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ARM: SMP: use a timing out completion for cpu hotplug

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Rather than open-coding the jiffy-based wait, and polling for the
secondary CPU to come online, use a completion instead.  This
removes the need to poll, instead we will be notified when the
secondary CPU has initialized.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2012-01-18 15:59:45 +00:00
parent 94e5a85b3b
commit 149c24151e
1 changed files with 6 additions and 11 deletions
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17
arch/arm/kernel/smp.c
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@ -58,6 +58,8 @@ enum ipi_msg_type {
IPI_CPU_STOP,
};
static DECLARE_COMPLETION(cpu_running);
int __cpuinit __cpu_up(unsigned int cpu)
{
struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
@ -98,20 +100,12 @@ int __cpuinit __cpu_up(unsigned int cpu)
*/
ret = boot_secondary(cpu, idle);
if (ret == 0) {
unsigned long timeout;
/*
* CPU was successfully started, wait for it
* to come online or time out.
*/
timeout = jiffies + HZ;
while (time_before(jiffies, timeout)) {
if (cpu_online(cpu))
break;
udelay(10);
barrier();
}
wait_for_completion_timeout(&cpu_running,
msecs_to_jiffies(1000));
if (!cpu_online(cpu)) {
pr_crit("CPU%u: failed to come online\n", cpu);
@ -300,9 +294,10 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
/*
* OK, now it's safe to let the boot CPU continue. Wait for
* the CPU migration code to notice that the CPU is online
* before we continue.
* before we continue - which happens after __cpu_up returns.
*/
set_cpu_online(cpu, true);
complete(&cpu_running);
/*
* Setup the percpu timer for this CPU.