Re: [PATCH/RFC 3/8] numa: x86_64: use generic percpu var for numa_node_id() implementation

[Lee Schermerhorn <Lee.Schermerhorn@hp.com>]

On Thu, 2010-03-04 at 12:47 -0600, Christoph Lameter wrote: 
> On Thu, 4 Mar 2010, Lee Schermerhorn wrote:
> 
> > Index: linux-2.6.33-mmotm-100302-1838/arch/x86/include/asm/percpu.h
> > ===================================================================
> > --- linux-2.6.33-mmotm-100302-1838.orig/arch/x86/include/asm/percpu.h
> > +++ linux-2.6.33-mmotm-100302-1838/arch/x86/include/asm/percpu.h
> > @@ -208,10 +208,12 @@ do {									\
> >  #define percpu_or(var, val)		percpu_to_op("or", var, val)
> >  #define percpu_xor(var, val)		percpu_to_op("xor", var, val)
> >
> > +#define __this_cpu_read(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
> >  #define __this_cpu_read_1(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
> >  #define __this_cpu_read_2(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
> >  #define __this_cpu_read_4(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
> >
> > +#define __this_cpu_write(pcp, val)	percpu_to_op("mov", (pcp), val)
> >  #define __this_cpu_write_1(pcp, val)	percpu_to_op("mov", (pcp), val)
> >  #define __this_cpu_write_2(pcp, val)	percpu_to_op("mov", (pcp), val)
> >  #define __this_cpu_write_4(pcp, val)	percpu_to_op("mov", (pcp), val)
> 
> 
> The functions added are already defined in linux/percpu.h and their
> definition here is wrong since the u64 case is not handled (percpu.h does
> that correctly).

Well, in linux/percpu-defs.h after the first patch in this series, but
x86 is overriding it with the percpu_to_op() implementation.  You're
saying that the x86 percpu_to_op() macro doesn't handle 8-byte 'pcp'
operands?  It appears to handle sizes 1, 2, 4 and 8.

But, I just tried the series with the above two definitions removed and
the kernel builds and boots.  And runs the hackbench test even faster.

2.6.33-mmotm-100302-1838 on 8x6 AMD x86_64 -- hackbench 400 process 200
[avg of 10 runs]:
no add'l patches:		3.332
my V3 series:			3.148
V3 + generic __this_cpu_xxx():  3.083  [removed x86 defs of
__this_cpu_xxx()]


So, I'll remove those definitions in V4.

Do we want to retain the x86 definitions of __this_cpu_xxx_[124]() or
remove those and let the generic definitions handle them? 

Lee





  
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