freebsd-skq/sys/sys/sched.h
Konstantin Belousov b5449c92b4 Use atomic_interrupt_fence() instead of bare __compiler_membar()
for the which which definitely use membar to sync with interrupt handlers.

libc and rtld uses of __compiler_membar() seems to want compiler barriers
proper.

The barrier in sched_unpin_lite() after td_pinned decrement seems to be not
needed and removed, instead of convertion.

Reviewed by:	markj
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D28956
2021-02-28 01:27:29 +02:00

270 lines
9.1 KiB
C

/*-
* SPDX-License-Identifier: (BSD-4-Clause AND BSD-2-Clause-FreeBSD)
*
* Copyright (c) 1996, 1997
* HD Associates, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by HD Associates, Inc
* and Jukka Antero Ukkonen.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*-
* Copyright (c) 2002-2008, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _SCHED_H_
#define _SCHED_H_
#ifdef _KERNEL
/*
* General scheduling info.
*
* sched_load:
* Total runnable non-ithread threads in the system.
*
* sched_runnable:
* Runnable threads for this processor.
*/
int sched_load(void);
int sched_rr_interval(void);
int sched_runnable(void);
/*
* Proc related scheduling hooks.
*/
void sched_exit(struct proc *p, struct thread *childtd);
void sched_fork(struct thread *td, struct thread *childtd);
void sched_fork_exit(struct thread *td);
void sched_class(struct thread *td, int class);
void sched_nice(struct proc *p, int nice);
/*
* Threads are switched in and out, block on resources, have temporary
* priorities inherited from their procs, and use up cpu time.
*/
void sched_exit_thread(struct thread *td, struct thread *child);
u_int sched_estcpu(struct thread *td);
void sched_fork_thread(struct thread *td, struct thread *child);
void sched_lend_prio(struct thread *td, u_char prio);
void sched_lend_user_prio(struct thread *td, u_char pri);
void sched_lend_user_prio_cond(struct thread *td, u_char pri);
fixpt_t sched_pctcpu(struct thread *td);
void sched_prio(struct thread *td, u_char prio);
void sched_sleep(struct thread *td, int prio);
void sched_switch(struct thread *td, int flags);
void sched_throw(struct thread *td);
void sched_unlend_prio(struct thread *td, u_char prio);
void sched_user_prio(struct thread *td, u_char prio);
void sched_userret_slowpath(struct thread *td);
#ifdef RACCT
#ifdef SCHED_4BSD
fixpt_t sched_pctcpu_delta(struct thread *td);
#endif
#endif
static inline void
sched_userret(struct thread *td)
{
/*
* XXX we cheat slightly on the locking here to avoid locking in
* the usual case. Setting td_priority here is essentially an
* incomplete workaround for not setting it properly elsewhere.
* Now that some interrupt handlers are threads, not setting it
* properly elsewhere can clobber it in the window between setting
* it here and returning to user mode, so don't waste time setting
* it perfectly here.
*/
KASSERT((td->td_flags & TDF_BORROWING) == 0,
("thread with borrowed priority returning to userland"));
if (__predict_false(td->td_priority != td->td_user_pri))
sched_userret_slowpath(td);
}
/*
* Threads are moved on and off of run queues
*/
void sched_add(struct thread *td, int flags);
struct thread *sched_choose(void);
void sched_clock(struct thread *td, int cnt);
void sched_idletd(void *);
void sched_preempt(struct thread *td);
void sched_relinquish(struct thread *td);
void sched_rem(struct thread *td);
void sched_wakeup(struct thread *td, int srqflags);
/*
* Binding makes cpu affinity permanent while pinning is used to temporarily
* hold a thread on a particular CPU.
*/
void sched_bind(struct thread *td, int cpu);
static __inline void sched_pin(void);
void sched_unbind(struct thread *td);
static __inline void sched_unpin(void);
int sched_is_bound(struct thread *td);
void sched_affinity(struct thread *td);
/*
* These procedures tell the process data structure allocation code how
* many bytes to actually allocate.
*/
int sched_sizeof_proc(void);
int sched_sizeof_thread(void);
/*
* This routine provides a consistent thread name for use with KTR graphing
* functions.
*/
char *sched_tdname(struct thread *td);
#ifdef KTR
void sched_clear_tdname(struct thread *td);
#endif
static __inline void
sched_pin(void)
{
curthread->td_pinned++;
atomic_interrupt_fence();
}
static __inline void
sched_unpin(void)
{
atomic_interrupt_fence();
curthread->td_pinned--;
}
/* sched_add arguments (formerly setrunqueue) */
#define SRQ_BORING 0x0000 /* No special circumstances. */
#define SRQ_YIELDING 0x0001 /* We are yielding (from mi_switch). */
#define SRQ_OURSELF 0x0002 /* It is ourself (from mi_switch). */
#define SRQ_INTR 0x0004 /* It is probably urgent. */
#define SRQ_PREEMPTED 0x0008 /* has been preempted.. be kind */
#define SRQ_BORROWING 0x0010 /* Priority updated due to prio_lend */
#define SRQ_HOLD 0x0020 /* Return holding original td lock */
#define SRQ_HOLDTD 0x0040 /* Return holding td lock */
/* Scheduler stats. */
#ifdef SCHED_STATS
DPCPU_DECLARE(long, sched_switch_stats[SWT_COUNT]);
#define SCHED_STAT_DEFINE_VAR(name, ptr, descr) \
static void name ## _add_proc(void *dummy __unused) \
{ \
\
SYSCTL_ADD_PROC(NULL, \
SYSCTL_STATIC_CHILDREN(_kern_sched_stats), OID_AUTO, \
#name, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, \
ptr, 0, sysctl_dpcpu_long, "LU", descr); \
} \
SYSINIT(name, SI_SUB_LAST, SI_ORDER_MIDDLE, name ## _add_proc, NULL);
#define SCHED_STAT_DEFINE(name, descr) \
DPCPU_DEFINE(unsigned long, name); \
SCHED_STAT_DEFINE_VAR(name, &DPCPU_NAME(name), descr)
/*
* Sched stats are always incremented in critical sections so no atomic
* is necesssary to increment them.
*/
#define SCHED_STAT_INC(var) DPCPU_GET(var)++;
#else
#define SCHED_STAT_DEFINE_VAR(name, descr, ptr)
#define SCHED_STAT_DEFINE(name, descr)
#define SCHED_STAT_INC(var) (void)0
#endif
/*
* Fixup scheduler state for proc0 and thread0
*/
void schedinit(void);
#endif /* _KERNEL */
/* POSIX 1003.1b Process Scheduling */
/*
* POSIX scheduling policies
*/
#define SCHED_FIFO 1
#define SCHED_OTHER 2
#define SCHED_RR 3
struct sched_param {
int sched_priority;
};
/*
* POSIX scheduling declarations for userland.
*/
#ifndef _KERNEL
#include <sys/cdefs.h>
#include <sys/_timespec.h>
#include <sys/_types.h>
#ifndef _PID_T_DECLARED
typedef __pid_t pid_t;
#define _PID_T_DECLARED
#endif
__BEGIN_DECLS
int sched_get_priority_max(int);
int sched_get_priority_min(int);
int sched_getparam(pid_t, struct sched_param *);
int sched_getscheduler(pid_t);
int sched_rr_get_interval(pid_t, struct timespec *);
int sched_setparam(pid_t, const struct sched_param *);
int sched_setscheduler(pid_t, int, const struct sched_param *);
int sched_yield(void);
__END_DECLS
#endif
#endif /* !_SCHED_H_ */