Re: [PATCH 0/1] x86: Convert cpuinfo_x86 array to a per_cpu arrayv3

From: Andrew Morton
Date: Tue Oct 16 2007 - 04:19:47 EST


On Mon, 24 Sep 2007 14:08:53 -0700 travis@xxxxxxx wrote:

>
> v3: fix compile errors in arch-i386-allmodconfig build
>
> v2: rebasing on 2.6.23-rc6-mm1
>
> Analyzing various data structures when NR_CPU count is raised
> to 4096 shows the following arrays over 128k. If the maximum
> number of cpus are not installed (about 99.99% of the time),
> then a large percentage of this memory is wasted.
> --
> 151289856 CALNDATA irq_desc
> 135530496 RMDATATA irq_cfg
> 3145728 CALNDATA cpu_data
> 2101248 BSS irq_lists
> 2097152 RMDATATA cpu_sibling_map
> 2097152 RMDATATA cpu_core_map
> 1575936 BSS irq_2_pin
> 1050624 BSS irq_timer_state
> 614400 INITDATA early_node_map
> 525376 PERCPU per_cpu__kstat
> 524608 DATA unix_proto
> 524608 DATA udpv6_prot
> 524608 DATA udplitev6_prot
> 524608 DATA udplite_prot
> 524608 DATA udp_prot
> 524608 DATA tcpv6_prot
> 524608 DATA tcp_prot
> 524608 DATA rawv6_prot
> 524608 DATA raw_prot
> 524608 DATA packet_proto
> 524608 DATA netlink_proto
> 524288 BSS cpu_devices
> 524288 BSS boot_pageset
> 524288 CALNDATA boot_cpu_pda
> 262144 RMDATATA node_to_cpumask
> 262144 BSS __log_buf
> 131072 BSS entries
>
> cpu_sibling_map and cpu_core_map have been taken care of in
> a prior patch. This patch deals with the cpu_data array of
> cpuinfo_x86 structs. The model that was used in sparc64
> architecture was adopted for x86.
>

This has mysteriously started to oops on me, only on x86_64.

http://userweb.kernel.org/~akpm/config-x.txt
http://userweb.kernel.org/~akpm/dsc00001.jpg

which is a bit strange since this patch doesn't touch sched.c. Maybe
there's something somewhere else in the -mm lineup which when combined with
this prevents it from oopsing, dunno. I'll hold it back for now and will
see what happens.


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