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futex_requeue_pi optimization

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This patch provides the futex_requeue_pi functionality, which allows some
threads waiting on a normal futex to be requeued on the wait-queue of a
PI-futex.

This provides an optimization, already used for (normal) futexes, to be used
with the PI-futexes.

This optimization is currently used by the glibc in pthread_broadcast, when
using "normal" mutexes.  With futex_requeue_pi, it can be used with
PRIO_INHERIT mutexes too.

Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Pierre Peiffer 2007-05-09 02:35:02 -07:00 committed by Linus Torvalds
parent c19384b5b2
commit d0aa7a70bf
5 changed files with 540 additions and 88 deletions
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9
include/linux/futex.h
View file

@ -17,6 +17,7 @@ union ktime;
#define FUTEX_LOCK_PI 6
#define FUTEX_UNLOCK_PI 7
#define FUTEX_TRYLOCK_PI 8
#define FUTEX_CMP_REQUEUE_PI 9
/*
* Support for robust futexes: the kernel cleans up held futexes at
@ -84,10 +85,15 @@ struct robust_list_head {
*/
#define FUTEX_OWNER_DIED 0x40000000
/*
* Some processes have been requeued on this PI-futex
*/
#define FUTEX_WAITER_REQUEUED 0x20000000
/*
* The rest of the robust-futex field is for the TID:
*/
#define FUTEX_TID_MASK 0x3fffffff
#define FUTEX_TID_MASK 0x0fffffff
/*
* This limit protects against a deliberately circular list.
@ -111,6 +117,7 @@ handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);
* We set bit 0 to indicate if it's an inode-based key.
*/
union futex_key {
u32 __user *uaddr;
struct {
unsigned long pgoff;
struct inode *inode;

