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authorIngo Molnar <mingo@elte.hu>2009-01-15 22:15:53 +0900
committerIngo Molnar <mingo@elte.hu>2009-01-16 14:20:31 +0100
commit6dbde3530850d4d8bfc1b6bd4006d92786a2787f (patch)
tree08c6dd55e860827311b889e2ecfe3de9f51421a0 /arch/x86/mach-voyager
parent004aa322f855a765741d9437a98dd8fe2e4f32a6 (diff)
percpu: add optimized generic percpu accessors
It is an optimization and a cleanup, and adds the following new generic percpu methods: percpu_read() percpu_write() percpu_add() percpu_sub() percpu_and() percpu_or() percpu_xor() and implements support for them on x86. (other architectures will fall back to a default implementation) The advantage is that for example to read a local percpu variable, instead of this sequence: return __get_cpu_var(var); ffffffff8102ca2b: 48 8b 14 fd 80 09 74 mov -0x7e8bf680(,%rdi,8),%rdx ffffffff8102ca32: 81 ffffffff8102ca33: 48 c7 c0 d8 59 00 00 mov $0x59d8,%rax ffffffff8102ca3a: 48 8b 04 10 mov (%rax,%rdx,1),%rax We can get a single instruction by using the optimized variants: return percpu_read(var); ffffffff8102ca3f: 65 48 8b 05 91 8f fd mov %gs:0x7efd8f91(%rip),%rax I also cleaned up the x86-specific APIs and made the x86 code use these new generic percpu primitives. tj: * fixed generic percpu_sub() definition as Roel Kluin pointed out * added percpu_and() for completeness's sake * made generic percpu ops atomic against preemption Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'arch/x86/mach-voyager')
-rw-r--r--arch/x86/mach-voyager/voyager_smp.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/mach-voyager/voyager_smp.c b/arch/x86/mach-voyager/voyager_smp.c
index 1a48368acb0..96f15b09a4c 100644
--- a/arch/x86/mach-voyager/voyager_smp.c
+++ b/arch/x86/mach-voyager/voyager_smp.c
@@ -402,7 +402,7 @@ void __init find_smp_config(void)
VOYAGER_SUS_IN_CONTROL_PORT);
current_thread_info()->cpu = boot_cpu_id;
- x86_write_percpu(cpu_number, boot_cpu_id);
+ percpu_write(cpu_number, boot_cpu_id);
}
/*
@@ -1782,7 +1782,7 @@ static void __init voyager_smp_cpus_done(unsigned int max_cpus)
void __init smp_setup_processor_id(void)
{
current_thread_info()->cpu = hard_smp_processor_id();
- x86_write_percpu(cpu_number, hard_smp_processor_id());
+ percpu_write(cpu_number, hard_smp_processor_id());
}
static void voyager_send_call_func(cpumask_t callmask)