From: Dave Hansen <dave.hansen@intel.com>
To: Yinghai Lu <yinghai@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] x86: Fix booting with DEBUG_PAGE_ALLOC with more than 512G RAM
Date: Mon, 12 Aug 2013 16:50:52 -0700 [thread overview]
Message-ID: <520974DC.60802@intel.com> (raw)
In-Reply-To: <1376351004-4015-1-git-send-email-yinghai@kernel.org>
On 08/12/2013 04:43 PM, Yinghai Lu wrote:
>> > commit 8170e6bed465b4b0c7687f93e9948aca4358a33b
>> > Author: H. Peter Anvin <hpa@zytor.com>
>> > Date: Thu Jan 24 12:19:52 2013 -0800
>> >
>> > x86, 64bit: Use a #PF handler to materialize early mappings on demand
> Before that, we have maping from [0,512M) in head_64.S, and we can
> spare two pages [0-1M). After that change, we can not reuse pages anymore.
>
> When we have more than 512M ram, we need extra page for pgd page with
> [512G, 1024g).
>
> Increase pages in BRK for page table to solve the booting problem.
So how much does this get us up to? 1TB? That's actually _fairly_
small today. I've got a fairly old machine with that much in it, and
it's only half full of DIMMs.
It's also a bit worrying that this is completely disconnected from the
other code in the kernel that is concerned with the amount of total
address space in the system: MAX_PHYSADDR_BITS.
next prev parent reply other threads:[~2013-08-12 23:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-09 23:18 x86: early boot crash: "alloc_low_page: ran out of memory" (bisected) Dave Hansen
2013-08-09 23:23 ` Yinghai Lu
2013-08-10 1:19 ` Dave Hansen
2013-08-10 2:10 ` Yinghai Lu
2013-08-10 2:21 ` Yinghai Lu
2013-08-12 16:27 ` Dave Hansen
2013-08-12 23:43 ` [PATCH] x86: Fix booting with DEBUG_PAGE_ALLOC with more than 512G RAM Yinghai Lu
2013-08-12 23:50 ` Dave Hansen [this message]
2013-08-12 23:59 ` Yinghai Lu
2013-08-20 8:22 ` [tip:x86/urgent] x86/mm: Fix boot crash with DEBUG_PAGE_ALLOC= y and " tip-bot for Yinghai Lu
2013-08-12 23:47 ` x86: early boot crash: "alloc_low_page: ran out of memory" (bisected) Yinghai Lu
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