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From: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: ak@suse.de, linux-kernel@vger.kernel.org, travis@sgi.com,
	Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: x86: Convert cpu_core_map to be a per cpu variable
Date: Tue, 17 Jul 2007 12:27:18 -0700	[thread overview]
Message-ID: <20070717192718.GF3318@linux-os.sc.intel.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0707122354340.17278@schroedinger.engr.sgi.com>

On Thu, Jul 12, 2007 at 11:58:06PM -0700, Christoph Lameter wrote:
> cpu_core_map is currently an array defined using NR_CPUS. This means that
> we overallocate since we will rarely really use the maximum 
> number of configured cpus. This may become a problem when we need to 
> increase the NR_CPUs on x86_64 for our new product line.
> 
> If we put the cpu_core_map into the per cpu area then it will be allocated
> for each processor as it comes online.
> 
> However, this means that the core map cannot be accessed until the per cpu 
> area has been allocated. Xen does a weird thing here looping over all 
> processors and zeroing the masks that are not yet allocated and that will 
> be zeroed when they are allocated. I commented the code out. Maybe there 
> is another purpose? Jeremy?

Is there a reason why cpu_sibling_map[] is left out in these changes?

thanks,
suresh

  parent reply	other threads:[~2007-07-17 19:32 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-13  6:58 x86: Convert cpu_core_map to be a per cpu variable Christoph Lameter
2007-07-13  7:08 ` David Miller
2007-07-13 16:34   ` Christoph Lameter
2007-07-13 22:41     ` David Miller
2007-07-13 22:50       ` Christoph Lameter
2007-07-13 22:51         ` David Miller
2007-07-13 13:49 ` Jeremy Fitzhardinge
2007-07-17 19:27 ` Siddha, Suresh B [this message]
2007-07-23 19:34   ` Christoph Lameter

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