From: John Hubbard <jhubbard@nvidia.com>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 02/10] mm/truncate: Inline invalidate_complete_page() into its one caller
Date: Mon, 14 Feb 2022 15:09:09 -0800 [thread overview]
Message-ID: <f711b39b-aea9-b514-1483-76fb128a2319@nvidia.com> (raw)
In-Reply-To: <20220214200017.3150590-3-willy@infradead.org>
On 2/14/22 12:00, Matthew Wilcox (Oracle) wrote:
> 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).
I just noticed this yesterday, when reviewing Rik's page poisoning fix.
I had a patch for it squirreled away, but I missed the point about
removing that extraneous mapping check. Glad you spotted it.
...
> @@ -309,7 +288,10 @@ int invalidate_inode_page(struct page *page)
It would be nice to retain some of the original comments. May I suggest
this (it has an additional paragraph) for an updated version of comments
above invalidate_inode_page():
/*
* Safely invalidate one page from its pagecache mapping.
* It only drops clean, unused pages. The page must be locked.
*
* This function can be called at any time, and is not supposed to throw away
* dirty pages. But pages can be marked dirty at any time too, so use
* remove_mapping(), which safely discards clean, unused pages.
*
* Returns 1 if the page is successfully invalidated, otherwise 0.
*/
Also, as long as you're there, a newline after the mapping declaration
would bring this routine into compliance with that convention.
hmmm, now I wonder why this isn't a boolean function. And I think the
reason is that it's quite old.
Either way, looks good:
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
thanks,
--
John Hubbard
NVIDIA
> return 0;
> if (page_mapped(page))
> return 0;
> - return invalidate_complete_page(mapping, page);
> + if (page_has_private(page) && !try_to_release_page(page, 0))
> + return 0;
> +
> + return remove_mapping(mapping, page);
> }
>
> /**
> @@ -584,7 +566,7 @@ void invalidate_mapping_pagevec(struct address_space *mapping,
> }
>
> /*
> - * This is like invalidate_complete_page(), except it ignores the page's
> + * This is like invalidate_inode_page(), except it ignores the page's
> * refcount. We do this because invalidate_inode_pages2() needs stronger
> * invalidation guarantees, and cannot afford to leave pages behind because
> * shrink_page_list() has a temp ref on them, or because they're transiently
next prev parent reply other threads:[~2022-02-14 23:09 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 20:00 [PATCH 00/10] Various fixes around invalidate_page() Matthew Wilcox (Oracle)
2022-02-14 20:00 ` [PATCH 01/10] splice: Use a folio in page_cache_pipe_buf_try_steal() Matthew Wilcox (Oracle)
2022-02-15 7:15 ` Christoph Hellwig
2022-02-15 8:32 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 02/10] mm/truncate: Inline invalidate_complete_page() into its one caller Matthew Wilcox (Oracle)
2022-02-14 23:09 ` John Hubbard [this message]
2022-02-14 23:32 ` Matthew Wilcox
2022-02-14 23:51 ` John Hubbard
2022-02-15 7:17 ` Christoph Hellwig
2022-02-15 7:45 ` Miaohe Lin
2022-02-15 20:09 ` Matthew Wilcox
2022-02-16 2:36 ` Miaohe Lin
2022-02-16 2:45 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 03/10] mm/truncate: Convert invalidate_inode_page() to use a folio Matthew Wilcox (Oracle)
2022-02-15 7:18 ` Christoph Hellwig
2022-02-15 8:32 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 04/10] mm/truncate: Replace page_mapped() call in invalidate_inode_page() Matthew Wilcox (Oracle)
2022-02-15 7:19 ` Christoph Hellwig
2022-02-15 20:12 ` Matthew Wilcox
2022-02-15 8:32 ` Miaohe Lin
2022-02-25 1:31 ` Matthew Wilcox
2022-02-25 3:27 ` Matthew Wilcox
2022-02-14 20:00 ` [PATCH 05/10] mm: Convert remove_mapping() to take a folio Matthew Wilcox (Oracle)
2022-02-15 7:21 ` Christoph Hellwig
2022-02-15 8:33 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 06/10] mm/truncate: Split invalidate_inode_page() into mapping_shrink_folio() Matthew Wilcox (Oracle)
2022-02-15 7:23 ` Christoph Hellwig
2022-02-15 9:37 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 07/10] mm/truncate: Convert __invalidate_mapping_pages() to use a folio Matthew Wilcox (Oracle)
2022-02-15 7:24 ` Christoph Hellwig
2022-02-15 9:37 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 08/10] mm: Turn deactivate_file_page() into deactivate_file_folio() Matthew Wilcox (Oracle)
2022-02-15 7:25 ` Christoph Hellwig
2022-02-15 8:26 ` Miaohe Lin
2022-02-15 20:33 ` Matthew Wilcox
2022-02-16 2:45 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 09/10] mm/truncate: Combine invalidate_mapping_pagevec() and __invalidate_mapping_pages() Matthew Wilcox (Oracle)
2022-02-15 7:26 ` Christoph Hellwig
2022-02-15 9:37 ` Miaohe Lin
2022-02-14 20:00 ` [PATCH 10/10] fs: Move many prototypes to pagemap.h Matthew Wilcox (Oracle)
2022-02-15 7:27 ` Christoph Hellwig
2022-02-15 9:38 ` Miaohe Lin
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