diff mbox series

[3/3] perf: arm_spe: Only show online CPUs in device's "cpumask" attribute

Message ID 20240603092812.46616-4-yangyicong@huawei.com (mailing list archive)
State New, archived
Headers show
Series Perf avoid opening events on offline CPUs | expand

Commit Message

Yicong Yang June 3, 2024, 9:28 a.m. UTC 
From: Yicong Yang <yangyicong@hisilicon.com>

When there're CPUs offline after system booting, perf will failed:
[root@localhost ~]# /home/yang/perf record -e arm_spe_0//
Error:
The sys_perf_event_open() syscall returned with 19 (No such device) for event (arm_spe_0//).
/bin/dmesg | grep -i perf may provide additional information.

This is due to PMU's "cpumask" is not updated and still contains offline
CPUs and perf will try to open perf event on the offlined CPUs.

Make "cpumask" attribute only shows online CPUs and introduced a new
"supported_cpus" where users can get the range of the CPUs this
PMU supported monitoring.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
---
 drivers/perf/arm_spe_pmu.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index 9100d82bfabc..2182f214c587 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c
@@ -254,13 +254,33 @@  static ssize_t cpumask_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
 	struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
+	cpumask_var_t mask;
+	ssize_t n;
 
-	return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
+	/* If allocation failed then show the supported_cpus */
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
+
+	cpumask_and(mask, &spe_pmu->supported_cpus, cpu_online_mask);
+	n = cpumap_print_to_pagebuf(true, buf, mask);
+	free_cpumask_var(mask);
+
+	return n;
 }
 static DEVICE_ATTR_RO(cpumask);
 
+static ssize_t supported_cpus_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
+
+	return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
+}
+static DEVICE_ATTR_RO(supported_cpus);
+
 static struct attribute *arm_spe_pmu_attrs[] = {
 	&dev_attr_cpumask.attr,
+	&dev_attr_supported_cpus.attr,
 	NULL,
 };