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Commit e28bb79d authored by Hendrik Brueckner's avatar Hendrik Brueckner Committed by Martin Schwidefsky
Browse files

s390/perf,oprofile: Share sampling facility 



Introduce reserve/release functions to share the sampling facility
between perf and oprofile.
Also improve error handling for the sampling facility support in perf.

Signed-off-by: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 55baa2f8

arch/s390/include/asm/perf_event.h

+4 −0
Original line number Diff line number Diff line
@@ -52,5 +52,9 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs); 
#define TEAR_REG(hwc)		((hwc)->last_tag)

#define SAMPL_RATE(hwc)		((hwc)->event_base)



/* Perf hardware reserve and release functions */

int perf_reserve_sampling(void);

void perf_release_sampling(void);



#endif /* CONFIG_64BIT */

#endif /* _ASM_S390_PERF_EVENT_H */

arch/s390/kernel/perf_cpum_sf.c

+12 −5
Original line number Diff line number Diff line
@@ -260,16 +260,12 @@ static int sf_disable(void) 


#define PMC_INIT      0

#define PMC_RELEASE   1

#define PMC_FAILURE   2

static void setup_pmc_cpu(void *flags)

{

	int err;

	struct cpu_hw_sf *cpusf = &__get_cpu_var(cpu_hw_sf);



	/* XXX Improve error handling and pass a flag in the *flags

	 *     variable to indicate failures.  Alternatively, ignore

	 *     (print) errors here and let the PMU functions fail if

	 *     the per-cpu PMU_F_RESERVED flag is not.

	 */

	err = 0;

	switch (*((int *) flags)) {

	case PMC_INIT:
@@ -299,6 +295,8 @@ static void setup_pmc_cpu(void *flags) 
				    "setup_pmc_cpu: released: cpuhw=%p\n", cpusf);

		break;

	}

	if (err)

		*((int *) flags) |= PMC_FAILURE;

}



static void release_pmc_hardware(void)
@@ -307,13 +305,22 @@ static void release_pmc_hardware(void) 


	irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);

	on_each_cpu(setup_pmc_cpu, &flags, 1);

	perf_release_sampling();

}



static int reserve_pmc_hardware(void)

{

	int flags = PMC_INIT;

	int err;



	err = perf_reserve_sampling();

	if (err)

		return err;

	on_each_cpu(setup_pmc_cpu, &flags, 1);

	if (flags & PMC_FAILURE) {

		release_pmc_hardware();

		return -ENODEV;

	}

	irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);



	return 0;

arch/s390/kernel/perf_event.c

+30 −0
Original line number Diff line number Diff line
@@ -208,3 +208,33 @@ ssize_t cpumf_events_sysfs_show(struct device *dev, 
	return sprintf(page, "event=0x%04llx,name=%s\n",

		       pmu_attr->id, attr->attr.name);

}



/* Reserve/release functions for sharing perf hardware */

static DEFINE_SPINLOCK(perf_hw_owner_lock);

static void *perf_sampling_owner;



int perf_reserve_sampling(void)

{

	int err;



	err = 0;

	spin_lock(&perf_hw_owner_lock);

	if (perf_sampling_owner) {

		pr_warn("The sampling facility is already reserved by %p\n",

			perf_sampling_owner);

		err = -EBUSY;

	} else

		perf_sampling_owner = __builtin_return_address(0);

	spin_unlock(&perf_hw_owner_lock);

	return err;

}

EXPORT_SYMBOL(perf_reserve_sampling);



void perf_release_sampling(void)

{

	spin_lock(&perf_hw_owner_lock);

	WARN_ON(!perf_sampling_owner);

	perf_sampling_owner = NULL;

	spin_unlock(&perf_hw_owner_lock);

}

EXPORT_SYMBOL(perf_release_sampling);

arch/s390/oprofile/hwsampler.c

+7 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ static DEFINE_MUTEX(hws_sem_oom); 


static unsigned char hws_flush_all;

static unsigned int hws_oom;

static unsigned int hws_alert;

static struct workqueue_struct *hws_wq;



static unsigned int hws_state;
@@ -182,6 +183,9 @@ static void hws_ext_handler(struct ext_code ext_code, 
	if (!(param32 & CPU_MF_INT_SF_MASK))

		return;



	if (!hws_alert)

		return;



	inc_irq_stat(IRQEXT_CMS);

	atomic_xchg(&cb->ext_params, atomic_read(&cb->ext_params) | param32);
@@ -941,6 +945,7 @@ int hwsampler_deallocate(void) 
		goto deallocate_exit;



	irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);

	hws_alert = 0;

	deallocate_sdbt();



	hws_state = HWS_DEALLOCATED;
@@ -1055,6 +1060,7 @@ int hwsampler_shutdown(void) 


		if (hws_state == HWS_STOPPED) {

			irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);

			hws_alert = 0;

			deallocate_sdbt();

		}

		if (hws_wq) {
@@ -1129,6 +1135,7 @@ int hwsampler_start_all(unsigned long rate) 
	hws_oom = 1;

	hws_flush_all = 0;

	/* now let them in, 1407 CPUMF external interrupts */

	hws_alert = 1;

	irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);



	return 0;

arch/s390/oprofile/init.c

+20 −3
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
 */



#include <linux/oprofile.h>

#include <linux/perf_event.h>

#include <linux/init.h>

#include <linux/errno.h>

#include <linux/fs.h>
@@ -67,6 +68,21 @@ module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0); 
MODULE_PARM_DESC(cpu_type, "Force legacy basic mode sampling"

		           "(report cpu_type \"timer\"");



static int __oprofile_hwsampler_start(void)

{

	int retval;



	retval = hwsampler_allocate(oprofile_sdbt_blocks, oprofile_sdb_blocks);

	if (retval)

		return retval;



	retval = hwsampler_start_all(oprofile_hw_interval);

	if (retval)

		hwsampler_deallocate();



	return retval;

}



static int oprofile_hwsampler_start(void)

{

	int retval;
@@ -76,13 +92,13 @@ static int oprofile_hwsampler_start(void) 
	if (!hwsampler_running)

		return timer_ops.start();



	retval = hwsampler_allocate(oprofile_sdbt_blocks, oprofile_sdb_blocks);

	retval = perf_reserve_sampling();

	if (retval)

		return retval;



	retval = hwsampler_start_all(oprofile_hw_interval);

	retval = __oprofile_hwsampler_start();

	if (retval)

		hwsampler_deallocate();

		perf_release_sampling();



	return retval;

}
@@ -96,6 +112,7 @@ static void oprofile_hwsampler_stop(void) 


	hwsampler_stop_all();

	hwsampler_deallocate();

	perf_release_sampling();

	return;

}