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Commit 149c2415 authored by Russell King's avatar Russell King
Browse files

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



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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 94e5a85b

arch/arm/kernel/smp.c

+6 −11
Original line number Diff line number Diff line
@@ -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.