From: Miaohe Lin <linmiaohe@huawei.com>
To: Yin Fengwei <fengwei.yin@intel.com>
Cc: <linux-mm@kvack.org>, <naoya.horiguchi@nec.com>,
<aaron.lu@intel.com>, <tony.luck@intel.com>,
<qiuxu.zhuo@intel.com>, Matthew Wilcox <willy@infradead.org>
Subject: Re: [RFC PATCH] mm/memory-failure: release private data before split THP
Date: Thu, 4 Aug 2022 09:19:45 +0800 [thread overview]
Message-ID: <410bb7b3-db57-47a9-f97c-1e3441aadb23@huawei.com> (raw)
In-Reply-To: <Yupxv9+ziR+utiHX@casper.infradead.org>
On 2022/8/3 21:01, Matthew Wilcox wrote:
> On Wed, Aug 03, 2022 at 10:52:43AM +0800, Yin Fengwei wrote:
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index da39ec8afca8..08e21973b120 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -1484,7 +1484,16 @@ static int identify_page_state(unsigned long pfn, struct page *p,
>>
>> static int try_to_split_thp_page(struct page *page, const char *msg)
>> {
>> + struct page *head = compound_head(page);
> > +
>> lock_page(page);
>> + /*
>> + * If thp page has private data attached, thp split will fail.
>> + * Release private data before split thp.
>> + */
>> + if (page_has_private(head))
>> + try_to_release_page(head, GFP_KERNEL);
>> +
>> if (unlikely(split_huge_page(page))) {
>> unsigned long pfn = page_to_pfn(page);
>
> It seems a shame to use the old page approach instead of the
> shiny new folio approach. We're quite close to being able to remove
> try_to_release_page() in 6.1 or 6.2 so adding a new caller is a bad idea.
> How about this:
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index da39ec8afca8..765b383288b1 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1484,16 +1484,21 @@ static int identify_page_state(unsigned long pfn, struct page *p,
>
> static int try_to_split_thp_page(struct page *page, const char *msg)
> {
> - lock_page(page);
> + struct folio *folio = page_folio(page);
> +
> + folio_lock(folio);
> + if (folio_test_private(folio))
> + filemap_release_folio(folio, GFP_KERNEL);
If filemap_release_folio fails, we could avoid trying split_huge_page here?
> if (unlikely(split_huge_page(page))) {
> unsigned long pfn = page_to_pfn(page);
>
> - unlock_page(page);
> + folio_unlock(folio);
> pr_info("%s: %#lx: thp split failed\n", msg, pfn);
> - put_page(page);
> + folio_put(folio);
> return -EBUSY;
> }
> - unlock_page(page);
> + folio = page_folio(page);
Above line (re-fetching folio) might need a comment to avoid future confusing ?
Anyway, this patch looks good to me. Thanks for fixing.
> + folio_unlock(folio);
>
> return 0;
> }
>
> .
>
next prev parent reply other threads:[~2022-08-04 1:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-03 2:52 [RFC PATCH] mm/memory-failure: release private data before split THP Yin Fengwei
2022-08-03 9:39 ` HORIGUCHI NAOYA(堀口 直也)
2022-08-03 14:42 ` Yin, Fengwei
2022-08-03 13:01 ` Matthew Wilcox
2022-08-03 13:32 ` Yin, Fengwei
2022-08-03 13:36 ` Matthew Wilcox
2022-08-03 13:40 ` Yin, Fengwei
2022-08-03 14:33 ` Yin, Fengwei
2022-08-03 15:26 ` Matthew Wilcox
2022-08-04 1:19 ` Miaohe Lin [this message]
2022-08-04 1:54 ` Yin Fengwei
2022-08-04 2:05 ` Miaohe Lin
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