sys/sys/thread.h

   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  * $DragonFly: src/sys/sys/thread.h,v 1.97 2008/09/20 04:31:02 sephe Exp $
  11  */
  12
  13 #ifndef _SYS_THREAD_H_
  14 #define _SYS_THREAD_H_
  15
  16 #ifndef _SYS_STDINT_H_
  17 #include <sys/stdint.h>         /* __int types */
  18 #endif
  19 #ifndef _SYS_PARAM_H_
  20 #include <sys/param.h>          /* MAXCOMLEN */
  21 #endif
  22 #ifndef _SYS_QUEUE_H_
  23 #include <sys/queue.h>          /* TAILQ_* macros */
  24 #endif
  25 #ifndef _SYS_MSGPORT_H_
  26 #include <sys/msgport.h>        /* lwkt_port */
  27 #endif
  28 #ifndef _SYS_TIME_H_
  29 #include <sys/time.h>           /* struct timeval */
  30 #endif
  31 #ifndef _SYS_SPINLOCK_H_
  32 #include <sys/spinlock.h>
  33 #endif
  34 #ifndef _SYS_IOSCHED_H_
  35 #include <sys/iosched.h>
  36 #endif
  37 #ifndef _MACHINE_THREAD_H_
  38 #include <machine/thread.h>
  39 #endif
  40
  41 struct globaldata;
  42 struct lwp;
  43 struct proc;
  44 struct thread;
  45 struct lwkt_queue;
  46 struct lwkt_token;
  47 struct lwkt_tokref;
  48 struct lwkt_ipiq;
  49 struct lwkt_cpu_msg;
  50 struct lwkt_cpu_port;
  51 struct lwkt_msg;
  52 struct lwkt_port;
  53 struct lwkt_cpusync;
  54 union sysunion;
  55
  56 typedef struct lwkt_queue       *lwkt_queue_t;
  57 typedef struct lwkt_token       *lwkt_token_t;
  58 typedef struct lwkt_tokref      *lwkt_tokref_t;
  59 typedef struct lwkt_cpu_msg     *lwkt_cpu_msg_t;
  60 typedef struct lwkt_cpu_port    *lwkt_cpu_port_t;
  61 typedef struct lwkt_ipiq        *lwkt_ipiq_t;
  62 typedef struct lwkt_cpusync     *lwkt_cpusync_t;
  63 typedef struct thread           *thread_t;
  64
  65 typedef TAILQ_HEAD(lwkt_queue, thread) lwkt_queue;
  66
  67 /*
  68  * Differentiation between kernel threads and user threads.  Userland
  69  * programs which want to access to kernel structures have to define
  70  * _KERNEL_STRUCTURES.  This is a kinda safety valve to prevent badly
  71  * written user programs from getting an LWKT thread that is neither the
  72  * kernel nor the user version.
  73  */
  74 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
  75 #ifndef _MACHINE_THREAD_H_
  76 #include <machine/thread.h>             /* md_thread */
  77 #endif
  78 #ifndef _MACHINE_FRAME_H_
  79 #include <machine/frame.h>
  80 #endif
  81 #else
  82 struct intrframe;
  83 #endif
  84
  85 /*
  86  * Tokens are used to serialize access to information.  They are 'soft'
  87  * serialization entities that only stay in effect while a thread is
  88  * running.  If the thread blocks, other threads can run holding the same
  89  * token(s).  The tokens are reacquired when the original thread resumes.
  90  *
  91  * A thread can depend on its serialization remaining intact through a
  92  * preemption.  An interrupt which attempts to use the same token as the
  93  * thread being preempted will reschedule itself for non-preemptive
  94  * operation, so the new token code is capable of interlocking against
  95  * interrupts as well as other cpus.  This means that your token can only
  96  * be (temporarily) lost if you *explicitly* block.
  97  *
  98  * Tokens are managed through a helper reference structure, lwkt_tokref,
  99  * which is typically declared on the caller's stack.  Multiple tokref's
 100  * may reference the same token.
 101  *
 102  * It is possible to detect that your token was temporarily lost via
 103  * lwkt_token_is_stale(), which uses the t_lastowner field.  This field
 104  * does NOT necessarily represent the current owner and can become stale
 105  * (not point to a valid structure).  It is used solely to detect
 106  * whether the token was temporarily lost to another thread.  The lost
 107  * state is cleared by the function.
