Gecko [ dataharbor.africa ]

Name	Size	Permission
addr-map.c	525 B	-rw-r--r--
alloc.c	1.16 KB	-rw-r--r--
arith.c	2.24 KB	-rw-r--r--
common_session_state.h	6.76 KB	-rw-r--r--
copy.c	4 KB	-rw-r--r--
debug.h	413 B	-rw-r--r--
ilog2.h	2.87 KB	-rw-r--r--
io.c	4.43 KB	-rw-r--r--
linux_defs.h	5.58 KB	-rw-r--r--
linux_hash.h	1.83 KB	-rw-r--r--
linux_types.h	654 B	-rw-r--r--
loc2c-runtime.h	2.44 KB	-rw-r--r--
map_list.h	1.03 KB	-rw-r--r--
map_runtime.h	5.04 KB	-rw-r--r--
namespaces.h	0 B	-rw-r--r--
offptr.h	4.68 KB	-rw-r--r--
offset_list.h	4.32 KB	-rw-r--r--
perf.c	0 B	-rw-r--r--
print.c	2.37 KB	-rw-r--r--
probe_lock.h	1.81 KB	-rw-r--r--
regs.c	2.14 KB	-rw-r--r--
runtime.h	9.49 KB	-rw-r--r--
runtime_context.h	6.4 KB	-rw-r--r--
runtime_defines.h	235 B	-rw-r--r--
session_attributes.c	1.68 KB	-rw-r--r--
session_attributes.h	772 B	-rw-r--r--
shm.c	6.03 KB	-rw-r--r--
stapdyn.h	3.37 KB	-rw-r--r--
stat_runtime.h	1.79 KB	-rw-r--r--
sym.c	40 B	-rw-r--r--
task_finder.c	0 B	-rw-r--r--
timer.c	2.71 KB	-rw-r--r--
transport.c	30.4 KB	-rw-r--r--
transport.h	3.88 KB	-rw-r--r--
unwind.c	0 B	-rw-r--r--
uprobes-regs.c	1.94 KB	-rw-r--r--
uprobes.c	1.76 KB	-rw-r--r--
uprobes.h	953 B	-rw-r--r--

Code Editor : linux_hash.h

#ifndef _LINUX_HASH_H
#define _LINUX_HASH_H
/* Fast hashing routine for ints,  longs and pointers.
   (C) 2002 William Lee Irwin III, IBM */

/*
 * Knuth recommends primes in approximately golden ratio to the maximum
 * integer representable by a machine word for multiplicative hashing.
 * Chuck Lever verified the effectiveness of this technique:
 * http://www.citi.umich.edu/techreports/reports/citi-tr-00-1.pdf
 *
 * These primes are chosen to be bit-sparse, that is operations on
 * them can use shifts and additions instead of multiplications for
 * machines where multiplications are slow.
 */

#include <asm/types.h>

/* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */
#define GOLDEN_RATIO_PRIME_32 0x9e370001UL
/*  2^63 + 2^61 - 2^57 + 2^54 - 2^51 - 2^18 + 1 */
#define GOLDEN_RATIO_PRIME_64 0x9e37fffffffc0001UL

#if BITS_PER_LONG == 32
#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_PRIME_32
#define hash_long(val, bits) hash_32(val, bits)
#elif BITS_PER_LONG == 64
#define hash_long(val, bits) hash_64(val, bits)
#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_PRIME_64
#else
#error Wordsize not 32 or 64
#endif

static inline u64 hash_64(u64 val, unsigned int bits)
{
	u64 hash = val;

/*  Sigh, gcc can't optimise this alone like it does for 32 bits. */
	u64 n = hash;
	n <<= 18;
	hash -= n;
	n <<= 33;
	hash -= n;
	n <<= 3;
	hash += n;
	n <<= 3;
	hash -= n;
	n <<= 4;
	hash += n;
	n <<= 2;
	hash += n;

/* High bits are more random, so use them. */
	return hash >> (64 - bits);
}

static inline u32 hash_32(u32 val, unsigned int bits)
{
	/* On some cpus multiply is faster, on others gcc will do shifts */
	u32 hash = val * GOLDEN_RATIO_PRIME_32;

/* High bits are more random, so use them. */
	return hash >> (32 - bits);
}

static inline unsigned long hash_ptr(const void *ptr, unsigned int bits)
{
	return hash_long((unsigned long)ptr, bits);
}
#endif /* _LINUX_HASH_H */

${this.title}

Code Editor : linux_hash.h