// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/bug.h>
#include <linux/compiler.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/processor.h>
#include <linux/smp.h>
#include <linux/topology.h>
#include <linux/sched/clock.h>
#include <asm/qspinlock.h>
#include <asm/paravirt.h>
#define MAX_NODES 4
struct qnode {
struct qnode *next;
struct qspinlock *lock;
int cpu;
u8 sleepy; /* 1 if the previous vCPU was preempted or
* if the previous node was sleepy */
u8 locked; /* 1 if lock acquired */
};
struct qnodes {
int count;
struct qnode nodes[MAX_NODES];
};
/* Tuning parameters */
static int steal_spins __read_mostly = (1 << 5);
static int remote_steal_spins __read_mostly = (1 << 2);
#if _Q_SPIN_TRY_LOCK_STEAL == 1
static const bool maybe_stealers = true;
#else
static bool maybe_stealers __read_mostly = true;
#endif
static int head_spins __read_mostly = (1 << 8);
static bool pv_yield_owner __read_mostly = true;
static bool pv_yield_allow_steal __read_mostly = false;
static bool pv_spin_on_preempted_owner __read_mostly = false;
static bool pv_sleepy_lock __read_mostly = true;
static bool pv_sleepy_lock_sticky __read_mostly = false;
static u64 pv_sleepy_lock_interval_ns __read_mostly = 0;
static int pv_sleepy_lock_factor __read_mostly = 256;
static bool pv_yield_prev __read_mostly = true;
static bool pv_yield_sleepy_owner __read_mostly = true;
static bool pv_prod_head __read_mostly = false;
static DEFINE_PER_CPU_ALIGNED(struct qnodes, qnodes);
static DEFINE_PER_CPU_ALIGNED(u64, sleepy_lock_seen_clock);
#if _Q_SPIN_SPEC_BARRIER == 1
#define spec_barrier() do { asm volatile("ori 31,31,0" ::: "memory"); } while (0)
#else
#define spec_barrier() do { } while (0)
#endif
static __always_inline bool recently_sleepy(void)
{
/* pv_sleepy_lock is true when this is called */
if (pv_sleepy_lock_interval_ns) {
u64 seen = this_cpu_read(sleepy_lock_seen_clock);
if (seen) {
u64 delta = sched_clock() - seen;
if (delta < pv_sleepy_lock_interval_ns)
return true;
this_cpu_write(sleepy_lock_seen_clock, 0);
}
}
return false;
}
static __always_inline int get_steal_spins(bool paravirt, bool sleepy)
{
if (paravirt && sleepy)
return steal_spins * pv_sleepy_lock_factor;
else
return steal_spins;
}
static __always_inline int get_remote_steal_spins(bool paravirt, bool sleepy)
{
if (paravirt && sleepy)
return remote_steal_spins * pv_sleepy_lock_factor;
else
return remote_steal_spins;
}
static __always_inline int get_head_spins(bool paravirt, bool sleepy)
{
if (paravirt && sleepy)
return head_spins * pv_sleepy_lock_factor;
else
return head_spins;
}
static inline u32 encode_tail_cpu(int cpu)
{
return (cpu + 1) << _Q_TAIL_CPU_OFFSET;
}
static inline int decode_tail_cpu(u32 val)
{
return (val >> _Q_TAIL_CPU_OFFSET) - 1;
}
static inline int get_owner_cpu(u32 val)
{
return (val & _Q_OWNER_CPU_MASK) >> _Q_OWNER_CPU_OFFSET;
}
/*
* Try to acquire the lock if it was not already locked. If the tail matches
* mytail then clear it, otherwise leave it unchnaged. Return previous value.
*
* This is used by the head of the queue to acquire the lock and clean up
* its tail if it was the last one queued.
