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Use unused fourth argument of umtx_op to pass flags to kernel for operation

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UMTX_OP_WAIT. Upper 16bits is enough to hold a clock id, and lower
16bits is used to pass flags. The change saves a clock_gettime() syscall
from libthr.
This commit is contained in:
David Xu 2012-02-22 03:22:49 +00:00
parent 57fa7d3101
commit b13a8fa78f
3 changed files with 47 additions and 34 deletions
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16
lib/libthr/thread/thr_umtx.c
View File

@ -200,20 +200,10 @@ int
_thr_umtx_timedwait_uint(volatile u_int *mtx, u_int id, int clockid,
const struct timespec *abstime, int shared)
{
struct timespec ts, ts2, *tsp;
if (abstime != NULL) {
clock_gettime(clockid, &ts);
TIMESPEC_SUB(&ts2, abstime, &ts);
if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0))
return (ETIMEDOUT);
tsp = &ts2;
} else {
tsp = NULL;
}
return _umtx_op_err(__DEVOLATILE(void *, mtx),
shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id, NULL,
tsp);
shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id,
abstime != NULL ? (void *)(uintptr_t)((clockid << 16) | UMTX_WAIT_ABSTIME) : 0,
__DECONST(void *, abstime));
}
int

63
sys/kern/kern_umtx.c
View File

@ -970,17 +970,26 @@ do_unlock_umtx32(struct thread *td, uint32_t *m, uint32_t id)
}
#endif
static inline int
tstohz(const struct timespec *tsp)
{
struct timeval tv;
TIMESPEC_TO_TIMEVAL(&tv, tsp);
return tvtohz(&tv);
}
/*
* Fetch and compare value, sleep on the address if value is not changed.
*/
static int
do_wait(struct thread *td, void *addr, u_long id,
struct timespec *timeout, int compat32, int is_private)
struct timespec *timeout, int compat32, int is_private, uint32_t flags)
{
struct umtx_q *uq;
struct timespec ts, ts2, ts3;
struct timeval tv;
struct timespec ets, cts, tts;
u_long tmp;
int clockid = (flags >> 16) & 0xFFFF;
int error = 0;
uq = td->td_umtxq;
@ -1005,12 +1014,22 @@ do_wait(struct thread *td, void *addr, u_long id,
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
} else {
getnanouptime(&ts);
timespecadd(&ts, timeout);
TIMESPEC_TO_TIMEVAL(&tv, timeout);
kern_clock_gettime(td, clockid, &cts);
if ((flags & UMTX_WAIT_ABSTIME) == 0) {
ets = cts;
timespecadd(&ets, timeout);
} else {
ets = *timeout;
}
umtxq_lock(&uq->uq_key);
for (;;) {
error = umtxq_sleep(uq, "uwait", tvtohz(&tv));
if (timespeccmp(&cts, &ets, >=)) {
error = ETIMEDOUT;
break;
}
tts = ets;
timespecsub(&tts, &cts);
error = umtxq_sleep(uq, "uwait", tstohz(&tts));
if (!(uq->uq_flags & UQF_UMTXQ)) {
error = 0;
break;
@ -1018,15 +1037,7 @@ do_wait(struct thread *td, void *addr, u_long id,
if (error != ETIMEDOUT)
break;
umtxq_unlock(&uq->uq_key);
getnanouptime(&ts2);
if (timespeccmp(&ts2, &ts, >=)) {
error = ETIMEDOUT;
umtxq_lock(&uq->uq_key);
break;
}
ts3 = ts;
timespecsub(&ts3, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts3);
kern_clock_gettime(td, clockid, &cts);
umtxq_lock(&uq->uq_key);
}
umtxq_remove(uq);
@ -2941,6 +2952,7 @@ __umtx_op_wait(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
uint32_t flags;
if (uap->uaddr2 == NULL)
ts = NULL;
@ -2950,7 +2962,8 @@ __umtx_op_wait(struct thread *td, struct _umtx_op_args *uap)
return (error);
ts = &timeout;
}
return do_wait(td, uap->obj, uap->val, ts, 0, 0);
flags = (uint32_t)(uintptr_t)uap->uaddr1;
return do_wait(td, uap->obj, uap->val, ts, 0, 0, flags);
}
static int
@ -2958,6 +2971,7 @@ __umtx_op_wait_uint(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
uint32_t flags;
if (uap->uaddr2 == NULL)
ts = NULL;
@ -2967,7 +2981,8 @@ __umtx_op_wait_uint(struct thread *td, struct _umtx_op_args *uap)
return (error);
ts = &timeout;
}
return do_wait(td, uap->obj, uap->val, ts, 1, 0);
flags = (uint32_t)(uintptr_t)uap->uaddr1;
return do_wait(td, uap->obj, uap->val, ts, 1, 0, flags);
}
static int
@ -2975,6 +2990,7 @@ __umtx_op_wait_uint_private(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
uint32_t flags;
if (uap->uaddr2 == NULL)
ts = NULL;
@ -2984,7 +3000,8 @@ __umtx_op_wait_uint_private(struct thread *td, struct _umtx_op_args *uap)
return (error);
ts = &timeout;
}
return do_wait(td, uap->obj, uap->val, ts, 1, 1);
flags = (uint32_t)(uintptr_t)uap->uaddr1;
return do_wait(td, uap->obj, uap->val, ts, 1, 1, flags);
}
static int
@ -3286,6 +3303,7 @@ __umtx_op_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
uint32_ flags;
if (uap->uaddr2 == NULL)
ts = NULL;
@ -3295,7 +3313,8 @@ __umtx_op_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
return (error);
ts = &timeout;
}
return do_wait(td, uap->obj, uap->val, ts, 1, 0);
flags = (uint32_t)(uintptr_t)uap->uaddr1;
return do_wait(td, uap->obj, uap->val, ts, 1, 0, flags);
}
static int
@ -3394,6 +3413,7 @@ __umtx_op_wait_uint_private_compat32(struct thread *td, struct _umtx_op_args *ua
{
struct timespec *ts, timeout;
int error;
uint32_t flags;
if (uap->uaddr2 == NULL)
ts = NULL;
@ -3403,7 +3423,8 @@ __umtx_op_wait_uint_private_compat32(struct thread *td, struct _umtx_op_args *ua
return (error);
ts = &timeout;
}
return do_wait(td, uap->obj, uap->val, ts, 1, 1);
flags = (uint32_t)(uintptr_t)uap->uaddr1;
return do_wait(td, uap->obj, uap->val, ts, 1, 1, flags);
}
static int

2
sys/sys/umtx.h
View File

@ -87,6 +87,8 @@
#define CVWAIT_ABSTIME 0x02
#define CVWAIT_CLOCKID 0x04
#define UMTX_WAIT_ABSTIME 0x01
#define UMTX_CHECK_UNPARKING CVWAIT_CHECK_UNPARKING
#ifndef _KERNEL