linux-kernel - Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear)

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: <20070307145042.GG18704@wotan.suse.de>
Date:	Wed, 7 Mar 2007 15:50:42 +0100
From:	Nick Piggin <npiggin@...e.de>
To:	Miklos Szeredi <miklos@...redi.hu>
Cc:	a.p.zijlstra@...llo.nl, akpm@...ux-foundation.org, mingo@...e.hu,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	benh@...nel.crashing.org, jdike@...toit.com
Subject: Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear)

On Wed, Mar 07, 2007 at 02:53:07PM +0100, Miklos Szeredi wrote:
> > > msync() might never get called and then we're back with the old
> > > behaviour where we can surprise the VM with a ton of dirty pages.
> > 
> > But we're root. With your patch, root *can't* do nonlinear writeback
> > well. Ever. With msync, at least you give them enough rope.
> 
> Restricting to root doesn't buy you much, nobody wants to be root.
> Restricting to mlock is similarly pointless.  UML _will_ want to get
> swapped out if there's no activity.

They could always not use nonlinear, or we could add a ulimit to the
size of nonlinear vaddr allowed. 

> Restricting to tmpfs makes sense, but it's probably not what UML
> wants.

I think it is OK. They might want some persistent storage to migrate
or something, but that can always be done by copying from tmpfs to
a block based filesystem.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/