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 1.77 2006/01/31 19:05:44 dillon 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
  32 struct globaldata;
  33 struct lwp;
  34 struct proc;
  35 struct thread;
  36 struct lwkt_queue;
  37 struct lwkt_token;
  38 struct lwkt_tokref;
  39 struct lwkt_wait;
  40 struct lwkt_ipiq;
  41 struct lwkt_cpu_msg;
  42 struct lwkt_cpu_port;
  43 struct lwkt_rwlock;
  44 struct lwkt_msg;
  45 struct lwkt_port;
  46 struct lwkt_cpusync;
  47 union sysunion;
  48
  49 typedef struct lwkt_queue       *lwkt_queue_t;
  50 typedef struct lwkt_token       *lwkt_token_t;
  51 typedef struct lwkt_tokref      *lwkt_tokref_t;
  52 typedef struct lwkt_wait        *lwkt_wait_t;
  53 typedef struct lwkt_cpu_msg     *lwkt_cpu_msg_t;
  54 typedef struct lwkt_cpu_port    *lwkt_cpu_port_t;
  55 typedef struct lwkt_rwlock      *lwkt_rwlock_t;
  56 typedef struct lwkt_ipiq        *lwkt_ipiq_t;
  57 typedef struct lwkt_cpusync     *lwkt_cpusync_t;
  58 typedef struct thread           *thread_t;
  59
  60 typedef TAILQ_HEAD(lwkt_queue, thread) lwkt_queue;
  61
  62 /*
  63  * Differentiation between kernel threads and user threads.  Userland
  64  * programs which want to access to kernel structures have to define
  65  * _KERNEL_STRUCTURES.  This is a kinda safety valve to prevent badly
  66  * written user programs from getting an LWKT thread that is neither the
  67  * kernel nor the user version.
  68  */
  69 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
  70 #ifndef _MACHINE_THREAD_H_
  71 #include <machine/thread.h>             /* md_thread */
  72 #endif
  73 #ifndef _MACHINE_FRAME_H_
  74 #include <machine/frame.h>
  75 #endif
  76 #else
  77 struct intrframe;
  78 #endif
  79
  80 /*
  81  * Tokens are used to serialize access to information.  They are 'soft'
  82  * serialization entities that only stay in effect while the thread is
  83  * running.  If the thread blocks, other threads can run holding the same
  84  * tokens.  The tokens are reacquired when the original thread resumes.
  85  *
  86  * A thread can depend on its serialization remaining intact through a
  87  * preemption.  An interrupt which attempts to use the same token as the
  88  * thread being preempted will reschedule itself for non-preemptive
  89  * operation, so the new token code is capable of interlocking against
  90  * interrupts as well as other cpus.
  91  *
  92  * Tokens are managed through a helper reference structure, lwkt_tokref,
  93  * which is typically declared on the caller's stack.  Multiple tokref's
  94  * may reference the same token.
  95  */
  96 typedef struct lwkt_token {
  97     struct globaldata   *t_cpu;         /* the current owner of the token */
  98     struct globaldata   *t_reqcpu;      /* requesting cpu */
  99     int                 t_unused01;     /* (used to be generation number) */
 100 } lwkt_token;
 101
 102 typedef struct lwkt_tokref {
 103     lwkt_token_t        tr_tok;         /* token in question */
 104     __uint32_t          tr_magic;       /* sanity check */
 105     lwkt_tokref_t       tr_next;        /* linked list */
 106     lwkt_tokref_t       tr_gdreqnext;   /* based at gd_tokreqbase */
 107     struct globaldata   *tr_reqgd;      /* requesting cpu */
 108     int                 tr_flags;       /* token state and debug flags */
 109 } lwkt_tokref;
 110
 111 /*
 112  * Token state and debug flags.
 113  */
 114 #define LWKT_TOKREF_CONTENDED   0x002   /* token ownership contention */
 115
 116 /*
 117  * The magic number indicates the trans-cpu state of a token reference.
 118  *
 119  * MAGIC1 - token reference is not in transit to another cpu
 120  * MAGIC2 - token reference is in transit to another cpu
 121  * MAGIC3 - token reference is in a state where it should not be
 122  *          checked by lwkt_chktoken().