*/
static __always_inline u32 trylock_clean_tail(struct qspinlock *lock, u32 tail)
{
u32 newval = queued_spin_encode_locked_val();
u32 prev, tmp;
asm volatile(
"1: lwarx %0,0,%2,%7 # trylock_clean_tail \n"
/* This test is necessary if there could be stealers */
" andi. %1,%0,%5 \n"
" bne 3f \n"
/* Test whether the lock tail == mytail */
" and %1,%0,%6 \n"
" cmpw 0,%1,%3 \n"
/* Merge the new locked value */
" or %1,%1,%4 \n"
" bne 2f \n"
/* If the lock tail matched, then clear it, otherwise leave it. */
" andc %1,%1,%6 \n"
"2: stwcx. %1,0,%2 \n"
" bne- 1b \n"
"\t" PPC_ACQUIRE_BARRIER " \n"
"3: \n"
: "=&r" (prev), "=&r" (tmp)
: "r" (&lock->val), "r"(tail), "r" (newval),
"i" (_Q_LOCKED_VAL),
"r" (_Q_TAIL_CPU_MASK),
"i" (_Q_SPIN_EH_HINT)
: "cr0", "memory");
return prev;
}
/*
* Publish our tail, replacing previous tail. Return previous value.
*
* This provides a release barrier for publishing node, this pairs with the
* acquire barrier in get_tail_qnode() when the next CPU finds this tail
* value.
*/
static __always_inline u32 publish_tail_cpu(struct qspinlock *lock, u32 tail)
{
u32 prev, tmp;
kcsan_release();
asm volatile(
"\t" PPC_RELEASE_BARRIER " \n"
"1: lwarx %0,0,%2 # publish_tail_cpu \n"
" andc %1,%0,%4 \n"
" or %1,%1,%3 \n"
" stwcx. %1,0,%2 \n"
" bne- 1b \n"
: "=&r" (prev), "=&r"(tmp)
: "r" (&lock->val), "r" (tail), "r"(_Q_TAIL_CPU_MASK)
: "cr0", "memory");
return prev;
}
static __always_inline u32 set_mustq(struct qspinlock *lock)
{
u32 prev;
asm volatile(
"1: lwarx %0,0,%1 # set_mustq \n"
" or %0,%0,%2 \n"
" stwcx. %0,0,%1 \n"
" bne- 1b \n"
: "=&r" (prev)
: "r" (&lock->val), "r" (_Q_MUST_Q_VAL)
: "cr0", "memory");
return prev;
}
static __always_inline u32 clear_mustq(struct qspinlock *lock)
{
u32 prev;
asm volatile(
"1: lwarx %0,0,%1 # clear_mustq \n"
" andc %0,%0,%2 \n"
" stwcx. %0,0,%1 \n"
" bne- 1b \n"
: "=&r" (prev)
: "r" (&lock->val), "r" (_Q_MUST_Q_VAL)
: "cr0", "memory");
return prev;
}
static __always_inline bool try_set_sleepy(struct qspinlock *lock, u32 old)
{
u32 prev;
u32 new = old | _Q_SLEEPY_VAL;
BUG_ON(!(old & _Q_LOCKED_VAL));
BUG_ON(old & _Q_SLEEPY_VAL);
asm volatile(
"1: lwarx %0,0,%1 # try_set_sleepy \n"
" cmpw 0,%0,%2 \n"
" bne- 2f \n"
" stwcx. %3,0,%1 \n"
" bne- 1b \n"
"2: \n"
: "=&r" (prev)
: "r" (&lock->val), "r"(old), "r" (new)
: "cr0", "memory");
return likely(prev == old);
}
static __always_inline void seen_sleepy_owner(struct qspinlock *lock, u32 val)
{
if (pv_sleepy_lock) {
if (pv_sleepy_lock_interval_ns)
this_cpu_write(sleepy_lock_seen_clock, sched_clock());
if (!(val & _Q_SLEEPY_VAL))
try_set_sleepy(lock, val);
}
}
static __always_inline void seen_sleepy_lock(void)
{
if (pv_sleepy_lock && pv_sleepy_lock_interval_ns)
this_cpu_write(sleepy_lock_seen_clock, sched_clock());
}
static __always_inline void seen_sleepy_node(void)
{
if (pv_sleepy_lock) {
if (pv_sleepy_lock_interval_ns)
this_cpu_write(sleepy_lock_seen_clock, sched_clock());
/* Don't set sleepy because we likely have a stale val */
}
}
static struct qnode *get_tail_qnode(struct qspinlock *lock, int prev_cpu)
{
struct qnodes *qnodesp = per_cpu_ptr(&qnodes, prev_cpu);
int idx;
/*
* After publishing the new tail and finding a previous tail in the
* previous val (which is the control dependency), this barrier
* orders the release barrier in publish_tail_cpu performed by the
* last CPU, with subsequently looking at its qnode structures
* after the barrier.
