xref: /dragonfly/sys/sys/thread.h (revision bb8c85ff)
1 /*
2  * SYS/THREAD.H
3  *
4  *	Implements the architecture independant portion of the LWKT
5  *	subsystem.
6  *
7  * Types which must already be defined when this header is included by
8  * userland:	struct md_thread
9  */
10 
11 #ifndef _SYS_THREAD_H_
12 #define _SYS_THREAD_H_
13 
14 #ifndef _SYS_STDINT_H_
15 #include <sys/stdint.h>		/* __int types */
16 #endif
17 #ifndef _SYS_PARAM_H_
18 #include <sys/param.h>		/* MAXCOMLEN */
19 #endif
20 #ifndef _SYS_QUEUE_H_
21 #include <sys/queue.h>		/* TAILQ_* macros */
22 #endif
23 #ifndef _SYS_MSGPORT_H_
24 #include <sys/msgport.h>	/* lwkt_port */
25 #endif
26 #ifndef _SYS_TIME_H_
27 #include <sys/time.h>   	/* struct timeval */
28 #endif
29 #ifndef _SYS_LOCK_H
30 #include <sys/lock.h>
31 #endif
32 #ifndef _SYS_SPINLOCK_H_
33 #include <sys/spinlock.h>
34 #endif
35 #ifndef _SYS_IOSCHED_H_
36 #include <sys/iosched.h>
37 #endif
38 #include <machine/thread.h>
39 
40 struct globaldata;
41 struct lwp;
42 struct proc;
43 struct thread;
44 struct lwkt_queue;
45 struct lwkt_token;
46 struct lwkt_tokref;
47 struct lwkt_ipiq;
48 struct lwkt_cpu_msg;
49 struct lwkt_cpu_port;
50 struct lwkt_cpusync;
51 union sysunion;
52 
53 typedef struct lwkt_queue	*lwkt_queue_t;
54 typedef struct lwkt_token	*lwkt_token_t;
55 typedef struct lwkt_tokref	*lwkt_tokref_t;
56 typedef struct lwkt_cpu_msg	*lwkt_cpu_msg_t;
57 typedef struct lwkt_cpu_port	*lwkt_cpu_port_t;
58 typedef struct lwkt_ipiq	*lwkt_ipiq_t;
59 typedef struct lwkt_cpusync	*lwkt_cpusync_t;
60 typedef struct thread 		*thread_t;
61 
62 typedef TAILQ_HEAD(lwkt_queue, thread) lwkt_queue;
63 
64 /*
65  * Differentiation between kernel threads and user threads.  Userland
66  * programs which want to access to kernel structures have to define
67  * _KERNEL_STRUCTURES.  This is a kinda safety valve to prevent badly
68  * written user programs from getting an LWKT thread that is neither the
69  * kernel nor the user version.
70  */
71 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
72 #ifndef _CPU_FRAME_H_
73 #include <machine/frame.h>
74 #endif
75 #else
76 struct intrframe;
77 #endif
78 
79 /*
80  * Tokens are used to serialize access to information.  They are 'soft'
81  * serialization entities that only stay in effect while a thread is
82  * running.  If the thread blocks, other threads can run holding the same
83  * token(s).  The tokens are reacquired when the original thread resumes.
84  *
85  * Tokens guarantee that no deadlock can happen regardless of type or
86  * ordering.  However, obtaining the same token first shared, then
87  * stacking exclusive, is not allowed and will panic.
88  *
89  * A thread can depend on its serialization remaining intact through a
90  * preemption.  An interrupt which attempts to use the same token as the
91  * thread being preempted will reschedule itself for non-preemptive
92  * operation, so the new token code is capable of interlocking against
93  * interrupts as well as other cpus.  This means that your token can only
94  * be (temporarily) lost if you *explicitly* block.
95  *
96  * Tokens are managed through a helper reference structure, lwkt_tokref.  Each
97  * thread has a stack of tokref's to keep track of acquired tokens.  Multiple
98  * tokref's may reference the same token.
99  *
100  * EXCLUSIVE TOKENS
101  *	Acquiring an exclusive token requires acquiring the EXCLUSIVE bit
102  *	with count == 0.  If the exclusive bit cannot be acquired, EXCLREQ
103  *	is set.  Once acquired, EXCLREQ is cleared (but could get set by
104  *	another thread also trying for an exclusive lock at any time).
