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From: Daniel Colascione <dancol@google.com>
Date: Mon, 21 May 2018 15:20:29 -0700
Message-ID: <CAKOZuetDX905PeLt5cs7e_maSeKHrP0DgM1Kr3vvOb-+n=a7Gw@mail.gmail.com>
Subject: Re: Why do we let munmap fail?
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To: dave.hansen@intel.com
Cc: linux-mm@kvack.org, Tim Murray <timmurray@google.com>, Minchan Kim <minchan@kernel.org>

On Mon, May 21, 2018 at 3:12 PM Dave Hansen <dave.hansen@intel.com> wrote:

> On 05/21/2018 03:07 PM, Daniel Colascione wrote:
> > Now let's return to max_map_count itself: what is it supposed to
achieve?
> > If we want to limit application kernel memory resource consumption,
let's
> > limit application kernel memory resource consumption, accounting for it
on
> > a byte basis the same way we account for other kernel objects allocated
on
> > behalf of userspace. Why should we have a separate cap just for the VMA
> > count?

> VMAs consume kernel memory and we can't reclaim them.  That's what it
> boils down to.

How is it different from memfd in that respect?