*/
smp_acquire__after_ctrl_dep();
for (idx = 0; idx < MAX_NODES; idx++) {
struct qnode *qnode = &qnodesp->nodes[idx];
if (qnode->lock == lock)
return qnode;
}
BUG();
}
/* Called inside spin_begin(). Returns whether or not the vCPU was preempted. */
static __always_inline bool __yield_to_locked_owner(struct qspinlock *lock, u32 val, bool paravirt, bool mustq)
{
int owner;
u32 yield_count;
bool preempted = false;
BUG_ON(!(val & _Q_LOCKED_VAL));
if (!paravirt)
goto relax;
if (!pv_yield_owner)
goto relax;
owner = get_owner_cpu(val);
yield_count = yield_count_of(owner);
if ((yield_count & 1) == 0)
goto relax; /* owner vcpu is running */
spin_end();
seen_sleepy_owner(lock, val);
preempted = true;
/*
* Read the lock word after sampling the yield count. On the other side
* there may a wmb because the yield count update is done by the
* hypervisor preemption and the value update by the OS, however this
* ordering might reduce the chance of out of order accesses and
* improve the heuristic.
*/
smp_rmb();
if (READ_ONCE(lock->val) == val) {
if (mustq)
clear_mustq(lock);
yield_to_preempted(owner, yield_count);
if (mustq)
set_mustq(lock);
spin_begin();
/* Don't relax if we yielded. Maybe we should? */
return preempted;
}
spin_begin();
relax:
spin_cpu_relax();
return preempted;
}
/* Called inside spin_begin(). Returns whether or not the vCPU was preempted. */
static __always_inline bool yield_to_locked_owner(struct qspinlock *lock, u32 val, bool paravirt)
{
return __yield_to_locked_owner(lock, val, paravirt, false);
}
/* Called inside spin_begin(). Returns whether or not the vCPU was preempted. */
static __always_inline bool yield_head_to_locked_owner(struct qspinlock *lock, u32 val, bool paravirt)
{
bool mustq = false;
if ((val & _Q_MUST_Q_VAL) && pv_yield_allow_steal)
mustq = true;
return __yield_to_locked_owner(lock, val, paravirt, mustq);
}
static __always_inline void propagate_sleepy(struct qnode *node, u32 val, bool paravirt)
{
struct qnode *next;
int owner;
if (!paravirt)
return;
if (!pv_yield_sleepy_owner)
return;
next = READ_ONCE(node->next);
if (!next)
return;
if (next->sleepy)
return;
owner = get_owner_cpu(val);
if (vcpu_is_preempted(owner))
next->sleepy = 1;
}
/* Called inside spin_begin() */
static __always_inline bool yield_to_prev(struct qspinlock *lock, struct qnode *node, int prev_cpu, bool paravirt)
{
u32 yield_count;
bool preempted = false;
if (!paravirt)
goto relax;
if (!pv_yield_sleepy_owner)
goto yield_prev;
/*
* If the previous waiter was preempted it might not be able to
* propagate sleepy to us, so check the lock in that case too.
*/
if (node->sleepy || vcpu_is_preempted(prev_cpu)) {
u32 val = READ_ONCE(lock->val);
if (val & _Q_LOCKED_VAL) {
if (node->next && !node->next->sleepy) {
/*
* Propagate sleepy to next waiter. Only if
* owner is preempted, which allows the queue
* to become "non-sleepy" if vCPU preemption
* ceases to occur, even if the lock remains
* highly contended.