 123  */
 124 #define LWKT_TOKREF_MAGIC1              \
 125                         ((__uint32_t)0x544f4b52)        /* normal */
 126 #define LWKT_TOKREF_MAGIC2              \
 127                         ((__uint32_t)0x544f4b53)        /* pending req */
 128 #define LWKT_TOKREF_MAGIC3              \
 129                         ((__uint32_t)0x544f4b54)        /* indeterminant */
 130 #define LWKT_TOKREF_INIT(tok)           \
 131                         { tok, LWKT_TOKREF_MAGIC1 }
 132 #define LWKT_TOKREF_DECLARE(name, tok)  \
 133                         lwkt_tokref name = LWKT_TOKREF_INIT(tok)
 134
 135 /*
 136  * Wait structures deal with blocked threads.  Due to the way remote cpus
 137  * interact with these structures stable storage must be used.
 138  */
 139 typedef struct lwkt_wait {
 140     lwkt_queue  wa_waitq;       /* list of waiting threads */
 141     lwkt_token  wa_token;       /* who currently owns the list */
 142     int         wa_gen;
 143     int         wa_count;
 144 } lwkt_wait;
 145
 146 #define MAXCPUFIFO      16      /* power of 2 */
 147 #define MAXCPUFIFO_MASK (MAXCPUFIFO - 1)
 148 #define LWKT_MAXTOKENS  16      /* max tokens beneficially held by thread */
 149
 150 /*
 151  * Always cast to ipifunc_t when registering an ipi.  The actual ipi function
 152  * is called with both the data and an interrupt frame, but the ipi function
 153  * that is registered might only declare a data argument.
 154  */
 155 typedef void (*ipifunc1_t)(void *arg);
 156 typedef void (*ipifunc2_t)(void *arg, int arg2);
 157 typedef void (*ipifunc3_t)(void *arg, int arg2, struct intrframe *frame);
 158
 159 typedef struct lwkt_ipiq {
 160     int         ip_rindex;      /* only written by target cpu */
 161     int         ip_xindex;      /* written by target, indicates completion */
 162     int         ip_windex;      /* only written by source cpu */
 163     ipifunc3_t  ip_func[MAXCPUFIFO];
 164     void        *ip_arg1[MAXCPUFIFO];
 165     int         ip_arg2[MAXCPUFIFO];
 166     u_int       ip_npoll;       /* synchronization to avoid excess IPIs */
 167 } lwkt_ipiq;
 168
 169 /*
 170  * CPU Synchronization structure.  See lwkt_cpusync_start() and
 171  * lwkt_cpusync_finish() for more information.
 172  */
 173 typedef void (*cpusync_func_t)(lwkt_cpusync_t poll);
 174 typedef void (*cpusync_func2_t)(void *data);
 175
 176 struct lwkt_cpusync {
 177     cpusync_func_t cs_run_func;         /* run (tandem w/ acquire) */
 178     cpusync_func_t cs_fin1_func;        /* fin1 (synchronized) */
 179     cpusync_func2_t cs_fin2_func;       /* fin2 (tandem w/ release) */
 180     void        *cs_data;
 181     int         cs_maxcount;
 182     volatile int cs_count;
 183     cpumask_t   cs_mask;
 184 };
 185
 186 /*
 187  * The standard message and queue structure used for communications between
 188  * cpus.  Messages are typically queued via a machine-specific non-linked
 189  * FIFO matrix allowing any cpu to send a message to any other cpu without
 190  * blocking.
 191  */
 192 typedef struct lwkt_cpu_msg {
 193     void        (*cm_func)(lwkt_cpu_msg_t msg); /* primary dispatch function */
 194     int         cm_code;                /* request code if applicable */
 195     int         cm_cpu;                 /* reply to cpu */
 196     thread_t    cm_originator;          /* originating thread for wakeup */
 197 } lwkt_cpu_msg;
 198
 199 /*
 200  * reader/writer lock
 201  */
 202 typedef struct lwkt_rwlock {
 203     lwkt_wait   rw_wait;
 204     thread_t    rw_owner;
 205     int         rw_count;
 206     int         rw_requests;
 207 } lwkt_rwlock;
 208
 209 #define rw_token        rw_wait.wa_token
 210
 211 /*
 212  * Thread structure.  Note that ownership of a thread structure is special
 213  * cased and there is no 'token'.  A thread is always owned by the cpu
 214  * represented by td_gd, any manipulation of the thread by some other cpu
 215  * must be done through cpu_*msg() functions.  e.g. you could request
 216  * ownership of a thread that way, or hand a thread off to another cpu.
 217  *
 218  * NOTE: td_pri is bumped by TDPRI_CRIT when entering a critical section,
 219  * but this does not effect how the thread is scheduled by LWKT.
