diff options
| author | Kajol Jain <kjain@linux.ibm.com> | 2020-07-09 10:48:35 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-07-16 13:12:41 +1000 |
| commit | 1a8f0886a6008c98a926bdeca49f2ef33015a491 (patch) | |
| tree | fc833fcf5de36958f781acd0745ede54498b35a2 | |
| parent | e978a3ccaa714b5ff125857d2cbecbb6fdf6c094 (diff) | |
powerpc/perf/hv-24x7: Add cpu hotplug support
Patch here adds cpu hotplug functions to hv_24x7 pmu.
A new cpuhp_state "CPUHP_AP_PERF_POWERPC_HV_24x7_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>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200709051836.723765-2-kjain@linux.ibm.com
| -rw-r--r-- | arch/powerpc/perf/hv-24x7.c | 46 | ||||
| -rw-r--r-- | include/linux/cpuhotplug.h | 1 |
2 files changed, 47 insertions, 0 deletions
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index db213eb7cb02..93b4700dcf8c 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -31,6 +31,8 @@ static int interface_version; /* Whether we have to aggregate result data for some domains. */ static bool aggregate_result_elements; +static cpumask_t hv_24x7_cpumask; + static bool domain_is_valid(unsigned domain) { switch (domain) { @@ -1641,6 +1643,45 @@ static struct pmu h_24x7_pmu = { .capabilities = PERF_PMU_CAP_NO_EXCLUDE, }; +static int ppc_hv_24x7_cpu_online(unsigned int cpu) +{ + if (cpumask_empty(&hv_24x7_cpumask)) + cpumask_set_cpu(cpu, &hv_24x7_cpumask); + + return 0; +} + +static int ppc_hv_24x7_cpu_offline(unsigned int cpu) +{ + int target; + + /* Check if exiting cpu is used for collecting 24x7 events */ + if (!cpumask_test_and_clear_cpu(cpu, &hv_24x7_cpumask)) + return 0; + + /* Find a new cpu to collect 24x7 events */ + target = cpumask_last(cpu_active_mask); + + if (target < 0 || target >= nr_cpu_ids) { + pr_err("hv_24x7: CPU hotplug init failed\n"); + return -1; + } + + /* Migrate 24x7 events to the new target */ + cpumask_set_cpu(target, &hv_24x7_cpumask); + perf_pmu_migrate_context(&h_24x7_pmu, cpu, target); + + return 0; +} + +static int hv_24x7_cpu_hotplug_init(void) +{ + return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE, + "perf/powerpc/hv_24x7:online", + ppc_hv_24x7_cpu_online, + ppc_hv_24x7_cpu_offline); +} + static int hv_24x7_init(void) { int r; @@ -1685,6 +1726,11 @@ static int hv_24x7_init(void) if (r) return r; + /* init cpuhotplug */ + r = hv_24x7_cpu_hotplug_init(); + if (r) + return r; + r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1); if (r) return r; diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 191772d4a4d7..a2710e654b64 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -181,6 +181,7 @@ enum cpuhp_state { CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE, CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE, CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE, + CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE, CPUHP_AP_WATCHDOG_ONLINE, CPUHP_AP_WORKQUEUE_ONLINE, CPUHP_AP_RCUTREE_ONLINE, |