*/
if (vcpu_is_preempted(get_owner_cpu(val)))
node->next->sleepy = 1;
}
preempted = yield_to_locked_owner(lock, val, paravirt);
if (preempted)
return preempted;
}
node->sleepy = false;
}
yield_prev:
if (!pv_yield_prev)
goto relax;
yield_count = yield_count_of(prev_cpu);
if ((yield_count & 1) == 0)
goto relax; /* owner vcpu is running */
spin_end();
preempted = true;
seen_sleepy_node();
smp_rmb(); /* See __yield_to_locked_owner comment */
if (!READ_ONCE(node->locked)) {
yield_to_preempted(prev_cpu, yield_count);
spin_begin();
return preempted;
}
spin_begin();
relax:
spin_cpu_relax();
return preempted;
}
static __always_inline bool steal_break(u32 val, int iters, bool paravirt, bool sleepy)
{
if (iters >= get_steal_spins(paravirt, sleepy))
return true;
if (IS_ENABLED(CONFIG_NUMA) &&
(iters >= get_remote_steal_spins(paravirt, sleepy))) {
int cpu = get_owner_cpu(val);
if (numa_node_id() != cpu_to_node(cpu))
return true;
}
return false;
}
static __always_inline bool try_to_steal_lock(struct qspinlock *lock, bool paravirt)
{
bool seen_preempted = false;
bool sleepy = false;
int iters = 0;
u32 val;
if (!steal_spins) {
/* XXX: should spin_on_preempted_owner do anything here? */
return false;
}
/* Attempt to steal the lock */
spin_begin();
do {
bool preempted = false;
val = READ_ONCE(lock->val);
if (val & _Q_MUST_Q_VAL)
break;
spec_barrier();
if (unlikely(!(val & _Q_LOCKED_VAL))) {
spin_end();
if (__queued_spin_trylock_steal(lock))
return true;
spin_begin();
} else {
preempted = yield_to_locked_owner(lock, val, paravirt);
}
if (paravirt && pv_sleepy_lock) {
if (!sleepy) {
if (val & _Q_SLEEPY_VAL) {
seen_sleepy_lock();
sleepy = true;
} else if (recently_sleepy()) {
sleepy = true;
}
}
if (pv_sleepy_lock_sticky && seen_preempted &&
!(val & _Q_SLEEPY_VAL)) {
if (try_set_sleepy(lock, val))
val |= _Q_SLEEPY_VAL;
}
}
if (preempted) {
seen_preempted = true;
sleepy = true;
if (!pv_spin_on_preempted_owner)
iters++;
/*
* pv_spin_on_preempted_owner don't increase iters
* while the owner is preempted -- we won't interfere
* with it by definition. This could introduce some
* latency issue if we continually observe preempted
* owners, but hopefully that's a rare corner case of
* a badly oversubscribed system.
*/
} else {
iters++;
}
} while (!steal_break(val, iters, paravirt, sleepy));
spin_end();
return false;
}
static __always_inline void queued_spin_lock_mcs_queue(struct qspinlock *lock, bool paravirt)
{
struct qnodes *qnodesp;
struct qnode *next, *node;
u32 val, old, tail;
bool seen_preempted = false;
bool sleepy = false;
bool mustq = false;
int idx;
int iters = 0;
BUILD_BUG_ON(CONFIG_NR_CPUS >= (1U << _Q_TAIL_CPU_BITS));
qnodesp = this_cpu_ptr(&qnodes);
if (unlikely(qnodesp->count >= MAX_NODES)) {
spec_barrier();
while (!queued_spin_trylock(lock))
cpu_relax();
return;
}
idx = qnodesp->count++;
/*
* Ensure that we increment the head node->count before initialising
* the actual node. If the compiler is kind enough to reorder these
* stores, then an IRQ could overwrite our assignments.
*/
barrier();
node = &qnodesp->nodes[idx];
node->next = NULL;
node->lock = lock;
node->cpu = smp_processor_id();
node->sleepy = 0;
node->locked = 0;
tail = encode_tail_cpu(node->cpu);
/*
* Assign all attributes of a node before it can be published.
