perf/x86/amd/ibs: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153333.921401190@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index feb90f6730e8aebc06780090dcb6738750dd0a43..1a59a181582b2638b70d36a64ad383f3e302563c 100644 (file)
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -721,13 +721,10 @@ static __init int perf_ibs_pmu_init(struct perf_ibs *perf_ibs, char *name)
        return ret;
 }
 
-static __init int perf_event_ibs_init(void)
+static __init void perf_event_ibs_init(void)
 {
        struct attribute **attr = ibs_op_format_attrs;
 
-       if (!ibs_caps)
-               return -ENODEV; /* ibs not supported by the cpu */
-
        perf_ibs_pmu_init(&perf_ibs_fetch, "ibs_fetch");
 
        if (ibs_caps & IBS_CAPS_OPCNT) {
@@ -738,13 +735,11 @@ static __init int perf_event_ibs_init(void)
 
        register_nmi_handler(NMI_LOCAL, perf_ibs_nmi_handler, 0, "perf_ibs");
        pr_info("perf: AMD IBS detected (0x%08x)\n", ibs_caps);
-
-       return 0;
 }
 
 #else /* defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD) */
 
-static __init int perf_event_ibs_init(void) { return 0; }
+static __init void perf_event_ibs_init(void) { }
 
 #endif
 
@@ -921,7 +916,7 @@ static inline int get_ibs_lvt_offset(void)
        return val & IBSCTL_LVT_OFFSET_MASK;
 }
 
-static void setup_APIC_ibs(void *dummy)
+static void setup_APIC_ibs(void)
 {
        int offset;
 
@@ -936,7 +931,7 @@ failed:
                smp_processor_id());
 }
 
-static void clear_APIC_ibs(void *dummy)
+static void clear_APIC_ibs(void)
 {
        int offset;
 
@@ -945,18 +940,24 @@ static void clear_APIC_ibs(void *dummy)
                setup_APIC_eilvt(offset, 0, APIC_EILVT_MSG_FIX, 1);
 }
 
+static int x86_pmu_amd_ibs_starting_cpu(unsigned int cpu)
+{
+       setup_APIC_ibs();
+       return 0;
+}
+
 #ifdef CONFIG_PM
 
 static int perf_ibs_suspend(void)
 {
-       clear_APIC_ibs(NULL);
+       clear_APIC_ibs();
        return 0;
 }
 
 static void perf_ibs_resume(void)
 {
        ibs_eilvt_setup();
-       setup_APIC_ibs(NULL);
+       setup_APIC_ibs();
 }
 
 static struct syscore_ops perf_ibs_syscore_ops = {
@@ -975,27 +976,15 @@ static inline void perf_ibs_pm_init(void) { }
 
 #endif
 
-static int
-perf_ibs_cpu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
+static int x86_pmu_amd_ibs_dying_cpu(unsigned int cpu)
 {
-       switch (action & ~CPU_TASKS_FROZEN) {
-       case CPU_STARTING:
-               setup_APIC_ibs(NULL);
-               break;
-       case CPU_DYING:
-               clear_APIC_ibs(NULL);
-               break;
-       default:
-               break;
-       }
-
-       return NOTIFY_OK;
+       clear_APIC_ibs();
+       return 0;
 }
 
 static __init int amd_ibs_init(void)
 {
        u32 caps;
-       int ret = -EINVAL;
 
        caps = __get_ibs_caps();
        if (!caps)
@@ -1004,22 +993,25 @@ static __init int amd_ibs_init(void)
        ibs_eilvt_setup();
 
        if (!ibs_eilvt_valid())
-               goto out;
+               return -EINVAL;
 
        perf_ibs_pm_init();
-       cpu_notifier_register_begin();
+
        ibs_caps = caps;
        /* make ibs_caps visible to other cpus: */
        smp_mb();
-       smp_call_function(setup_APIC_ibs, NULL, 1);
-       __perf_cpu_notifier(perf_ibs_cpu_notifier);
-       cpu_notifier_register_done();
+       /*
+        * x86_pmu_amd_ibs_starting_cpu will be called from core on
+        * all online cpus.
+        */
+       cpuhp_setup_state(CPUHP_AP_PERF_X86_AMD_IBS_STARTING,
+                         "AP_PERF_X86_AMD_IBS_STARTING",
+                         x86_pmu_amd_ibs_starting_cpu,
+                         x86_pmu_amd_ibs_dying_cpu);
 
-       ret = perf_event_ibs_init();
-out:
-       if (ret)
-               pr_err("Failed to setup IBS, %d\n", ret);
-       return ret;
+       perf_event_ibs_init();
+
+       return 0;
 }
 
 /* Since we need the pci subsystem to init ibs we can't do this earlier: */

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 569d057cc7d5573a088a331bffe96ba8d974a6e2..46720197b307adb4b66422c26db7f1028632614a 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -23,6 +23,7 @@ enum cpuhp_state {
        CPUHP_AP_PERF_X86_UNCORE_STARTING,
        CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
        CPUHP_AP_PERF_X86_STARTING,
+       CPUHP_AP_PERF_X86_AMD_IBS_STARTING,
        CPUHP_AP_NOTIFY_STARTING,
        CPUHP_AP_ONLINE,
        CPUHP_TEARDOWN_CPU,