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Commit	Line	Data
	1	/*
	2	* SYS/THREAD2.H
	3	*
	4	* Implements inline procedure support for the LWKT subsystem.
	5	*
	6	* Generally speaking these routines only operate on threads associated
	7	* with the current cpu. For example, a higher priority thread pending
	8	* on a different cpu will not be immediately scheduled by a yield() on
	9	* this cpu.
	10	*
	11	* $DragonFly: src/sys/sys/thread2.h,v 1.16 2004/07/29 08:55:48 dillon Exp $
	12	*/
	13
	14	#ifndef _SYS_THREAD2_H_
	15	#define _SYS_THREAD2_H_
	16
	17	/*
	18	* Userland will have its own globaldata which it includes prior to this.
	19	*/
	20	#if defined(_KERNEL) \|\| defined(_KERNEL_STRUCTURES)
	21	#ifndef _SYS_GLOBALDATA_H_
	22	#include <sys/globaldata.h>
	23	#endif
	24	#ifndef _MACHINE_CPUFUNC_H_
	25	#include <machine/cpufunc.h>
	26	#endif
	27	#endif
	28
	29	/*
	30	* Critical sections prevent preemption by raising a thread's priority
	31	* above the highest possible interrupting priority. Additionally, the
	32	* current cpu will not be able to schedule a new thread but will instead
	33	* place it on a pending list (with interrupts physically disabled) and
	34	* set mycpu->gd_reqflags to indicate that work needs to be done, which
	35	* lwkt_yield_quick() takes care of.
	36	*
	37	* Some of these routines take a struct thread pointer as an argument. This
	38	* pointer MUST be curthread and is only passed as an optimization.
	39	*
	40	* Synchronous switching and blocking is allowed while in a critical section.
	41	*/
	42
	43	static __inline void
	44	crit_enter(void)
	45	{
	46	struct thread *td = curthread;
	47
	48	td->td_pri += TDPRI_CRIT;
	49	#ifdef INVARIANTS
	50	if (td->td_pri < 0)
	51	crit_panic();
	52	#endif
	53	}
	54
	55	static __inline void
	56	crit_enter_quick(struct thread *curtd)
	57	{
	58	curtd->td_pri += TDPRI_CRIT;
	59	}
	60
	61	static __inline void
	62	crit_enter_gd(globaldata_t mygd)
	63	{
	64	crit_enter_quick(mygd->gd_curthread);
	65	}
	66
	67	static __inline void
	68	crit_exit_noyield(struct thread *curtd)
	69	{
	70	curtd->td_pri -= TDPRI_CRIT;
	71	#ifdef INVARIANTS
	72	if (curtd->td_pri < 0)
	73	crit_panic();
	74	#endif
	75	}
	76
	77	static __inline void
	78	crit_exit(void)
	79	{
	80	thread_t td = curthread;
	81
	82	td->td_pri -= TDPRI_CRIT;
	83	#ifdef INVARIANTS
	84	if (td->td_pri < 0)
	85	crit_panic();
	86	#endif
	87	cpu_mb1(); /* must flush td_pri before checking gd_reqflags */
	88	if (td->td_gd->gd_reqflags && td->td_pri < TDPRI_CRIT)
	89	lwkt_yield_quick();
	90	}
	91
	92	static __inline void
	93	crit_exit_quick(struct thread *curtd)
	94	{
	95	globaldata_t gd = curtd->td_gd;
	96
	97	curtd->td_pri -= TDPRI_CRIT;
	98	cpu_mb1(); /* must flush td_pri before checking gd_reqflags */
	99	if (gd->gd_reqflags && curtd->td_pri < TDPRI_CRIT)
	100	lwkt_yield_quick();
	101	}
	102
	103	static __inline void
	104	crit_exit_gd(globaldata_t mygd)
	105	{
	106	crit_exit_quick(mygd->gd_curthread);
	107	}
	108
	109	static __inline int
	110	crit_panic_save(void)
	111	{
	112	thread_t td = curthread;
	113	int pri = td->td_pri;
	114	td->td_pri = td->td_pri & TDPRI_MASK;
	115	return(pri);
	116	}
	117
	118	static __inline void
	119	crit_panic_restore(int cpri)
	120	{
	121	curthread->td_pri = cpri;
	122	}
	123
	124	/*
	125	* Initialize a tokref_t. We only need to initialize the token pointer
	126	* and the magic number. We do not have to initialize tr_next, tr_gdreqnext,
	127	* or tr_reqgd.
	128	*/
	129	static __inline void
	130	lwkt_tokref_init(lwkt_tokref_t ref, lwkt_token_t tok)
	131	{
	132	ref->tr_magic = LWKT_TOKREF_MAGIC1;
	133	ref->tr_tok = tok;
	134	}
	135
	136	/*
	137	* Return whether any threads are runnable, whether they meet mp_lock
	138	* requirements or not.
	139	*/
	140	static __inline int
	141	lwkt_runnable(void)
	142	{
	143	return (mycpu->gd_runqmask != 0);
	144	}
	145
	146	static __inline int
	147	lwkt_getpri(thread_t td)
	148	{
	149	return(td->td_pri & TDPRI_MASK);
	150	}
	151
	152	static __inline int
	153	lwkt_getpri_self(void)
	154	{
	155	return(lwkt_getpri(curthread));
	156	}
	157
	158	#endif
	159