[deliverable/linux.git] / arch / x86 / xen / spinlock.c

/*
 * Split spinlock implementation out into its own file, so it can be
 * compiled in a FTRACE-compatible way.
 */
#include <linux/kernel_stat.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/log2.h>
#include <linux/gfp.h>
#include <linux/slab.h>

#include <asm/paravirt.h>

#include <xen/interface/xen.h>
#include <xen/events.h>

#include "xen-ops.h"
#include "debugfs.h"

enum xen_contention_stat {
	TAKEN_SLOW,
	TAKEN_SLOW_PICKUP,
	TAKEN_SLOW_SPURIOUS,
	RELEASED_SLOW,
	RELEASED_SLOW_KICKED,
	NR_CONTENTION_STATS
};


#ifdef CONFIG_XEN_DEBUG_FS
#define HISTO_BUCKETS	30
static struct xen_spinlock_stats
{
	u32 contention_stats[NR_CONTENTION_STATS];
	u32 histo_spin_blocked[HISTO_BUCKETS+1];
	u64 time_blocked;
} spinlock_stats;

static u8 zero_stats;

static inline void check_zero(void)
{
	u8 ret;
	u8 old = ACCESS_ONCE(zero_stats);
	if (unlikely(old)) {
		ret = cmpxchg(&zero_stats, old, 0);
		/* This ensures only one fellow resets the stat */
		if (ret == old)
			memset(&spinlock_stats, 0, sizeof(spinlock_stats));
	}
}

static inline void add_stats(enum xen_contention_stat var, u32 val)
{
	check_zero();
	spinlock_stats.contention_stats[var] += val;
}

static inline u64 spin_time_start(void)
{
	return xen_clocksource_read();
}

static void __spin_time_accum(u64 delta, u32 *array)
{
	unsigned index = ilog2(delta);

	check_zero();

	if (index < HISTO_BUCKETS)
		array[index]++;
	else
		array[HISTO_BUCKETS]++;
}

static inline void spin_time_accum_blocked(u64 start)
{
	u32 delta = xen_clocksource_read() - start;

	__spin_time_accum(delta, spinlock_stats.histo_spin_blocked);
	spinlock_stats.time_blocked += delta;
}
#else  /* !CONFIG_XEN_DEBUG_FS */
static inline void add_stats(enum xen_contention_stat var, u32 val)
{
}

static inline u64 spin_time_start(void)
{
	return 0;
}

static inline void spin_time_accum_blocked(u64 start)
{
}
#endif  /* CONFIG_XEN_DEBUG_FS */

struct xen_lock_waiting {
	struct arch_spinlock *lock;
	__ticket_t want;
};

static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
static DEFINE_PER_CPU(char *, irq_name);
static DEFINE_PER_CPU(struct xen_lock_waiting, lock_waiting);
static cpumask_t waiting_cpus;

static bool xen_pvspin = true;
static void xen_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
{
	int irq = __this_cpu_read(lock_kicker_irq);
	struct xen_lock_waiting *w = &__get_cpu_var(lock_waiting);
	int cpu = smp_processor_id();
	u64 start;
	unsigned long flags;

	/* If kicker interrupts not initialized yet, just spin */
	if (irq == -1)
		return;

	start = spin_time_start();

	/*
	 * Make sure an interrupt handler can't upset things in a
	 * partially setup state.
	 */
	local_irq_save(flags);
	/*
	 * We don't really care if we're overwriting some other
	 * (lock,want) pair, as that would mean that we're currently
	 * in an interrupt context, and the outer context had
	 * interrupts enabled.  That has already kicked the VCPU out
	 * of xen_poll_irq(), so it will just return spuriously and
	 * retry with newly setup (lock,want).
	 *
	 * The ordering protocol on this is that the "lock" pointer
	 * may only be set non-NULL if the "want" ticket is correct.
	 * If we're updating "want", we must first clear "lock".
	 */
	w->lock = NULL;
	smp_wmb();
	w->want = want;
	smp_wmb();
	w->lock = lock;

	/* This uses set_bit, which atomic and therefore a barrier */
	cpumask_set_cpu(cpu, &waiting_cpus);
	add_stats(TAKEN_SLOW, 1);

