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perf_counter, x86: generic use of cpuc->active 

cpuc->active will now be used to indicate an enabled counter which
implies also valid pointers of cpuc->counters[]. In contrast,
cpuc->used only locks the counter, but it can be still uninitialized.

[ Impact: refactor and generalize code ]

Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1241002046-8832-20-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Robert Richter 2009-04-29 12:47:16 +02:00 committed by Ingo Molnar
parent 9390496693
commit 095342389e
1 changed files with 9 additions and 11 deletions
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20
arch/x86/kernel/cpu/perf_counter.c
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@ -424,7 +424,6 @@ static void amd_pmu_enable_counter(int idx, u64 config)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
set_bit(idx, cpuc->active);
if (cpuc->enabled)
config |= ARCH_PERFMON_EVENTSEL0_ENABLE;
@ -446,9 +445,6 @@ static void intel_pmu_disable_counter(int idx, u64 config)
static void amd_pmu_disable_counter(int idx, u64 config)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
clear_bit(idx, cpuc->active);
wrmsrl(MSR_K7_EVNTSEL0 + idx, config);
}
@ -633,10 +629,7 @@ static int x86_pmu_enable(struct perf_counter *counter)
__x86_pmu_disable(counter, hwc, idx);
cpuc->counters[idx] = counter;
/*
* Make it visible before enabling the hw:
*/
barrier();
set_bit(idx, cpuc->active);
x86_perf_counter_set_period(counter, hwc, idx);
__x86_pmu_enable(counter, hwc, idx);
@ -700,10 +693,13 @@ static void x86_pmu_disable(struct perf_counter *counter)
struct hw_perf_counter *hwc = &counter->hw;
unsigned int idx = hwc->idx;
/*
* Must be done before we disable, otherwise the nmi handler
* could reenable again:
*/
clear_bit(idx, cpuc->active);
__x86_pmu_disable(counter, hwc, idx);
clear_bit(idx, cpuc->used);
cpuc->counters[idx] = NULL;
/*
* Make sure the cleared pointer becomes visible before we
* (potentially) free the counter:
@ -715,6 +711,8 @@ static void x86_pmu_disable(struct perf_counter *counter)
* that we are disabling:
*/
x86_perf_counter_update(counter, hwc, idx);
cpuc->counters[idx] = NULL;
clear_bit(idx, cpuc->used);
}
/*
@ -763,7 +761,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs, int nmi)
struct perf_counter *counter = cpuc->counters[bit];
clear_bit(bit, (unsigned long *) &status);
if (!counter)
if (!test_bit(bit, cpuc->active))
continue;
intel_pmu_save_and_restart(counter);