From b38b24ead33417146e051453d04bf60b8d2d7e25 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 23 Mar 2010 19:31:15 +0100 Subject: [PATCH] perf, x86: Fix AMD hotplug & constraint initialization Commit 3f6da39 ("perf: Rework and fix the arch CPU-hotplug hooks") moved the amd northbridge allocation from CPUS_ONLINE to CPUS_PREPARE_UP however amd_nb_id() doesn't work yet on prepare so it would simply bail basically reverting to a state where we do not properly track node wide constraints - causing weird perf results. Fix up the AMD NorthBridge initialization code by allocating from CPU_UP_PREPARE and installing it from CPU_STARTING once we have the proper nb_id. It also properly deals with the allocation failing. Signed-off-by: Peter Zijlstra [ robustify using amd_has_nb() ] Signed-off-by: Stephane Eranian LKML-Reference: <1269353485.5109.48.camel@twins> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 8 ++-- arch/x86/kernel/cpu/perf_event_amd.c | 80 +++++++++++++++++++++--------------- 2 files changed, 52 insertions(+), 36 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 5fb490c6ee5c..bd28cf9d8a82 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -158,7 +158,7 @@ struct x86_pmu { struct perf_event *event); struct event_constraint *event_constraints; - void (*cpu_prepare)(int cpu); + int (*cpu_prepare)(int cpu); void (*cpu_starting)(int cpu); void (*cpu_dying)(int cpu); void (*cpu_dead)(int cpu); @@ -1333,11 +1333,12 @@ static int __cpuinit x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long)hcpu; + int ret = NOTIFY_OK; switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: if (x86_pmu.cpu_prepare) - x86_pmu.cpu_prepare(cpu); + ret = x86_pmu.cpu_prepare(cpu); break; case CPU_STARTING: @@ -1350,6 +1351,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) x86_pmu.cpu_dying(cpu); break; + case CPU_UP_CANCELED: case CPU_DEAD: if (x86_pmu.cpu_dead) x86_pmu.cpu_dead(cpu); @@ -1359,7 +1361,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) break; } - return NOTIFY_OK; + return ret; } static void __init pmu_check_apic(void) diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c index b87e0b6970cb..db6f7d4056e1 100644 --- a/arch/x86/kernel/cpu/perf_event_amd.c +++ b/arch/x86/kernel/cpu/perf_event_amd.c @@ -137,6 +137,13 @@ static inline int amd_is_nb_event(struct hw_perf_event *hwc) return (hwc->config & 0xe0) == 0xe0; } +static inline int amd_has_nb(struct cpu_hw_events *cpuc) +{ + struct amd_nb *nb = cpuc->amd_nb; + + return nb && nb->nb_id != -1; +} + static void amd_put_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) { @@ -147,7 +154,7 @@ static void amd_put_event_constraints(struct cpu_hw_events *cpuc, /* * only care about NB events */ - if (!(nb && amd_is_nb_event(hwc))) + if (!(amd_has_nb(cpuc) && amd_is_nb_event(hwc))) return; /* @@ -214,7 +221,7 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) /* * if not NB event or no NB, then no constraints */ - if (!(nb && amd_is_nb_event(hwc))) + if (!(amd_has_nb(cpuc) && amd_is_nb_event(hwc))) return &unconstrained; /* @@ -293,51 +300,55 @@ static struct amd_nb *amd_alloc_nb(int cpu, int nb_id) return nb; } -static void amd_pmu_cpu_online(int cpu) +static int amd_pmu_cpu_prepare(int cpu) +{ + struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu); + + WARN_ON_ONCE(cpuc->amd_nb); + + if (boot_cpu_data.x86_max_cores < 2) + return NOTIFY_OK; + + cpuc->amd_nb = amd_alloc_nb(cpu, -1); + if (!cpuc->amd_nb) + return NOTIFY_BAD; + + return NOTIFY_OK; +} + +static void amd_pmu_cpu_starting(int cpu) { - struct cpu_hw_events *cpu1, *cpu2; - struct amd_nb *nb = NULL; + struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu); + struct amd_nb *nb; int i, nb_id; if (boot_cpu_data.x86_max_cores < 2) return; - /* - * function may be called too early in the - * boot process, in which case nb_id is bogus - */ nb_id = amd_get_nb_id(cpu); - if (nb_id == BAD_APICID) - return; - - cpu1 = &per_cpu(cpu_hw_events, cpu); - cpu1->amd_nb = NULL; + WARN_ON_ONCE(nb_id == BAD_APICID); raw_spin_lock(&amd_nb_lock); for_each_online_cpu(i) { - cpu2 = &per_cpu(cpu_hw_events, i); - nb = cpu2->amd_nb; - if (!nb) + nb = per_cpu(cpu_hw_events, i).amd_nb; + if (WARN_ON_ONCE(!nb)) continue; - if (nb->nb_id == nb_id) - goto found; - } - nb = amd_alloc_nb(cpu, nb_id); - if (!nb) { - pr_err("perf_events: failed NB allocation for CPU%d\n", cpu); - raw_spin_unlock(&amd_nb_lock); - return; + if (nb->nb_id == nb_id) { + kfree(cpuc->amd_nb); + cpuc->amd_nb = nb; + break; + } } -found: - nb->refcnt++; - cpu1->amd_nb = nb; + + cpuc->amd_nb->nb_id = nb_id; + cpuc->amd_nb->refcnt++; raw_spin_unlock(&amd_nb_lock); } -static void amd_pmu_cpu_offline(int cpu) +static void amd_pmu_cpu_dead(int cpu) { struct cpu_hw_events *cpuhw; @@ -349,8 +360,10 @@ static void amd_pmu_cpu_offline(int cpu) raw_spin_lock(&amd_nb_lock); if (cpuhw->amd_nb) { - if (--cpuhw->amd_nb->refcnt == 0) - kfree(cpuhw->amd_nb); + struct amd_nb *nb = cpuhw->amd_nb; + + if (nb->nb_id == -1 || --nb->refcnt == 0) + kfree(nb); cpuhw->amd_nb = NULL; } @@ -379,8 +392,9 @@ static __initconst struct x86_pmu amd_pmu = { .get_event_constraints = amd_get_event_constraints, .put_event_constraints = amd_put_event_constraints, - .cpu_prepare = amd_pmu_cpu_online, - .cpu_dead = amd_pmu_cpu_offline, + .cpu_prepare = amd_pmu_cpu_prepare, + .cpu_starting = amd_pmu_cpu_starting, + .cpu_dead = amd_pmu_cpu_dead, }; static __init int amd_pmu_init(void) -- 2.11.0