105  *
106  * SHARED TOKENS
107  *	Acquiring a shared token requires waiting for the EXCLUSIVE bit
108  *	to be cleared and then acquiring a count.  A shared lock request
109  *	can temporarily acquire a count and then back it out if it is
110  *	unable to obtain the EXCLUSIVE bit, allowing fetchadd to be used.
111  *
112  *	A thread attempting to get a single shared token will defer to
113  *	pending exclusive requesters.  However, a thread already holding
114  *	one or more tokens and trying to get an additional shared token
115  *	cannot defer to exclusive requesters because doing so can lead
116  *	to a deadlock.
117  *
118  * Multiple exclusive tokens are handled by treating the additional tokens
119  * as a special case of the shared token, incrementing the count value.  This
120  * reduces the complexity of the token release code.
121  */
122 
123 typedef struct lwkt_token {
124     long		t_count;	/* Shared/exclreq/exclusive access */
125     struct lwkt_tokref	*t_ref;		/* Exclusive ref */
126     long		t_collisions;	/* Collision counter */
127     const char		*t_desc;	/* Descriptive name */
128 } lwkt_token;
129 
130 #define TOK_EXCLUSIVE	0x00000001	/* Exclusive lock held */
131 #define TOK_EXCLREQ	0x00000002	/* Exclusive request pending */
132 #define TOK_INCR	4		/* Shared count increment */
133 #define TOK_COUNTMASK	(~(long)(TOK_EXCLUSIVE|TOK_EXCLREQ))
134 
135 /*
136  * Static initialization for a lwkt_token.
137  */
138 #define LWKT_TOKEN_INITIALIZER(name)	\
139 {					\
140 	.t_count = 0,			\
141 	.t_ref = NULL,			\
142 	.t_collisions = 0,		\
143 	.t_desc = #name			\
144 }
145 
146 /*
147  * Assert that a particular token is held
148  */
149 #define LWKT_TOKEN_HELD_ANY(tok)	_lwkt_token_held_any(tok, curthread)
150 #define LWKT_TOKEN_HELD_EXCL(tok)	_lwkt_token_held_excl(tok, curthread)
151 
152 #define ASSERT_LWKT_TOKEN_HELD(tok)		\
153 	KKASSERT(LWKT_TOKEN_HELD_ANY(tok))
154 
155 #define ASSERT_LWKT_TOKEN_HELD_EXCL(tok)	\
156 	KKASSERT(LWKT_TOKEN_HELD_EXCL(tok))
157 
158 #define ASSERT_NO_TOKENS_HELD(td)	\
159 	KKASSERT((td)->td_toks_stop == &td->td_toks_array[0])
160 
161 struct lwkt_tokref {
162     lwkt_token_t	tr_tok;		/* token in question */
163     long		tr_count;	/* TOK_EXCLUSIVE|TOK_EXCLREQ or 0 */
164     struct thread	*tr_owner;	/* me */
165 };
166 
167 #define MAXCPUFIFO      32	/* power of 2 */
168 #define MAXCPUFIFO_MASK	(MAXCPUFIFO - 1)
169 #define LWKT_MAXTOKENS	32	/* max tokens beneficially held by thread */
170 
171 /*
172  * Always cast to ipifunc_t when registering an ipi.  The actual ipi function
173  * is called with both the data and an interrupt frame, but the ipi function
174  * that is registered might only declare a data argument.
175  */
176 typedef void (*ipifunc1_t)(void *arg);
177 typedef void (*ipifunc2_t)(void *arg, int arg2);
178 typedef void (*ipifunc3_t)(void *arg, int arg2, struct intrframe *frame);
179 
180 struct lwkt_ipiq {
181     int		ip_rindex;      /* only written by target cpu */
182     int		ip_xindex;      /* written by target, indicates completion */
183     int		ip_windex;      /* only written by source cpu */
184     int		ip_drain;	/* drain source limit */
185     struct {
186 	ipifunc3_t	func;
187 	void		*arg1;
188 	int		arg2;
189 	char		filler[32 - sizeof(int) - sizeof(void *) * 2];
190     } ip_info[MAXCPUFIFO];
191 };
192 
193 /*
194  * CPU Synchronization structure.  See lwkt_cpusync_start() and
195  * lwkt_cpusync_finish() for more information.
