Commit 050a0938 authored by Anton Blanchard's avatar Anton Blanchard Committed by Linus Torvalds
Browse files

[PATCH] ppc64: pSeries idle fixups 



- separate out sleep logic in dedicated_idle, it was so far indented
  that it got squashed against the right side of the screen.
- add runlatch support, looping on runlatch disable.

Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3c57bb9f

arch/ppc64/kernel/pSeries_setup.c

+62 −51
Original line number Diff line number Diff line
@@ -83,8 +83,8 @@ int fwnmi_active; /* TRUE if an FWNMI handler is present */ 
extern void pSeries_system_reset_exception(struct pt_regs *regs);

extern int pSeries_machine_check_exception(struct pt_regs *regs);



static int shared_idle(void);

static int dedicated_idle(void);

static int pseries_shared_idle(void);

static int pseries_dedicated_idle(void);



static volatile void __iomem * chrp_int_ack_special;

struct mpic *pSeries_mpic;
@@ -238,10 +238,10 @@ static void __init pSeries_setup_arch(void) 
	if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) {

		if (get_paca()->lppaca.shared_proc) {

			printk(KERN_INFO "Using shared processor idle loop\n");

			ppc_md.idle_loop = shared_idle;

			ppc_md.idle_loop = pseries_shared_idle;

		} else {

			printk(KERN_INFO "Using dedicated idle loop\n");

			ppc_md.idle_loop = dedicated_idle;

			ppc_md.idle_loop = pseries_dedicated_idle;

		}

	} else {

		printk(KERN_INFO "Using default idle loop\n");
@@ -438,15 +438,47 @@ static int __init pSeries_probe(int platform) 


DECLARE_PER_CPU(unsigned long, smt_snooze_delay);



int dedicated_idle(void)

static inline void dedicated_idle_sleep(unsigned int cpu)

{

	struct paca_struct *ppaca = &paca[cpu ^ 1];



	/* Only sleep if the other thread is not idle */

	if (!(ppaca->lppaca.idle)) {

		local_irq_disable();



		/*

		 * We are about to sleep the thread and so wont be polling any

		 * more.

		 */

		clear_thread_flag(TIF_POLLING_NRFLAG);



		/*

		 * SMT dynamic mode. Cede will result in this thread going

		 * dormant, if the partner thread is still doing work.  Thread

		 * wakes up if partner goes idle, an interrupt is presented, or

		 * a prod occurs.  Returning from the cede enables external

		 * interrupts.

		 */

		if (!need_resched())

			cede_processor();

		else

			local_irq_enable();

	} else {

		/*

		 * Give the HV an opportunity at the processor, since we are

		 * not doing any work.

		 */

		poll_pending();

	}

}



static int pseries_dedicated_idle(void)

{

	long oldval;

	struct paca_struct *lpaca = get_paca(), *ppaca;

	struct paca_struct *lpaca = get_paca();

	unsigned int cpu = smp_processor_id();

	unsigned long start_snooze;

	unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);

	unsigned int cpu = smp_processor_id();



	ppaca = &paca[cpu ^ 1];



	while (1) {

		/*
@@ -458,9 +490,13 @@ int dedicated_idle(void) 
		oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);

		if (!oldval) {

			set_thread_flag(TIF_POLLING_NRFLAG);



			start_snooze = __get_tb() +

				*smt_snooze_delay * tb_ticks_per_usec;



			while (!need_resched() && !cpu_is_offline(cpu)) {

				ppc64_runlatch_off();



				/*

				 * Go into low thread priority and possibly

				 * low power mode.
@@ -468,60 +504,31 @@ int dedicated_idle(void) 
				HMT_low();

				HMT_very_low();



				if (*smt_snooze_delay == 0 ||

				    __get_tb() < start_snooze)

					continue;



				if (*smt_snooze_delay != 0 &&

				    __get_tb() > start_snooze) {

					HMT_medium();



				if (!(ppaca->lppaca.idle)) {

					local_irq_disable();



					/*

					 * We are about to sleep the thread

					 * and so wont be polling any

					 * more.

					 */

					clear_thread_flag(TIF_POLLING_NRFLAG);



					/*

					 * SMT dynamic mode. Cede will result

					 * in this thread going dormant, if the

					 * partner thread is still doing work.

					 * Thread wakes up if partner goes idle,

					 * an interrupt is presented, or a prod

					 * occurs.  Returning from the cede

					 * enables external interrupts.

					 */

					if (!need_resched())

						cede_processor();

					else

						local_irq_enable();

				} else {

					/*

					 * Give the HV an opportunity at the

					 * processor, since we are not doing

					 * any work.

					 */

					poll_pending();

					dedicated_idle_sleep(cpu);

				}



			}



			HMT_medium();

			clear_thread_flag(TIF_POLLING_NRFLAG);

		} else {

			set_need_resched();

		}



		HMT_medium();

		lpaca->lppaca.idle = 0;

		ppc64_runlatch_on();



		schedule();



		if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)

			cpu_die();

	}

	return 0;

}



static int shared_idle(void)

static int pseries_shared_idle(void)

{

	struct paca_struct *lpaca = get_paca();

	unsigned int cpu = smp_processor_id();
@@ -535,6 +542,7 @@ static int shared_idle(void) 


		while (!need_resched() && !cpu_is_offline(cpu)) {

			local_irq_disable();

			ppc64_runlatch_off();



			/*

			 * Yield the processor to the hypervisor.  We return if
@@ -550,13 +558,16 @@ static int shared_idle(void) 
				cede_processor();

			else

				local_irq_enable();

		}



			HMT_medium();

		}



		lpaca->lppaca.idle = 0;

		ppc64_runlatch_on();



		schedule();

		if (cpu_is_offline(smp_processor_id()) &&

		    system_state == SYSTEM_RUNNING)



		if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)

			cpu_die();

	}

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