Messages in this thread Patch in this message | | | Date | Tue, 30 Nov 2010 19:11:45 +0100 | From | Tejun Heo <> | Subject | [PATCH UPDATED#2 04/16] x86: Use local variable to cache smp_processor_id() in setup_local_APIC() |
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This is a trivial clean up.
* Move initialization of @cpu inside preemption disabled region as suggested by Cyrill Gorcunov.
Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> --- Alright, updated yet again, but I frankly don't see the point in these changes. If setup_local_APIC() is being run from a different CPU, we have a much larger problem. We're already accessing cpu local resources (tsc, lapic) outside of preemption disabled area. But, anyways, I don't think it matters one way or the other.
Thanks.
arch/x86/kernel/apic/apic.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
Index: work/arch/x86/kernel/apic/apic.c =================================================================== --- work.orig/arch/x86/kernel/apic/apic.c +++ work/arch/x86/kernel/apic/apic.c @@ -1202,7 +1202,7 @@ static void __cpuinit lapic_setup_esr(vo void __cpuinit setup_local_APIC(void) { unsigned int value, queued; - int i, j, acked = 0; + int cpu, i, j, acked = 0; unsigned long long tsc = 0, ntsc; long long max_loops = cpu_khz;
@@ -1226,6 +1226,7 @@ void __cpuinit setup_local_APIC(void) perf_events_lapic_init();
preempt_disable(); + cpu = smp_processor_id();
/* * Double-check whether this APIC is really registered. @@ -1342,21 +1343,19 @@ void __cpuinit setup_local_APIC(void) * TODO: set up through-local-APIC from through-I/O-APIC? --macro */ value = apic_read(APIC_LVT0) & APIC_LVT_MASKED; - if (!smp_processor_id() && (pic_mode || !value)) { + if (!cpu && (pic_mode || !value)) { value = APIC_DM_EXTINT; - apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", - smp_processor_id()); + apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", cpu); } else { value = APIC_DM_EXTINT | APIC_LVT_MASKED; - apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n", - smp_processor_id()); + apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n", cpu); } apic_write(APIC_LVT0, value);
/* * only the BP should see the LINT1 NMI signal, obviously. */ - if (!smp_processor_id()) + if (!cpu) value = APIC_DM_NMI; else value = APIC_DM_NMI | APIC_LVT_MASKED;
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