 220  */
 221 struct md_intr_info;
 222 struct caps_kinfo;
 223
 224 struct thread {
 225     TAILQ_ENTRY(thread) td_threadq;
 226     TAILQ_ENTRY(thread) td_allq;
 227     lwkt_port   td_msgport;     /* built-in message port for replies */
 228     struct lwp  *td_lwp;        /* (optional) associated lwp */
 229     struct proc *td_proc;       /* (optional) associated process */
 230     struct pcb  *td_pcb;        /* points to pcb and top of kstack */
 231     struct globaldata *td_gd;   /* associated with this cpu */
 232     const char  *td_wmesg;      /* string name for blockage */
 233     void        *td_wchan;      /* waiting on channel */
 234     int         td_pri;         /* 0-31, 31=highest priority (note 1) */
 235     int         td_flags;       /* TDF flags */
 236     int         td_wdomain;     /* domain for wchan address (typ 0) */
 237     void        (*td_preemptable)(struct thread *td, int critpri);
 238     void        (*td_release)(struct thread *td);
 239     char        *td_kstack;     /* kernel stack */
 240     int         td_kstack_size; /* size of kernel stack */
 241     char        *td_sp;         /* kernel stack pointer for LWKT restore */
 242     void        (*td_switch)(struct thread *ntd);
 243     lwkt_wait_t td_wait;        /* thread sitting on wait structure */
 244     __uint64_t  td_uticks;      /* Statclock hits in user mode (uS) */
 245     __uint64_t  td_sticks;      /* Statclock hits in system mode (uS) */
 246     __uint64_t  td_iticks;      /* Statclock hits processing intr (uS) */
 247     int         td_locks;       /* lockmgr lock debugging */
 248     int         td_spinlocks;   /* spinlock debugging */
 249     int         td_refs;        /* hold position in gd_tdallq / hold free */
 250     int         td_nest_count;  /* prevent splz nesting */
 251 #ifdef SMP
 252     int         td_mpcount;     /* MP lock held (count) */
 253     int         td_cscount;     /* cpu synchronization master */
 254 #else
 255     int         td_mpcount_unused;      /* filler so size matches */
 256     int         td_cscount_unused;
 257 #endif
 258     struct timeval td_start;    /* start time for a thread/process */
 259     char        td_comm[MAXCOMLEN+1]; /* typ 16+1 bytes */
 260     struct thread *td_preempted; /* we preempted this thread */
 261     struct caps_kinfo *td_caps; /* list of client and server registrations */
 262     lwkt_tokref_t td_toks;      /* tokens beneficially held */
 263 #ifdef DEBUG_CRIT_SECTIONS
 264 #define CRIT_DEBUG_ARRAY_SIZE   32
 265 #define CRIT_DEBUG_ARRAY_MASK   (CRIT_DEBUG_ARRAY_SIZE - 1)
 266     const char  *td_crit_debug_array[CRIT_DEBUG_ARRAY_SIZE];
 267     int         td_crit_debug_index;
 268     int         td_in_crit_report;
 269 #endif
 270     struct md_thread td_mach;
 271 };
 272
 273 /*
 274  * Thread flags.  Note that TDF_RUNNING is cleared on the old thread after
 275  * we switch to the new one, which is necessary because LWKTs don't need
 276  * to hold the BGL.  This flag is used by the exit code and the managed
 277  * thread migration code.  Note in addition that preemption will cause
 278  * TDF_RUNNING to be cleared temporarily, so any code checking TDF_RUNNING
 279  * must also check TDF_PREEMPT_LOCK.
 280  *
 281  * LWKT threads stay on their (per-cpu) run queue while running, not to
 282  * be confused with user processes which are removed from the user scheduling
 283  * run queue while actually running.
 284  *
 285  * td_threadq can represent the thread on one of three queues... the LWKT
 286  * run queue, a tsleep queue, or an lwkt blocking queue.  The LWKT subsystem
 287  * does not allow a thread to be scheduled if it already resides on some
 288  * queue.
