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s390/perf,oprofile: Share sampling facility

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Introduce reserve/release functions to share the sampling facility
between perf and oprofile.
Also improve error handling for the sampling facility support in perf.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Hendrik Brueckner
2013-12-12 16:52:48 +01:00
committed by Martin Schwidefsky
parent 55baa2f831
commit e28bb79d99
5 changed files with 73 additions and 8 deletions
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30
arch/s390/kernel/perf_event.c
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@@ -208,3 +208,33 @@ ssize_t cpumf_events_sysfs_show(struct device *dev,
return sprintf(page, "event=0x%04llx,name=%s\n",
pmu_attr->id, attr->attr.name);
}
/* Reserve/release functions for sharing perf hardware */
static DEFINE_SPINLOCK(perf_hw_owner_lock);
static void *perf_sampling_owner;
int perf_reserve_sampling(void)
{
int err;
err = 0;
spin_lock(&perf_hw_owner_lock);
if (perf_sampling_owner) {
pr_warn("The sampling facility is already reserved by %p\n",
perf_sampling_owner);
err = -EBUSY;
} else
perf_sampling_owner = __builtin_return_address(0);
spin_unlock(&perf_hw_owner_lock);
return err;
}
EXPORT_SYMBOL(perf_reserve_sampling);
void perf_release_sampling(void)
{
spin_lock(&perf_hw_owner_lock);
WARN_ON(!perf_sampling_owner);
perf_sampling_owner = NULL;
spin_unlock(&perf_hw_owner_lock);
}
EXPORT_SYMBOL(perf_release_sampling);