From: "Jan Beulich" <JBeulich@suse.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: <andrew.cooper3@citrix.com>, <x86@kernel.org>,
<tglx@linutronix.de>, <kexec@lists.infradead.org>,
<virtualization@lists.linux-foundation.org>,
<xen-devel@lists.xensource.com>,
"Daniel Kiper" <daniel.kiper@oracle.com>,
<konrad.wilk@oracle.com>, <mingo@redhat.com>,
<linux-kernel@vger.kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH v2 01/11] kexec: introduce kexec_ops struct
Date: Fri, 23 Nov 2012 09:56:52 +0000 [thread overview]
Message-ID: <50AF567402000078000AABF6@nat28.tlf.novell.com> (raw)
In-Reply-To: <50AE62E9.3000602@zytor.com>
>>> On 22.11.12 at 18:37, "H. Peter Anvin" <hpa@zytor.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
next prev parent reply other threads:[~2012-11-23 9:55 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-20 15:04 [PATCH v2 00/11] xen: Initial kexec/kdump implementation Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 01/11] kexec: introduce kexec_ops struct Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 02/11] x86/kexec: Add extra pointers to transition page table PGD, PUD, PMD and PTE Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 03/11] xen: Introduce architecture independent data for kexec/kdump Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 04/11] x86/xen: Introduce architecture dependent " Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 05/11] x86/xen: Register resources required by kexec-tools Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 06/11] x86/xen: Add i386 kexec/kdump implementation Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 07/11] x86/xen: Add x86_64 " Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 08/11] x86/xen: Add kexec/kdump makefile rules Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 09/11] x86/xen/enlighten: Add init and crash kexec/kdump hooks Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 10/11] drivers/xen: Export vmcoreinfo through sysfs Daniel Kiper
2012-11-20 15:04 ` [PATCH v2 11/11] x86: Add Xen kexec control code size check to linker script Daniel Kiper
2012-11-20 15:52 ` [PATCH v2 02/11] x86/kexec: Add extra pointers to transition page table PGD, PUD, PMD and PTE Jan Beulich
2012-11-20 16:40 ` [PATCH v2 01/11] kexec: introduce kexec_ops struct Eric W. Biederman
2012-11-21 10:52 ` Daniel Kiper
2012-11-22 12:15 ` Eric W. Biederman
2012-11-22 17:37 ` H. Peter Anvin
2012-11-23 9:56 ` Jan Beulich [this message]
2012-11-23 10:53 ` [Xen-devel] " Ian Campbell
2012-11-22 17:47 ` H. Peter Anvin
2012-11-22 18:07 ` Andrew Cooper
2012-11-22 22:26 ` H. Peter Anvin
2014-03-31 10:50 ` Petr Tesarik
2012-11-23 0:12 ` Andrew Cooper
2012-11-23 1:34 ` H. Peter Anvin
2012-11-23 1:38 ` H. Peter Anvin
2012-11-23 1:56 ` Andrew Cooper
2012-11-23 9:53 ` Jan Beulich
2012-11-23 10:37 ` Daniel Kiper
2012-11-23 10:51 ` [Xen-devel] " Ian Campbell
2012-11-23 11:13 ` Daniel Kiper
2012-11-23 10:51 ` Jan Beulich
2012-11-23 11:08 ` Daniel Kiper
2012-11-23 9:47 ` Daniel Kiper
2012-11-23 20:24 ` Eric W. Biederman
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