[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <50AF567402000078000AABF6@nat28.tlf.novell.com>
Date: Fri, 23 Nov 2012 09:56:52 +0000
From: "Jan Beulich" <JBeulich@...e.com>
To: "H. Peter Anvin" <hpa@...or.com>
Cc: <andrew.cooper3@...rix.com>, <x86@...nel.org>,
<tglx@...utronix.de>, <kexec@...ts.infradead.org>,
<virtualization@...ts.linux-foundation.org>,
<xen-devel@...ts.xensource.com>,
"Daniel Kiper" <daniel.kiper@...cle.com>, <konrad.wilk@...cle.com>,
<mingo@...hat.com>, <linux-kernel@...r.kernel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [PATCH v2 01/11] kexec: introduce kexec_ops struct
>>> On 22.11.12 at 18:37, "H. Peter Anvin" <hpa@...or.com> wrote:
> I actually talked to Ian Jackson at LCE, and mentioned among other
> things the bogosity of requiring a PUD page for three-level paging in
> Linux -- a bogosity which has spread from Xen into native. It's a page
> wasted for no good reason, since it only contains 32 bytes worth of
> data, *inherently*. Furthermore, contrary to popular belief, it is
> *not* pa page table per se.
>
> Ian told me: "I didn't know we did that, and we shouldn't have to."
> Here we have suffered this overhead for at least six years, ...
Even the Xen kernel only needs the full page when running on a
64-bit hypervisor (now that we don't have a 32-bit hypervisor
anymore, that of course basically means always). But yes, I too
never liked this enforced over-allocation for native kernels (and
was surprised that it was allowed in at all).
Jan
--
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/
Powered by blists - more mailing lists