linux-kernel - [PATCH 1/2] perf/x86/rapl: Move the pmu allocation out of CPU hotplug

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Message-Id: <20240913171033.2144124-1-kan.liang@linux.intel.com>
Date: Fri, 13 Sep 2024 10:10:32 -0700
From: kan.liang@...ux.intel.com
To: peterz@...radead.org,
	mingo@...hat.com,
	linux-kernel@...r.kernel.org
Cc: Kan Liang <kan.liang@...ux.intel.com>,
	Oliver Sang <oliver.sang@...el.com>,
	Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Subject: [PATCH 1/2] perf/x86/rapl: Move the pmu allocation out of CPU hotplug

From: Kan Liang <kan.liang@...ux.intel.com>

The rapl pmu just needs to be allocated once. It doesn't matter to be
allocated at each CPU hotplug, or the global init_rapl_pmus().

Move the pmu allocation to the init_rapl_pmus(). So the generic hotplug
supports can be applied.

Tested-by: Oliver Sang <oliver.sang@...el.com>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
Cc: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
---

Rebase on top of perf/core branch
commit bac2a553dbf2 ("perf/x86/intel: Add PMU support for ArrowLake-H")
Close the UBSAN issue.
https://lore.kernel.org/oe-lkp/202409111521.c7c6d56f-lkp@intel.com/

 arch/x86/events/rapl.c | 50 +++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index a481a939862e..a6f31978a5b4 100644
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -602,19 +602,8 @@ static int rapl_cpu_online(unsigned int cpu)
 	struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
 	int target;
 
-	if (!pmu) {
-		pmu = kzalloc_node(sizeof(*pmu), GFP_KERNEL, cpu_to_node(cpu));
-		if (!pmu)
-			return -ENOMEM;
-
-		raw_spin_lock_init(&pmu->lock);
-		INIT_LIST_HEAD(&pmu->active_list);
-		pmu->pmu = &rapl_pmus->pmu;
-		pmu->timer_interval = ms_to_ktime(rapl_timer_ms);
-		rapl_hrtimer_init(pmu);
-
-		rapl_pmus->pmus[rapl_pmu_idx] = pmu;
-	}
+	if (!pmu)
+		return -ENOMEM;
 
 	/*
 	 * Check if there is an online cpu in the package which collects rapl
@@ -707,6 +696,38 @@ static const struct attribute_group *rapl_attr_update[] = {
 	NULL,
 };
 
+static void __init init_rapl_pmu(void)
+{
+	struct rapl_pmu *pmu;
+	s32 rapl_pmu_idx;
+	int cpu;
+
+	cpus_read_lock();
+
+	for_each_cpu(cpu, cpu_online_mask) {
+		pmu = cpu_to_rapl_pmu(cpu);
+		if (pmu)
+			continue;
+		rapl_pmu_idx = get_rapl_pmu_idx(cpu);
+		if (WARN_ON_ONCE(rapl_pmu_idx < 0))
+			continue;
+
+		pmu = kzalloc_node(sizeof(*pmu), GFP_KERNEL, cpu_to_node(cpu));
+		if (!pmu)
+			continue;
+
+		raw_spin_lock_init(&pmu->lock);
+		INIT_LIST_HEAD(&pmu->active_list);
+		pmu->pmu = &rapl_pmus->pmu;
+		pmu->timer_interval = ms_to_ktime(rapl_timer_ms);
+		rapl_hrtimer_init(pmu);
+
+		rapl_pmus->pmus[rapl_pmu_idx] = pmu;
+	}
+
+	cpus_read_unlock();
+}
+
 static int __init init_rapl_pmus(void)
 {
 	int nr_rapl_pmu = topology_max_packages();
@@ -730,6 +751,9 @@ static int __init init_rapl_pmus(void)
 	rapl_pmus->pmu.read		= rapl_pmu_event_read;
 	rapl_pmus->pmu.module		= THIS_MODULE;
 	rapl_pmus->pmu.capabilities	= PERF_PMU_CAP_NO_EXCLUDE;
+
+	init_rapl_pmu();
+
 	return 0;
 }
 
-- 
2.38.1