freebsd-nq/include/sys/condvar.h
Ned Bass 184c687387 Emulate illumos interface cv_timedwait_hires()
Needed for Illumos #3582. This interface is supposed to support
a variable-resolution timeout with nanosecond granularity.  This
implementation rounds up to microsecond resolution, as nanosecond-
precision timing is rarely needed for real-world performance
tuning and may incur unnecessary busy-waiting.  usleep_range() is
used if available, otherwise udelay() or msleep() are used
depending on the length of the delay interval.

Add flags from sys/callo.h as these are used to control the behavior of
cv_timedwait_hires().  Specifically,

CALLOUT_FLAG_ABSOLUTE
    Normally, the expiration passed to the timeout API functions is
    an expiration interval. If this flag is specified, then it is
    interpreted as the expiration time itself.

CALLOUT_FLAG_ROUNDUP
    Roundup the expiration time to the next resolution boundary. If this
    flag is not specified, the expiration time is rounded down.

References:
    https://www.illumos.org/issues/3582
    illumos/illumos-gate@0689f76

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #304
2013-11-04 09:49:24 -08:00

78 lines
3.0 KiB
C

/*****************************************************************************\
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://zfsonlinux.org/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
\*****************************************************************************/
#ifndef _SPL_CONDVAR_H
#define _SPL_CONDVAR_H
#include <linux/module.h>
#include <linux/wait.h>
#include <linux/delay_compat.h>
#include <sys/kmem.h>
#include <sys/mutex.h>
#include <sys/callo.h>
/*
* The kcondvar_t struct is protected by mutex taken externally before
* calling any of the wait/signal funs, and passed into the wait funs.
*/
#define CV_MAGIC 0x346545f4
#define CV_DESTROY 0x346545f5
typedef struct {
int cv_magic;
wait_queue_head_t cv_event;
wait_queue_head_t cv_destroy;
atomic_t cv_refs;
atomic_t cv_waiters;
kmutex_t *cv_mutex;
} kcondvar_t;
typedef enum { CV_DEFAULT=0, CV_DRIVER } kcv_type_t;
extern void __cv_init(kcondvar_t *cvp, char *name, kcv_type_t type, void *arg);
extern void __cv_destroy(kcondvar_t *cvp);
extern void __cv_wait(kcondvar_t *cvp, kmutex_t *mp);
extern void __cv_wait_io(kcondvar_t *cvp, kmutex_t *mp);
extern void __cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp);
extern clock_t __cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time);
extern clock_t __cv_timedwait_interruptible(kcondvar_t *cvp, kmutex_t *mp,
clock_t exp_time);
extern clock_t cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp,
hrtime_t tim, hrtime_t res, int flag);
extern void __cv_signal(kcondvar_t *cvp);
extern void __cv_broadcast(kcondvar_t *cvp);
#define cv_init(cvp, name, type, arg) __cv_init(cvp, name, type, arg)
#define cv_destroy(cvp) __cv_destroy(cvp)
#define cv_wait(cvp, mp) __cv_wait(cvp, mp)
#define cv_wait_io(cvp, mp) __cv_wait_io(cvp, mp)
#define cv_wait_interruptible(cvp, mp) __cv_wait_interruptible(cvp,mp)
#define cv_timedwait(cvp, mp, t) __cv_timedwait(cvp, mp, t)
#define cv_timedwait_interruptible(cvp, mp, t) \
__cv_timedwait_interruptible(cvp, mp, t)
#define cv_signal(cvp) __cv_signal(cvp)
#define cv_broadcast(cvp) __cv_broadcast(cvp)
#endif /* _SPL_CONDVAR_H */