[PATCH] Define __raw_get_cpu_var and use it

There are several instances of per_cpu(foo, raw_smp_processor_id()), which
is semantically equivalent to __get_cpu_var(foo) but without the warning
that smp_processor_id() can give if CONFIG_DEBUG_PREEMPT is enabled.  For
those architectures with optimized per-cpu implementations, namely ia64,
powerpc, s390, sparc64 and x86_64, per_cpu() turns into more and slower
code than __get_cpu_var(), so it would be preferable to use __get_cpu_var
on those platforms.

This defines a __raw_get_cpu_var(x) macro which turns into per_cpu(x,
raw_smp_processor_id()) on architectures that use the generic per-cpu
implementation, and turns into __get_cpu_var(x) on the architectures that
have an optimized per-cpu implementation.

Signed-off-by: Paul Mackerras <[email protected]>
Acked-by: David S. Miller <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Acked-by: Martin Schwidefsky <[email protected]>
Cc: Rusty Russell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Paul Mackerras 2006-06-25 05:47:14 -07:00 • committed by Linus Torvalds
commit bfe5d83419
11 changed files with 19 additions and 7 deletions

View file

@ -40,6 +40,7 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
__typeof__(type) per_cpu__##name
#define __get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
#define __raw_get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
#define per_cpu(var,cpu) __reloc_hide(var,__per_cpu_offset[cpu])
/* A macro to avoid #include hell... */
@ -57,6 +58,7 @@ do { \
__typeof__(type) per_cpu__##name
#define __get_cpu_var(var) __reloc_hide(var,0)
#define __raw_get_cpu_var(var) __reloc_hide(var,0)
#define per_cpu(var,cpu) __reloc_hide(var,0)
#endif /* SMP */