	/* clear pending */
	xen_clear_irq_pending(irq);

	/* Only check lock once pending cleared */
	barrier();

	/*
	 * Mark entry to slowpath before doing the pickup test to make
	 * sure we don't deadlock with an unlocker.
	 */
	__ticket_enter_slowpath(lock);

	/*
	 * check again make sure it didn't become free while
	 * we weren't looking
	 */
	if (ACCESS_ONCE(lock->tickets.head) == want) {
		add_stats(TAKEN_SLOW_PICKUP, 1);
		goto out;
	}

	/* Allow interrupts while blocked */
	local_irq_restore(flags);

	/*
	 * If an interrupt happens here, it will leave the wakeup irq
	 * pending, which will cause xen_poll_irq() to return
	 * immediately.
	 */

	/* Block until irq becomes pending (or perhaps a spurious wakeup) */
	xen_poll_irq(irq);
	add_stats(TAKEN_SLOW_SPURIOUS, !xen_test_irq_pending(irq));

	local_irq_save(flags);

	kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
out:
	cpumask_clear_cpu(cpu, &waiting_cpus);
	w->lock = NULL;

	local_irq_restore(flags);

	spin_time_accum_blocked(start);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_lock_spinning);

static void xen_unlock_kick(struct arch_spinlock *lock, __ticket_t next)
{
	int cpu;

	add_stats(RELEASED_SLOW, 1);

	for_each_cpu(cpu, &waiting_cpus) {
		const struct xen_lock_waiting *w = &per_cpu(lock_waiting, cpu);

		/* Make sure we read lock before want */
		if (ACCESS_ONCE(w->lock) == lock &&
		    ACCESS_ONCE(w->want) == next) {
			add_stats(RELEASED_SLOW_KICKED, 1);
			xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
			break;
		}
	}
}

static irqreturn_t dummy_handler(int irq, void *dev_id)
{
	BUG();
	return IRQ_HANDLED;
}

void xen_init_lock_cpu(int cpu)
{
	int irq;
	char *name;

	if (!xen_pvspin)
		return;

	WARN(per_cpu(lock_kicker_irq, cpu) >= 0, "spinlock on CPU%d exists on IRQ%d!\n",
	     cpu, per_cpu(lock_kicker_irq, cpu));

	name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
	irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
				     cpu,
				     dummy_handler,
				     IRQF_PERCPU|IRQF_NOBALANCING,
				     name,
				     NULL);

	if (irq >= 0) {
		disable_irq(irq); /* make sure it's never delivered */
		per_cpu(lock_kicker_irq, cpu) = irq;
		per_cpu(irq_name, cpu) = name;
	}

	printk("cpu %d spinlock event irq %d\n", cpu, irq);
}

void xen_uninit_lock_cpu(int cpu)
{
	if (!xen_pvspin)
		return;

	unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL);
	per_cpu(lock_kicker_irq, cpu) = -1;
	kfree(per_cpu(irq_name, cpu));
	per_cpu(irq_name, cpu) = NULL;
}


/*
 * Our init of PV spinlocks is split in two init functions due to us
 * using paravirt patching and jump labels patching and having to do
 * all of this before SMP code is invoked.
 *
 * The paravirt patching needs to be done _before_ the alternative asm code
 * is started, otherwise we would not patch the core kernel code.
 */
void __init xen_init_spinlocks(void)
{

	if (!xen_pvspin) {
		printk(KERN_DEBUG "xen: PV spinlocks disabled\n");
		return;
	}

	pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
	pv_lock_ops.unlock_kick = xen_unlock_kick;
}

/*
 * While the jump_label init code needs to happend _after_ the jump labels are
 * enabled and before SMP is started. Hence we use pre-SMP initcall level
 * init. We cannot do it in xen_init_spinlocks as that is done before
 * jump labels are activated.
 */
static __init int xen_init_spinlocks_jump(void)
{
	if (!xen_pvspin)
		return 0;

	static_key_slow_inc(&paravirt_ticketlocks_enabled);
	return 0;
}
early_initcall(xen_init_spinlocks_jump);

static __init int xen_parse_nopvspin(char *arg)
{
	xen_pvspin = false;
	return 0;
}
early_param("xen_nopvspin", xen_parse_nopvspin);

