Messages in this thread | | | Date | Tue, 21 Jan 2014 11:09:20 -0500 | From | Waiman Long <> | Subject | Re: [PATCH v9 3/5] qrwlock, x86 - Treat all data type not bigger than long as atomic in x86 |
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On 01/21/2014 10:39 AM, Peter Zijlstra wrote: > On Tue, Jan 21, 2014 at 10:36:48AM -0500, Waiman Long wrote: >> On 01/20/2014 10:03 AM, Peter Zijlstra wrote: >>> On Tue, Jan 14, 2014 at 11:44:05PM -0500, Waiman Long wrote: >>>> The generic __native_word() macro defined in include/linux/compiler.h >>>> only allows "int" and "long" data types to be treated as native and >>>> atomic. The x86 architecture, however, allow the use of char and short >>>> data types as atomic as well. >>>> >>>> This patch extends the data type allowed in the __native_word() macro to >>>> allow the use of char and short. >>>> >>>> Signed-off-by: Waiman Long<Waiman.Long@hp.com> >>>> --- >>>> arch/x86/include/asm/barrier.h | 8 ++++++++ >>>> 1 files changed, 8 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h >>>> index 04a4890..4d3e30a 100644 >>>> --- a/arch/x86/include/asm/barrier.h >>>> +++ b/arch/x86/include/asm/barrier.h >>>> @@ -24,6 +24,14 @@ >>>> #define wmb() asm volatile("sfence" ::: "memory") >>>> #endif >>>> >>>> +/* >>>> + * All data types<= long are atomic in x86 >>>> + */ >>>> +#ifdef __native_word >>>> +#undef __native_word >>>> +#endif >>>> +#define __native_word(t) (sizeof(t)<= sizeof(long)) >>> Yeah, not going to happen. >> Does explicit list of acceptable sizes work for you? >> >> #define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == >> sizeof(short) || sizeof(t) == sizeof(int ) || >> sizeof(t) == sizeof(long)) > No, generic primitives should not have arch specific behaviour.
OK, will something like the following acceptable to you:
arch/x86/include/asm/barrier.h:
#define __arch_native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int ) || sizeof(t) == sizeof(long))
include/linux/compiler.h:
#ifndef __native_word # ifdef __arch_native_word(t) # define __native_word(t) __arch_native_word(t) # else # define __native_word(t) (sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) # endif #endif
-Longman
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