diff options
Diffstat (limited to 'sys/kern/kern_umtx.c')
| -rw-r--r-- | sys/kern/kern_umtx.c | 84 |
1 files changed, 82 insertions, 2 deletions
diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c index 5c57166..71b19e7 100644 --- a/sys/kern/kern_umtx.c +++ b/sys/kern/kern_umtx.c @@ -1319,6 +1319,78 @@ do_wake_umutex(struct thread *td, struct umutex *m) return (0); } +/* + * Check if the mutex has waiters and tries to fix contention bit. + */ +static int +do_wake2_umutex(struct thread *td, struct umutex *m, uint32_t flags) +{ + struct umtx_key key; + uint32_t owner, old; + int type; + int error; + int count; + + switch(flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) { + case 0: + type = TYPE_NORMAL_UMUTEX; + break; + case UMUTEX_PRIO_INHERIT: + type = TYPE_PI_UMUTEX; + break; + case UMUTEX_PRIO_PROTECT: + type = TYPE_PP_UMUTEX; + break; + default: + return (EINVAL); + } + if ((error = umtx_key_get(m, type, GET_SHARE(flags), + &key)) != 0) + return (error); + + owner = 0; + umtxq_lock(&key); + umtxq_busy(&key); + count = umtxq_count(&key); + umtxq_unlock(&key); + /* + * Only repair contention bit if there is a waiter, this means the mutex + * is still being referenced by userland code, otherwise don't update + * any memory. + */ + if (count > 1) { + owner = fuword32(__DEVOLATILE(uint32_t *, &m->m_owner)); + while ((owner & UMUTEX_CONTESTED) ==0) { + old = casuword32(&m->m_owner, owner, + owner|UMUTEX_CONTESTED); + if (old == owner) + break; + owner = old; + } + } else if (count == 1) { + owner = fuword32(__DEVOLATILE(uint32_t *, &m->m_owner)); + while ((owner & ~UMUTEX_CONTESTED) != 0 && + (owner & UMUTEX_CONTESTED) == 0) { + old = casuword32(&m->m_owner, owner, + owner|UMUTEX_CONTESTED); + if (old == owner) + break; + owner = old; + } + } + umtxq_lock(&key); + if (owner == -1) { + error = EFAULT; + umtxq_signal(&key, INT_MAX); + } + else if (count != 0 && (owner & ~UMUTEX_CONTESTED) == 0) + umtxq_signal(&key, 1); + umtxq_unbusy(&key); + umtxq_unlock(&key); + umtx_key_release(&key); + return (error); +} + static inline struct umtx_pi * umtx_pi_alloc(int flags) { @@ -3152,6 +3224,12 @@ __umtx_op_sem_wake(struct thread *td, struct _umtx_op_args *uap) return do_sem_wake(td, uap->obj); } +static int +__umtx_op_wake2_umutex(struct thread *td, struct _umtx_op_args *uap) +{ + return do_wake2_umutex(td, uap->obj, uap->val); +} + typedef int (*_umtx_op_func)(struct thread *td, struct _umtx_op_args *uap); static _umtx_op_func op_table[] = { @@ -3176,7 +3254,8 @@ static _umtx_op_func op_table[] = { __umtx_op_wake_umutex, /* UMTX_OP_UMUTEX_WAKE */ __umtx_op_sem_wait, /* UMTX_OP_SEM_WAIT */ __umtx_op_sem_wake, /* UMTX_OP_SEM_WAKE */ - __umtx_op_nwake_private /* UMTX_OP_NWAKE_PRIVATE */ + __umtx_op_nwake_private, /* UMTX_OP_NWAKE_PRIVATE */ + __umtx_op_wake2_umutex /* UMTX_OP_UMUTEX_WAKE2 */ }; int @@ -3478,7 +3557,8 @@ static _umtx_op_func op_table_compat32[] = { __umtx_op_wake_umutex, /* UMTX_OP_UMUTEX_WAKE */ __umtx_op_sem_wait_compat32, /* UMTX_OP_SEM_WAIT */ __umtx_op_sem_wake, /* UMTX_OP_SEM_WAKE */ - __umtx_op_nwake_private32 /* UMTX_OP_NWAKE_PRIVATE */ + __umtx_op_nwake_private32, /* UMTX_OP_NWAKE_PRIVATE */ + __umtx_op_wake2_umutex /* UMTX_OP_UMUTEX_WAKE2 */ }; int |