#ifdef CONFIG_XEN_DEBUG_FS

static struct dentry *d_spin_debug;

static int __init xen_spinlock_debugfs(void)
{
	struct dentry *d_xen = xen_init_debugfs();

	if (d_xen == NULL)
		return -ENOMEM;

	if (!xen_pvspin)
		return 0;

	d_spin_debug = debugfs_create_dir("spinlocks", d_xen);

	debugfs_create_u8("zero_stats", 0644, d_spin_debug, &zero_stats);

	debugfs_create_u32("taken_slow", 0444, d_spin_debug,
			   &spinlock_stats.contention_stats[TAKEN_SLOW]);
	debugfs_create_u32("taken_slow_pickup", 0444, d_spin_debug,
			   &spinlock_stats.contention_stats[TAKEN_SLOW_PICKUP]);
	debugfs_create_u32("taken_slow_spurious", 0444, d_spin_debug,
			   &spinlock_stats.contention_stats[TAKEN_SLOW_SPURIOUS]);

	debugfs_create_u32("released_slow", 0444, d_spin_debug,
			   &spinlock_stats.contention_stats[RELEASED_SLOW]);
	debugfs_create_u32("released_slow_kicked", 0444, d_spin_debug,
			   &spinlock_stats.contention_stats[RELEASED_SLOW_KICKED]);

	debugfs_create_u64("time_blocked", 0444, d_spin_debug,
			   &spinlock_stats.time_blocked);

	debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,
				spinlock_stats.histo_spin_blocked, HISTO_BUCKETS + 1);

	return 0;
}
fs_initcall(xen_spinlock_debugfs);