* Issues an lwsync, serving as a release barrier, as well as a
* compiler barrier.
*/
old = publish_tail_cpu(lock, tail);
/*
* If there was a previous node; link it and wait until reaching the
* head of the waitqueue.
*/
if (old & _Q_TAIL_CPU_MASK) {
int prev_cpu = decode_tail_cpu(old);
struct qnode *prev = get_tail_qnode(lock, prev_cpu);
/* Link @node into the waitqueue. */
WRITE_ONCE(prev->next, node);
/* Wait for mcs node lock to be released */
spin_begin();
while (!READ_ONCE(node->locked)) {
spec_barrier();
if (yield_to_prev(lock, node, prev_cpu, paravirt))
seen_preempted = true;
}
spec_barrier();
spin_end();
smp_rmb(); /* acquire barrier for the mcs lock */
/*
* Generic qspinlocks have this prefetch here, but it seems
* like it could cause additional line transitions because
* the waiter will keep loading from it.
*/
if (_Q_SPIN_PREFETCH_NEXT) {
next = READ_ONCE(node->next);
if (next)
prefetchw(next);
}
}
/* We're at the head of the waitqueue, wait for the lock. */
again:
spin_begin();
for (;;) {
bool preempted;
val = READ_ONCE(lock->val);
if (!(val & _Q_LOCKED_VAL))
break;
spec_barrier();
if (paravirt && pv_sleepy_lock && maybe_stealers) {
if (!sleepy) {
if (val & _Q_SLEEPY_VAL) {
seen_sleepy_lock();
sleepy = true;
} else if (recently_sleepy()) {
sleepy = true;
}
}
if (pv_sleepy_lock_sticky && seen_preempted &&
!(val & _Q_SLEEPY_VAL)) {
if (try_set_sleepy(lock, val))
val |= _Q_SLEEPY_VAL;
}
}
propagate_sleepy(node, val, paravirt);
preempted = yield_head_to_locked_owner(lock, val, paravirt);
if (!maybe_stealers)
continue;
if (preempted)
seen_preempted = true;
if (paravirt && preempted) {
sleepy = true;
if (!pv_spin_on_preempted_owner)
iters++;
} else {
iters++;
}
if (!mustq && iters >= get_head_spins(paravirt, sleepy)) {
mustq = true;
set_mustq(lock);
val |= _Q_MUST_Q_VAL;
}
}
spec_barrier();
spin_end();
/* If we're the last queued, must clean up the tail. */
old = trylock_clean_tail(lock, tail);
if (unlikely(old & _Q_LOCKED_VAL)) {
BUG_ON(!maybe_stealers);
goto again; /* Can only be true if maybe_stealers. */
}
if ((old & _Q_TAIL_CPU_MASK) == tail)
goto release; /* We were the tail, no next. */
/* There is a next, must wait for node->next != NULL (MCS protocol) */
next = READ_ONCE(node->next);
if (!next) {
spin_begin();
while (!(next = READ_ONCE(node->next)))
cpu_relax();
spin_end();
}
spec_barrier();
/*
* Unlock the next mcs waiter node. Release barrier is not required
* here because the acquirer is only accessing the lock word, and
* the acquire barrier we took the lock with orders that update vs
* this store to locked. The corresponding barrier is the smp_rmb()
* acquire barrier for mcs lock, above.
*/
if (paravirt && pv_prod_head) {
int next_cpu = next->cpu;
WRITE_ONCE(next->locked, 1);
if (_Q_SPIN_MISO)
asm volatile("miso" ::: "memory");
if (vcpu_is_preempted(next_cpu))
prod_cpu(next_cpu);
} else {
WRITE_ONCE(next->locked, 1);
if (_Q_SPIN_MISO)
asm volatile("miso" ::: "memory");
}
release:
qnodesp->count--; /* release the node */
}
void queued_spin_lock_slowpath(struct qspinlock *lock)
{
/*
* This looks funny, but it induces the compiler to inline both
* sides of the branch rather than share code as when the condition
* is passed as the paravirt argument to the functions.
