linux-kernel - Re: [PATCH v2 1/4] mm: Set folio swapbacked iff folios are dirty in try_to_unmap

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Message-ID: <e36243bb-5a6f-4ef7-ae3e-99d204009afb@redhat.com>
Date: Mon, 13 Jan 2025 14:20:59 +0100
From: David Hildenbrand <david@...hat.com>
To: Barry Song <21cnbao@...il.com>, akpm@...ux-foundation.org,
 linux-mm@...ck.org
Cc: baolin.wang@...ux.alibaba.com, chrisl@...nel.org, ioworker0@...il.com,
 kasong@...cent.com, linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org, ryan.roberts@....com, v-songbaohua@...o.com,
 x86@...nel.org, linux-riscv@...ts.infradead.org, ying.huang@...el.com,
 zhengtangquan@...o.com, lorenzo.stoakes@...cle.com
Subject: Re: [PATCH v2 1/4] mm: Set folio swapbacked iff folios are dirty in
 try_to_unmap_one

On 13.01.25 14:19, David Hildenbrand wrote:
> On 13.01.25 04:38, Barry Song wrote:
>> From: Barry Song <v-songbaohua@...o.com>
>>
>> The refcount may be temporarily or long-term increased, but this does
>> not change the fundamental nature of the folio already being lazy-
>> freed. Therefore, we only reset 'swapbacked' when we are certain the
>> folio is dirty and not droppable.
>>
>> Suggested-by: David Hildenbrand <david@...hat.com>
>> Signed-off-by: Barry Song <v-songbaohua@...o.com>
>> ---
> 
> Acked-by: David Hildenbrand <david@...hat.com>
> 

Ah, should this have a Fixes: ?

Because of a speculative reference, we might not reclaim MADV_FREE 
folios as we silently mark them as swapbacked again, which sounds fairly 
wrong.

-- 
Cheers,

David / dhildenb