#endif	/* CONFIG_XEN_DEBUG_FS */
Commit	Line	Data
d5de8841 JF	1	/*
	2	* Split spinlock implementation out into its own file, so it can be
	3	* compiled in a FTRACE-compatible way.
	4	*/
	5	#include <linux/kernel_stat.h>
	6	#include <linux/spinlock.h>
994025ca JF	7	#include <linux/debugfs.h>
994025ca JF	8	#include <linux/log2.h>
5a0e3ad6	9	#include <linux/gfp.h>
354e7b76	10	#include <linux/slab.h>
d5de8841 JF	11
	12	#include <asm/paravirt.h>
	13
	14	#include <xen/interface/xen.h>
	15	#include <xen/events.h>
	16
	17	#include "xen-ops.h"
994025ca JF	18	#include "debugfs.h"
994025ca JF	19
80bd58fe JF	20	enum xen_contention_stat {
	21	TAKEN_SLOW,
	22	TAKEN_SLOW_PICKUP,
	23	TAKEN_SLOW_SPURIOUS,
	24	RELEASED_SLOW,
	25	RELEASED_SLOW_KICKED,
	26	NR_CONTENTION_STATS
	27	};
994025ca	28
994025ca	29
80bd58fe	30	#ifdef CONFIG_XEN_DEBUG_FS
f8eca41f	31	#define HISTO_BUCKETS 30
80bd58fe JF	32	static struct xen_spinlock_stats
	33	{
	34	u32 contention_stats[NR_CONTENTION_STATS];
f8eca41f	35	u32 histo_spin_blocked[HISTO_BUCKETS+1];
f8eca41f	36	u64 time_blocked;
994025ca JF	37	} spinlock_stats;
	38
	39	static u8 zero_stats;
	40
994025ca JF	41	static inline void check_zero(void)
994025ca JF	42	{
80bd58fe JF	43	u8 ret;
	44	u8 old = ACCESS_ONCE(zero_stats);
	45	if (unlikely(old)) {
	46	ret = cmpxchg(&zero_stats, old, 0);
	47	/* This ensures only one fellow resets the stat */
	48	if (ret == old)
	49	memset(&spinlock_stats, 0, sizeof(spinlock_stats));
994025ca JF	50	}
	51	}
	52
80bd58fe JF	53	static inline void add_stats(enum xen_contention_stat var, u32 val)
	54	{
	55	check_zero();
	56	spinlock_stats.contention_stats[var] += val;
	57	}
994025ca JF	58
	59	static inline u64 spin_time_start(void)
	60	{
	61	return xen_clocksource_read();
	62	}
	63
	64	static void __spin_time_accum(u64 delta, u32 *array)
	65	{
	66	unsigned index = ilog2(delta);
	67
	68	check_zero();
	69
	70	if (index < HISTO_BUCKETS)
	71	array[index]++;
	72	else
	73	array[HISTO_BUCKETS]++;
	74	}
	75
f8eca41f	76	static inline void spin_time_accum_blocked(u64 start)
994025ca JF	77	{
	78	u32 delta = xen_clocksource_read() - start;
	79
f8eca41f JF	80	__spin_time_accum(delta, spinlock_stats.histo_spin_blocked);
f8eca41f JF	81	spinlock_stats.time_blocked += delta;
994025ca JF	82	}
994025ca JF	83	#else /* !CONFIG_XEN_DEBUG_FS */
80bd58fe JF	84	static inline void add_stats(enum xen_contention_stat var, u32 val)
	85	{
	86	}
994025ca JF	87
	88	static inline u64 spin_time_start(void)
	89	{
	90	return 0;
	91	}
	92
f8eca41f	93	static inline void spin_time_accum_blocked(u64 start)
994025ca JF	94	{
	95	}
	96	#endif /* CONFIG_XEN_DEBUG_FS */
d5de8841	97
80bd58fe JF	98	struct xen_lock_waiting {
	99	struct arch_spinlock *lock;
	100	__ticket_t want;
d5de8841 JF	101	};
d5de8841 JF	102
545ac138	103	static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
354e7b76	104	static DEFINE_PER_CPU(char *, irq_name);
80bd58fe JF	105	static DEFINE_PER_CPU(struct xen_lock_waiting, lock_waiting);
80bd58fe JF	106	static cpumask_t waiting_cpus;
d5de8841	107
c3b7cb1f	108	static bool xen_pvspin = true;
80bd58fe	109	static void xen_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
d5de8841	110	{
780f36d8	111	int irq = __this_cpu_read(lock_kicker_irq);
80bd58fe JF	112	struct xen_lock_waiting *w = &__get_cpu_var(lock_waiting);
80bd58fe JF	113	int cpu = smp_processor_id();
f8eca41f	114	u64 start;
80bd58fe	115	unsigned long flags;
d5de8841 JF	116
	117	/* If kicker interrupts not initialized yet, just spin */
	118	if (irq == -1)
80bd58fe	119	return;
d5de8841	120
f8eca41f JF	121	start = spin_time_start();
f8eca41f JF	122
80bd58fe JF	123	/*
	124	* Make sure an interrupt handler can't upset things in a
