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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	William Kucharski <william.kucharski@oracle.com>
Subject: Re: [PATCH 12/15] mm: Support removing arbitrary sized pages from mapping
Date: Tue, 1 Oct 2019 13:39:39 +0300	[thread overview]
Message-ID: <20191001103939.gglcqk2gzezkrpnc@box> (raw)
In-Reply-To: <20190925005214.27240-13-willy@infradead.org>

On Tue, Sep 24, 2019 at 05:52:11PM -0700, Matthew Wilcox wrote:
> From: William Kucharski <william.kucharski@oracle.com>
> 
> __remove_mapping() assumes that pages can only be either base pages
> or HPAGE_PMD_SIZE.  Ask the page what size it is.

You also fixes the issue CONFIG_READ_ONLY_THP_FOR_FS=y with this patch.
The new feature makes the refcount calculation relevant not only for
PageSwapCache(). It should go to v5.4.

> 
> Signed-off-by: William Kucharski <william.kucharski@oracle.com>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

> ---
>  mm/vmscan.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index a7f9f379e523..9f44868e640b 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -932,10 +932,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
>  	 * Note that if SetPageDirty is always performed via set_page_dirty,
>  	 * and thus under the i_pages lock, then this ordering is not required.
>  	 */
> -	if (unlikely(PageTransHuge(page)) && PageSwapCache(page))
> -		refcount = 1 + HPAGE_PMD_NR;
> -	else
> -		refcount = 2;
> +	refcount = 1 + compound_nr(page);
>  	if (!page_ref_freeze(page, refcount))
>  		goto cannot_free;
>  	/* note: atomic_cmpxchg in page_ref_freeze provides the smp_rmb */
> -- 
> 2.23.0
> 
> 

-- 
 Kirill A. Shutemov

  reply	other threads:[~2019-10-01 10:39 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-25  0:51 [RFC 00/15] Large pages in the page-cache Matthew Wilcox
2019-09-25  0:52 ` [PATCH 01/15] mm: Use vm_fault error code directly Matthew Wilcox
2019-09-26 13:55   ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 02/15] fs: Introduce i_blocks_per_page Matthew Wilcox
2019-09-25  8:36   ` Dave Chinner
2019-10-04 19:28     ` Matthew Wilcox
2019-10-08  3:53       ` Dave Chinner
2019-09-25  0:52 ` [PATCH 03/15] mm: Add file_offset_of_ helpers Matthew Wilcox
2019-09-26 14:02   ` Kirill A. Shutemov
2019-10-04 19:39     ` Matthew Wilcox
2019-09-25  0:52 ` [PATCH 04/15] iomap: Support large pages Matthew Wilcox
2019-09-25  0:52 ` [PATCH 05/15] xfs: " Matthew Wilcox
2019-09-25  0:52 ` [PATCH 06/15] xfs: Pass a page to xfs_finish_page_writeback Matthew Wilcox
2019-09-25  0:52 ` [PATCH 07/15] mm: Make prep_transhuge_page tail-callable Matthew Wilcox
2019-09-26 14:13   ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 08/15] mm: Add __page_cache_alloc_order Matthew Wilcox
2019-09-26 14:15   ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 09/15] mm: Allow large pages to be added to the page cache Matthew Wilcox
2019-09-26 14:22   ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 10/15] mm: Allow find_get_page to be used for large pages Matthew Wilcox
2019-10-01 10:32   ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 11/15] mm: Remove hpage_nr_pages Matthew Wilcox
2019-10-01 10:35   ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 12/15] mm: Support removing arbitrary sized pages from mapping Matthew Wilcox
2019-10-01 10:39   ` Kirill A. Shutemov [this message]
2019-09-25  0:52 ` [PATCH 13/15] mm: Add a huge page fault handler for files Matthew Wilcox
2019-10-01 10:42   ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 14/15] mm: Align THP mappings for non-DAX Matthew Wilcox
2019-10-01 10:45   ` Kirill A. Shutemov
2019-10-01 11:21     ` William Kucharski
2019-10-01 11:32       ` Kirill A. Shutemov
2019-10-01 12:18         ` William Kucharski
2019-10-01 14:20           ` Kirill A. Shutemov
2019-10-01 16:08             ` William Kucharski
2019-10-02  0:15               ` Kirill A. Shutemov
2019-09-25  0:52 ` [PATCH 15/15] xfs: Use filemap_huge_fault Matthew Wilcox
     [not found] ` <20191002130753.7680-1-hdanton@sina.com>
2019-10-04 19:33   ` [PATCH 03/15] mm: Add file_offset_of_ helpers Matthew Wilcox
     [not found] ` <20191002133211.15696-1-hdanton@sina.com>
2019-10-04 19:34   ` [PATCH 04/15] iomap: Support large pages Matthew Wilcox
     [not found] ` <20191003040846.17604-1-hdanton@sina.com>
2019-10-04 19:35   ` [PATCH 06/15] xfs: Pass a page to xfs_finish_page_writeback Matthew Wilcox
     [not found] ` <20191003050859.18140-1-hdanton@sina.com>
2019-10-04 19:36   ` [PATCH 11/15] mm: Remove hpage_nr_pages Matthew Wilcox

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