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From: Andi Kleen <andi@firstfloor.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tejun Heo <tj@kernel.org>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	linux-arch@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de,
	cl@linux-foundation.org
Subject: Re: [PATCHSET] percpu: generalize first chunk allocators and improve lpage NUMA support
Date: Thu, 25 Jun 2009 21:54:08 +0200	[thread overview]
Message-ID: <20090625195408.GW6760@one.firstfloor.org> (raw)
In-Reply-To: <4A43871F.9030507@zytor.com>

On Thu, Jun 25, 2009 at 07:18:07AM -0700, H. Peter Anvin wrote:
> Andi Kleen wrote:
> >>>
> >> *Ahem* virtual machines *ahem*...
> > 
> > And? Even there's not that big typically. 
> > 
> > The traditional problem was just for 128 NR_CPUs kernel were nothing
> > was sized based on machine capacity.
> > 
> > Also on large systems the VMs shouldn't be sized for full capacity.
> > 
> 
> We have already have cases where the "possible" CPUs have eaten up the
> entire vmalloc area on 32 bits.  In real use.  It's a real problem.

That's hard to believe or a serious bug/misconfiguration somewhere. 

Each per CPU data should be <100k (let's say 200k with some slack for modules), 
so to fill vmalloc you would need hundreds of CPUs, which a 32bit
kernel doesn't really support anyways because it doesn't support
enough memory for that many CPUs.

Perhaps you had firmware/hypervisor who passed a gigantic impossible
value here? If yes thy

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

  reply	other threads:[~2009-06-25 19:54 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-24 13:30 [PATCHSET] percpu: generalize first chunk allocators and improve lpage NUMA support Tejun Heo
2009-06-24 13:30 ` Tejun Heo
2009-06-24 13:30 ` [PATCH 01/10] x86: make pcpu_chunk_addr_search() matching stricter Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 02/10] percpu: drop @unit_size from embed first chunk allocator Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 03/10] x86,percpu: generalize 4k " Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 04/10] percpu: make 4k first chunk allocator map memory Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-07-13 10:12   ` David Howells
2009-07-15  3:17     ` Tejun Heo
2009-06-24 13:30 ` [PATCH 05/10] x86,percpu: generalize lpage first chunk allocator Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 06/10] percpu: simplify pcpu_setup_first_chunk() Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 07/10] percpu: reorder a few functions in mm/percpu.c Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 08/10] percpu: drop pcpu_chunk->page[] Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 09/10] percpu: allow non-linear / sparse cpu -> unit mapping Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 13:30 ` [PATCH 10/10] percpu: teach large page allocator about NUMA Tejun Heo
2009-06-24 13:30   ` Tejun Heo
2009-06-24 23:55 ` [PATCHSET] percpu: generalize first chunk allocators and improve lpage NUMA support Andrew Morton
2009-06-25  0:02   ` Andi Kleen
2009-06-25  0:13     ` H. Peter Anvin
2009-06-25  9:19       ` Andi Kleen
2009-06-25 14:18         ` H. Peter Anvin
2009-06-25 19:54           ` Andi Kleen [this message]
2009-06-25 20:15             ` H. Peter Anvin
2009-06-25 20:26               ` Andi Kleen
2009-06-26  0:40                 ` Tejun Heo
2009-06-26  2:02                   ` H. Peter Anvin
2009-06-26  6:54                   ` Andi Kleen
2009-06-25  2:35   ` Tejun Heo
2009-06-25  9:20     ` Ingo Molnar
2009-06-29 23:20   ` Christoph Lameter
2009-06-29 23:39     ` Andrew Morton
2009-06-30 14:24       ` Christoph Lameter
2009-06-30 19:15       ` Ingo Molnar
2009-06-30 19:39         ` Christoph Lameter
2009-06-30 20:21           ` Scott Lurndal
2009-06-30 21:31           ` Ingo Molnar
2009-06-30 22:16             ` Christoph Lameter
2009-06-30 22:31               ` Ingo Molnar
2009-06-30 22:40                 ` Andi Kleen
2009-07-01  0:48                   ` Tejun Heo
2009-06-30 22:55                 ` Christoph Lameter
2009-06-30 23:07                   ` Ingo Molnar
2009-06-30 23:18                     ` Christoph Lameter
2009-06-30 23:30                       ` Ingo Molnar
2009-07-01  6:34                     ` Andi Kleen
2009-06-30 23:20               ` Tejun Heo
2009-06-30 23:31                 ` Ingo Molnar
2009-06-30 23:34                   ` H. Peter Anvin
2009-07-01  6:42                 ` Andi Kleen
2009-07-01 10:21                   ` Tejun Heo
2009-07-01 12:23                     ` Andi Kleen
2009-07-01 12:53                       ` Tejun Heo
2009-07-01 13:11                         ` Andi Kleen
2009-07-01 17:33                           ` Christoph Lameter
2009-07-01 22:42                             ` Tejun Heo
2009-07-03 23:14 ` Tejun Heo
2009-07-03 23:14   ` Tejun Heo

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