	125	* partially setup state.
	126	*/
	127	local_irq_save(flags);
1ed7bf5f JF	128	/*
	129	* We don't really care if we're overwriting some other
	130	* (lock,want) pair, as that would mean that we're currently
	131	* in an interrupt context, and the outer context had
	132	* interrupts enabled. That has already kicked the VCPU out
	133	* of xen_poll_irq(), so it will just return spuriously and
	134	* retry with newly setup (lock,want).
	135	*
	136	* The ordering protocol on this is that the "lock" pointer
	137	* may only be set non-NULL if the "want" ticket is correct.
	138	* If we're updating "want", we must first clear "lock".
	139	*/
	140	w->lock = NULL;
	141	smp_wmb();
80bd58fe JF	142	w->want = want;
	143	smp_wmb();
	144	w->lock = lock;
4d576b57	145
80bd58fe JF	146	/* This uses set_bit, which atomic and therefore a barrier */
	147	cpumask_set_cpu(cpu, &waiting_cpus);
	148	add_stats(TAKEN_SLOW, 1);
4d576b57	149
80bd58fe JF	150	/* clear pending */
80bd58fe JF	151	xen_clear_irq_pending(irq);
4d576b57	152
80bd58fe JF	153	/* Only check lock once pending cleared */
80bd58fe JF	154	barrier();
d5de8841	155
1ed7bf5f JF	156	/*
	157	* Mark entry to slowpath before doing the pickup test to make
	158	* sure we don't deadlock with an unlocker.
	159	*/
96f853ea JF	160	__ticket_enter_slowpath(lock);
96f853ea JF	161
1ed7bf5f JF	162	/*
	163	* check again make sure it didn't become free while
	164	* we weren't looking
	165	*/
80bd58fe JF	166	if (ACCESS_ONCE(lock->tickets.head) == want) {
	167	add_stats(TAKEN_SLOW_PICKUP, 1);
	168	goto out;
	169	}
1ed7bf5f JF	170
	171	/* Allow interrupts while blocked */
	172	local_irq_restore(flags);
	173
	174	/*
	175	* If an interrupt happens here, it will leave the wakeup irq
	176	* pending, which will cause xen_poll_irq() to return
	177	* immediately.
	178	*/
	179
80bd58fe JF	180	/* Block until irq becomes pending (or perhaps a spurious wakeup) */
	181	xen_poll_irq(irq);
	182	add_stats(TAKEN_SLOW_SPURIOUS, !xen_test_irq_pending(irq));
1ed7bf5f JF	183
	184	local_irq_save(flags);
	185
d6c88a50	186	kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
d5de8841	187	out:
80bd58fe JF	188	cpumask_clear_cpu(cpu, &waiting_cpus);
80bd58fe JF	189	w->lock = NULL;
1ed7bf5f	190
80bd58fe	191	local_irq_restore(flags);
1ed7bf5f	192
f8eca41f	193	spin_time_accum_blocked(start);
d5de8841	194	}
354714dd	195	PV_CALLEE_SAVE_REGS_THUNK(xen_lock_spinning);
d5de8841	196
80bd58fe	197	static void xen_unlock_kick(struct arch_spinlock *lock, __ticket_t next)
d5de8841 JF	198	{
	199	int cpu;
	200
80bd58fe JF	201	add_stats(RELEASED_SLOW, 1);
	202
	203	for_each_cpu(cpu, &waiting_cpus) {
	204	const struct xen_lock_waiting *w = &per_cpu(lock_waiting, cpu);
994025ca	205
1ed7bf5f JF	206	/* Make sure we read lock before want */
	207	if (ACCESS_ONCE(w->lock) == lock &&
	208	ACCESS_ONCE(w->want) == next) {
80bd58fe	209	add_stats(RELEASED_SLOW_KICKED, 1);
d5de8841	210	xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
80bd58fe	211	break;
d5de8841 JF	212	}
	213	}
	214	}
	215
d5de8841 JF	216	static irqreturn_t dummy_handler(int irq, void *dev_id)
	217	{
	218	BUG();
	219	return IRQ_HANDLED;
	220	}
	221
148f9bb8	222	void xen_init_lock_cpu(int cpu)
d5de8841 JF	223	{
d5de8841 JF	224	int irq;
354e7b76	225	char *name;
d5de8841	226
3310bbed KRW	227	if (!xen_pvspin)
	228	return;
	229
cb91f8f4	230	WARN(per_cpu(lock_kicker_irq, cpu) >= 0, "spinlock on CPU%d exists on IRQ%d!\n",
cb9c6f15 KRW	231	cpu, per_cpu(lock_kicker_irq, cpu));
cb9c6f15 KRW	232
d5de8841 JF	233	name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
	234	irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
	235	cpu,
	236	dummy_handler,
9d71cee6	237	IRQF_PERCPU\|IRQF_NOBALANCING,
