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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /include/linux/prefetch.h | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'include/linux/prefetch.h')
-rw-r--r-- | include/linux/prefetch.h | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/include/linux/prefetch.h b/include/linux/prefetch.h new file mode 100644 index 00000000..a3bfbdf6 --- /dev/null +++ b/include/linux/prefetch.h @@ -0,0 +1,64 @@ +/* + * Generic cache management functions. Everything is arch-specific, + * but this header exists to make sure the defines/functions can be + * used in a generic way. + * + * 2000-11-13 Arjan van de Ven <arjan@fenrus.demon.nl> + * + */ + +#ifndef _LINUX_PREFETCH_H +#define _LINUX_PREFETCH_H + +#include <linux/types.h> +#include <asm/processor.h> +#include <asm/cache.h> + +/* + prefetch(x) attempts to pre-emptively get the memory pointed to + by address "x" into the CPU L1 cache. + prefetch(x) should not cause any kind of exception, prefetch(0) is + specifically ok. + + prefetch() should be defined by the architecture, if not, the + #define below provides a no-op define. + + There are 3 prefetch() macros: + + prefetch(x) - prefetches the cacheline at "x" for read + prefetchw(x) - prefetches the cacheline at "x" for write + spin_lock_prefetch(x) - prefetches the spinlock *x for taking + + there is also PREFETCH_STRIDE which is the architecure-preferred + "lookahead" size for prefetching streamed operations. + +*/ + +#ifndef ARCH_HAS_PREFETCH +#define prefetch(x) __builtin_prefetch(x) +#endif + +#ifndef ARCH_HAS_PREFETCHW +#define prefetchw(x) __builtin_prefetch(x,1) +#endif + +#ifndef ARCH_HAS_SPINLOCK_PREFETCH +#define spin_lock_prefetch(x) prefetchw(x) +#endif + +#ifndef PREFETCH_STRIDE +#define PREFETCH_STRIDE (4*L1_CACHE_BYTES) +#endif + +static inline void prefetch_range(void *addr, size_t len) +{ +#ifdef ARCH_HAS_PREFETCH + char *cp; + char *end = addr + len; + + for (cp = addr; cp < end; cp += PREFETCH_STRIDE) + prefetch(cp); +#endif +} + +#endif |