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 _MACHINE_THREAD_H_
  35 #include <machine/thread.h>
  36 #endif
  37
  38 struct globaldata;
  39 struct lwp;
  40 struct proc;
  41 struct thread;
  42 struct lwkt_queue;
  43 struct lwkt_token;
  44 struct lwkt_tokref;
  45 struct lwkt_ipiq;
  46 struct lwkt_cpu_msg;
  47 struct lwkt_cpu_port;
  48 struct lwkt_msg;
  49 struct lwkt_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 _MACHINE_THREAD_H_
  73 #include <machine/thread.h>             /* md_thread */
  74 #endif
  75 #ifndef _MACHINE_FRAME_H_
  76 #include <machine/frame.h>
  77 #endif
  78 #else
  79 struct intrframe;
  80 #endif
  81
  82 /*
  83  * Tokens are used to serialize access to information.  They are 'soft'
  84  * serialization entities that only stay in effect while a thread is
  85  * running.  If the thread blocks, other threads can run holding the same
  86  * token(s).  The tokens are reacquired when the original thread resumes.
  87  *
  88  * A thread can depend on its serialization remaining intact through a
  89  * preemption.  An interrupt which attempts to use the same token as the
  90  * thread being preempted will reschedule itself for non-preemptive
  91  * operation, so the new token code is capable of interlocking against
  92  * interrupts as well as other cpus.  This means that your token can only
  93  * be (temporarily) lost if you *explicitly* block.
  94  *
  95  * Tokens are managed through a helper reference structure, lwkt_tokref,
  96  * which is typically declared on the caller's stack.  Multiple tokref's
  97  * may reference the same token.
  98  *
  99  * It is possible to detect that your token was temporarily lost via
 100  * lwkt_token_is_stale(), which uses the t_lastowner field.  This field
 101  * does NOT necessarily represent the current owner and can become stale
 102  * (not point to a valid structure).  It is used solely to detect
 103  * whether the token was temporarily lost to another thread.  The lost
 104  * state is cleared by the function.
 105  */
 106
 107 typedef struct lwkt_token {
 108 #ifdef SMP
 109     struct spinlock     t_spinlock;     /* Controls access */
 110 #else
 111     struct spinlock     t_unused01;
 112 #endif
 113     struct thread       *t_owner;       /* The current owner of the token */
 114     int                 t_count;        /* Per-thread count */
 115     struct thread       *t_lastowner;   /* Last owner that acquired token */
 116 } lwkt_token;
 117
 118 #ifdef SMP
 119 #define LWKT_TOKEN_INITIALIZER(head) \
 120 { \
 121         .t_spinlock = SPINLOCK_INITIALIZER(head.t_spinlock), \
 122         .t_owner = NULL, \
 123         .t_lastowner = NULL, \
 124         .t_count = 0 \
 125 }
 126 #else
 127 #define LWKT_TOKEN_INITIALIZER(head) \
 128 { \
 129         .t_owner = NULL, \
 130         .t_lastowner = NULL, \
 131         .t_count = 0 \
 132 }
 133 #endif
 134
 135 typedef struct lwkt_tokref {
 136     lwkt_token_t        tr_tok;         /* token in question */
 137     lwkt_tokref_t       tr_next;        /* linked list */
 138     int                 tr_state;       /* 0 = don't have, 1 = have */
 139 } lwkt_tokref;
 140
 141 #define LWKT_TOKREF_INIT(tok)           \
 142                         { tok, NULL, 0 }
 143 #define LWKT_TOKREF_DECLARE(name, tok)  \
 144                         lwkt_tokref name = LWKT_TOKREF_INIT(tok)
 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  * Thread structure.  Note that ownership of a thread structure is special
 201  * cased and there is no 'token'.  A thread is always owned by the cpu
 202  * represented by td_gd, any manipulation of the thread by some other cpu
 203  * must be done through cpu_*msg() functions.  e.g. you could request
 204  * ownership of a thread that way, or hand a thread off to another cpu.
 205  *
 206  * NOTE: td_pri is bumped by TDPRI_CRIT when entering a critical section,
 207  * but this does not effect how the thread is scheduled by LWKT.
