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s390/atomic: optimize atomic_add() for constant values 

If the interlocked-access facility 1 is available we can use the asi
and agsi instructions for interlocked updates if the to be added
value is a contanst and small (in the range of -128..127).
asi and agsi do not not return the old or new value, therefore these
instructions can only be used for atomic_(add|sub|inc|dec)[64].

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2013-09-16 10:44:54 +02:00 committed by Martin Schwidefsky
parent eddf0d5b31
commit 5692e4d11c
1 changed files with 40 additions and 8 deletions
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48
arch/s390/include/asm/atomic.h
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@ -82,15 +82,31 @@ static inline int atomic_add_return(int i, atomic_t *v)
return __ATOMIC_LOOP(v, i, __ATOMIC_ADD) + i;
}
#define atomic_add(_i, _v) atomic_add_return(_i, _v)
static inline void atomic_add(int i, atomic_t *v)
{
#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
if (__builtin_constant_p(i) && (i > -129) && (i < 128)) {
asm volatile(
"asi %0,%1\n"
: "+Q" (v->counter)
: "i" (i)
: "cc", "memory");
} else {
atomic_add_return(i, v);
}
#else
atomic_add_return(i, v);
#endif
}
#define atomic_add_negative(_i, _v) (atomic_add_return(_i, _v) < 0)
#define atomic_inc(_v) atomic_add_return(1, _v)
#define atomic_inc(_v) atomic_add(1, _v)
#define atomic_inc_return(_v) atomic_add_return(1, _v)
#define atomic_inc_and_test(_v) (atomic_add_return(1, _v) == 0)
#define atomic_sub(_i, _v) atomic_add(-(int)(_i), _v)
#define atomic_sub_return(_i, _v) atomic_add_return(-(int)(_i), _v)
#define atomic_sub(_i, _v) atomic_sub_return(_i, _v)
#define atomic_sub_and_test(_i, _v) (atomic_sub_return(_i, _v) == 0)
#define atomic_dec(_v) atomic_sub_return(1, _v)
#define atomic_dec(_v) atomic_sub(1, _v)
#define atomic_dec_return(_v) atomic_sub_return(1, _v)
#define atomic_dec_and_test(_v) (atomic_sub_return(1, _v) == 0)
@ -314,6 +330,23 @@ static inline void atomic64_clear_mask(unsigned long long mask, atomic64_t *v)
#endif /* CONFIG_64BIT */
static inline void atomic64_add(long long i, atomic64_t *v)
{
#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
if (__builtin_constant_p(i) && (i > -129) && (i < 128)) {
asm volatile(
"agsi %0,%1\n"
: "+Q" (v->counter)
: "i" (i)
: "cc", "memory");
} else {
atomic64_add_return(i, v);
}
#else
atomic64_add_return(i, v);
#endif
}
static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u)
{
long long c, old;
@ -347,15 +380,14 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v)
return dec;
}
#define atomic64_add(_i, _v) atomic64_add_return(_i, _v)
#define atomic64_add_negative(_i, _v) (atomic64_add_return(_i, _v) < 0)
#define atomic64_inc(_v) atomic64_add_return(1, _v)
#define atomic64_inc(_v) atomic64_add(1, _v)
#define atomic64_inc_return(_v) atomic64_add_return(1, _v)
#define atomic64_inc_and_test(_v) (atomic64_add_return(1, _v) == 0)
#define atomic64_sub_return(_i, _v) atomic64_add_return(-(long long)(_i), _v)
#define atomic64_sub(_i, _v) atomic64_sub_return(_i, _v)
#define atomic64_sub(_i, _v) atomic64_add(-(long long)(_i), _v)
#define atomic64_sub_and_test(_i, _v) (atomic64_sub_return(_i, _v) == 0)
#define atomic64_dec(_v) atomic64_sub_return(1, _v)
#define atomic64_dec(_v) atomic64_sub(1, _v)
#define atomic64_dec_return(_v) atomic64_sub_return(1, _v)
#define atomic64_dec_and_test(_v) (atomic64_sub_return(1, _v) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)