*/
if (IS_ENABLED(CONFIG_PARAVIRT_SPINLOCKS) && is_shared_processor()) {
if (try_to_steal_lock(lock, true)) {
spec_barrier();
return;
}
queued_spin_lock_mcs_queue(lock, true);
} else {
if (try_to_steal_lock(lock, false)) {
spec_barrier();
return;
}
queued_spin_lock_mcs_queue(lock, false);
}
}
EXPORT_SYMBOL(queued_spin_lock_slowpath);
#ifdef CONFIG_PARAVIRT_SPINLOCKS
void pv_spinlocks_init(void)
{
}
#endif
#include <linux/debugfs.h>
static int steal_spins_set(void *data, u64 val)
{
#if _Q_SPIN_TRY_LOCK_STEAL == 1
/* MAYBE_STEAL remains true */
steal_spins = val;
#else
static DEFINE_MUTEX(lock);
/*
* The lock slow path has a !maybe_stealers case that can assume
* the head of queue will not see concurrent waiters. That waiter
* is unsafe in the presence of stealers, so must keep them away
* from one another.
*/
mutex_lock(&lock);
if (val && !steal_spins) {
maybe_stealers = true;
/* wait for queue head waiter to go away */
synchronize_rcu();
steal_spins = val;
} else if (!val && steal_spins) {
steal_spins = val;
/* wait for all possible stealers to go away */
synchronize_rcu();
maybe_stealers = false;
} else {
steal_spins = val;
}
mutex_unlock(&lock);
#endif
return 0;
}
static int steal_spins_get(void *data, u64 *val)
{
*val = steal_spins;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_steal_spins, steal_spins_get, steal_spins_set, "%llu\n");
static int remote_steal_spins_set(void *data, u64 val)
{
remote_steal_spins = val;
return 0;
}
static int remote_steal_spins_get(void *data, u64 *val)
{
*val = remote_steal_spins;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_remote_steal_spins, remote_steal_spins_get, remote_steal_spins_set, "%llu\n");
static int head_spins_set(void *data, u64 val)
{
head_spins = val;
return 0;
}
static int head_spins_get(void *data, u64 *val)
{
*val = head_spins;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_head_spins, head_spins_get, head_spins_set, "%llu\n");
static int pv_yield_owner_set(void *data, u64 val)
{
pv_yield_owner = !!val;
return 0;
}
static int pv_yield_owner_get(void *data, u64 *val)
{
*val = pv_yield_owner;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_yield_owner, pv_yield_owner_get, pv_yield_owner_set, "%llu\n");
static int pv_yield_allow_steal_set(void *data, u64 val)
{
pv_yield_allow_steal = !!val;
return 0;
}
static int pv_yield_allow_steal_get(void *data, u64 *val)
{
*val = pv_yield_allow_steal;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_yield_allow_steal, pv_yield_allow_steal_get, pv_yield_allow_steal_set, "%llu\n");
static int pv_spin_on_preempted_owner_set(void *data, u64 val)
{
pv_spin_on_preempted_owner = !!val;
return 0;
}
static int pv_spin_on_preempted_owner_get(void *data, u64 *val)
{
*val = pv_spin_on_preempted_owner;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_spin_on_preempted_owner, pv_spin_on_preempted_owner_get, pv_spin_on_preempted_owner_set, "%llu\n");
static int pv_sleepy_lock_set(void *data, u64 val)
{
pv_sleepy_lock = !!val;
return 0;
}
static int pv_sleepy_lock_get(void *data, u64 *val)
{
*val = pv_sleepy_lock;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_sleepy_lock, pv_sleepy_lock_get, pv_sleepy_lock_set, "%llu\n");
static int pv_sleepy_lock_sticky_set(void *data, u64 val)
{
pv_sleepy_lock_sticky = !!val;
return 0;
}
