From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
linux-mm@kvack.org, Hugh Dickins <hughd@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: Issue with 8K folio size in __filemap_get_folio()
Date: Mon, 4 Dec 2023 17:17:30 +0000 [thread overview]
Message-ID: <ZW4JqpKAc56aIUhF@casper.infradead.org> (raw)
In-Reply-To: <22d5bd19-c1a7-4a6c-9be4-e4cb1213e439@redhat.com>
On Mon, Dec 04, 2023 at 04:09:36PM +0100, David Hildenbrand wrote:
> I think for the pagecache it should work. In the context of [1], a total
> mapcount would likely still be possible. Anything beyond that likely not, if
> we ever care.
I confess I hadn't gone through your patches.
https://lore.kernel.org/all/20231124132626.235350-8-david@redhat.com/
is the critical one. It's actually going to walk off the end of order-2
folios today (which we'll create, eg with XFS).
You can put _rmap_val0 and _rmap_val1 in page2 and _rmap_val2-5 in page3
to fix this. Once we're allocating order-1 folios, I think you can
avoid this scheme and just check page0 and page1 mapcounts independently.
next prev parent reply other threads:[~2023-12-04 17:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <B467D07C-00D2-47C6-A034-2D88FE88A092@dubeyko.com>
2023-12-03 21:27 ` Issue with 8K folio size in __filemap_get_folio() Matthew Wilcox
2023-12-03 23:12 ` Matthew Wilcox
2023-12-04 5:57 ` Hugh Dickins
2023-12-04 15:09 ` David Hildenbrand
2023-12-04 16:51 ` David Hildenbrand
2023-12-04 17:17 ` Matthew Wilcox [this message]
2023-12-04 17:22 ` David Hildenbrand
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