From 9858a1f3fb9af4ca7d7f6b59d9b3e44d27cdfae6 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 30 Jul 2018 14:09:19 +0200 Subject: [PATCH] allow cpu_down() to be called earlier The function's use of the stop-machine logic has so far prevented its use ahead of the processing of the "ordinary" initcalls. Since at this early time we're in a controlled environment anyway, there's no need for such a heavy tool. Additionally this ought to have less of a performance impact especially on large systems, compared to the alternative of making stop-machine functionality available earlier. Signed-off-by: Jan Beulich Reviewed-by: Wei Liu Reviewed-by: Andrew Cooper master commit: 5894c0a2da66243a89088d309c7e1ea212ab28d6 master date: 2018-07-16 15:15:12 +0200 --- xen/common/cpu.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/xen/common/cpu.c b/xen/common/cpu.c index 497e0cbb51..2b29309831 100644 --- a/xen/common/cpu.c +++ b/xen/common/cpu.c @@ -68,12 +68,17 @@ void __init register_cpu_notifier(struct notifier_block *nb) spin_unlock(&cpu_add_remove_lock); } -static int take_cpu_down(void *unused) +static void _take_cpu_down(void *unused) { void *hcpu = (void *)(long)smp_processor_id(); int notifier_rc = notifier_call_chain(&cpu_chain, CPU_DYING, hcpu, NULL); BUG_ON(notifier_rc != NOTIFY_DONE); __cpu_disable(); +} + +static int take_cpu_down(void *arg) +{ + _take_cpu_down(arg); return 0; } @@ -99,7 +104,9 @@ int cpu_down(unsigned int cpu) goto fail; } - if ( (err = stop_machine_run(take_cpu_down, NULL, cpu)) < 0 ) + if ( unlikely(system_state < SYS_STATE_active) ) + on_selected_cpus(cpumask_of(cpu), _take_cpu_down, NULL, 1); + else if ( (err = stop_machine_run(take_cpu_down, NULL, cpu)) < 0 ) goto fail; __cpu_die(cpu); -- 2.39.5