Re: [PATCH] x86: Add optimized popcnt variants

[Borislav Petkov]

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Tue, Mar 09, 2010 at 04:50:40PM +0100

> Should all be fine as it is, that patch
> ( http://lkml.org/lkml/2010/2/4/119 ) is against a kernel with fce877e3
> in, I've just checked and it still applies to tip/master as of this
> writing (although it grew a single 2 line offset for 1 hunk).

Well, this way, I'm getting

...
In file included from include/linux/kernel.h:15,
                 from /home/linux-2.6/arch/x86/include/asm/percpu.h:45,
                 from /home/linux-2.6/arch/x86/include/asm/current.h:5,
                 from /home/linux-2.6/arch/x86/include/asm/processor.h:15,
                 from /home/linux-2.6/arch/x86/include/asm/atomic.h:6,
                 from include/linux/crypto.h:20,
                 from arch/x86/kernel/asm-offsets_64.c:8,
                 from arch/x86/kernel/asm-offsets.c:4:
include/linux/bitops.h:52:1: warning: "HWEIGHT8" redefined
...

due to the fact that we have multiple definitions of HWEIGHT*:

The one batch is in <include/linux/bitops.h> introduced by fce877e3.

The other is in <include/asm-generic/bitops/const_hweight.h> which
is pulled in into <include/linux/bitops.h> through "#include
<asm/bitops.h>", which, in turn, <includes asm/arch_hweight.h> and
<include/asm-generic/bitops/const_hweight.h>.

The obvious resolution is to remove the HWEIGHT* batch from
<include/asm-generic/bitops/const_hweight.h> since they're functionally
identical with the ones in <include/linux/bitops.h>, no?

-- 
Regards/Gruss,
Boris.

-
Advanced Micro Devices, Inc.
Operating Systems Research Center
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