| Message ID | 1395330365-9901-1-git-send-email-ian.campbell@citrix.com |
|---|---|
| State | Superseded |
| Headers | show |
>>> On 20.03.14 at 16:45, Ian Campbell <ian.campbell@citrix.com> wrote: > Quoting Andi Kleen in Linux b483570a13be from 2007: > gcc 3.2+ supports __builtin_prefetch, so it's possible to use it on all > architectures. Change the generic fallback in linux/prefetch.h to use it > instead of noping it out. gcc should do the right thing when the > architecture doesn't support prefetching > > Undefine the x86-64 inline assembler version and use the fallback. > > ARM wants to use the builtins. > > Fix a pair of spelling errors, one of which was from Lucas De Marchi in the > Linux tree. > > Signed-off-by: Ian Campbell <ian.campbell@citrix.com> > Cc: Keir Fraser <keir@xen.org> Reviewed-by: Jan Beulich <jbeulich@suse.com> > --- > xen/include/xen/prefetch.h | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) > > diff --git a/xen/include/xen/prefetch.h b/xen/include/xen/prefetch.h > index 8d7d3ff..ba73998 100644 > --- a/xen/include/xen/prefetch.h > +++ b/xen/include/xen/prefetch.h > @@ -28,24 +28,17 @@ > prefetchw(x) - prefetches the cacheline at "x" for write > spin_lock_prefetch(x) - prefectches the spinlock *x for taking > > - there is also PREFETCH_STRIDE which is the architecure-prefered > + there is also PREFETCH_STRIDE which is the architecture-preferred > "lookahead" size for prefetching streamed operations. > > */ > > -/* > - * These cannot be do{}while(0) macros. See the mental gymnastics in > - * the loop macro. > - */ > - > #ifndef ARCH_HAS_PREFETCH > -#define ARCH_HAS_PREFETCH > -static inline void prefetch(const void *x) {;} > +#define prefetch(x) __builtin_prefetch(x) > #endif > > #ifndef ARCH_HAS_PREFETCHW > -#define ARCH_HAS_PREFETCHW > -static inline void prefetchw(const void *x) {;} > +#define prefetchw(x) __builtin_prefetch(x,1) > #endif > > #ifndef ARCH_HAS_SPINLOCK_PREFETCH > -- > 1.7.10.4
diff --git a/xen/include/xen/prefetch.h b/xen/include/xen/prefetch.h index 8d7d3ff..ba73998 100644 --- a/xen/include/xen/prefetch.h +++ b/xen/include/xen/prefetch.h @@ -28,24 +28,17 @@ prefetchw(x) - prefetches the cacheline at "x" for write spin_lock_prefetch(x) - prefectches the spinlock *x for taking - there is also PREFETCH_STRIDE which is the architecure-prefered + there is also PREFETCH_STRIDE which is the architecture-preferred "lookahead" size for prefetching streamed operations. */ -/* - * These cannot be do{}while(0) macros. See the mental gymnastics in - * the loop macro. - */ - #ifndef ARCH_HAS_PREFETCH -#define ARCH_HAS_PREFETCH -static inline void prefetch(const void *x) {;} +#define prefetch(x) __builtin_prefetch(x) #endif #ifndef ARCH_HAS_PREFETCHW -#define ARCH_HAS_PREFETCHW -static inline void prefetchw(const void *x) {;} +#define prefetchw(x) __builtin_prefetch(x,1) #endif #ifndef ARCH_HAS_SPINLOCK_PREFETCH
Quoting Andi Kleen in Linux b483570a13be from 2007: gcc 3.2+ supports __builtin_prefetch, so it's possible to use it on all architectures. Change the generic fallback in linux/prefetch.h to use it instead of noping it out. gcc should do the right thing when the architecture doesn't support prefetching Undefine the x86-64 inline assembler version and use the fallback. ARM wants to use the builtins. Fix a pair of spelling errors, one of which was from Lucas De Marchi in the Linux tree. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Keir Fraser <keir@xen.org> Cc: Jan Beulich <jbeulich@suse.com> --- xen/include/xen/prefetch.h | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-)