541
kernel/futex.c
View file

@ -53,6 +53,12 @@
#include "rtmutex_common.h"
#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
#else
# include "rtmutex.h"
#endif
#define FUTEX_HASHBITS (CONFIG_BASE_SMALL ? 4 : 8)
/*
@ -102,6 +108,12 @@ struct futex_q {
/* Optional priority inheritance state: */
struct futex_pi_state *pi_state;
struct task_struct *task;
/*
* This waiter is used in case of requeue from a
* normal futex to a PI-futex
*/
struct rt_mutex_waiter waiter;
};
/*
@ -180,6 +192,9 @@ int get_futex_key(u32 __user *uaddr, union futex_key *key)
if (unlikely((vma->vm_flags & (VM_IO|VM_READ)) != VM_READ))
return (vma->vm_flags & VM_IO) ? -EPERM : -EACCES;
/* Save the user address in the ley */
key->uaddr = uaddr;
/*
* Private mappings are handled in a simple way.
*
@ -439,7 +454,8 @@ void exit_pi_state_list(struct task_struct *curr)
}
static int
lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me)
lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
union futex_key *key, struct futex_pi_state **ps)
{
struct futex_pi_state *pi_state = NULL;
struct futex_q *this, *next;
@ -450,7 +466,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me)
head = &hb->chain;
plist_for_each_entry_safe(this, next, head, list) {
if (match_futex(&this->key, &me->key)) {
if (match_futex(&this->key, key)) {
/*
* Another waiter already exists - bump up
* the refcount and return its pi_state:
@ -465,7 +481,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me)
WARN_ON(!atomic_read(&pi_state->refcount));
atomic_inc(&pi_state->refcount);
me->pi_state = pi_state;
*ps = pi_state;
return 0;
}
@ -492,7 +508,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me)
rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p);
/* Store the key for possible exit cleanups: */
pi_state->key = me->key;
pi_state->key = *key;
spin_lock_irq(&p->pi_lock);
WARN_ON(!list_empty(&pi_state->list));
@ -502,7 +518,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me)
put_task_struct(p);
me->pi_state = pi_state;
*ps = pi_state;
return 0;
}
@ -562,6 +578,8 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
*/
if (!(uval & FUTEX_OWNER_DIED)) {
newval = FUTEX_WAITERS | new_owner->pid;
/* Keep the FUTEX_WAITER_REQUEUED flag if it was set */
newval |= (uval & FUTEX_WAITER_REQUEUED);
pagefault_disable();
curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
@ -665,6 +683,254 @@ out:
return ret;
}
/*
* Called from futex_requeue_pi.
* Set FUTEX_WAITERS and FUTEX_WAITER_REQUEUED flags on the
* PI-futex value; search its associated pi_state if an owner exist
* or create a new one without owner.
*/
static inline int
lookup_pi_state_for_requeue(u32 __user *uaddr, struct futex_hash_bucket *hb,
union futex_key *key,
struct futex_pi_state **pi_state)
{
u32 curval, uval, newval;
retry:
/*
* We can't handle a fault cleanly because we can't
* release the locks here. Simply return the fault.
*/
if (get_futex_value_locked(&curval, uaddr))
return -EFAULT;
/* set the flags FUTEX_WAITERS and FUTEX_WAITER_REQUEUED */
if ((curval & (FUTEX_WAITERS | FUTEX_WAITER_REQUEUED))
!= (FUTEX_WAITERS | FUTEX_WAITER_REQUEUED)) {
/*
* No waiters yet, we prepare the futex to have some waiters.
*/
uval = curval;
newval = uval | FUTEX_WAITERS | FUTEX_WAITER_REQUEUED;
pagefault_disable();
curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
pagefault_enable();
if (unlikely(curval == -EFAULT))
return -EFAULT;
if (unlikely(curval != uval))
goto retry;
}
if (!(curval & FUTEX_TID_MASK)
|| lookup_pi_state(curval, hb, key, pi_state)) {
/* the futex has no owner (yet) or the lookup failed:
allocate one pi_state without owner */
*pi_state = alloc_pi_state();
/* Already stores the key: */
