Could someone explain why we get the message below in kernel in SMP environment?
CPU1 failed to come online
Source kernel_msm-4.9/kernel/arch/arm/kernel/smp.c:
if (!cpu_online(cpu))
{
pr_crit("CPU%u: failed to come online\n", cpu);
ret = -EIO;
}
It could be possible that CPU 1 is set offline in the system to not schedule, receive interrupts form the devices. Below we can see 4 cores are available, and when one of the core is disabled using sysfs option it became offline.
[root@ucc1 bin]# cat /sys/devices/system/cpu/online
0-3
[root@ucc1 bin]# echo 0 > /sys/devices/system/cpu/cpu3/online
[root@ucc1 bin]# cat /sys/devices/system/cpu/online
0-2
[root@ucc1 bin]# cat /sys/devices/system/cpu/offline
3