 289  */
 290 #define TDF_RUNNING             0x0001  /* thread still active */
 291 #define TDF_RUNQ                0x0002  /* on an LWKT run queue */
 292 #define TDF_PREEMPT_LOCK        0x0004  /* I have been preempted */
 293 #define TDF_PREEMPT_DONE        0x0008  /* acknowledge preemption complete */
 294 #define TDF_IDLE_NOHLT          0x0010  /* we need to spin */
 295 #define TDF_MIGRATING           0x0020  /* thread is being migrated */
 296 #define TDF_SINTR               0x0040  /* interruptability hint for 'ps' */
 297 #define TDF_TSLEEPQ             0x0080  /* on a tsleep wait queue */
 298
 299 #define TDF_SYSTHREAD           0x0100  /* system thread */
 300 #define TDF_ALLOCATED_THREAD    0x0200  /* zalloc allocated thread */
 301 #define TDF_ALLOCATED_STACK     0x0400  /* zalloc allocated stack */
 302 #define TDF_VERBOSE             0x0800  /* verbose on exit */
 303 #define TDF_DEADLKTREAT         0x1000  /* special lockmgr deadlock treatment */
 304 #define TDF_STOPREQ             0x2000  /* suspend_kproc */
 305 #define TDF_WAKEREQ             0x4000  /* resume_kproc */
 306 #define TDF_TIMEOUT             0x8000  /* tsleep timeout */
 307 #define TDF_INTTHREAD           0x00010000      /* interrupt thread */
 308 #define TDF_NORESCHED           0x00020000      /* Do not reschedule on wake */
 309 #define TDF_BLOCKED             0x00040000      /* Thread is blocked */
 310 #define TDF_PANICWARN           0x00080000      /* panic warning in switch */
 311 #define TDF_BLOCKQ              0x00100000      /* on block queue */
 312 #define TDF_MPSAFE              0x00200000      /* (thread creation) */
 313 #define TDF_EXITING             0x00400000      /* thread exiting */
 314
 315 /*
 316  * Thread priorities.  Typically only one thread from any given
 317  * user process scheduling queue is on the LWKT run queue at a time.
 318  * Remember that there is one LWKT run queue per cpu.
 319  *
 320  * Critical sections are handled by bumping td_pri above TDPRI_MAX, which
 321  * causes interrupts to be masked as they occur.  When this occurs a
 322  * rollup flag will be set in mycpu->gd_reqflags.
 323  */
 324 #define TDPRI_IDLE_THREAD       0       /* the idle thread */
 325 #define TDPRI_USER_IDLE         4       /* user scheduler idle */
 326 #define TDPRI_USER_NORM         6       /* user scheduler normal */
 327 #define TDPRI_USER_REAL         8       /* user scheduler real time */
 328 #define TDPRI_KERN_LPSCHED      9       /* scheduler helper for userland sch */
 329 #define TDPRI_KERN_USER         10      /* kernel / block in syscall */
 330 #define TDPRI_KERN_DAEMON       12      /* kernel daemon (pageout, etc) */
 331 #define TDPRI_SOFT_NORM         14      /* kernel / normal */
 332 #define TDPRI_SOFT_TIMER        16      /* kernel / timer */
 333 #define TDPRI_EXITING           19      /* exiting thread */
 334 #define TDPRI_INT_SUPPORT       20      /* kernel / high priority support */
 335 #define TDPRI_INT_LOW           27      /* low priority interrupt */
 336 #define TDPRI_INT_MED           28      /* medium priority interrupt */
 337 #define TDPRI_INT_HIGH          29      /* high priority interrupt */
 338 #define TDPRI_MAX               31
 339
 340 #define TDPRI_MASK              31
 341 #define TDPRI_CRIT              32      /* high bits of td_pri used for crit */
 342
 343 #ifdef _KERNEL
 344 #define LWKT_THREAD_STACK       (UPAGES * PAGE_SIZE)
 345 #endif
 346
 347 #define CACHE_NTHREADS          6
 348
 349 #define IN_CRITICAL_SECT(td)    ((td)->td_pri >= TDPRI_CRIT)
 350
 351 #ifdef _KERNEL
 352
 353 extern struct vm_zone   *thread_zone;
 354
 355 #endif
 356
 357 /*
 358  * Applies both to the kernel and to liblwkt.
