lkml.org 
[lkml]   [2022]   [Aug]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC 05/10] perf/arm-dsu: Make dsu_pmu_cpu_teardown() parallel
Date
In the case of kexec quick reboot, dsu_pmu_cpu_teardown() confronts
parallel and lock are needed to protect the contest on a dsu_pmu.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
To: linux-kernel@vger.kernel.org
---
drivers/perf/arm_dsu_pmu.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c
index a36698a90d2f..aa9f4393ff0c 100644
--- a/drivers/perf/arm_dsu_pmu.c
+++ b/drivers/perf/arm_dsu_pmu.c
@@ -833,16 +833,23 @@ static int dsu_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
struct dsu_pmu *dsu_pmu = hlist_entry_safe(node, struct dsu_pmu,
cpuhp_node);

- if (!cpumask_test_and_clear_cpu(cpu, &dsu_pmu->active_cpu))
+ raw_spin_lock(&dsu_pmu->pmu_lock);
+ if (!cpumask_test_and_clear_cpu(cpu, &dsu_pmu->active_cpu)) {
+ raw_spin_unlock(&dsu_pmu->pmu_lock);
return 0;
+ }

dst = dsu_pmu_get_online_cpu_any_but(dsu_pmu, cpu);
/* If there are no active CPUs in the DSU, leave IRQ disabled */
- if (dst >= nr_cpu_ids)
+ if (dst >= nr_cpu_ids) {
+ raw_spin_unlock(&dsu_pmu->pmu_lock);
return 0;
+ }

- perf_pmu_migrate_context(&dsu_pmu->pmu, cpu, dst);
+ /* dst should not be in dying mask. So after setting, blocking parallel */
dsu_pmu_set_active_cpu(dst, dsu_pmu);
+ raw_spin_unlock(&dsu_pmu->pmu_lock);
+ perf_pmu_migrate_context(&dsu_pmu->pmu, cpu, dst);

return 0;
}
@@ -858,6 +865,7 @@ static int __init dsu_pmu_init(void)
if (ret < 0)
return ret;
dsu_pmu_cpuhp_state = ret;
+ cpuhp_set_step_parallel(ret);
return platform_driver_register(&dsu_pmu_driver);
}

--
2.31.1
\
 
 \ /
  Last update: 2022-08-22 04:17    [W:0.163 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site