(*pi_state)->key = *key;
/* init the mutex without owner */
__rt_mutex_init(&(*pi_state)->pi_mutex, NULL);
}
return 0;
}
/*
* Keep the first nr_wake waiter from futex1, wake up one,
* and requeue the next nr_requeue waiters following hashed on
* one physical page to another physical page (PI-futex uaddr2)
*/
static int futex_requeue_pi(u32 __user *uaddr1, u32 __user *uaddr2,
int nr_wake, int nr_requeue, u32 *cmpval)
{
union futex_key key1, key2;
struct futex_hash_bucket *hb1, *hb2;
struct plist_head *head1;
struct futex_q *this, *next;
struct futex_pi_state *pi_state2 = NULL;
struct rt_mutex_waiter *waiter, *top_waiter = NULL;
struct rt_mutex *lock2 = NULL;
int ret, drop_count = 0;
if (refill_pi_state_cache())
return -ENOMEM;
retry:
/*
* First take all the futex related locks:
*/
down_read(&current->mm->mmap_sem);
ret = get_futex_key(uaddr1, &key1);
if (unlikely(ret != 0))
goto out;
ret = get_futex_key(uaddr2, &key2);
if (unlikely(ret != 0))
goto out;
hb1 = hash_futex(&key1);
hb2 = hash_futex(&key2);
double_lock_hb(hb1, hb2);
if (likely(cmpval != NULL)) {
u32 curval;
ret = get_futex_value_locked(&curval, uaddr1);
if (unlikely(ret)) {
spin_unlock(&hb1->lock);
if (hb1 != hb2)
spin_unlock(&hb2->lock);
/*
* If we would have faulted, release mmap_sem, fault
* it in and start all over again.
*/
up_read(&current->mm->mmap_sem);
ret = get_user(curval, uaddr1);
if (!ret)
goto retry;
return ret;
}
if (curval != *cmpval) {
ret = -EAGAIN;
goto out_unlock;
}
}
head1 = &hb1->chain;
plist_for_each_entry_safe(this, next, head1, list) {
if (!match_futex (&this->key, &key1))
continue;
if (++ret <= nr_wake) {
wake_futex(this);
} else {
/*
* FIRST: get and set the pi_state
*/
if (!pi_state2) {
int s;
/* do this only the first time we requeue someone */
s = lookup_pi_state_for_requeue(uaddr2, hb2,
&key2, &pi_state2);
if (s) {
ret = s;
goto out_unlock;
}
lock2 = &pi_state2->pi_mutex;
spin_lock(&lock2->wait_lock);
/* Save the top waiter of the wait_list */
if (rt_mutex_has_waiters(lock2))
top_waiter = rt_mutex_top_waiter(lock2);
} else
atomic_inc(&pi_state2->refcount);
this->pi_state = pi_state2;
/*
* SECOND: requeue futex_q to the correct hashbucket
*/
/*
* If key1 and key2 hash to the same bucket, no need to
* requeue.
*/
if (likely(head1 != &hb2->chain)) {
plist_del(&this->list, &hb1->chain);
plist_add(&this->list, &hb2->chain);
this->lock_ptr = &hb2->lock;
#ifdef CONFIG_DEBUG_PI_LIST
this->list.plist.lock = &hb2->lock;
#endif
}
this->key = key2;
get_futex_key_refs(&key2);
drop_count++;
/*
* THIRD: queue it to lock2
*/
spin_lock_irq(&this->task->pi_lock);
waiter = &this->waiter;
waiter->task = this->task;
waiter->lock = lock2;
plist_node_init(&waiter->list_entry, this->task->prio);
plist_node_init(&waiter->pi_list_entry, this->task->prio);
plist_add(&waiter->list_entry, &lock2->wait_list);
this->task->pi_blocked_on = waiter;
spin_unlock_irq(&this->task->pi_lock);
if (ret - nr_wake >= nr_requeue)
break;
}
}
/* If we've requeued some tasks and the top_waiter of the rt_mutex
has changed, we must adjust the priority of the owner, if any */
if (drop_count) {
struct task_struct *owner = rt_mutex_owner(lock2);
if (owner &&
(top_waiter != (waiter = rt_mutex_top_waiter(lock2)))) {
int chain_walk = 0;
spin_lock_irq(&owner->pi_lock);
if (top_waiter)
plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters);
else
/*
* There was no waiters before the requeue,
* the flag must be updated
*/
mark_rt_mutex_waiters(lock2);
plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
__rt_mutex_adjust_prio(owner);
if (owner->pi_blocked_on) {
chain_walk = 1;
get_task_struct(owner);
}
spin_unlock_irq(&owner->pi_lock);
spin_unlock(&lock2->wait_lock);
