From: David Hildenbrand <david@redhat.com>
To: Lance Yang <ioworker0@gmail.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: akpm@linux-foundation.org, 21cnbao@gmail.com,
ryan.roberts@arm.com, dev.jain@arm.com, shy828301@gmail.com,
ziy@nvidia.com, libang.li@antgroup.com,
baolin.wang@linux.alibaba.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Liam.Howlett@oracle.com, vbabka@suse.cz,
jannh@google.com, Jason@zx2c4.com,
Mingzhe Yang <mingzhe.yang@ly.com>
Subject: Re: [RFC 1/1] mm/madvise: fail MADV_PAGEOUT on VM_DROPPABLE VMA
Date: Mon, 20 Jan 2025 14:56:54 +0100 [thread overview]
Message-ID: <1cbd3b3d-48b7-42b0-88e1-a9316e4acc53@redhat.com> (raw)
In-Reply-To: <CAK1f24=7G-Cz=Ztm0+q_8YwxBRPmKQEmeM3mpzpk-rdycENw7Q@mail.gmail.com>
On 20.01.25 14:47, Lance Yang wrote:
> Hi Barry, David and Lorenzo,
>
> Thanks a lot for taking time to review!
>
> On Mon, Jan 20, 2025 at 6:45 PM Lorenzo Stoakes
> <lorenzo.stoakes@oracle.com> wrote:
>>
>> Sorry but NACK again on this :(
>>
>> On Mon, Jan 20, 2025 at 09:30:38AM +0800, Lance Yang wrote:
>>> MADV_PAGEOUT should fail on VMAs with the VM_DROPPABLE flag. While
>>> MADV_PAGEOUT is intended to move anonymous pages to swap, VM_DROPPABLE
>>> should not be swapped out.
>>>
>>> There is an issue where using MADV_PAGEOUT on a VMA with the VM_DROPPABLE
>>> flag behaves like MADV_DONTNEED, causing the pages to be dropped. This
>>> could break the semantics of MADV_PAGEOUT, IMO.
>>>
>>> So, let's add a check to detect the VM_DROPPABLE flag before doing
>>> MADV_PAGEOUT and returns -EINVAL.
>>
>> No, let's not.
>
> I think I completely got it wrong. Learning so much from your patient responses!
Maybe you can make the documentation (man pages?) clearer in that
regard? Thanks!
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-01-20 13:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-20 1:30 Lance Yang
2025-01-20 2:02 ` Barry Song
2025-01-20 8:03 ` David Hildenbrand
2025-01-20 10:45 ` Lorenzo Stoakes
2025-01-20 13:47 ` Lance Yang
2025-01-20 13:56 ` David Hildenbrand [this message]
2025-01-21 2:28 ` Lance Yang
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