linux-kernel - Re: [RFC PATCH v4 0/6] Promotion of Unmapped Page Cache Folios.

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: <Z_m1bNEuhcVkwEE2@casper.infradead.org>
Date: Sat, 12 Apr 2025 01:35:56 +0100
From: Matthew Wilcox <willy@...radead.org>
To: Gregory Price <gourry@...rry.net>
Cc: linux-mm@...ck.org, cgroups@...r.kernel.org,
	linux-kernel@...r.kernel.org, kernel-team@...a.com,
	akpm@...ux-foundation.org, mingo@...hat.com, peterz@...radead.org,
	juri.lelli@...hat.com, vincent.guittot@...aro.org,
	hannes@...xchg.org, mhocko@...nel.org, roman.gushchin@...ux.dev,
	shakeel.butt@...ux.dev, donettom@...ux.ibm.com,
	Huang Ying <ying.huang@...ux.alibaba.com>,
	Keith Busch <kbusch@...a.com>, Feng Tang <feng.tang@...el.com>,
	Neha Gholkar <nehagholkar@...a.com>
Subject: Re: [RFC PATCH v4 0/6] Promotion of Unmapped Page Cache Folios.

On Fri, Apr 11, 2025 at 08:09:55PM -0400, Gregory Price wrote:
> On Sat, Apr 12, 2025 at 12:49:18AM +0100, Matthew Wilcox wrote:
> > On Fri, Apr 11, 2025 at 06:11:05PM -0400, Gregory Price wrote:
> > > Unmapped page cache pages can be demoted to low-tier memory, but
> > 
> > No.  Page cache should never be demoted to low-tier memory.
> > NACK this patchset.
> 
> This wasn't a statement of approval page cache being on lower tiers,
> it's a statement of fact.  Enabling demotion causes this issue.

Then that's the bug that needs to be fixed.  Not adding 200+ lines
of code to recover from a situation that should never happen.