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MFcalloutng:

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Fix kern_select() and sys_poll() so that they can handle sub-tick
precision for timeouts (in the same fashion it was done for nanosleep()
in r247797).

Sponsored by:	Google Summer of Code 2012, iXsystems inc.
Tested by:	flo, marius, ian, markj, Fabian Keil
This commit is contained in:
davide 2013-03-04 16:41:27 +00:00
parent 0aca596713
commit 473ef72351
1 changed files with 36 additions and 47 deletions
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83
sys/kern/sys_generic.c
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@ -103,7 +103,7 @@ static int dofilewrite(struct thread *, int, struct file *, struct uio *,
off_t, int);
static void doselwakeup(struct selinfo *, int);
static void seltdinit(struct thread *);
static int seltdwait(struct thread *, int);
static int seltdwait(struct thread *, sbintime_t, sbintime_t);
static void seltdclear(struct thread *);
/*
@ -950,9 +950,10 @@ kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
*/
fd_mask s_selbits[howmany(2048, NFDBITS)];
fd_mask *ibits[3], *obits[3], *selbits, *sbp;
struct timeval atv, rtv, ttv;
int error, lf, ndu, timo;
struct timeval rtv;
sbintime_t asbt, precision, rsbt;
u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
int error, lf, ndu;
if (nd < 0)
return (EINVAL);
@ -1042,35 +1043,29 @@ kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
if (nbufbytes != 0)
bzero(selbits, nbufbytes / 2);
precision = 0;
if (tvp != NULL) {
atv = *tvp;
if (itimerfix(&atv)) {
rtv = *tvp;
if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
rtv.tv_usec >= 1000000) {
error = EINVAL;
goto done;
}
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
rsbt = tvtosbt(rtv);
precision = rsbt;
precision >>= tc_precexp;
if (TIMESEL(&asbt, rsbt))
asbt += tc_tick_sbt;
asbt += rsbt;
} else
asbt = -1;
seltdinit(td);
/* Iterate until the timeout expires or descriptors become ready. */
for (;;) {
error = selscan(td, ibits, obits, nd);
if (error || td->td_retval[0] != 0)
break;
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=))
break;
ttv = atv;
timevalsub(&ttv, &rtv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
error = seltdwait(td, timo);
error = seltdwait(td, asbt, precision);
if (error)
break;
error = selrescan(td, ibits, obits);
@ -1278,9 +1273,9 @@ sys_poll(td, uap)
{
struct pollfd *bits;
struct pollfd smallbits[32];
struct timeval atv, rtv, ttv;
int error, timo;
sbintime_t asbt, precision, rsbt;
u_int nfds;
int error;
size_t ni;
nfds = uap->nfds;
@ -1294,36 +1289,27 @@ sys_poll(td, uap)
error = copyin(uap->fds, bits, ni);
if (error)
goto done;
precision = 0;
if (uap->timeout != INFTIM) {
atv.tv_sec = uap->timeout / 1000;
atv.tv_usec = (uap->timeout % 1000) * 1000;
if (itimerfix(&atv)) {
if (uap->timeout < 0) {
error = EINVAL;
goto done;
}
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
rsbt = SBT_1MS * uap->timeout;
precision = rsbt;
precision >>= tc_precexp;
if (TIMESEL(&asbt, rsbt))
asbt += tc_tick_sbt;
asbt += rsbt;
} else
asbt = -1;
seltdinit(td);
/* Iterate until the timeout expires or descriptors become ready. */
for (;;) {
error = pollscan(td, bits, nfds);
if (error || td->td_retval[0] != 0)
break;
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=))
break;
ttv = atv;
timevalsub(&ttv, &rtv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
error = seltdwait(td, timo);
error = seltdwait(td, asbt, precision);
if (error)
break;
error = pollrescan(td);
@ -1667,7 +1653,7 @@ seltdinit(struct thread *td)
}
static int
seltdwait(struct thread *td, int timo)
seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
{
struct seltd *stp;
int error;
@ -1686,8 +1672,11 @@ seltdwait(struct thread *td, int timo)
mtx_unlock(&stp->st_mtx);
return (0);
}
if (timo > 0)
error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo);
if (sbt == 0)
error = EWOULDBLOCK;
else if (sbt != -1)
error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
sbt, precision, C_ABSOLUTE);
else
error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
mtx_unlock(&stp->st_mtx);