From: Matthew Wilcox <willy@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Christoph Hellwig <hch@infradead.org>,
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 00/27] Memory Folios
Date: Thu, 1 Apr 2021 13:52:01 +0100 [thread overview]
Message-ID: <20210401125201.GD351017@casper.infradead.org> (raw)
In-Reply-To: <20210401122803.GB2710221@ziepe.ca>
On Thu, Apr 01, 2021 at 09:28:03AM -0300, Jason Gunthorpe wrote:
> On Thu, Apr 01, 2021 at 12:26:56PM +0100, Matthew Wilcox wrote:
> > On Thu, Apr 01, 2021 at 08:05:37AM +0100, Christoph Hellwig wrote:
> > > On Wed, Mar 31, 2021 at 07:47:01PM +0100, Matthew Wilcox (Oracle) wrote:
> > > > - Mirror members of struct page (for pagecache / anon) into struct folio,
> > > > so (eg) you can use folio->mapping instead of folio->page.mapping
> > >
> > > Eww, why?
> >
> > So that eventually we can rename page->mapping to page->_mapping and
> > prevent the bugs from people doing page->mapping on a tail page. eg
> > https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2103102214170.7159@eggly.anvils/
>
> Is that gcc structure layout randomization stuff going to be a problem
> here?
>
> Add some
> static_assert(offsetof(struct folio,..) == offsetof(struct page,..))
>
> tests to force it?
You sound like the kind of person who hasn't read patch 1.
diff --git a/mm/util.c b/mm/util.c
index 0b6dd9d81da7..521a772f06eb 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -686,6 +686,25 @@ struct anon_vma *page_anon_vma(struct page *page)
return __page_rmapping(page);
}
+static inline void folio_build_bug(void)
+{
+#define FOLIO_MATCH(pg, fl) \
+BUILD_BUG_ON(offsetof(struct page, pg) != offsetof(struct folio, fl));
+
+ FOLIO_MATCH(flags, flags);
+ FOLIO_MATCH(lru, lru);
+ FOLIO_MATCH(mapping, mapping);
+ FOLIO_MATCH(index, index);
+ FOLIO_MATCH(private, private);
+ FOLIO_MATCH(_mapcount, _mapcount);
+ FOLIO_MATCH(_refcount, _refcount);
+#ifdef CONFIG_MEMCG
+ FOLIO_MATCH(memcg_data, memcg_data);
+#endif
+#undef FOLIO_MATCH
+ BUILD_BUG_ON(sizeof(struct page) != sizeof(struct folio));
+}
+
struct address_space *page_mapping(struct page *page)
{
struct address_space *mapping;
next prev parent reply other threads:[~2021-04-01 18:24 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
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 [this message]
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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