 108  */
 109
 110 typedef struct lwkt_token {
 111 #ifdef SMP
 112     struct spinlock     t_spinlock;     /* Controls access */
 113 #else
 114     struct spinlock     t_unused01;
 115 #endif
 116     struct thread       *t_owner;       /* The current owner of the token */
 117     int                 t_count;        /* Per-thread count */
 118     struct thread       *t_lastowner;   /* Last owner that acquired token */
 119 } lwkt_token;
 120
 121 #ifdef SMP
 122 #define LWKT_TOKEN_INITIALIZER(head) \
 123 { \
 124         .t_spinlock = SPINLOCK_INITIALIZER(head.t_spinlock), \
 125         .t_owner = NULL, \
 126         .t_lastowner = NULL, \
 127         .t_count = 0 \
 128 }
 129 #else
 130 #define LWKT_TOKEN_INITIALIZER(head) \
 131 { \
 132         .t_owner = NULL, \
 133         .t_lastowner = NULL, \
 134         .t_count = 0 \
 135 }
 136 #endif
 137
 138 #define ASSERT_LWKT_TOKEN_HELD(token) \
 139         KKASSERT((token)->t_owner == curthread)
 140
 141 typedef struct lwkt_tokref {
 142     lwkt_token_t        tr_tok;         /* token in question */
 143     lwkt_tokref_t       tr_next;        /* linked list */
 144     int                 tr_state;       /* 0 = don't have, 1 = have */
 145 } lwkt_tokref;
 146
 147 #define LWKT_TOKREF_INIT(tok)           \
 148                         { tok, NULL, 0 }
 149 #define LWKT_TOKREF_DECLARE(name, tok)  \
 150                         lwkt_tokref name = LWKT_TOKREF_INIT(tok)
 151
 152 #define MAXCPUFIFO      16      /* power of 2 */
 153 #define MAXCPUFIFO_MASK (MAXCPUFIFO - 1)
 154 #define LWKT_MAXTOKENS  16      /* max tokens beneficially held by thread */
 155
 156 /*
 157  * Always cast to ipifunc_t when registering an ipi.  The actual ipi function
 158  * is called with both the data and an interrupt frame, but the ipi function
 159  * that is registered might only declare a data argument.
 160  */
 161 typedef void (*ipifunc1_t)(void *arg);
 162 typedef void (*ipifunc2_t)(void *arg, int arg2);
 163 typedef void (*ipifunc3_t)(void *arg, int arg2, struct intrframe *frame);
 164
 165 typedef struct lwkt_ipiq {
 166     int         ip_rindex;      /* only written by target cpu */
 167     int         ip_xindex;      /* written by target, indicates completion */
 168     int         ip_windex;      /* only written by source cpu */
 169     ipifunc3_t  ip_func[MAXCPUFIFO];
 170     void        *ip_arg1[MAXCPUFIFO];
 171     int         ip_arg2[MAXCPUFIFO];
 172     u_int       ip_npoll;       /* synchronization to avoid excess IPIs */
 173 } lwkt_ipiq;
 174
 175 /*
 176  * CPU Synchronization structure.  See lwkt_cpusync_start() and
 177  * lwkt_cpusync_finish() for more information.
 178  */
 179 typedef void (*cpusync_func_t)(lwkt_cpusync_t poll);
 180 typedef void (*cpusync_func2_t)(void *data);
 181
 182 struct lwkt_cpusync {
 183     cpusync_func_t cs_run_func;         /* run (tandem w/ acquire) */
 184     cpusync_func_t cs_fin1_func;        /* fin1 (synchronized) */
 185     cpusync_func2_t cs_fin2_func;       /* fin2 (tandem w/ release) */
 186     void        *cs_data;
 187     int         cs_maxcount;
 188     volatile int cs_count;
 189     cpumask_t   cs_mask;
 190 };
 191
 192 /*
 193  * The standard message and queue structure used for communications between
 194  * cpus.  Messages are typically queued via a machine-specific non-linked
 195  * FIFO matrix allowing any cpu to send a message to any other cpu without
 196  * blocking.
 197  */
 198 typedef struct lwkt_cpu_msg {
 199     void        (*cm_func)(lwkt_cpu_msg_t msg); /* primary dispatch function */
 200     int         cm_code;                /* request code if applicable */
 201     int         cm_cpu;                 /* reply to cpu */
 202     thread_t    cm_originator;          /* originating thread for wakeup */
 203 } lwkt_cpu_msg;
 204
 205 /*
 206  * Thread structure.  Note that ownership of a thread structure is special
 207  * cased and there is no 'token'.  A thread is always owned by the cpu
 208  * represented by td_gd, any manipulation of the thread by some other cpu
 209  * must be done through cpu_*msg() functions.  e.g. you could request
 210  * ownership of a thread that way, or hand a thread off to another cpu.
