From: Frederic Weisbecker <frederic@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
Marco Crivellari <marco.crivellari@suse.com>,
Peter Zijlstra <peterz@infradead.org>,
Phil Auld <pauld@redhat.com>,
Russell King <linux@armlinux.org.uk>,
Thomas Gleixner <tglx@kernel.org>,
Waiman Long <longman@redhat.com>,
linux-arm-kernel@lists.infradead.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH 17/47] ARM: vfp: Move CPUHP_AP_ARM_VFP_STARTING post stop_machine()
Date: Thu, 5 Nov 2026 17:30:15 +0100 [thread overview]
Message-ID: <20261105163045.38862-18-frederic@kernel.org> (raw)
In-Reply-To: <20261105163045.38862-1-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 only removes the local VFP state which is
never accessed remotely. As such it 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 a9c5b0c1974b..4952a53e028b 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_PERF_XTENSA_STARTING);
+ enum cpuhp_state target = max((int)st->target, CPUHP_AP_ARM_VFP_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_PERF_XTENSA_STARTING);
+ WARN_ON(st->state != CPUHP_AP_ARM_VFP_STARTING);
/*
* Invoke the former CPU_DYING callbacks. DYING must not fail!
*/
--
2.53.0
next prev parent reply other threads:[~2026-11-05 16:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20261105163045.38862-1-frederic@kernel.org>
2026-11-05 16:30 ` [PATCH 05/47] cpuidle: Move CPUHP_AP_CPU_PM_STARTING post stop_machine() Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 07/47] irqchip/bcm2836: Move CPUHP_AP_IRQ_BCM2836_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` Frederic Weisbecker [this message]
2026-11-05 16:30 ` [PATCH 19/47] perf/arm_pmu: Move CPUHP_AP_PERF_ARM_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 20/47] perf: RISC-V: Move CPUHP_AP_PERF_RISCV_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 21/47] ARM: l2c: Move CPUHP_AP_ARM_L2X0_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 22/47] clocksource/drivers/exynos_mct: Move CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 23/47] clocksource/drivers/arm_arch_timer: Move CPUHP_AP_ARM_ARCH_TIMER_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 24/47] clocksource/drivers/arm_arch_timer: Move CPUHP_AP_ARM_ARCH_TIMER_EVTSTRM_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 25/47] clocksource/drivers/arm_global_timer: Move CPUHP_AP_ARM_GLOBAL_TIMER_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 27/47] ARM: smp_twd: Move CPUHP_AP_ARM_TWD_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 41/47] ARM: xen: Move CPUHP_AP_ARM_XEN_STARTING " Frederic Weisbecker
2026-11-05 16:30 ` [PATCH 47/47] ARM: mm: Move CPUHP_AP_ARM_CACHE_B15_RAC_DYING " Frederic Weisbecker
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