On 1/15/19 5:51 AM, Christoph Hellwig wrote:
void *__cpu_up_stack_pointer[NR_CPUS];
void *__cpu_up_task_pointer[NR_CPUS];
+static DECLARE_COMPLETION(cpu_running);
void __init smp_prepare_boot_cpu(void)
{
@@ -81,6 +82,7 @@ void __init setup_smp(void)
int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
+ int ret = 0;
int hartid = cpuid_to_hartid_map(cpu);
tidle->thread_info.cpu = cpu;
@@ -96,10 +98,15 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
task_stack_page(tidle) + THREAD_SIZE);
WRITE_ONCE(__cpu_up_task_pointer[hartid], tidle);
- while (!cpu_online(cpu))
- cpu_relax();
+ wait_for_completion_timeout(&cpu_running,
+ msecs_to_jiffies(1000));
Having a global completion here worries me. I bet we have some higher
level serialization, but can we comment or even better lockdep assert on
that?
Yes. It is serialized from smp.c in smp_init(). It brings one cpu online
at a time for preset_cpu mask.
Do we still need a lockdep assert ?
Regards,
Atish
Also please use up your available lines (72 in commit logs, 80 in source
files) instead of adding spurious line wraps.
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