linux-kernel - Re: [PATCH v21 1/4] mm: add VM_DROPPABLE for designating always lazily freeable mappings

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Message-ID: <ZovwO8KJ5Cv5fa26@zx2c4.com>
Date: Mon, 8 Jul 2024 15:57:15 +0200
From: "Jason A. Donenfeld" <Jason@...c4.com>
To: David Hildenbrand <david@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, patches@...ts.linux.dev,
	tglx@...utronix.de, linux-crypto@...r.kernel.org,
	linux-api@...r.kernel.org, x86@...nel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Adhemerval Zanella Netto <adhemerval.zanella@...aro.org>,
	Carlos O'Donell <carlos@...hat.com>,
	Florian Weimer <fweimer@...hat.com>, Arnd Bergmann <arnd@...db.de>,
	Jann Horn <jannh@...gle.com>,
	Christian Brauner <brauner@...nel.org>,
	David Hildenbrand <dhildenb@...hat.com>, linux-mm@...ck.org
Subject: Re: [PATCH v21 1/4] mm: add VM_DROPPABLE for designating always
 lazily freeable mappings

On Mon, Jul 08, 2024 at 10:23:10AM +0200, David Hildenbrand wrote:
> > As a side note, I'll raise that I am not a particular fan of the
> > "droppable" terminology, at least with the "read 0s" approach.
> > 
> >   From a user perspective, the memory might suddenly lose its state and
> > read as 0s just like volatile memory when it loses power. "dropping
> > pages" sounds more like an implementation detail.
>
> Long story short: it's the hypervisor that could be effectively 
> dropping/zeroing out that memory, not the guest VM. "NONVOLATILE" might 
> be clearer than "DROPPABLE".

Surely you mean "VOLATILE", not "NONVOLATILE", right?

Jason