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From: Christoph Hellwig <hch@infradead.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-cachefs@redhat.com,
	linux-afs@lists.infradead.org
Subject: Re: [PATCH v6 01/27] mm: Introduce struct folio
Date: Wed, 7 Apr 2021 07:09:00 +0100	[thread overview]
Message-ID: <20210407060900.GA3333828@infradead.org> (raw)
In-Reply-To: <20210406162530.GT2531743@casper.infradead.org>

On Tue, Apr 06, 2021 at 05:25:30PM +0100, Matthew Wilcox wrote:
> About a third of ->index can be folio_offset(), based on a crude:
> 
> $ git grep 'page->index.*PAGE_' |wc -l
> 101
> 
> and I absolutely don't mind cleaning that up as part of the folio work,
> but that still leaves 200-250 instances that would need to be changed
> later.
> 
> I don't want to change the page->mapping to calls to folio_mapping().
> That's a lot of extra work for a page which the filesystem knows belongs
> to it.  folio_mapping() only needs to be used for pages which might not
> belong to a filesystem.
> 
> page_file_mapping() absolutely needs to go away.  The way to do that
> is to change swap-over-nfs to use direct IO, and then NFS can use
> folio->mapping like all other filesystems.  f2fs is just terminally
> confused and shouldn't be using page_file_mapping at all.  I'll fix
> that as part of the folio work.

Thanks.  So my opinion for now remains preferably just don't add
the union and derefence through the page.  But I'm not going to block
the series for it, as I think it is a huge and badly needed cleanup
required to make further use of larger pages / large chunks of memory
in the pagecache and the file systems.


  reply	other threads:[~2021-04-07  6:09 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-31 18:47 [PATCH v6 00/27] Memory Folios Matthew Wilcox (Oracle)
2021-03-31 18:47 ` [PATCH v6 01/27] mm: Introduce struct folio Matthew Wilcox (Oracle)
2021-04-06 12:29   ` Kirill A. Shutemov
2021-04-06 12:48     ` Matthew Wilcox
2021-04-06 14:21       ` Kirill A. Shutemov
2021-04-06 14:31       ` Christoph Hellwig
2021-04-06 14:40         ` Matthew Wilcox
2021-04-06 14:47           ` Christoph Hellwig
2021-04-06 14:55             ` Matthew Wilcox
2021-04-06 15:05               ` Christoph Hellwig
2021-04-06 16:25                 ` Matthew Wilcox
2021-04-07  6:09                   ` Christoph Hellwig [this message]
2021-04-08  9:01   ` Rasmus Villemoes
2021-03-31 18:47 ` [PATCH v6 02/27] mm: Add folio_pgdat and folio_zone Matthew Wilcox (Oracle)
2021-04-06 13:23   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 03/27] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-04-06 13:25   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 04/27] mm/debug: Add VM_BUG_ON_FOLIO and VM_WARN_ON_ONCE_FOLIO Matthew Wilcox (Oracle)
2021-04-06 13:26   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 05/27] mm: Add folio reference count functions Matthew Wilcox (Oracle)
2021-04-06 13:30   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 06/27] mm: Add put_folio Matthew Wilcox (Oracle)
2021-04-06 13:31   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 07/27] mm: Add get_folio Matthew Wilcox (Oracle)
2021-04-06 13:32   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 08/27] mm: Create FolioFlags Matthew Wilcox (Oracle)
2021-04-06 13:34   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 09/27] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-04-06 13:37   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 10/27] mm/filemap: Add folio_index, folio_file_page and folio_contains Matthew Wilcox (Oracle)
2021-04-06 13:39   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 11/27] mm/filemap: Add folio_next_index Matthew Wilcox (Oracle)
2021-04-06 13:40   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 12/27] mm/filemap: Add folio_offset and folio_file_offset Matthew Wilcox (Oracle)
2021-04-06 13:42   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 13/27] mm/util: Add folio_mapping and folio_file_mapping Matthew Wilcox (Oracle)
2021-04-06 13:45   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 14/27] mm: Add folio_mapcount Matthew Wilcox (Oracle)
2021-04-06 13:46   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 15/27] mm/memcg: Add folio wrappers for various functions Matthew Wilcox (Oracle)
2021-04-06 13:48   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 16/27] mm/filemap: Add unlock_folio Matthew Wilcox (Oracle)
2021-04-06 13:51   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 17/27] mm/filemap: Add lock_folio Matthew Wilcox (Oracle)
2021-04-06 13:52   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 18/27] mm/filemap: Add lock_folio_killable Matthew Wilcox (Oracle)
2021-04-06 13:53   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 19/27] mm/filemap: Add __lock_folio_async Matthew Wilcox (Oracle)
2021-04-06 13:55   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 20/27] mm/filemap: Add __lock_folio_or_retry Matthew Wilcox (Oracle)
2021-04-06 13:57   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 21/27] mm/filemap: Add wait_on_folio_locked Matthew Wilcox (Oracle)
2021-04-06 14:11   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 22/27] mm/filemap: Add end_folio_writeback Matthew Wilcox (Oracle)
2021-04-06 14:13   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 23/27] mm/writeback: Add wait_on_folio_writeback Matthew Wilcox (Oracle)
2021-04-06 14:15   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 24/27] mm/writeback: Add wait_for_stable_folio Matthew Wilcox (Oracle)
2021-04-06 14:18   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 25/27] mm/filemap: Convert wait_on_page_bit to wait_on_folio_bit Matthew Wilcox (Oracle)
2021-04-06 14:19   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 26/27] mm/filemap: Convert wake_up_page_bit to wake_up_folio_bit Matthew Wilcox (Oracle)
2021-04-06 14:23   ` Christoph Hellwig
2021-03-31 18:47 ` [PATCH v6 27/27] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
2021-04-06 14:25   ` Christoph Hellwig
2021-04-01  7:05 ` [PATCH v6 00/27] Memory Folios Christoph Hellwig
2021-04-01 11:26   ` Matthew Wilcox
2021-04-01 12:28     ` Jason Gunthorpe
2021-04-01 12:52       ` Matthew Wilcox
2021-04-01 13:30         ` Jason Gunthorpe
2021-04-02 14:37     ` Christoph Hellwig
2021-04-02 14:49       ` Matthew Wilcox
2021-04-03  0:31 ` Kent Overstreet
2021-04-05 19:14 ` Jeff Layton
2021-04-05 19:31   ` Matthew Wilcox
2021-04-06 15:14     ` Jeff Layton

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