196  */
197 typedef void (*cpusync_func_t)(void *arg);
198 
199 struct lwkt_cpusync {
200     cpumask_t	cs_mask;		/* cpus running the sync */
201     cpumask_t	cs_mack;		/* mask acknowledge */
202     cpusync_func_t cs_func;		/* function to execute */
203     void	*cs_data;		/* function data */
204 };
205 
206 /*
207  * The standard message and queue structure used for communications between
208  * cpus.  Messages are typically queued via a machine-specific non-linked
209  * FIFO matrix allowing any cpu to send a message to any other cpu without
210  * blocking.
211  */
212 typedef struct lwkt_cpu_msg {
213     void	(*cm_func)(lwkt_cpu_msg_t msg);	/* primary dispatch function */
214     int		cm_code;		/* request code if applicable */
215     int		cm_cpu;			/* reply to cpu */
216     thread_t	cm_originator;		/* originating thread for wakeup */
217 } lwkt_cpu_msg;
218 
219 /*
220  * Thread structure.  Note that ownership of a thread structure is special
221  * cased and there is no 'token'.  A thread is always owned by the cpu
222  * represented by td_gd, any manipulation of the thread by some other cpu
223  * must be done through cpu_*msg() functions.  e.g. you could request
224  * ownership of a thread that way, or hand a thread off to another cpu.
225  *
226  * NOTE: td_ucred is synchronized from the p_ucred on user->kernel syscall,
227  *	 trap, and AST/signal transitions to provide a stable ucred for
228  *	 (primarily) system calls.  This field will be NULL for pure kernel
229  *	 threads.
230  */
231 struct md_intr_info;
232 
233 struct thread {
234     TAILQ_ENTRY(thread) td_threadq;
235     TAILQ_ENTRY(thread) td_allq;
236     TAILQ_ENTRY(thread) td_sleepq;
237     lwkt_port	td_msgport;	/* built-in message port for replies */
238     struct lwp	*td_lwp;	/* (optional) associated lwp */
239     struct proc	*td_proc;	/* (optional) associated process */
240     struct pcb	*td_pcb;	/* points to pcb and top of kstack */
241     struct globaldata *td_gd;	/* associated with this cpu */
242     const char	*td_wmesg;	/* string name for blockage */
243     const volatile void	*td_wchan;	/* waiting on channel */
244     int		td_pri;		/* 0-31, 31=highest priority (note 1) */
245     int		td_critcount;	/* critical section priority */
246     u_int	td_flags;	/* TDF flags */
247     int		td_wdomain;	/* domain for wchan address (typ 0) */
248     void	(*td_preemptable)(struct thread *td, int critcount);
249     void	(*td_release)(struct thread *td);
250     char	*td_kstack;	/* kernel stack */
251     int		td_kstack_size;	/* size of kernel stack */
252     char	*td_sp;		/* kernel stack pointer for LWKT restore */
253     thread_t	(*td_switch)(struct thread *ntd);
254     __uint64_t	td_uticks;	/* Statclock hits in user mode (uS) */
255     __uint64_t	td_sticks;      /* Statclock hits in system mode (uS) */
256     __uint64_t	td_iticks;	/* Statclock hits processing intr (uS) */
257     int		td_locks;	/* lockmgr lock debugging */
258     void	*td_unused01;	/* (future I/O scheduler heuristic) */
259     int		td_refs;	/* hold position in gd_tdallq / hold free */
260     int		td_nest_count;	/* prevent splz nesting */
261     u_int	td_contended;	/* token contention count */
262     u_int	td_mpflags;	/* flags can be set by foreign cpus */
263     int		td_cscount;	/* cpu synchronization master */
264     int		td_wakefromcpu;	/* who woke me up? */
265     int		td_upri;	/* user priority (sub-priority under td_pri) */
266     int		td_type;	/* thread type, TD_TYPE_ */
267     int		td_tracker;	/* for callers to debug lock counts */
