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freebsd/sys/sys/callout.h
Jeff Roberson 8d809d5061 Implement per-cpu callout threads, wheels, and locks.
- Move callout thread creation from kern_intr.c to kern_timeout.c
 - Call callout_tick() on every processor via hardclock_cpu() rather than
   inspecting callout internal details in kern_clock.c.
 - Remove callout implementation details from callout.h
 - Package up all of the global variables into a per-cpu callout structure.
 - Start one thread per-cpu.  Threads are not strictly bound.  They prefer
   to execute on the native cpu but may migrate temporarily if interrupts
   are starving callout processing.
 - Run all callouts by default in the thread for cpu0 to maintain current
   ordering and concurrency guarantees.  Many consumers may not properly
   handle concurrent execution.
 - The new callout_reset_on() api allows specifying a particular cpu to
   execute the callout on.  This may migrate a callout to a new cpu.
   callout_reset() schedules on the last assigned cpu while
   callout_reset_curcpu() schedules on the current cpu.

Reviewed by:	phk
Sponsored by:	Nokia
2008-04-02 11:20:30 +00:00

100 lines
4.0 KiB
C

/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS 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.
*
* @(#)callout.h 8.2 (Berkeley) 1/21/94
* $FreeBSD$
*/
#ifndef _SYS_CALLOUT_H_
#define _SYS_CALLOUT_H_
#include <sys/queue.h>
struct lock_object;
SLIST_HEAD(callout_list, callout);
TAILQ_HEAD(callout_tailq, callout);
struct callout {
union {
SLIST_ENTRY(callout) sle;
TAILQ_ENTRY(callout) tqe;
} c_links;
int c_time; /* ticks to the event */
void *c_arg; /* function argument */
void (*c_func)(void *); /* function to call */
struct lock_object *c_lock; /* lock to handle */
int c_flags; /* state of this entry */
volatile int c_cpu; /* CPU we're scheduled on */
};
#define CALLOUT_LOCAL_ALLOC 0x0001 /* was allocated from callfree */
#define CALLOUT_ACTIVE 0x0002 /* callout is currently active */
#define CALLOUT_PENDING 0x0004 /* callout is waiting for timeout */
#define CALLOUT_MPSAFE 0x0008 /* callout handler is mp safe */
#define CALLOUT_RETURNUNLOCKED 0x0010 /* handler returns with mtx unlocked */
#define CALLOUT_SHAREDLOCK 0x0020 /* callout lock held in shared mode */
struct callout_handle {
struct callout *callout;
};
#ifdef _KERNEL
extern int ncallout;
#define callout_active(c) ((c)->c_flags & CALLOUT_ACTIVE)
#define callout_deactivate(c) ((c)->c_flags &= ~CALLOUT_ACTIVE)
#define callout_drain(c) _callout_stop_safe(c, 1)
void callout_init(struct callout *, int);
void _callout_init_lock(struct callout *, struct lock_object *, int);
#define callout_init_mtx(c, mtx, flags) \
_callout_init_lock((c), ((mtx) != NULL) ? &(mtx)->lock_object : \
NULL, (flags))
#define callout_init_rw(c, rw, flags) \
_callout_init_lock((c), ((rw) != NULL) ? &(rw)->lock_object : \
NULL, (flags))
#define callout_pending(c) ((c)->c_flags & CALLOUT_PENDING)
int callout_reset_on(struct callout *, int, void (*)(void *), void *, int);
#define callout_reset(c, on_tick, fn, arg) \
callout_reset_on((c), (on_tick), (fn), (arg), (c)->c_cpu)
#define callout_reset_curcpu(c, on_tick, fn, arg) \
callout_reset_on((c), (on_tick), (fn), (arg), PCPU_GET(cpuid))
#define callout_stop(c) _callout_stop_safe(c, 0)
int _callout_stop_safe(struct callout *, int);
void callout_tick(void);
#endif
#endif /* _SYS_CALLOUT_H_ */