linux-kernel - Re: [PATCH v1 3/5] s390/uv: convert PG_arch

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Message-ID: <da266113-37da-4b61-ba6f-47f0761e3cb8@redhat.com>
Date: Thu, 11 Apr 2024 12:41:10 +0200
From: David Hildenbrand <david@...hat.com>
To: Matthew Wilcox <willy@...radead.org>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 linux-s390@...r.kernel.org, kvm@...r.kernel.org,
 Heiko Carstens <hca@...ux.ibm.com>, Vasily Gorbik <gor@...ux.ibm.com>,
 Alexander Gordeev <agordeev@...ux.ibm.com>,
 Christian Borntraeger <borntraeger@...ux.ibm.com>,
 Sven Schnelle <svens@...ux.ibm.com>, Janosch Frank <frankja@...ux.ibm.com>,
 Claudio Imbrenda <imbrenda@...ux.ibm.com>,
 Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
 Thomas Huth <thuth@...hat.com>
Subject: Re: [PATCH v1 3/5] s390/uv: convert PG_arch_1 users to only work on
 small folios

On 05.04.24 05:36, Matthew Wilcox wrote:
> On Thu, Apr 04, 2024 at 06:36:40PM +0200, David Hildenbrand wrote:
>> Now that make_folio_secure() may only set PG_arch_1 for small folios,
>> let's convert relevant remaining UV code to only work on (small) folios
>> and simply reject large folios early. This way, we'll never end up
>> touching PG_arch_1 on tail pages of a large folio in UV code.
>>
>> The folio_get()/folio_put() for functions that are documented to already
>> hold a folio reference look weird and it should probably be removed.
>> Similarly, uv_destroy_owned_page() and uv_convert_owned_from_secure()
>> should really consume a folio reference instead. But these are cleanups for
>> another day.
> 
> Yes, and we should convert arch_make_page_accessible() to
> arch_make_folio_accessible() ... one of the two callers already has the
> folio (and page-writeback already calls arch_make_folio_accessible()
> 

Yes. We should then get rid of the arch_make_folio_accessible() loop 
over pages. Arch code can handle that, if required. Will include that in 
this series.

-- 
Cheers,

David / dhildenb