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authorJeff Garzik <jeff@garzik.org>2006-03-29 17:18:49 -0500
committerJeff Garzik <jeff@garzik.org>2006-03-29 17:18:49 -0500
commite02a4cabfcb9a999b74a2e2e6f13ffcb7ff2d606 (patch)
tree2f3db60be4c57eca2a4c3ab3f3122dcf1ec0c624 /include/asm-generic/bitops/sched.h
parent600511e86babe3727264a0883a3a264f6fb6caf5 (diff)
parentf3cab8a0b1a772dc8b055b7affa567a366627c9e (diff)
Merge branch 'master'
Diffstat (limited to 'include/asm-generic/bitops/sched.h')
-rw-r--r--include/asm-generic/bitops/sched.h36
1 files changed, 36 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/sched.h b/include/asm-generic/bitops/sched.h
new file mode 100644
index 00000000000..5ef93a4d009
--- /dev/null
+++ b/include/asm-generic/bitops/sched.h
@@ -0,0 +1,36 @@
+#ifndef _ASM_GENERIC_BITOPS_SCHED_H_
+#define _ASM_GENERIC_BITOPS_SCHED_H_
+
+#include <linux/compiler.h> /* unlikely() */
+#include <asm/types.h>
+
+/*
+ * Every architecture must define this function. It's the fastest
+ * way of searching a 140-bit bitmap where the first 100 bits are
+ * unlikely to be set. It's guaranteed that at least one of the 140
+ * bits is cleared.
+ */
+static inline int sched_find_first_bit(const unsigned long *b)
+{
+#if BITS_PER_LONG == 64
+ if (unlikely(b[0]))
+ return __ffs(b[0]);
+ if (unlikely(b[1]))
+ return __ffs(b[1]) + 64;
+ return __ffs(b[2]) + 128;
+#elif BITS_PER_LONG == 32
+ if (unlikely(b[0]))
+ return __ffs(b[0]);
+ if (unlikely(b[1]))
+ return __ffs(b[1]) + 32;
+ if (unlikely(b[2]))
+ return __ffs(b[2]) + 64;
+ if (b[3])
+ return __ffs(b[3]) + 96;
+ return __ffs(b[4]) + 128;
+#else
+#error BITS_PER_LONG not defined
+#endif
+}
+
+#endif /* _ASM_GENERIC_BITOPS_SCHED_H_ */