From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH 2/6] x86/numa: Correct the extern of
	cpu_to_node
Date: Thu, 9 Apr 2015 16:05:36 +0100
Message-ID: <55269540.309@citrix.com>
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To: Tim Deegan <tim@xen.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>, Keir Fraser <keir@xen.org>, Jan Beulich <JBeulich@suse.com>, Xen-devel <xen-devel@lists.xen.org>
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On 09/04/15 16:00, Tim Deegan wrote:
> At 18:26 +0100 on 07 Apr (1428431176), Andrew Cooper wrote:
>> --- a/xen/include/asm-x86/numa.h
>> +++ b/xen/include/asm-x86/numa.h
>> @@ -9,7 +9,7 @@
>>  
>>  extern int srat_rev;
>>  
>> -extern unsigned char cpu_to_node[];
>> +extern nodeid_t      cpu_to_node[NR_CPUS];
> Does the compiler do anything useful with the array size here?

Specifying the size allows ARRAY_SIZE(cpu_to_node) to work in other
translation units.  It also allows static analysers to perform bounds
checks, should they wish.

> In particular does it check that it matches the size at the definition?

It will complain if they are mismatched.

~Andrew