On 6/28/21 3:47 PM, Kajol Jain wrote:

The performance reporting driver added cpu hotplug feature but it didn't add pmu migration call in cpu offline function. This can create an issue incase the current designated cpu being used to collect fme pmu data got offline, as based on current code we are not migrating fme pmu to new target cpu. Because of that perf will still try to fetch data from that offline cpu and hence we will not get counter data.

Patch fixed this issue by adding pmu_migrate_context call in fme_perf_offline_cpu function.

Adding stable@vger.kernel.org in cc list as suggested by Moritz Fischer.

Thanks, Kajol Jain

Fixes: 724142f8c42a ("fpga: dfl: fme: add performance reporting support") Tested-by: Xu Yilun yilun.xu@intel.com Signed-off-by: Kajol Jain kjain@linux.ibm.com

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drivers/fpga/dfl-fme-perf.c | 4 ++++ 1 file changed, 4 insertions(+)

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Changelog:

• Remove RFC tag
• Did nits changes on subject and commit message as suggested by Xu Yilun
• Added Tested-by tag
• Link to rfc patch: https://lkml.org/lkml/2021/6/28/112

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diff --git a/drivers/fpga/dfl-fme-perf.c b/drivers/fpga/dfl-fme-perf.c index 4299145ef347..b9a54583e505 100644 --- a/drivers/fpga/dfl-fme-perf.c +++ b/drivers/fpga/dfl-fme-perf.c @@ -953,6 +953,10 @@ static int fme_perf_offline_cpu(unsigned int cpu, struct hlist_node *node) return 0; priv->cpu = target;

• /* Migrate fme_perf pmu events to the new target cpu */
• perf_pmu_migrate_context(&priv->pmu, cpu, target);
• return 0;

}