From: Keir Fraser <keir.fraser@eu.citrix.com>
To: Dave McCracken <dcm@mccr.org>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Jan Beulich <JBeulich@novell.com>
Subject: Re: Baffled by multipage_allocation_permitted()
Date: Tue, 16 Jun 2009 14:21:00 +0100 [thread overview]
Message-ID: <C65D5ACC.819F%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <200906160810.29184.dcm@mccr.org>
On 16/06/2009 14:10, "Dave McCracken" <dcm@mccr.org> wrote:
> Thanks for the change. That resolves my problem.
>
> Out of curiosity, why is it necessary to restrict the size of multipage
> allocations at all? I'd think the memory size limits would adequately protect
> against any guest going wild with it. What harm could come from, for example,
> a guest asking for a 16M contiguous page? I don't know of any current need
> for such a thing. I'm just wondering why we restrict it.
Such regions could be a precious resource when driving some hardware devices
which communicate via large contiguous memory areas. As I said, we haven't
thought about it too hard, so it may indeed be sensible to relax this
further in future.
-- Keir
next prev parent reply other threads:[~2009-06-16 13:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-15 21:44 Baffled by multipage_allocation_permitted() Dave McCracken
2009-06-15 21:57 ` Keir Fraser
2009-06-16 9:19 ` Jan Beulich
2009-06-16 9:41 ` Keir Fraser
2009-06-16 13:10 ` Dave McCracken
2009-06-16 13:21 ` Keir Fraser [this message]
2009-06-16 13:23 ` Jan Beulich
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