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Date: Tue, 11 Nov 2025 09:02:28 +0530
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Subject: Re: [PATCH] mm/ptdesc: Derive from the compound head in page_ptdesc()
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org, vishal.moola@gmail.com,
 Andrew Morton <akpm@linux-foundation.org>,
 David Hildenbrand <david@redhat.com>,
 Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
 "Liam R . Howlett" <Liam.Howlett@oracle.com>,
 Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
 Suren Baghdasaryan <surenb@google.com>, Michal Hocko <mhocko@suse.com>,
 linux-kernel@vger.kernel.org
References: <20251110063725.3118037-1-anshuman.khandual@arm.com>
 <aRHq4OdBCtC_V0eS@casper.infradead.org>
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From: Anshuman Khandual <anshuman.khandual@arm.com>
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On 10/11/25 7:08 PM, Matthew Wilcox wrote:
> On Mon, Nov 10, 2025 at 06:37:25AM +0000, Anshuman Khandual wrote:
>> struct ptdesc (including all relevant helpers) support multi order compound
>> pages. But page_ptdesc() coverts given page into its own ptdesc rather than
>> deriving from its compound head as would have been expected otherwise. Just
>> change the macro to fetch the struct ptdesc from the compound head instead,
>> so that the same struct ptdesc is reached from all tail pages.
> 
> Please review
> https://lore.kernel.org/linux-mm/20251020001652.2116669-1-willy@infradead.org/
> instead.

Sure, will do. Thanks for the pointer.