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Message-ID: <1c693242-9d64-a730-6590-b7b8180ccfc6@redhat.com>
Date: Mon, 16 Sep 2019 09:41:57 +0200
From: David Hildenbrand <david@...hat.com>
To: Oscar Salvador <osalvador@...e.de>, n-horiguchi@...jp.nec.com
Cc: mhocko@...nel.org, mike.kravetz@...cle.com, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/10] mm,hwpoison-inject: don't pin for hwpoison_filter
On 10.09.19 12:30, Oscar Salvador wrote:
> From: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
>
> Another memory error injection interface debugfs:hwpoison/corrupt-pfn
> also takes bogus refcount for hwpoison_filter(). It's justified
> because this does a coarse filter, expecting that memory_failure()
> redoes the check for sure.
>
> Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
> Signed-off-by: Oscar Salvador <osalvador@...e.de>
> ---
> mm/hwpoison-inject.c | 18 +++++-------------
> 1 file changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
> index 5b7430bd83a6..0c8cdb80fd7d 100644
> --- a/mm/hwpoison-inject.c
> +++ b/mm/hwpoison-inject.c
> @@ -26,11 +26,6 @@ static int hwpoison_inject(void *data, u64 val)
>
> p = pfn_to_page(pfn);
> hpage = compound_head(p);
> - /*
> - * This implies unable to support free buddy pages.
> - */
> - if (!get_hwpoison_page(p))
> - return 0;
>
> if (!hwpoison_filter_enable)
> goto inject;
> @@ -40,23 +35,20 @@ static int hwpoison_inject(void *data, u64 val)
> * This implies unable to support non-LRU pages.
> */
> if (!PageLRU(hpage) && !PageHuge(p))
> - goto put_out;
> + return 0;
>
> /*
> - * do a racy check with elevated page count, to make sure PG_hwpoison
> - * will only be set for the targeted owner (or on a free page).
> + * do a racy check to make sure PG_hwpoison will only be set for
> + * the targeted owner (or on a free page).
> * memory_failure() will redo the check reliably inside page lock.
> */
> err = hwpoison_filter(hpage);
> if (err)
> - goto put_out;
> + return 0;
>
> inject:
> pr_info("Injecting memory failure at pfn %#lx\n", pfn);
> - return memory_failure(pfn, MF_COUNT_INCREASED);
> -put_out:
> - put_hwpoison_page(p);
> - return 0;
> + return memory_failure(pfn, 0);
> }
>
> static int hwpoison_unpoison(void *data, u64 val)
>
After this change, get_hwpoison_page() is only used in
mm/memory-failure.c - you might be able to un-export it and make it static.
--
Thanks,
David / dhildenb
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