diff options
| author | Kajol Jain <kjain@linux.ibm.com> | 2020-10-03 13:19:42 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-10-07 22:34:48 +1100 |
| commit | dcb5cdf60a1fbbdb3b4dd2abc562206481f09ef1 (patch) | |
| tree | 12c43e4e8ed857eae86eb62bea20a0516a4b419f | |
| parent | 435387dd1f6fc03c64e3fdb4cc8737904c08a4db (diff) | |
powerpc/perf/hv-gpci: Add cpu hotplug support
Patch here adds cpu hotplug functions to hv_gpci pmu.
A new cpuhp_state "CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE" enum
is added.
The online callback function updates the cpumask only if its
empty. As the primary intention of adding hotplug support
is to designate a CPU to make HCALL to collect the
counter data.
The offline function test and clear corresponding cpu in a cpumask
and update cpumask to any other active cpu.
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201003074943.338618-4-kjain@linux.ibm.com
| -rw-r--r-- | arch/powerpc/perf/hv-gpci.c | 46 | ||||
| -rw-r--r-- | include/linux/cpuhotplug.h | 1 |
2 files changed, 47 insertions, 0 deletions
diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c index 1667315b82e9..1bca0c1a6cfe 100644 --- a/arch/powerpc/perf/hv-gpci.c +++ b/arch/powerpc/perf/hv-gpci.c @@ -48,6 +48,8 @@ EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31); /* u32, byte offset */ EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63); +static cpumask_t hv_gpci_cpumask; + static struct attribute *format_attrs[] = { &format_attr_request.attr, &format_attr_starting_index.attr, @@ -266,6 +268,45 @@ static struct pmu h_gpci_pmu = { .capabilities = PERF_PMU_CAP_NO_EXCLUDE, }; +static int ppc_hv_gpci_cpu_online(unsigned int cpu) +{ + if (cpumask_empty(&hv_gpci_cpumask)) + cpumask_set_cpu(cpu, &hv_gpci_cpumask); + + return 0; +} + +static int ppc_hv_gpci_cpu_offline(unsigned int cpu) +{ + int target; + + /* Check if exiting cpu is used for collecting gpci events */ + if (!cpumask_test_and_clear_cpu(cpu, &hv_gpci_cpumask)) + return 0; + + /* Find a new cpu to collect gpci events */ + target = cpumask_last(cpu_active_mask); + + if (target < 0 || target >= nr_cpu_ids) { + pr_err("hv_gpci: CPU hotplug init failed\n"); + return -1; + } + + /* Migrate gpci events to the new target */ + cpumask_set_cpu(target, &hv_gpci_cpumask); + perf_pmu_migrate_context(&h_gpci_pmu, cpu, target); + + return 0; +} + +static int hv_gpci_cpu_hotplug_init(void) +{ + return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE, + "perf/powerpc/hv_gcpi:online", + ppc_hv_gpci_cpu_online, + ppc_hv_gpci_cpu_offline); +} + static int hv_gpci_init(void) { int r; @@ -286,6 +327,11 @@ static int hv_gpci_init(void) return -ENODEV; } + /* init cpuhotplug */ + r = hv_gpci_cpu_hotplug_init(); + if (r) + return r; + /* sampling not supported */ h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT; diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 3215023d4852..5d08ed922510 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -183,6 +183,7 @@ enum cpuhp_state { CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE, CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE, CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE, + CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE, CPUHP_AP_WATCHDOG_ONLINE, CPUHP_AP_WORKQUEUE_ONLINE, CPUHP_AP_RCUTREE_ONLINE, |