268     int		td_unused03[4];	/* for future fields */
269     struct iosched_data td_iosdata;	/* Dynamic I/O scheduling data */
270     struct timeval td_start;	/* start time for a thread/process */
271     char	td_comm[MAXCOMLEN+1]; /* typ 16+1 bytes */
272     struct thread *td_preempted; /* we preempted this thread */
273     struct ucred *td_ucred;		/* synchronized from p_ucred */
274     void	 *td_vmm;	/* vmm private data */
275     lwkt_tokref_t td_toks_have;		/* tokens we own */
276     lwkt_tokref_t td_toks_stop;		/* tokens we want */
277     struct lwkt_tokref td_toks_array[LWKT_MAXTOKENS];
278     int		td_fairq_load;		/* fairq */
279     int		td_fairq_count;		/* fairq */
280     struct globaldata *td_migrate_gd;	/* target gd for thread migration */
281 #ifdef DEBUG_CRIT_SECTIONS
282 #define CRIT_DEBUG_ARRAY_SIZE   32
283 #define CRIT_DEBUG_ARRAY_MASK   (CRIT_DEBUG_ARRAY_SIZE - 1)
284     const char	*td_crit_debug_array[CRIT_DEBUG_ARRAY_SIZE];
285     int		td_crit_debug_index;
286     int		td_in_crit_report;
287 #endif
288     struct md_thread td_mach;
289 #ifdef DEBUG_LOCKS
290 #define SPINLOCK_DEBUG_ARRAY_SIZE	32
291    int 	td_spinlock_stack_id[SPINLOCK_DEBUG_ARRAY_SIZE];
292    struct spinlock *td_spinlock_stack[SPINLOCK_DEBUG_ARRAY_SIZE];
293    void 	*td_spinlock_caller_pc[SPINLOCK_DEBUG_ARRAY_SIZE];
294 
295     /*
296      * Track lockmgr locks held; lk->lk_filename:lk->lk_lineno is the holder
297      */
298 #define LOCKMGR_DEBUG_ARRAY_SIZE	8
299     int		td_lockmgr_stack_id[LOCKMGR_DEBUG_ARRAY_SIZE];
300     struct lock	*td_lockmgr_stack[LOCKMGR_DEBUG_ARRAY_SIZE];
301 #endif
302 };
303 
304 #define td_toks_base		td_toks_array[0]
305 #define td_toks_end		td_toks_array[LWKT_MAXTOKENS]
306 
307 #define TD_TOKS_HELD(td)	((td)->td_toks_stop != &(td)->td_toks_base)
308 #define TD_TOKS_NOT_HELD(td)	((td)->td_toks_stop == &(td)->td_toks_base)
309 
310 /*
311  * Thread flags.  Note that TDF_RUNNING is cleared on the old thread after
312  * we switch to the new one, which is necessary because LWKTs don't need
313  * to hold the BGL.  This flag is used by the exit code and the managed
314  * thread migration code.  Note in addition that preemption will cause
315  * TDF_RUNNING to be cleared temporarily, so any code checking TDF_RUNNING
316  * must also check TDF_PREEMPT_LOCK.
317  *
318  * LWKT threads stay on their (per-cpu) run queue while running, not to
319  * be confused with user processes which are removed from the user scheduling
320  * run queue while actually running.
321  *
322  * td_threadq can represent the thread on one of three queues... the LWKT
323  * run queue, a tsleep queue, or an lwkt blocking queue.  The LWKT subsystem
324  * does not allow a thread to be scheduled if it already resides on some
325  * queue.
326  */
327 #define TDF_RUNNING		0x00000001	/* thread still active */
328 #define TDF_RUNQ		0x00000002	/* on an LWKT run queue */
329 #define TDF_PREEMPT_LOCK	0x00000004	/* I have been preempted */
330 #define TDF_PREEMPT_DONE	0x00000008	/* ac preemption complete */
331 #define TDF_NOSTART		0x00000010	/* do not schedule on create */
332 #define TDF_MIGRATING		0x00000020	/* thread is being migrated */
333 #define TDF_SINTR		0x00000040	/* interruptability for 'ps' */
334 #define TDF_TSLEEPQ		0x00000080	/* on a tsleep wait queue */
335 
336 #define TDF_SYSTHREAD		0x00000100	/* reserve memory may be used */
337 #define TDF_ALLOCATED_THREAD	0x00000200	/* objcache allocated thread */
338 #define TDF_ALLOCATED_STACK	0x00000400	/* objcache allocated stack */
