x86, percpu: Optimize this_cpu_ptr
Allow arches to implement __this_cpu_ptr, and provide an x86 version.
Before:
movq $foo, %rax
movq %gs:this_cpu_off, %rdx
addq %rdx, %rax
After:
movq $foo, %rax
addq %gs:this_cpu_off, %rax
The benefit is doing it in one less instruction and not clobbering
a temporary register.
tj: * Beefed up the comment a bit and renamed in-macro temp variable
to match neighboring macros.
* Folded fix for const pointer case found in linux-next.
* Fixed sparse notation.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 08923b6..ec64311 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -60,9 +60,14 @@
#define __raw_get_cpu_var(var) \
(*SHIFT_PERCPU_PTR(&(var), __my_cpu_offset))
-#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
+#ifndef __this_cpu_ptr
#define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
-
+#endif
+#ifdef CONFIG_DEBUG_PREEMPT
+#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
+#else
+#define this_cpu_ptr(ptr) __this_cpu_ptr(ptr)
+#endif
#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
extern void setup_per_cpu_areas(void);