if (chain_walk)
rt_mutex_adjust_prio_chain(owner, 0, lock2, NULL,
current);
} else {
/* No owner or the top_waiter does not change */
mark_rt_mutex_waiters(lock2);
spin_unlock(&lock2->wait_lock);
}
}
out_unlock:
spin_unlock(&hb1->lock);
if (hb1 != hb2)
spin_unlock(&hb2->lock);
/* drop_futex_key_refs() must be called outside the spinlocks. */
while (--drop_count >= 0)
drop_futex_key_refs(&key1);
out:
up_read(&current->mm->mmap_sem);
return ret;
}
/*
* Wake up all waiters hashed on the physical page that is mapped
* to this virtual address:
@ -984,9 +1250,10 @@ static int unqueue_me(struct futex_q *q)
/*
* PI futexes can not be requeued and must remove themself from the
* hash bucket. The hash bucket lock is held on entry and dropped here.
* hash bucket. The hash bucket lock (i.e. lock_ptr) is held on entry
* and dropped here.
*/
static void unqueue_me_pi(struct futex_q *q, struct futex_hash_bucket *hb)
static void unqueue_me_pi(struct futex_q *q)
{
WARN_ON(plist_node_empty(&q->list));
plist_del(&q->list, &q->list.plist);
@ -995,11 +1262,65 @@ static void unqueue_me_pi(struct futex_q *q, struct futex_hash_bucket *hb)
free_pi_state(q->pi_state);
q->pi_state = NULL;
spin_unlock(&hb->lock);
spin_unlock(q->lock_ptr);
drop_futex_key_refs(&q->key);
}
/*
* Fixup the pi_state owner with current.
*
* The cur->mm semaphore must be held, it is released at return of this
* function.
*/
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
struct futex_hash_bucket *hb,
struct task_struct *curr)
{
u32 newtid = curr->pid | FUTEX_WAITERS;
struct futex_pi_state *pi_state = q->pi_state;
u32 uval, curval, newval;
int ret;
/* Owner died? */
if (pi_state->owner != NULL) {
spin_lock_irq(&pi_state->owner->pi_lock);
WARN_ON(list_empty(&pi_state->list));
list_del_init(&pi_state->list);
spin_unlock_irq(&pi_state->owner->pi_lock);
} else
newtid |= FUTEX_OWNER_DIED;
pi_state->owner = curr;
spin_lock_irq(&curr->pi_lock);
WARN_ON(!list_empty(&pi_state->list));
list_add(&pi_state->list, &curr->pi_state_list);
spin_unlock_irq(&curr->pi_lock);
/* Unqueue and drop the lock */
unqueue_me_pi(q);
up_read(&curr->mm->mmap_sem);
/*
* We own it, so we have to replace the pending owner
* TID. This must be atomic as we have preserve the
* owner died bit here.
*/
ret = get_user(uval, uaddr);
while (!ret) {
newval = (uval & FUTEX_OWNER_DIED) | newtid;
newval |= (uval & FUTEX_WAITER_REQUEUED);
curval = futex_atomic_cmpxchg_inatomic(uaddr,
uval, newval);
if (curval == -EFAULT)
ret = -EFAULT;
if (curval == uval)
break;
uval = curval;
}
return ret;
}
static long futex_wait_restart(struct restart_block *restart);
static int futex_wait(u32 __user *uaddr, u32 val, ktime_t *abs_time)
{
@ -1009,7 +1330,7 @@ static int futex_wait(u32 __user *uaddr, u32 val, ktime_t *abs_time)
struct futex_q q;
u32 uval;
int ret;
struct hrtimer_sleeper t;
struct hrtimer_sleeper t, *to = NULL;
int rem = 0;
q.pi_state = NULL;
@ -1063,6 +1384,14 @@ static int futex_wait(u32 __user *uaddr, u32 val, ktime_t *abs_time)
if (uval != val)
goto out_unlock_release_sem;
/*
* This rt_mutex_waiter structure is prepared here and will
* be used only if this task is requeued from a normal futex to
* a PI-futex with futex_requeue_pi.
*/
debug_rt_mutex_init_waiter(&q.waiter);
q.waiter.task = NULL;
/* Only actually queue if *uaddr contained val. */
__queue_me(&q, hb);
@ -1092,6 +1421,7 @@ static int futex_wait(u32 __user *uaddr, u32 val, ktime_t *abs_time)
if (!abs_time)
schedule();
else {
to = &t;
hrtimer_init(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
hrtimer_init_sleeper(&t, current);
t.timer.expires = *abs_time;
@ -1119,6 +1449,66 @@ static int futex_wait(u32 __user *uaddr, u32 val, ktime_t *abs_time)
