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Message-ID: <1377186772-rb1um2cz-mutt-n-horiguchi@ah.jp.nec.com>
Date: Thu, 22 Aug 2013 11:52:52 -0400
From: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To: Wanpeng Li <liwanp@...ux.vnet.ibm.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Andi Kleen <andi@...stfloor.org>,
Fengguang Wu <fengguang.wu@...el.com>,
Tony Luck <tony.luck@...el.com>, gong.chen@...ux.intel.com,
linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/6] mm/hwpoison: don't need to hold compound lock for
hugetlbfs page
On Thu, Aug 22, 2013 at 05:48:23PM +0800, Wanpeng Li wrote:
> compound lock is introduced by commit e9da73d67("thp: compound_lock."),
> it is used to serialize put_page against __split_huge_page_refcount().
> In addition, transparent hugepages will be splitted in hwpoison handler
> and just one subpage will be poisoned. There is unnecessary to hold
> compound lock for hugetlbfs page. This patch replace compound_trans_order
> by compond_order in the place where the page is hugetlbfs page.
>
> Signed-off-by: Wanpeng Li <liwanp@...ux.vnet.ibm.com>
> ---
> mm/memory-failure.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 2c13aa7..5092e06 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -206,7 +206,7 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
> #ifdef __ARCH_SI_TRAPNO
> si.si_trapno = trapno;
> #endif
> - si.si_addr_lsb = compound_trans_order(compound_head(page)) + PAGE_SHIFT;
> + si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT;
>
> if ((flags & MF_ACTION_REQUIRED) && t == current) {
> si.si_code = BUS_MCEERR_AR;
> @@ -983,7 +983,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
> static void set_page_hwpoison_huge_page(struct page *hpage)
> {
> int i;
> - int nr_pages = 1 << compound_trans_order(hpage);
> + int nr_pages = 1 << compound_order(hpage);
> for (i = 0; i < nr_pages; i++)
> SetPageHWPoison(hpage + i);
> }
> @@ -991,7 +991,7 @@ static void set_page_hwpoison_huge_page(struct page *hpage)
> static void clear_page_hwpoison_huge_page(struct page *hpage)
> {
> int i;
> - int nr_pages = 1 << compound_trans_order(hpage);
> + int nr_pages = 1 << compound_order(hpage);
> for (i = 0; i < nr_pages; i++)
> ClearPageHWPoison(hpage + i);
> }
> @@ -1491,7 +1491,7 @@ static int soft_offline_huge_page(struct page *page, int flags)
> } else {
> set_page_hwpoison_huge_page(hpage);
> dequeue_hwpoisoned_huge_page(hpage);
> - atomic_long_add(1 << compound_trans_order(hpage),
> + atomic_long_add(1 << compound_order(hpage),
> &num_poisoned_pages);
> }
> return ret;
> @@ -1551,7 +1551,7 @@ int soft_offline_page(struct page *page, int flags)
> if (PageHuge(page)) {
> set_page_hwpoison_huge_page(hpage);
> dequeue_hwpoisoned_huge_page(hpage);
> - atomic_long_add(1 << compound_trans_order(hpage),
> + atomic_long_add(1 << compound_order(hpage),
> &num_poisoned_pages);
> } else {
> SetPageHWPoison(page);
We have one more compound_trans_order() in unpoison_memory(), so could you
replace that too?
With that change ...
Reviewed-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Thanks,
Naoya Horiguchi
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