 211  *
 212  * NOTE: td_pri is bumped by TDPRI_CRIT when entering a critical section,
 213  * but this does not effect how the thread is scheduled by LWKT.
 214  */
 215 struct md_intr_info;
 216 struct caps_kinfo;
 217
 218 struct thread {
 219     TAILQ_ENTRY(thread) td_threadq;
 220     TAILQ_ENTRY(thread) td_allq;
 221     TAILQ_ENTRY(thread) td_sleepq;
 222     lwkt_port   td_msgport;     /* built-in message port for replies */
 223     struct lwp  *td_lwp;        /* (optional) associated lwp */
 224     struct proc *td_proc;       /* (optional) associated process */
 225     struct pcb  *td_pcb;        /* points to pcb and top of kstack */
 226     struct globaldata *td_gd;   /* associated with this cpu */
 227     const char  *td_wmesg;      /* string name for blockage */
 228     void        *td_wchan;      /* waiting on channel */
 229     int         td_pri;         /* 0-31, 31=highest priority (note 1) */
 230     int         td_flags;       /* TDF flags */
 231     int         td_wdomain;     /* domain for wchan address (typ 0) */
 232     void        (*td_preemptable)(struct thread *td, int critpri);
 233     void        (*td_release)(struct thread *td);
 234     char        *td_kstack;     /* kernel stack */
 235     int         td_kstack_size; /* size of kernel stack */
 236     char        *td_sp;         /* kernel stack pointer for LWKT restore */
 237     void        (*td_switch)(struct thread *ntd);
 238     __uint64_t  td_uticks;      /* Statclock hits in user mode (uS) */
 239     __uint64_t  td_sticks;      /* Statclock hits in system mode (uS) */
 240     __uint64_t  td_iticks;      /* Statclock hits processing intr (uS) */
 241     int         td_locks;       /* lockmgr lock debugging */
 242     int         td_unused01;
 243     int         td_refs;        /* hold position in gd_tdallq / hold free */
 244     int         td_nest_count;  /* prevent splz nesting */
 245 #ifdef SMP
 246     int         td_mpcount;     /* MP lock held (count) */
 247     int         td_cscount;     /* cpu synchronization master */
 248 #else
 249     int         td_mpcount_unused;      /* filler so size matches */
 250     int         td_cscount_unused;
 251 #endif
 252     struct iosched_data td_iosdata;     /* Dynamic I/O scheduling data */
 253     struct timeval td_start;    /* start time for a thread/process */
 254     char        td_comm[MAXCOMLEN+1]; /* typ 16+1 bytes */
 255     struct thread *td_preempted; /* we preempted this thread */
 256     struct caps_kinfo *td_caps; /* list of client and server registrations */
 257     lwkt_tokref_t td_toks;      /* tokens beneficially held */
 258 #ifdef DEBUG_CRIT_SECTIONS
 259 #define CRIT_DEBUG_ARRAY_SIZE   32
 260 #define CRIT_DEBUG_ARRAY_MASK   (CRIT_DEBUG_ARRAY_SIZE - 1)
 261     const char  *td_crit_debug_array[CRIT_DEBUG_ARRAY_SIZE];
 262     int         td_crit_debug_index;
 263     int         td_in_crit_report;
 264 #endif
 265     struct md_thread td_mach;
 266 };
 267
 268 /*
 269  * Thread flags.  Note that TDF_RUNNING is cleared on the old thread after
 270  * we switch to the new one, which is necessary because LWKTs don't need
 271  * to hold the BGL.  This flag is used by the exit code and the managed
 272  * thread migration code.  Note in addition that preemption will cause
 273  * TDF_RUNNING to be cleared temporarily, so any code checking TDF_RUNNING
 274  * must also check TDF_PREEMPT_LOCK.
 275  *
 276  * LWKT threads stay on their (per-cpu) run queue while running, not to
 277  * be confused with user processes which are removed from the user scheduling
 278  * run queue while actually running.
 279  *
 280  * td_threadq can represent the thread on one of three queues... the LWKT
 281  * run queue, a tsleep queue, or an lwkt blocking queue.  The LWKT subsystem
 282  * does not allow a thread to be scheduled if it already resides on some
 283  * queue.