339 #define TDF_VERBOSE		0x00000800	/* verbose on exit */
340 #define TDF_DEADLKTREAT		0x00001000	/* special lockmgr treatment */
341 #define TDF_MARKER		0x00002000	/* tdallq list scan marker */
342 #define TDF_TIMEOUT_RUNNING	0x00004000	/* tsleep timeout race */
343 #define TDF_TIMEOUT		0x00008000	/* tsleep timeout */
344 #define TDF_INTTHREAD		0x00010000	/* interrupt thread */
345 #define TDF_TSLEEP_DESCHEDULED	0x00020000	/* tsleep core deschedule */
346 #define TDF_BLOCKED		0x00040000	/* Thread is blocked */
347 #define TDF_PANICWARN		0x00080000	/* panic warning in switch */
348 #define TDF_BLOCKQ		0x00100000	/* on block queue */
349 #define TDF_FORCE_SPINPORT	0x00200000
350 #define TDF_EXITING		0x00400000	/* thread exiting */
351 #define TDF_USINGFP		0x00800000	/* thread using fp coproc */
352 #define TDF_KERNELFP		0x01000000	/* kernel using fp coproc */
353 #define TDF_DELAYED_WAKEUP	0x02000000
354 #define TDF_FIXEDCPU		0x04000000	/* running cpu is fixed */
355 #define TDF_USERMODE		0x08000000	/* in or entering user mode */
356 #define TDF_NOFAULT		0x10000000	/* force onfault on fault */
357 
358 #define TDF_MP_STOPREQ		0x00000001	/* suspend_kproc */
359 #define TDF_MP_WAKEREQ		0x00000002	/* resume_kproc */
360 #define TDF_MP_EXITWAIT		0x00000004	/* reaper, see lwp_wait() */
361 #define TDF_MP_EXITSIG		0x00000008	/* reaper, see lwp_wait() */
362 #define TDF_MP_BATCH_DEMARC	0x00000010	/* batch mode handling */
363 #define TDF_MP_DIDYIELD		0x00000020	/* effects scheduling */
364 
365 #define TD_TYPE_GENERIC		0		/* generic thread */
366 #define TD_TYPE_CRYPTO		1		/* crypto thread */
367 #define TD_TYPE_NETISR		2		/* netisr thread */
368 
369 /*
370  * Thread priorities.  Typically only one thread from any given
371  * user process scheduling queue is on the LWKT run queue at a time.
372  * Remember that there is one LWKT run queue per cpu.
373  *
374  * Critical sections are handled by bumping td_pri above TDPRI_MAX, which
375  * causes interrupts to be masked as they occur.  When this occurs a
376  * rollup flag will be set in mycpu->gd_reqflags.
377  */
378 #define TDPRI_IDLE_THREAD	0	/* the idle thread */
379 #define TDPRI_IDLE_WORK		1	/* idle work (page zero, etc) */
380 #define TDPRI_USER_SCHEDULER	2	/* user scheduler helper */
381 #define TDPRI_USER_IDLE		4	/* user scheduler idle */
382 #define TDPRI_USER_NORM		6	/* user scheduler normal */
383 #define TDPRI_USER_REAL		8	/* user scheduler real time */
384 #define TDPRI_KERN_LPSCHED	9	/* (comparison point only) */
385 #define TDPRI_KERN_USER		10	/* kernel / block in syscall */
386 #define TDPRI_KERN_DAEMON	12	/* kernel daemon (pageout, etc) */
387 #define TDPRI_SOFT_NORM		14	/* kernel / normal */
388 #define TDPRI_SOFT_TIMER	16	/* kernel / timer */
389 #define TDPRI_UNUSED19		19
390 #define TDPRI_INT_SUPPORT	20	/* kernel / high priority support */
391 #define TDPRI_INT_LOW		27	/* low priority interrupt */
392 #define TDPRI_INT_MED		28	/* medium priority interrupt */
393 #define TDPRI_INT_HIGH		29	/* high priority interrupt */
394 #define TDPRI_MAX		31
395 
396 #define LWKT_THREAD_STACK	(UPAGES * PAGE_SIZE)
397 
398 #define IN_CRITICAL_SECT(td)	((td)->td_critcount)
399 
400 #ifdef _KERNEL
401 
402 /*
403  * Global tokens
404  */
405 extern struct lwkt_token mp_token;
406 extern struct lwkt_token pmap_token;
407 extern struct lwkt_token dev_token;
408 extern struct lwkt_token vm_token;
409 extern struct lwkt_token vmspace_token;
410 extern struct lwkt_token kvm_token;
411 extern struct lwkt_token sigio_token;
