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Date: Wed, 12 Jun 2002 19:13:26 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Anton Altaparmakov <aia21@mole.bio.cam.ac.uk>
CC: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] 2.5.21 Nonlinear CPU support
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Anton Altaparmakov wrote:
> 
> allocate_compression_buffers() currently allocates all buffers up
> smp_num_cpus which is fine without hotswap cpus. Once hotswap cpus path
> goes in, then the allocation will be (pseudo code):
> 
> 	for (i = 0; i < NR_CPUS; i++) {
> 		if (cpu_possible(i)) {
> 			ntfs_compression_buffer[i] = vmalloc();
> 			// TODO handle errors
> 		}
> 	}
> 
> That means in words that we allocate buffers only once and for all
> existing cpu SOCKETS, i.e. including all potentially hotpluggable cpus
> which are currently offline. - If someone invents hotpluggable cpu sockets
> at some point then they should be burnt at the stake! (-;
> 

Note that with my code, you don't allocate any memory until you have 
actually seen a particular CPU being *used.*  All very simple...

	-hpa


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