cow-optimization.patch
> mm-hugetlb-add-vm_noreserve-check-in-vma_has_reserves.patch
> mm-hugetlb-remove-decrement_hugepage_resv_vma.patch
> mm-hugetlb-decrement-reserve-count-if-vm_noreserve-alloc-page-cache.patch
> mm-hugetlb-decrement-reserve-count-if-vm_noreserve-alloc-page-cache-fix.patch
> mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization.patch
> mm-move-pgtable-related-functions-to-right-place.patch
> swap-clean-up-ifdef-in-page_mapping.patch
> mm-vmalloc-remove-useless-variable-in-vmap_block.patch
> mm-vmalloc-use-well-defined-find_last_bit-func.patch
>
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--
Thanks.
Zhang Yanfei
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