Re: [PATCH] slub: Disable the lockless allocator

[Christoph Lameter]

On Sat, 26 Mar 2011, Linus Torvalds wrote:

> Wouldn't something like the attached be better?

On first glance I cannot find fault with it. arch/x86/include/asm/percpu.h |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index a09e1f0..d475b43 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -45,7 +45,7 @@
 #include <linux/stringify.h>
 
 #ifdef CONFIG_SMP
-#define __percpu_arg(x)		"%%"__stringify(__percpu_seg)":%P" #x
+#define __percpu_prefix		"%%"__stringify(__percpu_seg)":"
 #define __my_cpu_offset		percpu_read(this_cpu_off)
 
 /*
@@ -62,9 +62,11 @@
 	(typeof(*(ptr)) __kernel __force *)tcp_ptr__;	\
 })
 #else
-#define __percpu_arg(x)		"%P" #x
+#define __percpu_prefix		""
 #endif
 
+#define __percpu_arg(x)		__percpu_prefix "%P" #x
+
 /*
  * Initialized pointers to per-cpu variables needed for the boot
  * processor need to use these macros to get the proper address
@@ -516,11 +518,11 @@ do {									\
 	typeof(o2) __n2 = n2;						\
 	typeof(o2) __dummy;						\
 	alternative_io("call this_cpu_cmpxchg16b_emu\n\t" P6_NOP4,	\
-		       "cmpxchg16b %%gs:(%%rsi)\n\tsetz %0\n\t",	\
+		       "cmpxchg16b " __percpu_prefix "(%%rsi)\n\tsetz %0\n\t",	\
 		       X86_FEATURE_CX16,				\
 		       ASM_OUTPUT2("=a"(__ret), "=d"(__dummy)),		\
 		       "S" (&pcp1), "b"(__n1), "c"(__n2),		\
-		       "a"(__o1), "d"(__o2));				\
+		       "a"(__o1), "d"(__o2) : "memory");		\
 	__ret;								\
 })