From: "H. Peter Anvin" <hpa@zytor.com>
To: Fenghua Yu <fenghua.yu@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@linux.intel.com>,
Ingo Molnar <mingo@elte.hu>,
Glenn Williamson <glenn.p.williamson@intel.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v2] X86-32: Allocate 256 bytes for pgd in PAE paging
Date: Thu, 18 Dec 2014 09:25:40 -0800 [thread overview]
Message-ID: <54930E14.30800@zytor.com> (raw)
In-Reply-To: <1418852859-18852-1-git-send-email-fenghua.yu@intel.com>
On 12/17/2014 01:47 PM, Fenghua Yu wrote:
> From: Fenghua Yu <fenghua.yu@intel.com>
>
> X86 32-bit machine and kernel use PAE paging, which currently wastes about
> 4K of memory per process on Linux where we have to reserve an entire page to
> support a single 256-byte PGD structure. It would be a very good thing if
> we could eliminate that wastage.
>
4*8 = 32 bytes, where did 256 bytes come from?
-hpa
next prev parent reply other threads:[~2014-12-18 17:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-17 21:47 [PATCH v2] X86-32: Allocate 256 bytes for pgd in PAE paging Fenghua Yu
2014-12-18 0:25 ` Dave Hansen
2014-12-18 14:52 ` Christoph Lameter
2014-12-18 15:36 ` Dave Hansen
2014-12-18 17:25 ` H. Peter Anvin [this message]
2014-12-18 17:51 ` Yu, Fenghua
2014-12-18 18:00 ` H. Peter Anvin
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