 359  */
 360 extern struct thread *lwkt_alloc_thread(struct thread *template, int stksize,
 361         int cpu, int flags);
 362 extern void lwkt_init_thread(struct thread *td, void *stack, int stksize,
 363         int flags, struct globaldata *gd);
 364 extern void lwkt_set_comm(thread_t td, const char *ctl, ...);
 365 extern void lwkt_wait_free(struct thread *td);
 366 extern void lwkt_free_thread(struct thread *td);
 367 extern void lwkt_wait_init(struct lwkt_wait *w);
 368 extern void lwkt_gdinit(struct globaldata *gd);
 369 extern void lwkt_switch(void);
 370 extern void lwkt_preempt(thread_t ntd, int critpri);
 371 extern void lwkt_schedule(thread_t td);
 372 extern void lwkt_schedule_self(thread_t td);
 373 extern void lwkt_deschedule(thread_t td);
 374 extern void lwkt_deschedule_self(thread_t td);
 375 extern void lwkt_acquire(thread_t td);
 376 extern void lwkt_yield(void);
 377 extern void lwkt_yield_quick(void);
 378 extern void lwkt_token_wait(void);
 379 extern void lwkt_hold(thread_t td);
 380 extern void lwkt_rele(thread_t td);
 381
 382 extern void lwkt_block(lwkt_wait_t w, const char *wmesg, int *gen);
 383 extern void lwkt_signal(lwkt_wait_t w, int count);
 384
 385 extern int lwkt_havetoken(lwkt_token_t tok);
 386 extern int lwkt_havetokref(lwkt_tokref_t xref);
 387 extern void lwkt_gettoken(lwkt_tokref_t ref, lwkt_token_t tok);
 388 extern int lwkt_trytoken(lwkt_tokref_t ref, lwkt_token_t tok);
 389 extern void lwkt_gettokref(lwkt_tokref_t ref);
 390 extern int  lwkt_trytokref(lwkt_tokref_t ref);
 391 extern void lwkt_reltoken(lwkt_tokref_t ref);
 392 extern int  lwkt_chktokens(thread_t td);
 393 extern void lwkt_drain_token_requests(void);
 394 extern void lwkt_token_init(lwkt_token_t tok);
 395 extern void lwkt_token_uninit(lwkt_token_t tok);
 396
 397 extern void lwkt_token_pool_init(void);
 398 extern lwkt_token_t lwkt_token_pool_get(void *ptraddr);
 399
 400 extern void lwkt_rwlock_init(lwkt_rwlock_t lock);
 401 extern void lwkt_rwlock_uninit(lwkt_rwlock_t lock);
 402 extern void lwkt_exlock(lwkt_rwlock_t lock, const char *wmesg);
 403 extern void lwkt_shlock(lwkt_rwlock_t lock, const char *wmesg);
 404 extern void lwkt_exunlock(lwkt_rwlock_t lock);
 405 extern void lwkt_shunlock(lwkt_rwlock_t lock);
 406
 407 extern void lwkt_setpri(thread_t td, int pri);
 408 extern void lwkt_setpri_self(int pri);
 409 extern int  lwkt_checkpri_self(void);
 410 extern void lwkt_setcpu_self(struct globaldata *rgd);
 411 extern void lwkt_migratecpu(int cpuid);
 412
 413 #ifdef SMP
 414
 415 extern int  lwkt_send_ipiq3(struct globaldata *targ, ipifunc3_t func,
 416                                 void *arg1, int arg2);
 417 extern int  lwkt_send_ipiq3_passive(struct globaldata *targ, ipifunc3_t func,
 418                                 void *arg1, int arg2);
 419 extern int  lwkt_send_ipiq3_nowait(struct globaldata *targ, ipifunc3_t func,
 420                                 void *arg1, int arg2);
 421 extern int  lwkt_send_ipiq3_bycpu(int dcpu, ipifunc3_t func,
 422                                 void *arg1, int arg2);
 423 extern int  lwkt_send_ipiq3_mask(cpumask_t mask, ipifunc3_t func,
 424                                 void *arg1, int arg2);
 425 extern void lwkt_wait_ipiq(struct globaldata *targ, int seq);
 426 extern int  lwkt_seq_ipiq(struct globaldata *targ);
 427 extern void lwkt_process_ipiq(void);
 428 #ifdef _KERNEL
 429 extern void lwkt_process_ipiq_frame(struct intrframe frame);
 430 #endif
 431 extern void lwkt_smp_stopped(void);
 432
 433 #endif /* SMP */
 434
 435 extern void lwkt_cpusync_simple(cpumask_t mask, cpusync_func_t func, void *data);
 436 extern void lwkt_cpusync_fastdata(cpumask_t mask, cpusync_func2_t func, void *data);
 437 extern void lwkt_cpusync_start(cpumask_t mask, lwkt_cpusync_t poll);
 438 extern void lwkt_cpusync_add(cpumask_t mask, lwkt_cpusync_t poll);
 439 extern void lwkt_cpusync_finish(lwkt_cpusync_t poll);
 440
 441 extern void crit_panic(void);
 442 extern struct lwp *lwkt_preempted_proc(void);
 443
 444 extern int  lwkt_create (void (*func)(void *), void *arg, struct thread **ptd,
 445                             struct thread *template, int tdflags, int cpu,
 446                             const char *ctl, ...);
 447 extern void lwkt_exit (void) __dead2;
 448
 449 #endif
 450