Re: [PATCH v2 2/3] mm/memory-failure.c: avoid calling invalidate_inode_page() with unexpected pages

Miaohe Lin
2022-03-14T01:58:55Z

On 2022/3/14 7:41, HORIGUCHI NAOYA(堀口 直也) wrote:
> On Sat, Mar 12, 2022 at 03:46:12PM +0800, Miaohe Lin wrote:
>> Since commit 042c4f32323b ("mm/truncate: Inline invalidate_complete_page()
>
> This commit ID does not exist in mainline (or in the latest mmotm?),
> so you can't use it in patch description. Could you update this part?
>

This commit is in the mmotm but not in mainline yet:

commit 042c4f32323beb28146c658202d3e69899e4f245
Author: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Sat Feb 12 15:27:42 2022 -0500

mm/truncate: Inline invalidate_complete_page() into its one caller

invalidate_inode_page() is the only caller of invalidate_complete_page()
and inlining it reveals that the first check is unnecessary (because we
hold the page locked, and we just retrieved the mapping from the page).
Actually, it does make a difference, in that tail pages no longer fail
at this check, so it's now possible to remove a tail page from a mapping.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Am I "not" supposed to use this commit id as it's not "stable" now?

Will update this part in next version. Many thanks.

> Thanks,
> Naoya Horiguchi
>
>> into its one caller"), invalidate_inode_page() can invalidate the pages in
>> the swap cache because the check of page->mapping != mapping is removed.
>> But invalidate_inode_page() is not expected to deal with the pages in swap
>> cache. Also non-lru movable page can reach here too. They're not page cache
>> pages. Skip these pages by checking PageSwapCache and PageLRU.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>> ---
>> mm/memory-failure.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index dabecd87ad3f..2ff7dd2078c4 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -2190,7 +2190,7 @@ static int __soft_offline_page(struct page *page)
>> return 0;
>> }
>>
>> - if (!PageHuge(page))
>> + if (!PageHuge(page) && PageLRU(page) && !PageSwapCache(page))
>> /*
>> * Try to invalidate first. This should work for
>> * non dirty unmapped page cache pages.
>> --
>> 2.23.0