diff options
Diffstat (limited to 'usr/src/uts/common/io/devpoll.c')
| -rw-r--r-- | usr/src/uts/common/io/devpoll.c | 60 |
1 files changed, 32 insertions, 28 deletions
diff --git a/usr/src/uts/common/io/devpoll.c b/usr/src/uts/common/io/devpoll.c index 111c4c243f..7d311aaa10 100644 --- a/usr/src/uts/common/io/devpoll.c +++ b/usr/src/uts/common/io/devpoll.c @@ -23,7 +23,9 @@ * Use is subject to license terms. */ -/* Copyright (c) 2011 by Delphix. All rights reserved. */ +/* + * Copyright (c) 2012 by Delphix. All rights reserved. + */ #include <sys/types.h> #include <sys/devops.h> @@ -695,9 +697,15 @@ dpioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *credp, int *rvalp) minor_t minor; dp_entry_t *dpep; pollcache_t *pcp; + hrtime_t now; int error = 0; STRUCT_DECL(dvpoll, dvpoll); + if (cmd == DP_POLL) { + /* do this now, before we sleep on DP_WRITER_PRESENT */ + now = gethrtime(); + } + minor = getminor(dev); mutex_enter(&devpoll_lock); ASSERT(minor < dptblsize); @@ -725,9 +733,7 @@ dpioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *credp, int *rvalp) pollstate_t *ps; nfds_t nfds; int fdcnt = 0; - int time_out; - clock_t *deltap = NULL; - clock_t delta; + hrtime_t deadline = 0; STRUCT_INIT(dvpoll, mode); error = copyin((caddr_t)arg, STRUCT_BUF(dvpoll), @@ -737,18 +743,16 @@ dpioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *credp, int *rvalp) return (EFAULT); } - time_out = STRUCT_FGET(dvpoll, dp_timeout); - if (time_out > 0) { + deadline = STRUCT_FGET(dvpoll, dp_timeout); + if (deadline > 0) { /* - * cv_relwaituntil_sig operates at the tick - * granularity, which by default is 10 ms. - * This results in rounding user specified - * timeouts up but prevents the system - * from being flooded with small high - * resolution timers. + * Convert the deadline from relative milliseconds + * to absolute nanoseconds. They must wait for at + * least a tick. */ - delta = MSEC_TO_TICK_ROUNDUP(time_out); - deltap = δ + deadline = deadline * NANOSEC / MILLISEC; + deadline = MAX(deadline, nsec_per_tick); + deadline += now; } if ((nfds = STRUCT_FGET(dvpoll, dp_nfds)) == 0) { @@ -758,16 +762,15 @@ dpioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *credp, int *rvalp) * Do not check for signals if we have a zero timeout. */ DP_REFRELE(dpep); - if (time_out == 0) + if (deadline == 0) return (0); mutex_enter(&curthread->t_delay_lock); - while ((delta = cv_relwaituntil_sig( - &curthread->t_delay_cv, &curthread->t_delay_lock, - deltap, TR_MILLISEC)) > 0) { + while ((error = + cv_timedwait_sig_hrtime(&curthread->t_delay_cv, + &curthread->t_delay_lock, deadline)) > 0) continue; - } mutex_exit(&curthread->t_delay_lock); - return (delta == 0 ? EINTR : 0); + return (error == 0 ? EINTR : 0); } /* @@ -814,21 +817,22 @@ dpioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *credp, int *rvalp) /* * Sleep until we are notified, signaled, or timed out. - * Do not check for signals if we have a zero timeout. */ - if (time_out == 0) /* immediate timeout */ + if (deadline == 0) { + /* immediate timeout; do not check signals */ break; - - delta = cv_relwaituntil_sig(&pcp->pc_cv, &pcp->pc_lock, - deltap, TR_MILLISEC); + } + error = cv_timedwait_sig_hrtime(&pcp->pc_cv, + &pcp->pc_lock, deadline); /* * If we were awakened by a signal or timeout * then break the loop, else poll again. */ - if (delta <= 0) { - if (delta == 0) /* signal */ - error = EINTR; + if (error <= 0) { + error = (error == 0) ? EINTR : 0; break; + } else { + error = 0; } } mutex_exit(&pcp->pc_lock); |