d5de8841 JF	238	name,
	239	NULL);
	240
	241	if (irq >= 0) {
	242	disable_irq(irq); /* make sure it's never delivered */
	243	per_cpu(lock_kicker_irq, cpu) = irq;
354e7b76	244	per_cpu(irq_name, cpu) = name;
d5de8841 JF	245	}
	246
	247	printk("cpu %d spinlock event irq %d\n", cpu, irq);
	248	}
	249
d68d82af AN	250	void xen_uninit_lock_cpu(int cpu)
d68d82af AN	251	{
3310bbed KRW	252	if (!xen_pvspin)
	253	return;
	254
d68d82af	255	unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL);
cb9c6f15	256	per_cpu(lock_kicker_irq, cpu) = -1;
354e7b76 KRW	257	kfree(per_cpu(irq_name, cpu));
354e7b76 KRW	258	per_cpu(irq_name, cpu) = NULL;
d68d82af AN	259	}
d68d82af AN	260
b8fa70b5	261
a945928e KRW	262	/*
	263	* Our init of PV spinlocks is split in two init functions due to us
	264	* using paravirt patching and jump labels patching and having to do
	265	* all of this before SMP code is invoked.
	266	*
	267	* The paravirt patching needs to be done _before_ the alternative asm code
	268	* is started, otherwise we would not patch the core kernel code.
	269	*/
d5de8841 JF	270	void __init xen_init_spinlocks(void)
d5de8841 JF	271	{
70dd4998	272
b8fa70b5 JF	273	if (!xen_pvspin) {
	274	printk(KERN_DEBUG "xen: PV spinlocks disabled\n");
	275	return;
	276	}
	277
354714dd	278	pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
80bd58fe	279	pv_lock_ops.unlock_kick = xen_unlock_kick;
d5de8841	280	}
994025ca	281
a945928e KRW	282	/*
	283	* While the jump_label init code needs to happend _after_ the jump labels are
	284	* enabled and before SMP is started. Hence we use pre-SMP initcall level
	285	* init. We cannot do it in xen_init_spinlocks as that is done before
	286	* jump labels are activated.
	287	*/
	288	static __init int xen_init_spinlocks_jump(void)
	289	{
	290	if (!xen_pvspin)
	291	return 0;
	292
	293	static_key_slow_inc(&paravirt_ticketlocks_enabled);
	294	return 0;
	295	}
	296	early_initcall(xen_init_spinlocks_jump);
	297
b8fa70b5 JF	298	static __init int xen_parse_nopvspin(char *arg)
	299	{
	300	xen_pvspin = false;
	301	return 0;
	302	}
	303	early_param("xen_nopvspin", xen_parse_nopvspin);
	304
994025ca JF	305	#ifdef CONFIG_XEN_DEBUG_FS
	306
	307	static struct dentry *d_spin_debug;
	308
	309	static int __init xen_spinlock_debugfs(void)
	310	{
	311	struct dentry *d_xen = xen_init_debugfs();
	312
	313	if (d_xen == NULL)
	314	return -ENOMEM;
	315
3310bbed KRW	316	if (!xen_pvspin)
	317	return 0;
	318
994025ca JF	319	d_spin_debug = debugfs_create_dir("spinlocks", d_xen);
	320
	321	debugfs_create_u8("zero_stats", 0644, d_spin_debug, &zero_stats);
	322
994025ca	323	debugfs_create_u32("taken_slow", 0444, d_spin_debug,
80bd58fe	324	&spinlock_stats.contention_stats[TAKEN_SLOW]);
994025ca	325	debugfs_create_u32("taken_slow_pickup", 0444, d_spin_debug,
80bd58fe	326	&spinlock_stats.contention_stats[TAKEN_SLOW_PICKUP]);
994025ca	327	debugfs_create_u32("taken_slow_spurious", 0444, d_spin_debug,
80bd58fe	328	&spinlock_stats.contention_stats[TAKEN_SLOW_SPURIOUS]);
994025ca	329
994025ca	330	debugfs_create_u32("released_slow", 0444, d_spin_debug,
80bd58fe	331	&spinlock_stats.contention_stats[RELEASED_SLOW]);
994025ca	332	debugfs_create_u32("released_slow_kicked", 0444, d_spin_debug,
80bd58fe	333	&spinlock_stats.contention_stats[RELEASED_SLOW_KICKED]);
994025ca	334
f8eca41f JF	335	debugfs_create_u64("time_blocked", 0444, d_spin_debug,
f8eca41f JF	336	&spinlock_stats.time_blocked);
994025ca	337
9fe2a701 SV	338	debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,
9fe2a701 SV	339	spinlock_stats.histo_spin_blocked, HISTO_BUCKETS + 1);
994025ca JF	340
	341	return 0;
	342	}
	343	fs_initcall(xen_spinlock_debugfs);
	344
	345	#endif /* CONFIG_XEN_DEBUG_FS */