From: Frederic Weisbecker <frederic@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: "Frederic Weisbecker" <frederic@kernel.org>,
"Thomas Weißschuh" <thomas.weissschuh@linutronix.de>,
"Arnd Bergmann" <arnd@arndb.de>,
"Huacai Chen" <chenhuacai@kernel.org>,
"Jiaxun Yang" <jiaxun.yang@flygoat.com>,
"Marco Crivellari" <marco.crivellari@suse.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Phil Auld" <pauld@redhat.com>,
"Thomas Gleixner" <tglx@kernel.org>,
"WANG Xuerui" <kernel@xen0n.name>,
"Waiman Long" <longman@redhat.com>,
loongarch@lists.linux.dev
Subject: [RFC PATCH 31/49] LoongArch: Move CPUHP_AP_LOONGARCH_ARCH_TIMER_STARTING post stop_machine()
Date: Mon, 19 Oct 2026 15:08:38 +0200 [thread overview]
Message-ID: <20261019130856.49711-32-frederic@kernel.org> (raw)
In-Reply-To: <20261019130856.49711-1-frederic@kernel.org>
Between CPUHP_TEARDOWN_CPU and CPUHP_AP_OFFLINE, stop_machine executes
all the teardown callbacks while stopping all CPUs in the system. This
doesn't mix-up well with running RT or isolated tasks.
In order to transition smoothly from global stop_machine to finer
grained synchronization between teardown callbacks and the other CPUs,
a new stop machine post function has been introduced to be executed
after the main one with IRQs still disabled while other CPUs can exit
stop_machine().
The teardown callback here simply clears the interrupt on the CSR,
operation that can run concurrently with other CPUs.
Move it to post stop_machine() accordingly.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
kernel/cpu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index daad3b496854..664831c50f0b 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1275,7 +1275,7 @@ void clear_tasks_mm_cpumask(int cpu)
static int take_cpu_down(void *_param)
{
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
- enum cpuhp_state target = max((int)st->target, CPUHP_AP_ARMADA_TIMER_STARTING);
+ enum cpuhp_state target = max((int)st->target, CPUHP_AP_LOONGARCH_ARCH_TIMER_STARTING);
int err, cpu = smp_processor_id();
/* Ensure this CPU doesn't handle any more interrupts. */
@@ -1303,7 +1303,7 @@ static int take_cpu_down_post(void *_param)
enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
int cpu = smp_processor_id();
- WARN_ON(st->state != CPUHP_AP_ARMADA_TIMER_STARTING);
+ WARN_ON(st->state != CPUHP_AP_LOONGARCH_ARCH_TIMER_STARTING);
/*
* Invoke the former CPU_DYING callbacks. DYING must not fail!
*/
--
2.53.0
prev parent reply other threads:[~2026-10-19 13:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20261019130856.49711-1-frederic@kernel.org>
2026-10-19 13:08 ` [RFC PATCH 09/49] irqchip/loongarch-avec: Move CPUHP_AP_IRQ_AVECINTC_STARTING post stop_machine() Frederic Weisbecker
2026-10-19 13:08 ` Frederic Weisbecker [this message]
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