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author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2011-05-23 08:24:32 (GMT) |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2011-05-23 08:24:29 (GMT) |
commit | 4c2241fd42298007d7c3a92318806a4a9490a93c (patch) | |
tree | 13e9af56e8f0badae7c8a238901e542163c115e2 /arch/s390/include | |
parent | add7490c273650c3aa8012f3e082aa64af86f17c (diff) | |
download | linux-4c2241fd42298007d7c3a92318806a4a9490a93c.tar.xz |
[S390] percpu: implement arch specific irqsafe_cpu_ops
Implement arch specific irqsafe_cpu ops. The arch specific ops do not
disable/enable interrupts since that is an expensive operation. Instead
we disable preemption and perform a compare and swap loop.
Since on server distros (the ones we care about) preemption is disabled
the preempt_disable()/preempt_enable() pair is a nop.
In the end this code should be faster than the generic one.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include')
-rw-r--r-- | arch/s390/include/asm/cmpxchg.h | 1 | ||||
-rw-r--r-- | arch/s390/include/asm/percpu.h | 68 |
2 files changed, 68 insertions, 1 deletions
diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h index 7488e52..81d7908 100644 --- a/arch/s390/include/asm/cmpxchg.h +++ b/arch/s390/include/asm/cmpxchg.h @@ -167,7 +167,6 @@ static inline unsigned long __cmpxchg(void *ptr, unsigned long old, #ifdef CONFIG_64BIT #define cmpxchg64(ptr, o, n) \ ({ \ - BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ cmpxchg((ptr), (o), (n)); \ }) #else /* CONFIG_64BIT */ diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h index f7ad871..5325c89 100644 --- a/arch/s390/include/asm/percpu.h +++ b/arch/s390/include/asm/percpu.h @@ -1,6 +1,9 @@ #ifndef __ARCH_S390_PERCPU__ #define __ARCH_S390_PERCPU__ +#include <linux/preempt.h> +#include <asm/cmpxchg.h> + /* * s390 uses its own implementation for per cpu data, the offset of * the cpu local data area is cached in the cpu's lowcore memory. @@ -16,6 +19,71 @@ #define ARCH_NEEDS_WEAK_PER_CPU #endif +#define arch_irqsafe_cpu_to_op(pcp, val, op) \ +do { \ + typedef typeof(pcp) pcp_op_T__; \ + pcp_op_T__ old__, new__, prev__; \ + pcp_op_T__ *ptr__; \ + preempt_disable(); \ + ptr__ = __this_cpu_ptr(&(pcp)); \ + prev__ = *ptr__; \ + do { \ + old__ = prev__; \ + new__ = old__ op (val); \ + switch (sizeof(*ptr__)) { \ + case 8: \ + prev__ = cmpxchg64(ptr__, old__, new__); \ + break; \ + default: \ + prev__ = cmpxchg(ptr__, old__, new__); \ + } \ + } while (prev__ != old__); \ + preempt_enable(); \ +} while (0) + +#define irqsafe_cpu_add_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) +#define irqsafe_cpu_add_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) +#define irqsafe_cpu_add_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) +#define irqsafe_cpu_add_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) + +#define irqsafe_cpu_and_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) +#define irqsafe_cpu_and_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) +#define irqsafe_cpu_and_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) +#define irqsafe_cpu_and_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) + +#define irqsafe_cpu_or_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) +#define irqsafe_cpu_or_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) +#define irqsafe_cpu_or_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) +#define irqsafe_cpu_or_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) + +#define irqsafe_cpu_xor_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) +#define irqsafe_cpu_xor_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) +#define irqsafe_cpu_xor_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) +#define irqsafe_cpu_xor_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) + +#define arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) \ +({ \ + typedef typeof(pcp) pcp_op_T__; \ + pcp_op_T__ ret__; \ + pcp_op_T__ *ptr__; \ + preempt_disable(); \ + ptr__ = __this_cpu_ptr(&(pcp)); \ + switch (sizeof(*ptr__)) { \ + case 8: \ + ret__ = cmpxchg64(ptr__, oval, nval); \ + break; \ + default: \ + ret__ = cmpxchg(ptr__, oval, nval); \ + } \ + preempt_enable(); \ + ret__; \ +}) + +#define irqsafe_cpu_cmpxchg_1(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) +#define irqsafe_cpu_cmpxchg_2(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) +#define irqsafe_cpu_cmpxchg_4(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) +#define irqsafe_cpu_cmpxchg_8(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) + #include <asm-generic/percpu.h> #endif /* __ARCH_S390_PERCPU__ */ |