 284  */
 285 #define TDF_RUNNING             0x0001  /* thread still active */
 286 #define TDF_RUNQ                0x0002  /* on an LWKT run queue */
 287 #define TDF_PREEMPT_LOCK        0x0004  /* I have been preempted */
 288 #define TDF_PREEMPT_DONE        0x0008  /* acknowledge preemption complete */
 289 #define TDF_IDLE_NOHLT          0x0010  /* we need to spin */
 290 #define TDF_MIGRATING           0x0020  /* thread is being migrated */
 291 #define TDF_SINTR               0x0040  /* interruptability hint for 'ps' */
 292 #define TDF_TSLEEPQ             0x0080  /* on a tsleep wait queue */
 293
 294 #define TDF_SYSTHREAD           0x0100  /* allocations may use reserve */
 295 #define TDF_ALLOCATED_THREAD    0x0200  /* objcache allocated thread */
 296 #define TDF_ALLOCATED_STACK     0x0400  /* objcache allocated stack */
 297 #define TDF_VERBOSE             0x0800  /* verbose on exit */
 298 #define TDF_DEADLKTREAT         0x1000  /* special lockmgr deadlock treatment */
 299 #define TDF_STOPREQ             0x2000  /* suspend_kproc */
 300 #define TDF_WAKEREQ             0x4000  /* resume_kproc */
 301 #define TDF_TIMEOUT             0x8000  /* tsleep timeout */
 302 #define TDF_INTTHREAD           0x00010000      /* interrupt thread */
 303 #define TDF_TSLEEP_DESCHEDULED  0x00020000      /* tsleep core deschedule */
 304 #define TDF_BLOCKED             0x00040000      /* Thread is blocked */
 305 #define TDF_PANICWARN           0x00080000      /* panic warning in switch */
 306 #define TDF_BLOCKQ              0x00100000      /* on block queue */
 307 #define TDF_MPSAFE              0x00200000      /* (thread creation) */
 308 #define TDF_EXITING             0x00400000      /* thread exiting */
 309 #define TDF_USINGFP             0x00800000      /* thread using fp coproc */
 310 #define TDF_KERNELFP            0x01000000      /* kernel using fp coproc */
 311 #define TDF_NETWORK             0x02000000      /* network proto thread */
 312
 313 /*
 314  * Thread priorities.  Typically only one thread from any given
 315  * user process scheduling queue is on the LWKT run queue at a time.
 316  * Remember that there is one LWKT run queue per cpu.
 317  *
 318  * Critical sections are handled by bumping td_pri above TDPRI_MAX, which
 319  * causes interrupts to be masked as they occur.  When this occurs a
 320  * rollup flag will be set in mycpu->gd_reqflags.
 321  */
 322 #define TDPRI_IDLE_THREAD       0       /* the idle thread */
 323 #define TDPRI_USER_SCHEDULER    2       /* user scheduler helper */
 324 #define TDPRI_USER_IDLE         4       /* user scheduler idle */
 325 #define TDPRI_USER_NORM         6       /* user scheduler normal */
 326 #define TDPRI_USER_REAL         8       /* user scheduler real time */
 327 #define TDPRI_KERN_LPSCHED      9       /* scheduler helper for userland sch */
 328 #define TDPRI_KERN_USER         10      /* kernel / block in syscall */
 329 #define TDPRI_KERN_DAEMON       12      /* kernel daemon (pageout, etc) */
 330 #define TDPRI_SOFT_NORM         14      /* kernel / normal */
 331 #define TDPRI_SOFT_TIMER        16      /* kernel / timer */
 332 #define TDPRI_EXITING           19      /* exiting thread */
 333 #define TDPRI_INT_SUPPORT       20      /* kernel / high priority support */
 334 #define TDPRI_INT_LOW           27      /* low priority interrupt */
 335 #define TDPRI_INT_MED           28      /* medium priority interrupt */
 336 #define TDPRI_INT_HIGH          29      /* high priority interrupt */
 337 #define TDPRI_MAX               31
 338
 339 #define TDPRI_MASK              31
 340 #define TDPRI_CRIT              32      /* high bits of td_pri used for crit */
 341
 342 #ifdef _KERNEL
 343 #define LWKT_THREAD_STACK       (UPAGES * PAGE_SIZE)
 344 #endif
 345