* we are the only user of it.
*/
if (q.pi_state) {
/*
* We were woken but have been requeued on a PI-futex.
* We have to complete the lock acquisition by taking
* the rtmutex.
*/
struct rt_mutex *lock = &q.pi_state->pi_mutex;
spin_lock(&lock->wait_lock);
if (unlikely(q.waiter.task)) {
remove_waiter(lock, &q.waiter);
}
spin_unlock(&lock->wait_lock);
if (rem)
ret = -ETIMEDOUT;
else
ret = rt_mutex_timed_lock(lock, to, 1);
down_read(&curr->mm->mmap_sem);
spin_lock(q.lock_ptr);
/*
* Got the lock. We might not be the anticipated owner if we
* did a lock-steal - fix up the PI-state in that case.
*/
if (!ret && q.pi_state->owner != curr) {
/*
* We MUST play with the futex we were requeued on,
* NOT the current futex.
* We can retrieve it from the key of the pi_state
*/
uaddr = q.pi_state->key.uaddr;
/* mmap_sem and hash_bucket lock are unlocked at
return of this function */
ret = fixup_pi_state_owner(uaddr, &q, hb, curr);
} else {
/*
* Catch the rare case, where the lock was released
* when we were on the way back before we locked
* the hash bucket.
*/
if (ret && q.pi_state->owner == curr) {
if (rt_mutex_trylock(&q.pi_state->pi_mutex))
ret = 0;
}
/* Unqueue and drop the lock */
unqueue_me_pi(&q);
up_read(&curr->mm->mmap_sem);
}
debug_rt_mutex_free_waiter(&q.waiter);
return ret;
}
debug_rt_mutex_free_waiter(&q.waiter);
/* If we were woken (and unqueued), we succeeded, whatever. */
if (!unqueue_me(&q))
return 0;
@ -1161,6 +1551,51 @@ static long futex_wait_restart(struct restart_block *restart)
}
static void set_pi_futex_owner(struct futex_hash_bucket *hb,
union futex_key *key, struct task_struct *p)
{
struct plist_head *head;
struct futex_q *this, *next;
struct futex_pi_state *pi_state = NULL;
struct rt_mutex *lock;
/* Search a waiter that should already exists */
head = &hb->chain;
plist_for_each_entry_safe(this, next, head, list) {
if (match_futex (&this->key, key)) {
pi_state = this->pi_state;
break;
}
}
BUG_ON(!pi_state);
/* set p as pi_state's owner */
lock = &pi_state->pi_mutex;
spin_lock(&lock->wait_lock);
spin_lock_irq(&p->pi_lock);
list_add(&pi_state->list, &p->pi_state_list);
pi_state->owner = p;
/* set p as pi_mutex's owner */
debug_rt_mutex_proxy_lock(lock, p);
WARN_ON(rt_mutex_owner(lock));
rt_mutex_set_owner(lock, p, 0);
rt_mutex_deadlock_account_lock(lock, p);
plist_add(&rt_mutex_top_waiter(lock)->pi_list_entry,
&p->pi_waiters);
__rt_mutex_adjust_prio(p);
spin_unlock_irq(&p->pi_lock);
spin_unlock(&lock->wait_lock);
}
/*
* Userspace tried a 0 -> TID atomic transition of the futex value
* and failed. The kernel side here does the whole locking operation:
@ -1175,7 +1610,7 @@ static int futex_lock_pi(u32 __user *uaddr, int detect, ktime_t *time,
struct futex_hash_bucket *hb;
u32 uval, newval, curval;
struct futex_q q;
int ret, attempt = 0;
int ret, lock_held, attempt = 0;
if (refill_pi_state_cache())
return -ENOMEM;
@ -1198,6 +1633,8 @@ static int futex_lock_pi(u32 __user *uaddr, int detect, ktime_t *time,
hb = queue_lock(&q, -1, NULL);
retry_locked:
lock_held = 0;
/*
* To avoid races, we attempt to take the lock here again
* (by doing a 0 -> TID atomic cmpxchg), while holding all
@ -1216,7 +1653,16 @@ static int futex_lock_pi(u32 __user *uaddr, int detect, ktime_t *time,
if (unlikely((curval & FUTEX_TID_MASK) == current->pid)) {
if (!detect && 0)
force_sig(SIGKILL, current);
ret = -EDEADLK;
/*
* Normally, this check is done in user space.
* In case of requeue, the owner may attempt to lock this futex,
* even if the ownership has already been given by the previous
* waker.
* In the usual case, this is a case of deadlock, but not in case
* of REQUEUE_PI.
*/
if (!(curval & FUTEX_WAITER_REQUEUED))
ret = -EDEADLK;
