linux-kernel - Re: [PATCH v2 0/5] Support large folios for tmpfs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <D5MV2HU1QPLI.1P2HM7OTCR997@samsung.com>
Date: Fri, 15 Nov 2024 16:35:11 +0100
From: Daniel Gomez <da.gomez@...sung.com>
To: David Hildenbrand <david@...hat.com>, Baolin Wang
	<baolin.wang@...ux.alibaba.com>, <akpm@...ux-foundation.org>,
	<hughd@...gle.com>
CC: <willy@...radead.org>, <wangkefeng.wang@...wei.com>,
	<21cnbao@...il.com>, <ryan.roberts@....com>, <ioworker0@...il.com>,
	<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 0/5] Support large folios for tmpfs

On Fri Nov 15, 2024 at 2:35 PM CET, David Hildenbrand wrote:
> On 15.11.24 14:16, Daniel Gomez wrote:
>> On Tue Nov 12, 2024 at 8:45 AM CET, Baolin Wang wrote:
>>> Traditionally, tmpfs only supported PMD-sized huge folios. However nowadays
>> 
>> Nitpick:
>> We are mixing here folios/page, PMD-size huge. For anyone not aware of
>> Memory Folios conversion in the kernel I think this makes it confusing.
>> Tmpfs has never supported folios so, this is not true. Can we rephrase
>> it?
>
> We had the exact same discussion when we added mTHP support to anonymous 
> memory.
>
> I suggest you read:
>
> https://lkml.kernel.org/r/65dbdf2a-9281-a3c3-b7e3-a79c5b60b357@redhat.com
>
> Folios are an implementation detail on how we manage metadata. Nobody in 
> user space should even have to be aware of how we manage metadata for 
> larger chunks of memory ("huge pages") in the kernel.

I read it and I can't find where the use of "PMD-size huge folios" could
be a valid term. Tmpfs has never supported "folios", so I think using
"PMD-size huge pages" is more appropiate.