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authorSrikant Patnaik2015-01-11 12:28:04 +0530
committerSrikant Patnaik2015-01-11 12:28:04 +0530
commit871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch)
tree8718f573808810c2a1e8cb8fb6ac469093ca2784 /include/linux/prefetch.h
parent9d40ac5867b9aefe0722bc1f110b965ff294d30d (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')
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diff --git a/include/linux/prefetch.h b/include/linux/prefetch.h
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+/*
+ * 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