goto out_unlock_release_sem;
}
@ -1228,7 +1674,18 @@ static int futex_lock_pi(u32 __user *uaddr, int detect, ktime_t *time,
goto out_unlock_release_sem;
uval = curval;
newval = uval | FUTEX_WAITERS;
/*
* In case of a requeue, check if there already is an owner
* If not, just take the futex.
*/
if ((curval & FUTEX_WAITER_REQUEUED) && !(curval & FUTEX_TID_MASK)) {
/* set current as futex owner */
newval = curval | current->pid;
lock_held = 1;
} else
/* Set the WAITERS flag, so the owner will know it has someone
to wake at next unlock */
newval = curval | FUTEX_WAITERS;
pagefault_disable();
curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
@ -1239,11 +1696,16 @@ static int futex_lock_pi(u32 __user *uaddr, int detect, ktime_t *time,
if (unlikely(curval != uval))
goto retry_locked;
if (lock_held) {
set_pi_futex_owner(hb, &q.key, curr);
goto out_unlock_release_sem;
}
/*
* We dont have the lock. Look up the PI state (or create it if
* we are the first waiter):
*/
ret = lookup_pi_state(uval, hb, &q);
ret = lookup_pi_state(uval, hb, &q.key, &q.pi_state);
if (unlikely(ret)) {
/*
@ -1306,45 +1768,10 @@ static int futex_lock_pi(u32 __user *uaddr, int detect, ktime_t *time,
* Got the lock. We might not be the anticipated owner if we
* did a lock-steal - fix up the PI-state in that case.
*/
if (!ret && q.pi_state->owner != curr) {
u32 newtid = current->pid | FUTEX_WAITERS;
/* Owner died? */
if (q.pi_state->owner != NULL) {
spin_lock_irq(&q.pi_state->owner->pi_lock);
WARN_ON(list_empty(&q.pi_state->list));
list_del_init(&q.pi_state->list);
spin_unlock_irq(&q.pi_state->owner->pi_lock);
} else
newtid |= FUTEX_OWNER_DIED;
q.pi_state->owner = current;
spin_lock_irq(&current->pi_lock);
WARN_ON(!list_empty(&q.pi_state->list));
list_add(&q.pi_state->list, &current->pi_state_list);
spin_unlock_irq(&current->pi_lock);
/* Unqueue and drop the lock */
unqueue_me_pi(&q, hb);
up_read(&curr->mm->mmap_sem);
/*
* We own it, so we have to replace the pending owner
* TID. This must be atomic as we have preserve the
* owner died bit here.
*/
ret = get_user(uval, uaddr);
while (!ret) {
newval = (uval & FUTEX_OWNER_DIED) | newtid;
curval = futex_atomic_cmpxchg_inatomic(uaddr,
uval, newval);
if (curval == -EFAULT)
ret = -EFAULT;
if (curval == uval)
break;
uval = curval;
}
} else {
if (!ret && q.pi_state->owner != curr)
/* mmap_sem is unlocked at return of this function */
ret = fixup_pi_state_owner(uaddr, &q, hb, curr);
else {
/*
* Catch the rare case, where the lock was released
* when we were on the way back before we locked
@ -1355,7 +1782,7 @@ static int futex_lock_pi(u32 __user *uaddr, int detect, ktime_t *time,
ret = 0;
}
/* Unqueue and drop the lock */
unqueue_me_pi(&q, hb);
unqueue_me_pi(&q);
up_read(&curr->mm->mmap_sem);
}
@ -1724,6 +2151,8 @@ retry:
* userspace.
*/
mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
/* Also keep the FUTEX_WAITER_REQUEUED flag if set */
mval |= (uval & FUTEX_WAITER_REQUEUED);
nval = futex_atomic_cmpxchg_inatomic(uaddr, uval, mval);
if (nval == -EFAULT)
@ -1854,6 +2283,9 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
case FUTEX_TRYLOCK_PI:
ret = futex_lock_pi(uaddr, 0, timeout, 1);
break;
case FUTEX_CMP_REQUEUE_PI:
ret = futex_requeue_pi(uaddr, uaddr2, val, val2, &val3);
break;
default:
ret = -ENOSYS;
}
@ -1883,7 +2315,8 @@ asmlinkage long sys_futex(u32 __user *uaddr, int op, u32 val,
/*
* requeue parameter in 'utime' if op == FUTEX_REQUEUE.
*/
if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE)
if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE
|| op == FUTEX_CMP_REQUEUE_PI)
val2 = (u32) (unsigned long) utime;
return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);

