Commit 5e97b930 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Linus Torvalds

local_t: architecture independent extension

This series extena and standardises local_t operations on each architecture,
allowing a rich set of atomic operations to be done on per-cpu data with
minimal performance impact.  On architectures where there seems to be no
difference between the SMP and UP operation (same memory barriers, same
LOCKing), local.h simply includes asm-generic/local.h, which removes
duplicated code from the current kernel tree.

This patch:

local_t: architecture independent extension
Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2856f5e3
...@@ -33,6 +33,19 @@ typedef struct ...@@ -33,6 +33,19 @@ typedef struct
#define local_add(i,l) atomic_long_add((i),(&(l)->a)) #define local_add(i,l) atomic_long_add((i),(&(l)->a))
#define local_sub(i,l) atomic_long_sub((i),(&(l)->a)) #define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
#define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a))
#define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a)
#define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a)
#define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a))
#define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a))
#define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a))
#define local_inc_return(l) atomic_long_inc_return(&(l)->a)
#define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n))
#define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n))
#define local_add_unless(l, a, u) atomic_long_add_unless((&(l)->a), (a), (u))
#define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a)
/* Non-atomic variants, ie. preemption disabled and won't be touched /* Non-atomic variants, ie. preemption disabled and won't be touched
* in interrupt, etc. Some archs can optimize this case well. */ * in interrupt, etc. Some archs can optimize this case well. */
#define __local_inc(l) local_set((l), local_read(l) + 1) #define __local_inc(l) local_set((l), local_read(l) + 1)
...@@ -44,19 +57,19 @@ typedef struct ...@@ -44,19 +57,19 @@ typedef struct
* much more efficient than these naive implementations. Note they take * much more efficient than these naive implementations. Note they take
* a variable (eg. mystruct.foo), not an address. * a variable (eg. mystruct.foo), not an address.
*/ */
#define cpu_local_read(v) local_read(&__get_cpu_var(v)) #define cpu_local_read(l) local_read(&__get_cpu_var(l))
#define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i)) #define cpu_local_set(l, i) local_set(&__get_cpu_var(l), (i))
#define cpu_local_inc(v) local_inc(&__get_cpu_var(v)) #define cpu_local_inc(l) local_inc(&__get_cpu_var(l))
#define cpu_local_dec(v) local_dec(&__get_cpu_var(v)) #define cpu_local_dec(l) local_dec(&__get_cpu_var(l))
#define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v)) #define cpu_local_add(i, l) local_add((i), &__get_cpu_var(l))
#define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v)) #define cpu_local_sub(i, l) local_sub((i), &__get_cpu_var(l))
/* Non-atomic increments, ie. preemption disabled and won't be touched /* Non-atomic increments, ie. preemption disabled and won't be touched
* in interrupt, etc. Some archs can optimize this case well. * in interrupt, etc. Some archs can optimize this case well.
*/ */
#define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v)) #define __cpu_local_inc(l) __local_inc(&__get_cpu_var(l))
#define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v)) #define __cpu_local_dec(l) __local_dec(&__get_cpu_var(l))
#define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v)) #define __cpu_local_add(i, l) __local_add((i), &__get_cpu_var(l))
#define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v)) #define __cpu_local_sub(i, l) __local_sub((i), &__get_cpu_var(l))
#endif /* _ASM_GENERIC_LOCAL_H */ #endif /* _ASM_GENERIC_LOCAL_H */
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