From: Konrad Rzeszutek Wilk <konrad@kernel.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>, Jacob Shin <jacob.shin@amd.com>,
Tejun Heo <tj@kernel.org>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 03/10] x86, mm: get early page table from BRK
Date: Wed, 10 Oct 2012 10:17:08 -0400 [thread overview]
Message-ID: <20121010141707.GH4005@phenom.dumpdata.com> (raw)
In-Reply-To: <CAE9FiQW8ubsQmtJk=bvZ5yGdBaBQSNWPpuACku+8sbb6_CG+rA@mail.gmail.com>
On Tue, Oct 09, 2012 at 06:03:33PM -0700, Yinghai Lu wrote:
> On Tue, Oct 9, 2012 at 9:01 AM, Konrad Rzeszutek Wilk <konrad@kernel.org> wrote:
> >> +RESERVE_BRK(early_pgt_alloc, 16384);
> >
> > How did you come up with 16KB being the right size? What is this
> > based on? Can you provide a comment explaining why 16KB is the
> > right value on 32-bit and 64-bit machines?
>
> good point, i add one line comment to the revised patch.
>
> +/* need 3 4k for initial PMD_SIZE, 4k for 0-ISA_END_ADDRESS */
Can you explain the math please? It sounds like this is based on
the assumption that this you are using huge pages. But what if you
are not? What if you can only do 4KB pages?
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next prev parent reply other threads:[~2012-10-10 14:29 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-09 4:39 [PATCH -v2 00/10] x86: Use BRK to pre mapping page table to make xen happy Yinghai Lu
2012-10-09 4:39 ` [PATCH 01/10] x86, mm: align start address to correct big page size Yinghai Lu
2012-10-09 4:39 ` [PATCH 02/10] x86, mm: Use big page size for small memory range Yinghai Lu
2012-10-09 4:39 ` [PATCH 03/10] x86, mm: get early page table from BRK Yinghai Lu
2012-10-09 16:01 ` Konrad Rzeszutek Wilk
2012-10-10 1:03 ` Yinghai Lu
2012-10-10 14:17 ` Konrad Rzeszutek Wilk [this message]
2012-10-10 15:49 ` Yinghai Lu
2012-10-11 14:41 ` Konrad Rzeszutek Wilk
2012-10-11 22:55 ` Yinghai Lu
2012-10-11 23:18 ` H. Peter Anvin
2012-10-09 4:39 ` [PATCH 04/10] x86, mm: Don't clear page table if next range is ram Yinghai Lu
2012-10-09 16:04 ` Konrad Rzeszutek Wilk
2012-10-10 1:08 ` Yinghai Lu
2012-10-09 4:39 ` [PATCH 05/10] x86, mm: Remove early_memremap workaround for page table accessing Yinghai Lu
2012-10-09 4:39 ` [PATCH 06/10] x86, mm: only keep initial mapping for ram Yinghai Lu
2012-10-09 4:39 ` [PATCH 07/10] x86, xen, mm: Do not need to check if page table is ioremap Yinghai Lu
2012-10-09 16:13 ` Konrad Rzeszutek Wilk
2012-10-09 4:39 ` [PATCH 08/10] x86, xen, mm: fix mapping_pagetable_reserve logic Yinghai Lu
2012-10-09 6:12 ` H. Peter Anvin
2012-10-09 6:33 ` Yinghai Lu
2012-10-09 7:22 ` H. Peter Anvin
2012-10-09 12:22 ` Stefano Stabellini
2012-10-09 14:15 ` H. Peter Anvin
2012-10-09 4:39 ` [PATCH 09/10] x86, mm: Hide pgt_buf_* into internal to xen Yinghai Lu
2012-10-09 4:39 ` [PATCH 10/10] x86, mm: Add early_pgt_buf_* Yinghai Lu
2012-10-09 6:07 ` [PATCH -v2 00/10] x86: Use BRK to pre mapping page table to make xen happy H. Peter Anvin
2012-10-09 6:21 ` Yinghai Lu
2012-10-09 6:25 ` H. Peter Anvin
2012-10-09 6:45 ` Yinghai Lu
2012-10-09 12:19 ` Stefano Stabellini
2012-10-09 18:27 ` Yinghai Lu
2012-10-10 0:00 ` Yinghai Lu
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