3
kernel/futex_compat.c
View file

@ -156,7 +156,8 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
t = ktime_add(ktime_get(), t);
tp = &t;
}
if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE)
if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE
|| op == FUTEX_CMP_REQUEUE_PI)
val2 = (int) (unsigned long) utime;
return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);

41
kernel/rtmutex.c
View file

@ -56,7 +56,7 @@
* state.
*/
static void
void
rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner,
unsigned long mask)
{
@ -80,29 +80,6 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
clear_rt_mutex_waiters(lock);
}
/*
* We can speed up the acquire/release, if the architecture
* supports cmpxchg and if there's no debugging state to be set up
*/
#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES)
# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c)
static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
{
unsigned long owner, *p = (unsigned long *) &lock->owner;
do {
owner = *p;
} while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner);
}
#else
# define rt_mutex_cmpxchg(l,c,n) (0)
static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
{
lock->owner = (struct task_struct *)
((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
}
#endif
/*
* Calculate task priority from the waiter list priority
*
@ -123,7 +100,7 @@ int rt_mutex_getprio(struct task_struct *task)
*
* This can be both boosting and unboosting. task->pi_lock must be held.
*/
static void __rt_mutex_adjust_prio(struct task_struct *task)
void __rt_mutex_adjust_prio(struct task_struct *task)
{
int prio = rt_mutex_getprio(task);
@ -159,11 +136,11 @@ int max_lock_depth = 1024;
* Decreases task's usage by one - may thus free the task.
* Returns 0 or -EDEADLK.
*/
static int rt_mutex_adjust_prio_chain(struct task_struct *task,
int deadlock_detect,
struct rt_mutex *orig_lock,
struct rt_mutex_waiter *orig_waiter,
struct task_struct *top_task)
int rt_mutex_adjust_prio_chain(struct task_struct *task,
int deadlock_detect,
struct rt_mutex *orig_lock,
struct rt_mutex_waiter *orig_waiter,
struct task_struct *top_task)
{
struct rt_mutex *lock;
struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
@ -524,8 +501,8 @@ static void wakeup_next_waiter(struct rt_mutex *lock)
*
* Must be called with lock->wait_lock held
*/
static void remove_waiter(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter)
void remove_waiter(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter)
{
int first = (waiter == rt_mutex_top_waiter(lock));
struct task_struct *owner = rt_mutex_owner(lock);

34
kernel/rtmutex_common.h
View file

@ -112,6 +112,29 @@ static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock)
return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING;
}
/*
* We can speed up the acquire/release, if the architecture
* supports cmpxchg and if there's no debugging state to be set up
*/
#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES)
# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c)
static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
{
unsigned long owner, *p = (unsigned long *) &lock->owner;
do {
owner = *p;
} while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner);
}
#else
# define rt_mutex_cmpxchg(l,c,n) (0)
static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
{
lock->owner = (struct task_struct *)
((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
}
#endif
/*
* PI-futex support (proxy locking functions, etc.):
*/
@ -120,4 +143,15 @@ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner);
extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
struct task_struct *proxy_owner);
extern void rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner,
unsigned long mask);
extern void __rt_mutex_adjust_prio(struct task_struct *task);
extern int rt_mutex_adjust_prio_chain(struct task_struct *task,
int deadlock_detect,
struct rt_mutex *orig_lock,
struct rt_mutex_waiter *orig_waiter,
struct task_struct *top_task);
extern void remove_waiter(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter);
#endif