 346 #define CACHE_NTHREADS          6
 347
 348 #define IN_CRITICAL_SECT(td)    ((td)->td_pri >= TDPRI_CRIT)
 349
 350 extern void lwkt_init(void);
 351 extern struct thread *lwkt_alloc_thread(struct thread *, int, int, int);
 352 extern void lwkt_init_thread(struct thread *, void *, int, int,
 353                              struct globaldata *);
 354 extern void lwkt_set_comm(thread_t, const char *, ...);
 355 extern void lwkt_wait_free(struct thread *);
 356 extern void lwkt_free_thread(struct thread *);
 357 extern void lwkt_gdinit(struct globaldata *);
 358 extern void lwkt_switch(void);
 359 extern void lwkt_preempt(thread_t, int);
 360 extern void lwkt_schedule(thread_t);
 361 extern void lwkt_schedule_noresched(thread_t);
 362 extern void lwkt_schedule_self(thread_t);
 363 extern void lwkt_deschedule(thread_t);
 364 extern void lwkt_deschedule_self(thread_t);
 365 extern void lwkt_yield(void);
 366 extern void lwkt_user_yield(void);
 367 extern void lwkt_token_wait(void);
 368 extern void lwkt_hold(thread_t);
 369 extern void lwkt_rele(thread_t);
 370 extern void lwkt_passive_release(thread_t);
 371
 372 extern void lwkt_gettoken(lwkt_tokref_t, lwkt_token_t);
 373 extern int lwkt_trytoken(lwkt_tokref_t, lwkt_token_t);
 374 extern void lwkt_gettokref(lwkt_tokref_t);
 375 extern int  lwkt_trytokref(lwkt_tokref_t);
 376 extern void lwkt_reltoken(lwkt_tokref_t);
 377 extern int  lwkt_getalltokens(thread_t);
 378 extern void lwkt_relalltokens(thread_t);
 379 extern void lwkt_drain_token_requests(void);
 380 extern void lwkt_token_init(lwkt_token_t);
 381 extern void lwkt_token_uninit(lwkt_token_t);
 382 extern int  lwkt_token_is_stale(lwkt_tokref_t);
 383
 384 extern void lwkt_token_pool_init(void);
 385 extern lwkt_token_t lwkt_token_pool_get(void *);
 386
 387 extern void lwkt_setpri(thread_t, int);
 388 extern void lwkt_setpri_self(int);
 389 extern int lwkt_check_resched(thread_t);
 390 extern void lwkt_setcpu_self(struct globaldata *);
 391 extern void lwkt_migratecpu(int);
 392
 393 #ifdef SMP
 394
 395 extern void lwkt_giveaway(struct thread *);
 396 extern void lwkt_acquire(struct thread *);
 397 extern int  lwkt_send_ipiq3(struct globaldata *, ipifunc3_t, void *, int);
 398 extern int  lwkt_send_ipiq3_passive(struct globaldata *, ipifunc3_t,
 399                                     void *, int);
 400 extern int  lwkt_send_ipiq3_nowait(struct globaldata *, ipifunc3_t,
 401                                    void *, int);
 402 extern int  lwkt_send_ipiq3_bycpu(int, ipifunc3_t, void *, int);
 403 extern int  lwkt_send_ipiq3_mask(cpumask_t, ipifunc3_t, void *, int);
 404 extern void lwkt_wait_ipiq(struct globaldata *, int);
 405 extern int  lwkt_seq_ipiq(struct globaldata *);
 406 extern void lwkt_process_ipiq(void);
 407 #ifdef _KERNEL
 408 extern void lwkt_process_ipiq_frame(struct intrframe *);
 409 #endif
 410 extern void lwkt_smp_stopped(void);
 411 extern void lwkt_synchronize_ipiqs(const char *);
 412
 413 #endif /* SMP */
 414
 415 extern void lwkt_cpusync_simple(cpumask_t, cpusync_func_t, void *);
 416 extern void lwkt_cpusync_fastdata(cpumask_t, cpusync_func2_t, void *);
 417 extern void lwkt_cpusync_start(cpumask_t, lwkt_cpusync_t);
 418 extern void lwkt_cpusync_add(cpumask_t, lwkt_cpusync_t);
 419 extern void lwkt_cpusync_finish(lwkt_cpusync_t);
 420
 421 extern void crit_panic(void);
 422 extern struct lwp *lwkt_preempted_proc(void);
 423
 424 extern int  lwkt_create (void (*func)(void *), void *, struct thread **,
 425                          struct thread *, int, int, const char *, ...);
 426 extern void lwkt_exit (void) __dead2;
 427 extern void lwkt_remove_tdallq (struct thread *);
 428 extern void lwkt_mp_lock_contested(void);
 429 extern void lwkt_mp_lock_uncontested(void);
 430
 431 #endif
 432