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perf_events: Fix validation of events using an extra reg

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The validate_group() function needs to validate events with
extra shared regs. Within an event group, only events with
the same value for the extra reg can co-exist. This was not
checked by validate_group() because it was missing the
shared_regs logic.

This patch changes the allocation of the fake cpuc used for
validation to also point to a fake shared_regs structure such
that group events be properly testing.

It modifies __intel_shared_reg_get_constraints() to use
spin_lock_irqsave() to avoid lockdep issues.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110606145708.GA7279@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Stephane Eranian
2011-06-06 16:57:08 +02:00
committed by Ingo Molnar
parent efc9f05df2
commit cd8a38d33e
2 changed files with 57 additions and 18 deletions
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59
arch/x86/kernel/cpu/perf_event.c
View File

@@ -1689,6 +1689,40 @@ static int x86_pmu_commit_txn(struct pmu *pmu)
perf_pmu_enable(pmu);
return 0;
}
/*
* a fake_cpuc is used to validate event groups. Due to
* the extra reg logic, we need to also allocate a fake
* per_core and per_cpu structure. Otherwise, group events
* using extra reg may conflict without the kernel being
* able to catch this when the last event gets added to
* the group.
*/
static void free_fake_cpuc(struct cpu_hw_events *cpuc)
{
kfree(cpuc->shared_regs);
kfree(cpuc);
}
static struct cpu_hw_events *allocate_fake_cpuc(void)
{
struct cpu_hw_events *cpuc;
int cpu = raw_smp_processor_id();
cpuc = kzalloc(sizeof(*cpuc), GFP_KERNEL);
if (!cpuc)
return ERR_PTR(-ENOMEM);
/* only needed, if we have extra_regs */
if (x86_pmu.extra_regs) {
cpuc->shared_regs = allocate_shared_regs(cpu);
if (!cpuc->shared_regs)
goto error;
}
return cpuc;
error:
free_fake_cpuc(cpuc);
return ERR_PTR(-ENOMEM);
}
/*
* validate that we can schedule this event
@@ -1699,9 +1733,9 @@ static int validate_event(struct perf_event *event)
struct event_constraint *c;
int ret = 0;
fake_cpuc = kmalloc(sizeof(*fake_cpuc), GFP_KERNEL | __GFP_ZERO);
if (!fake_cpuc)
return -ENOMEM;
fake_cpuc = allocate_fake_cpuc();
if (IS_ERR(fake_cpuc))
return PTR_ERR(fake_cpuc);
c = x86_pmu.get_event_constraints(fake_cpuc, event);
@@ -1711,7 +1745,7 @@ static int validate_event(struct perf_event *event)
if (x86_pmu.put_event_constraints)
x86_pmu.put_event_constraints(fake_cpuc, event);
kfree(fake_cpuc);
free_fake_cpuc(fake_cpuc);
return ret;
}
@@ -1731,35 +1765,32 @@ static int validate_group(struct perf_event *event)
{
struct perf_event *leader = event->group_leader;
struct cpu_hw_events *fake_cpuc;
int ret, n;
int ret = -ENOSPC, n;
ret = -ENOMEM;
fake_cpuc = kmalloc(sizeof(*fake_cpuc), GFP_KERNEL | __GFP_ZERO);
if (!fake_cpuc)
goto out;
fake_cpuc = allocate_fake_cpuc();
if (IS_ERR(fake_cpuc))
return PTR_ERR(fake_cpuc);
/*
* the event is not yet connected with its
* siblings therefore we must first collect
* existing siblings, then add the new event
* before we can simulate the scheduling
*/
ret = -ENOSPC;
n = collect_events(fake_cpuc, leader, true);
if (n < 0)
goto out_free;
goto out;
fake_cpuc->n_events = n;
n = collect_events(fake_cpuc, event, false);
if (n < 0)
goto out_free;
goto out;
fake_cpuc->n_events = n;
ret = x86_pmu.schedule_events(fake_cpuc, n, NULL);
out_free:
kfree(fake_cpuc);
out:
free_fake_cpuc(fake_cpuc);
return ret;
}