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Date: Mon, 17 Feb 2003 18:51:12 +0100 (MET)
From: Mikael Pettersson <mikpe@csd.uu.se>
Message-Id: <200302171751.SAA19069@kim.it.uu.se>
To: ak@suse.de
Subject: 2.5.61: x86_64 num_online_cpus() buglet?
Cc: linux-kernel@vger.kernel.org
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Andi,

Kernel 2.5.61's include/asm-x86_64/smp.h contains:

extern unsigned long cpu_online_map;
...
extern inline unsigned int num_online_cpus(void)
{ 
	return hweight32(cpu_online_map);
} 

and similarly for cpu_callout_map.

hweight32() truncates a 64-bit operand to 32-bits, so either
- the maps should be int rather than long, or
- x86_64 needs to define and use a new hweight64(), or
- CONFIG_NR_CPUS must not exceed 32 on x86_64.

Comments?

/Mikael