 208  */
 209 struct md_intr_info;
 210 struct caps_kinfo;
 211
 212 struct thread {
 213     TAILQ_ENTRY(thread) td_threadq;
 214     TAILQ_ENTRY(thread) td_allq;
 215     lwkt_port   td_msgport;     /* built-in message port for replies */
 216     struct lwp  *td_lwp;        /* (optional) associated lwp */
 217     struct proc *td_proc;       /* (optional) associated process */
 218     struct pcb  *td_pcb;        /* points to pcb and top of kstack */
 219     struct globaldata *td_gd;   /* associated with this cpu */
 220     const char  *td_wmesg;      /* string name for blockage */
 221     void        *td_wchan;      /* waiting on channel */
 222     int         td_pri;         /* 0-31, 31=highest priority (note 1) */
 223     int         td_flags;       /* TDF flags */
 224     int         td_wdomain;     /* domain for wchan address (typ 0) */
 225     void        (*td_preemptable)(struct thread *td, int critpri);
 226     void        (*td_release)(struct thread *td);
 227     char        *td_kstack;     /* kernel stack */
 228     int         td_kstack_size; /* size of kernel stack */
 229     char        *td_sp;         /* kernel stack pointer for LWKT restore */
 230     void        (*td_switch)(struct thread *ntd);
 231     __uint64_t  td_uticks;      /* Statclock hits in user mode (uS) */
 232     __uint64_t  td_sticks;      /* Statclock hits in system mode (uS) */
 233     __uint64_t  td_iticks;      /* Statclock hits processing intr (uS) */
 234     int         td_locks;       /* lockmgr lock debugging */
 235     int         td_unused01;
 236     int         td_refs;        /* hold position in gd_tdallq / hold free */
 237     int         td_nest_count;  /* prevent splz nesting */
 238 #ifdef SMP
 239     int         td_mpcount;     /* MP lock held (count) */
 240     int         td_cscount;     /* cpu synchronization master */
 241 #else
 242     int         td_mpcount_unused;      /* filler so size matches */
 243     int         td_cscount_unused;
 244 #endif
 245     struct timeval td_start;    /* start time for a thread/process */
 246     char        td_comm[MAXCOMLEN+1]; /* typ 16+1 bytes */
 247     struct thread *td_preempted; /* we preempted this thread */
 248     struct caps_kinfo *td_caps; /* list of client and server registrations */
 249     lwkt_tokref_t td_toks;      /* tokens beneficially held */
 250 #ifdef DEBUG_CRIT_SECTIONS
 251 #define CRIT_DEBUG_ARRAY_SIZE   32
 252 #define CRIT_DEBUG_ARRAY_MASK   (CRIT_DEBUG_ARRAY_SIZE - 1)
 253     const char  *td_crit_debug_array[CRIT_DEBUG_ARRAY_SIZE];
 254     int         td_crit_debug_index;
 255     int         td_in_crit_report;
 256 #endif
 257     struct md_thread td_mach;
 258 };
 259
 260 /*
 261  * Thread flags.  Note that TDF_RUNNING is cleared on the old thread after
 262  * we switch to the new one, which is necessary because LWKTs don't need
 263  * to hold the BGL.  This flag is used by the exit code and the managed
 264  * thread migration code.  Note in addition that preemption will cause
 265  * TDF_RUNNING to be cleared temporarily, so any code checking TDF_RUNNING
 266  * must also check TDF_PREEMPT_LOCK.
 267  *
 268  * LWKT threads stay on their (per-cpu) run queue while running, not to
 269  * be confused with user processes which are removed from the user scheduling
 270  * run queue while actually running.
 271  *
 272  * td_threadq can represent the thread on one of three queues... the LWKT
 273  * run queue, a tsleep queue, or an lwkt blocking queue.  The LWKT subsystem
 274  * does not allow a thread to be scheduled if it already resides on some
 275  * queue.
