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MIPS: SMP: Move the AP sync point before the non-parallel aware functions

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When CONFIG_HOTPLUG_PARALLEL is enabled, the code executing before
cpuhp_ap_sync_alive() is executed in parallel, while after it is
serialized. The functions set_cpu_sibling_map() and set_cpu_core_map()
were not designed to be executed in parallel, so by moving the
cpuhp_ap_sync_alive() before cpuhp_ap_sync_alive(), we then ensure
they will be called serialized.

The measurement done on EyeQ5 did not show any relevant boot time
increase after applying this patch.

Fixes: 76c43eb507 ("MIPS: SMP: Implement parallel CPU bring up for EyeQ")
Reported-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Gregory CLEMENT 2025-05-05 14:57:58 +02:00 • committed by Thomas Bogendoerfer
parent 3b3704261e
commit 4cc7543eb4
1 changed files with 3 additions and 3 deletions
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6
arch/mips/kernel/smp.c
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@ -374,13 +374,13 @@ asmlinkage void start_secondary(void)
calibrate_delay();
cpu_data[cpu].udelay_val = loops_per_jiffy;
#ifdef CONFIG_HOTPLUG_PARALLEL
cpuhp_ap_sync_alive();
#endif
set_cpu_sibling_map(cpu);
set_cpu_core_map(cpu);
cpumask_set_cpu(cpu, &cpu_coherent_mask);
#ifdef CONFIG_HOTPLUG_PARALLEL
cpuhp_ap_sync_alive();
#endif
notify_cpu_starting(cpu);
#ifndef CONFIG_HOTPLUG_PARALLEL