412 extern struct lwkt_token tty_token;
413 extern struct lwkt_token vnode_token;
414 extern struct lwkt_token revoke_token;
415 
416 /*
417  * Procedures
418  */
419 extern struct thread *lwkt_alloc_thread(struct thread *, int, int, int);
420 extern void lwkt_init_thread(struct thread *, void *, int, int,
421 			     struct globaldata *);
422 extern void lwkt_set_interrupt_support_thread(void);
423 extern void lwkt_set_comm(thread_t, const char *, ...) __printflike(2, 3);
424 extern void lwkt_free_thread(struct thread *);
425 extern void lwkt_gdinit(struct globaldata *);
426 extern void lwkt_switch(void);
427 extern void lwkt_switch_return(struct thread *);
428 extern void lwkt_preempt(thread_t, int);
429 extern void lwkt_schedule(thread_t);
430 extern void lwkt_schedule_noresched(thread_t);
431 extern void lwkt_schedule_self(thread_t);
432 extern void lwkt_deschedule(thread_t);
433 extern void lwkt_deschedule_self(thread_t);
434 extern void lwkt_yield(void);
435 extern void lwkt_yield_quick(void);
436 extern void lwkt_user_yield(void);
437 extern void lwkt_hold(thread_t);
438 extern void lwkt_rele(thread_t);
439 extern void lwkt_passive_release(thread_t);
440 extern void lwkt_maybe_splz(thread_t);
441 
442 extern void lwkt_gettoken(lwkt_token_t);
443 extern void lwkt_gettoken_shared(lwkt_token_t);
444 extern int  lwkt_trytoken(lwkt_token_t);
445 extern void lwkt_reltoken(lwkt_token_t);
446 extern int  lwkt_cnttoken(lwkt_token_t, thread_t);
447 extern int  lwkt_getalltokens(thread_t, int);
448 extern void lwkt_relalltokens(thread_t);
449 extern void lwkt_token_init(lwkt_token_t, const char *);
450 extern void lwkt_token_uninit(lwkt_token_t);
451 
452 extern void lwkt_token_pool_init(void);
453 extern lwkt_token_t lwkt_token_pool_lookup(void *);
454 extern lwkt_token_t lwkt_getpooltoken(void *);
455 extern void lwkt_relpooltoken(void *);
456 
457 extern void lwkt_token_swap(void);
458 
459 extern void lwkt_setpri(thread_t, int);
460 extern void lwkt_setpri_initial(thread_t, int);
461 extern void lwkt_setpri_self(int);
462 extern void lwkt_schedulerclock(thread_t td);
463 extern void lwkt_setcpu_self(struct globaldata *);
464 extern void lwkt_migratecpu(int);
465 
466 extern void lwkt_giveaway(struct thread *);
467 extern void lwkt_acquire(struct thread *);
468 extern int  lwkt_send_ipiq3(struct globaldata *, ipifunc3_t, void *, int);
469 extern int  lwkt_send_ipiq3_passive(struct globaldata *, ipifunc3_t,
470 				    void *, int);
471 extern int  lwkt_send_ipiq3_bycpu(int, ipifunc3_t, void *, int);
472 extern int  lwkt_send_ipiq3_mask(cpumask_t, ipifunc3_t, void *, int);
473 extern void lwkt_wait_ipiq(struct globaldata *, int);
474 extern void lwkt_process_ipiq(void);
475 extern void lwkt_process_ipiq_frame(struct intrframe *);
476 extern void lwkt_smp_stopped(void);
477 extern void lwkt_synchronize_ipiqs(const char *);
478 
479 /* lwkt_cpusync_init() - inline function in sys/thread2.h */
480 extern void lwkt_cpusync_simple(cpumask_t, cpusync_func_t, void *);
481 extern void lwkt_cpusync_interlock(lwkt_cpusync_t);
482 extern void lwkt_cpusync_deinterlock(lwkt_cpusync_t);
483 extern void lwkt_cpusync_quick(lwkt_cpusync_t);
484 
485 extern void crit_panic(void) __dead2;
486 extern struct lwp *lwkt_preempted_proc(void);
487 
488 extern int  lwkt_create (void (*func)(void *), void *, struct thread **,
489 		struct thread *, int, int,
490 		const char *, ...) __printflike(7, 8);
491 extern void lwkt_exit (void) __dead2;
492 extern void lwkt_remove_tdallq (struct thread *);
493 
494 #endif
495 
496 #endif
497 
498