From f07048270423622a2428a9b90929c76e92777caa Mon Sep 17 00:00:00 2001 From: Richard Cochran Date: Wed, 13 Jul 2016 17:16:16 +0000 Subject: [PATCH] perf/x86/intel/cqm: Convert Intel CQM 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: Richard Cochran Signed-off-by: Anna-Maria Gleixner Reviewed-by: Sebastian Andrzej Siewior Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Jiri Olsa Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Tony Luck Cc: Vikas Shivappa Cc: Vince Weaver Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153334.096956222@linutronix.de Signed-off-by: Ingo Molnar --- arch/x86/events/intel/cqm.c | 49 ++++++++++++++----------------------- include/linux/cpuhotplug.h | 2 ++ 2 files changed, 20 insertions(+), 31 deletions(-) diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c index 7b5fd811ef45..783c49ddef29 100644 --- a/arch/x86/events/intel/cqm.c +++ b/arch/x86/events/intel/cqm.c @@ -1577,7 +1577,7 @@ static inline void cqm_pick_event_reader(int cpu) cpumask_set_cpu(cpu, &cqm_cpumask); } -static void intel_cqm_cpu_starting(unsigned int cpu) +static int intel_cqm_cpu_starting(unsigned int cpu) { struct intel_pqr_state *state = &per_cpu(pqr_state, cpu); struct cpuinfo_x86 *c = &cpu_data(cpu); @@ -1588,39 +1588,26 @@ static void intel_cqm_cpu_starting(unsigned int cpu) WARN_ON(c->x86_cache_max_rmid != cqm_max_rmid); WARN_ON(c->x86_cache_occ_scale != cqm_l3_scale); + + cqm_pick_event_reader(cpu); + return 0; } -static void intel_cqm_cpu_exit(unsigned int cpu) +static int intel_cqm_cpu_exit(unsigned int cpu) { int target; /* Is @cpu the current cqm reader for this package ? */ if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask)) - return; + return 0; /* Find another online reader in this package */ target = cpumask_any_but(topology_core_cpumask(cpu), cpu); if (target < nr_cpu_ids) cpumask_set_cpu(target, &cqm_cpumask); -} -static int intel_cqm_cpu_notifier(struct notifier_block *nb, - unsigned long action, void *hcpu) -{ - unsigned int cpu = (unsigned long)hcpu; - - switch (action & ~CPU_TASKS_FROZEN) { - case CPU_DOWN_PREPARE: - intel_cqm_cpu_exit(cpu); - break; - case CPU_STARTING: - intel_cqm_cpu_starting(cpu); - cqm_pick_event_reader(cpu); - break; - } - - return NOTIFY_OK; + return 0; } static const struct x86_cpu_id intel_cqm_match[] = { @@ -1682,7 +1669,7 @@ out: static int __init intel_cqm_init(void) { char *str = NULL, scale[20]; - int i, cpu, ret; + int cpu, ret; if (x86_match_cpu(intel_cqm_match)) cqm_enabled = true; @@ -1705,8 +1692,7 @@ static int __init intel_cqm_init(void) * * Also, check that the scales match on all cpus. */ - cpu_notifier_register_begin(); - + get_online_cpus(); for_each_online_cpu(cpu) { struct cpuinfo_x86 *c = &cpu_data(cpu); @@ -1743,11 +1729,6 @@ static int __init intel_cqm_init(void) if (ret) goto out; - for_each_online_cpu(i) { - intel_cqm_cpu_starting(i); - cqm_pick_event_reader(i); - } - if (mbm_enabled) ret = intel_mbm_init(); if (ret && !cqm_enabled) @@ -1772,12 +1753,18 @@ static int __init intel_cqm_init(void) pr_info("Intel MBM enabled\n"); /* - * Register the hot cpu notifier once we are sure cqm + * Setup the hot cpu notifier once we are sure cqm * is enabled to avoid notifier leak. */ - __perf_cpu_notifier(intel_cqm_cpu_notifier); + cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_STARTING, + "AP_PERF_X86_CQM_STARTING", + intel_cqm_cpu_starting, NULL); + cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_ONLINE, "AP_PERF_X86_CQM_ONLINE", + NULL, intel_cqm_cpu_exit); + out: - cpu_notifier_register_done(); + put_online_cpus(); + if (ret) { kfree(str); cqm_cleanup(); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 06d77fd0fda3..f9399eeba263 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -25,6 +25,7 @@ enum cpuhp_state { CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING, CPUHP_AP_PERF_X86_STARTING, CPUHP_AP_PERF_X86_AMD_IBS_STARTING, + CPUHP_AP_PERF_X86_CQM_STARTING, CPUHP_AP_NOTIFY_STARTING, CPUHP_AP_ONLINE, CPUHP_TEARDOWN_CPU, @@ -36,6 +37,7 @@ enum cpuhp_state { CPUHP_AP_PERF_X86_UNCORE_ONLINE, CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE, CPUHP_AP_PERF_X86_RAPL_ONLINE, + CPUHP_AP_PERF_X86_CQM_ONLINE, CPUHP_AP_NOTIFY_ONLINE, CPUHP_AP_ONLINE_DYN, CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30,