ARM: SMP: avoid using bitmasks and locks for IPIs, use hardware instead (24480d98) · Commits · 戴 / test

arch/arm/kernel/smp.c

+26 −61

Original line number	Diff line number	Diff line
		@@ -48,20 +48,15 @@ struct secondary_data secondary_data;

		/*
		* structures for inter-processor calls
		* - A collection of single bit ipi messages.
		*/
		struct ipi_data {
		spinlock_t lock;
		unsigned long ipi_count;
		unsigned long bits;
		};

		static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
		.lock = SPIN_LOCK_UNLOCKED,
		};
		static DEFINE_PER_CPU(struct ipi_data, ipi_data);

		enum ipi_msg_type {
		IPI_TIMER,
		IPI_TIMER = 2,
		IPI_RESCHEDULE,
		IPI_CALL_FUNC,
		IPI_CALL_FUNC_SINGLE,
		@@ -389,22 +384,13 @@ void __init smp_prepare_boot_cpu(void)
		static void send_ipi_message(const struct cpumask *mask, enum ipi_msg_type msg)
		{
		unsigned long flags;
		unsigned int cpu;

		local_irq_save(flags);

		for_each_cpu(cpu, mask) {
		struct ipi_data *ipi = &per_cpu(ipi_data, cpu);

		spin_lock(&ipi->lock);
		ipi->bits \|= 1 << msg;
		spin_unlock(&ipi->lock);
		}

		/*
		* Call the platform specific cross-CPU call function.
		*/
		smp_cross_call(mask, 1);
		smp_cross_call(mask, msg);

		local_irq_restore(flags);
		}
		@@ -546,25 +532,7 @@ asmlinkage void __exception do_IPI(int ipinr, struct pt_regs *regs)

		ipi->ipi_count++;

		for (;;) {
		unsigned long msgs;

		spin_lock(&ipi->lock);
		msgs = ipi->bits;
		ipi->bits = 0;
		spin_unlock(&ipi->lock);

		if (!msgs)
		break;

		do {
		unsigned nextmsg;

		nextmsg = msgs & -msgs;
		msgs &= ~nextmsg;
		nextmsg = ffz(~nextmsg);

		switch (nextmsg) {
		switch (ipinr) {
		case IPI_TIMER:
		ipi_timer();
		break;
		@@ -590,12 +558,9 @@ asmlinkage void __exception do_IPI(int ipinr, struct pt_regs *regs)

		default:
		printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
		cpu, nextmsg);
		cpu, ipinr);
		break;
		}
		} while (msgs);
		}

		set_irq_regs(old_regs);
		}

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