Release 4.8 arch/x86/include/asm/mutex_64.h
/*
* Assembly implementation of the mutex fastpath, based on atomic
* decrement/increment.
*
* started by Ingo Molnar:
*
* Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#ifndef _ASM_X86_MUTEX_64_H
#define _ASM_X86_MUTEX_64_H
/**
* __mutex_fastpath_lock - decrement and call function if negative
* @v: pointer of type atomic_t
* @fail_fn: function to call if the result is negative
*
* Atomically decrements @v and calls <fail_fn> if the result is negative.
*/
#ifdef CC_HAVE_ASM_GOTO
static inline void __mutex_fastpath_lock(atomic_t *v,
void (*fail_fn)(atomic_t *))
{
asm_volatile_goto(LOCK_PREFIX " decl %0\n"
" jns %l[exit]\n"
: : "m" (v->counter)
: "memory", "cc"
: exit);
fail_fn(v);
exit:
return;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| wedson almeida filho | wedson almeida filho | 32 | 64.00% | 1 | 50.00% |
| ingo molnar | ingo molnar | 18 | 36.00% | 1 | 50.00% |
| Total | 50 | 100.00% | 2 | 100.00% |
#else
#define __mutex_fastpath_lock(v, fail_fn) \
do { \
unsigned long dummy; \
\
typecheck(atomic_t *, v); \
typecheck_fn(void (*)(atomic_t *), fail_fn); \
\
asm volatile(LOCK_PREFIX " decl (%%rdi)\n" \
" jns 1f \n" \
" call " #fail_fn "\n" \
"1:" \
: "=D" (dummy) \
: "D" (v) \
: "rax", "rsi", "rdx", "rcx", \
"r8", "r9", "r10", "r11", "memory"); \
} while (0)
#endif
/**
* __mutex_fastpath_lock_retval - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
*
* Change the count from 1 to a value lower than 1. This function returns 0
* if the fastpath succeeds, or -1 otherwise.
*/
static inline int __mutex_fastpath_lock_retval(atomic_t *count)
{
if (unlikely(atomic_dec_return(count) < 0))
return -1;
else
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| ingo molnar | ingo molnar | 26 | 83.87% | 2 | 50.00% |
| glauber de oliveira costa | glauber de oliveira costa | 3 | 9.68% | 1 | 25.00% |
| maarten lankhorst | maarten lankhorst | 2 | 6.45% | 1 | 25.00% |
| Total | 31 | 100.00% | 4 | 100.00% |
/**
* __mutex_fastpath_unlock - increment and call function if nonpositive
* @v: pointer of type atomic_t
* @fail_fn: function to call if the result is nonpositive
*
* Atomically increments @v and calls <fail_fn> if the result is nonpositive.
*/
#ifdef CC_HAVE_ASM_GOTO
static inline void __mutex_fastpath_unlock(atomic_t *v,
void (*fail_fn)(atomic_t *))
{
asm_volatile_goto(LOCK_PREFIX " incl %0\n"
" jg %l[exit]\n"
: : "m" (v->counter)
: "memory", "cc"
: exit);
fail_fn(v);
exit:
return;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| wedson almeida filho | wedson almeida filho | 32 | 64.00% | 1 | 50.00% |
| ingo molnar | ingo molnar | 18 | 36.00% | 1 | 50.00% |
| Total | 50 | 100.00% | 2 | 100.00% |
#else
#define __mutex_fastpath_unlock(v, fail_fn) \
do { \
unsigned long dummy; \
\
typecheck(atomic_t *, v); \
typecheck_fn(void (*)(atomic_t *), fail_fn); \
\
asm volatile(LOCK_PREFIX " incl (%%rdi)\n" \
" jg 1f\n" \
" call " #fail_fn "\n" \
"1:" \
: "=D" (dummy) \
: "D" (v) \
: "rax", "rsi", "rdx", "rcx", \
"r8", "r9", "r10", "r11", "memory"); \
} while (0)
#endif
#define __mutex_slowpath_needs_to_unlock() 1
/**
* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
*
* @count: pointer of type atomic_t
* @fail_fn: fallback function
*
* Change the count from 1 to 0 and return 1 (success), or return 0 (failure)
* if it wasn't 1 originally. [the fallback function is never used on
* x86_64, because all x86_64 CPUs have a CMPXCHG instruction.]
*/
static inline int __mutex_fastpath_trylock(atomic_t *count,
int (*fail_fn)(atomic_t *))
{
if (likely(atomic_read(count) == 1 && atomic_cmpxchg(count, 1, 0) == 1))
return 1;
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| ingo molnar | ingo molnar | 42 | 84.00% | 2 | 50.00% |
| peter zijlstra | peter zijlstra | 7 | 14.00% | 1 | 25.00% |
| linus torvalds | linus torvalds | 1 | 2.00% | 1 | 25.00% |
| Total | 50 | 100.00% | 4 | 100.00% |
#endif /* _ASM_X86_MUTEX_64_H */
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| ingo molnar | ingo molnar | 137 | 58.55% | 2 | 22.22% |
| wedson almeida filho | wedson almeida filho | 78 | 33.33% | 1 | 11.11% |
| peter zijlstra | peter zijlstra | 7 | 2.99% | 1 | 11.11% |
| h. peter anvin | h. peter anvin | 3 | 1.28% | 1 | 11.11% |
| maarten lankhorst | maarten lankhorst | 3 | 1.28% | 1 | 11.11% |
| glauber de oliveira costa | glauber de oliveira costa | 3 | 1.28% | 1 | 11.11% |
| joe perches | joe perches | 2 | 0.85% | 1 | 11.11% |
| linus torvalds | linus torvalds | 1 | 0.43% | 1 | 11.11% |
| Total | 234 | 100.00% | 9 | 100.00% |
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