 276  */
 277 #define TDF_RUNNING             0x0001  /* thread still active */
 278 #define TDF_RUNQ                0x0002  /* on an LWKT run queue */
 279 #define TDF_PREEMPT_LOCK        0x0004  /* I have been preempted */
 280 #define TDF_PREEMPT_DONE        0x0008  /* acknowledge preemption complete */
 281 #define TDF_IDLE_NOHLT          0x0010  /* we need to spin */
 282 #define TDF_MIGRATING           0x0020  /* thread is being migrated */
 283 #define TDF_SINTR               0x0040  /* interruptability hint for 'ps' */
 284 #define TDF_TSLEEPQ             0x0080  /* on a tsleep wait queue */
 285
 286 #define TDF_SYSTHREAD           0x0100  /* allocations may use reserve */
 287 #define TDF_ALLOCATED_THREAD    0x0200  /* objcache allocated thread */
 288 #define TDF_ALLOCATED_STACK     0x0400  /* objcache allocated stack */
 289 #define TDF_VERBOSE             0x0800  /* verbose on exit */
 290 #define TDF_DEADLKTREAT         0x1000  /* special lockmgr deadlock treatment */
 291 #define TDF_STOPREQ             0x2000  /* suspend_kproc */
 292 #define TDF_WAKEREQ             0x4000  /* resume_kproc */
 293 #define TDF_TIMEOUT             0x8000  /* tsleep timeout */
 294 #define TDF_INTTHREAD           0x00010000      /* interrupt thread */
 295 #define TDF_UNUSED20000         0x00020000
 296 #define TDF_BLOCKED             0x00040000      /* Thread is blocked */
 297 #define TDF_PANICWARN           0x00080000      /* panic warning in switch */
 298 #define TDF_BLOCKQ              0x00100000      /* on block queue */
 299 #define TDF_MPSAFE              0x00200000      /* (thread creation) */
 300 #define TDF_EXITING             0x00400000      /* thread exiting */
 301 #define TDF_USINGFP             0x00800000      /* thread using fp coproc */
 302 #define TDF_KERNELFP            0x01000000      /* kernel using fp coproc */
 303 #define TDF_NETWORK             0x02000000      /* network proto thread */
 304
 305 /*
 306  * Thread priorities.  Typically only one thread from any given
 307  * user process scheduling queue is on the LWKT run queue at a time.
 308  * Remember that there is one LWKT run queue per cpu.
 309  *
 310  * Critical sections are handled by bumping td_pri above TDPRI_MAX, which
 311  * causes interrupts to be masked as they occur.  When this occurs a
 312  * rollup flag will be set in mycpu->gd_reqflags.
 313  */
 314 #define TDPRI_IDLE_THREAD       0       /* the idle thread */
 315 #define TDPRI_USER_SCHEDULER    2       /* user scheduler helper */
 316 #define TDPRI_USER_IDLE         4       /* user scheduler idle */
 317 #define TDPRI_USER_NORM         6       /* user scheduler normal */
 318 #define TDPRI_USER_REAL         8       /* user scheduler real time */
 319 #define TDPRI_KERN_LPSCHED      9       /* scheduler helper for userland sch */
 320 #define TDPRI_KERN_USER         10      /* kernel / block in syscall */
 321 #define TDPRI_KERN_DAEMON       12      /* kernel daemon (pageout, etc) */
 322 #define TDPRI_SOFT_NORM         14      /* kernel / normal */
 323 #define TDPRI_SOFT_TIMER        16      /* kernel / timer */
 324 #define TDPRI_EXITING           19      /* exiting thread */
 325 #define TDPRI_INT_SUPPORT       20      /* kernel / high priority support */
 326 #define TDPRI_INT_LOW           27      /* low priority interrupt */
 327 #define TDPRI_INT_MED           28      /* medium priority interrupt */
 328 #define TDPRI_INT_HIGH          29      /* high priority interrupt */
 329 #define TDPRI_MAX               31
 330
 331 #define TDPRI_MASK              31
 332 #define TDPRI_CRIT              32      /* high bits of td_pri used for crit */
 333
 334 #ifdef _KERNEL
 335 #define LWKT_THREAD_STACK       (UPAGES * PAGE_SIZE)
 336 #endif