static int pv_sleepy_lock_sticky_get(void *data, u64 *val)
{
*val = pv_sleepy_lock_sticky;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_sleepy_lock_sticky, pv_sleepy_lock_sticky_get, pv_sleepy_lock_sticky_set, "%llu\n");
static int pv_sleepy_lock_interval_ns_set(void *data, u64 val)
{
pv_sleepy_lock_interval_ns = val;
return 0;
}
static int pv_sleepy_lock_interval_ns_get(void *data, u64 *val)
{
*val = pv_sleepy_lock_interval_ns;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_sleepy_lock_interval_ns, pv_sleepy_lock_interval_ns_get, pv_sleepy_lock_interval_ns_set, "%llu\n");
static int pv_sleepy_lock_factor_set(void *data, u64 val)
{
pv_sleepy_lock_factor = val;
return 0;
}
static int pv_sleepy_lock_factor_get(void *data, u64 *val)
{
*val = pv_sleepy_lock_factor;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_sleepy_lock_factor, pv_sleepy_lock_factor_get, pv_sleepy_lock_factor_set, "%llu\n");
static int pv_yield_prev_set(void *data, u64 val)
{
pv_yield_prev = !!val;
return 0;
}
static int pv_yield_prev_get(void *data, u64 *val)
{
*val = pv_yield_prev;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_yield_prev, pv_yield_prev_get, pv_yield_prev_set, "%llu\n");
static int pv_yield_sleepy_owner_set(void *data, u64 val)
{
pv_yield_sleepy_owner = !!val;
return 0;
}
static int pv_yield_sleepy_owner_get(void *data, u64 *val)
{
*val = pv_yield_sleepy_owner;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_yield_sleepy_owner, pv_yield_sleepy_owner_get, pv_yield_sleepy_owner_set, "%llu\n");
static int pv_prod_head_set(void *data, u64 val)
{
pv_prod_head = !!val;
return 0;
}
static int pv_prod_head_get(void *data, u64 *val)
{
*val = pv_prod_head;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pv_prod_head, pv_prod_head_get, pv_prod_head_set, "%llu\n");
static __init int spinlock_debugfs_init(void)
{
debugfs_create_file("qspl_steal_spins", 0600, arch_debugfs_dir, NULL, &fops_steal_spins);
debugfs_create_file("qspl_remote_steal_spins", 0600, arch_debugfs_dir, NULL, &fops_remote_steal_spins);
debugfs_create_file("qspl_head_spins", 0600, arch_debugfs_dir, NULL, &fops_head_spins);
if (is_shared_processor()) {
debugfs_create_file("qspl_pv_yield_owner", 0600, arch_debugfs_dir, NULL, &fops_pv_yield_owner);
debugfs_create_file("qspl_pv_yield_allow_steal", 0600, arch_debugfs_dir, NULL, &fops_pv_yield_allow_steal);
debugfs_create_file("qspl_pv_spin_on_preempted_owner", 0600, arch_debugfs_dir, NULL, &fops_pv_spin_on_preempted_owner);
debugfs_create_file("qspl_pv_sleepy_lock", 0600, arch_debugfs_dir, NULL, &fops_pv_sleepy_lock);
debugfs_create_file("qspl_pv_sleepy_lock_sticky", 0600, arch_debugfs_dir, NULL, &fops_pv_sleepy_lock_sticky);
debugfs_create_file("qspl_pv_sleepy_lock_interval_ns", 0600, arch_debugfs_dir, NULL, &fops_pv_sleepy_lock_interval_ns);
debugfs_create_file("qspl_pv_sleepy_lock_factor", 0600, arch_debugfs_dir, NULL, &fops_pv_sleepy_lock_factor);
debugfs_create_file("qspl_pv_yield_prev", 0600, arch_debugfs_dir, NULL, &fops_pv_yield_prev);
debugfs_create_file("qspl_pv_yield_sleepy_owner", 0600, arch_debugfs_dir, NULL, &fops_pv_yield_sleepy_owner);
debugfs_create_file("qspl_pv_prod_head", 0600, arch_debugfs_dir, NULL, &fops_pv_prod_head);
}
return 0;
}
device_initcall(spinlock_debugfs_init);
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