 337
 338 #define CACHE_NTHREADS          6
 339
 340 #define IN_CRITICAL_SECT(td)    ((td)->td_pri >= TDPRI_CRIT)
 341
 342 extern void lwkt_init(void);
 343 extern struct thread *lwkt_alloc_thread(struct thread *, int, int, int);
 344 extern void lwkt_init_thread(struct thread *, void *, int, int,
 345                              struct globaldata *);
 346 extern void lwkt_set_comm(thread_t, const char *, ...);
 347 extern void lwkt_wait_free(struct thread *);
 348 extern void lwkt_free_thread(struct thread *);
 349 extern void lwkt_gdinit(struct globaldata *);
 350 extern void lwkt_switch(void);
 351 extern void lwkt_preempt(thread_t, int);
 352 extern void lwkt_schedule(thread_t);
 353 extern void lwkt_schedule_noresched(thread_t);
 354 extern void lwkt_schedule_self(thread_t);
 355 extern void lwkt_deschedule(thread_t);
 356 extern void lwkt_deschedule_self(thread_t);
 357 extern void lwkt_yield(void);
 358 extern void lwkt_yield_quick(void);
 359 extern void lwkt_token_wait(void);
 360 extern void lwkt_hold(thread_t);
 361 extern void lwkt_rele(thread_t);
 362
 363 extern void lwkt_gettoken(lwkt_tokref_t, lwkt_token_t);
 364 extern int lwkt_trytoken(lwkt_tokref_t, lwkt_token_t);
 365 extern void lwkt_gettokref(lwkt_tokref_t);
 366 extern int  lwkt_trytokref(lwkt_tokref_t);
 367 extern void lwkt_reltoken(lwkt_tokref_t);
 368 extern int  lwkt_getalltokens(thread_t);
 369 extern void lwkt_relalltokens(thread_t);
 370 extern void lwkt_drain_token_requests(void);
 371 extern void lwkt_token_init(lwkt_token_t);
 372 extern void lwkt_token_uninit(lwkt_token_t);
 373 extern int  lwkt_token_is_stale(lwkt_tokref_t);
 374
 375 extern void lwkt_token_pool_init(void);
 376 extern lwkt_token_t lwkt_token_pool_get(void *);
 377
 378 extern void lwkt_setpri(thread_t, int);
 379 extern void lwkt_setpri_self(int);
 380 extern int lwkt_check_resched(thread_t);
 381 extern void lwkt_setcpu_self(struct globaldata *);
 382 extern void lwkt_migratecpu(int);
 383
 384 #ifdef SMP
 385
 386 extern void lwkt_giveaway(struct thread *);
 387 extern void lwkt_acquire(struct thread *);
 388 extern int  lwkt_send_ipiq3(struct globaldata *, ipifunc3_t, void *, int);
 389 extern int  lwkt_send_ipiq3_passive(struct globaldata *, ipifunc3_t,
 390                                     void *, int);
 391 extern int  lwkt_send_ipiq3_nowait(struct globaldata *, ipifunc3_t,
 392                                    void *, int);
 393 extern int  lwkt_send_ipiq3_bycpu(int, ipifunc3_t, void *, int);
 394 extern int  lwkt_send_ipiq3_mask(cpumask_t, ipifunc3_t, void *, int);
 395 extern void lwkt_wait_ipiq(struct globaldata *, int);
 396 extern int  lwkt_seq_ipiq(struct globaldata *);
 397 extern void lwkt_process_ipiq(void);
 398 #ifdef _KERNEL
 399 extern void lwkt_process_ipiq_frame(struct intrframe *);
 400 #endif
 401 extern void lwkt_smp_stopped(void);
 402 extern void lwkt_synchronize_ipiqs(const char *);
 403
 404 #endif /* SMP */
 405
 406 extern void lwkt_cpusync_simple(cpumask_t, cpusync_func_t, void *);
 407 extern void lwkt_cpusync_fastdata(cpumask_t, cpusync_func2_t, void *);
 408 extern void lwkt_cpusync_start(cpumask_t, lwkt_cpusync_t);
 409 extern void lwkt_cpusync_add(cpumask_t, lwkt_cpusync_t);
 410 extern void lwkt_cpusync_finish(lwkt_cpusync_t);
 411
 412 extern void crit_panic(void);
 413 extern struct lwp *lwkt_preempted_proc(void);
 414
 415 extern int  lwkt_create (void (*func)(void *), void *, struct thread **,
 416                          struct thread *, int, int, const char *, ...);
 417 extern void lwkt_exit (void) __dead2;
 418 extern void lwkt_remove_tdallq (struct thread *);
 419 extern void lwkt_mp_lock_contested(void);
 420 extern void lwkt_mp_lock_uncontested(void);
 421
 422 #endif
 423