0.9.3.41: gc trigger
[sbcl.git] / src / runtime / thread.c
1 #include <stdlib.h>
2 #include <stdio.h>
3 #include <string.h>
4 #include <sched.h>
5 #include <signal.h>
6 #include <stddef.h>
7 #include <errno.h>
8 #include <sys/types.h>
9 #include <sys/wait.h>
10
11 #include "sbcl.h"
12 #include "runtime.h"
13 #include "validate.h"           /* for CONTROL_STACK_SIZE etc */
14 #include "alloc.h"
15 #include "thread.h"
16 #include "arch.h"
17 #include "target-arch-os.h"
18 #include "os.h"
19 #include "globals.h"
20 #include "dynbind.h"
21 #include "genesis/cons.h"
22 #include "genesis/fdefn.h"
23 #include "interr.h"             /* for lose() */
24 #include "gc-internal.h"
25
26 #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
27
28 int dynamic_values_bytes=4096*sizeof(lispobj);  /* same for all threads */
29 struct thread *all_threads;
30 volatile lispobj all_threads_lock;
31 extern struct interrupt_data * global_interrupt_data;
32 extern int linux_no_threads_p;
33
34 #ifdef LISP_FEATURE_SB_THREAD
35 /* When trying to get all_threads_lock one should make sure that
36  * sig_stop_for_gc is not blocked. Else there would be a possible
37  * deadlock: gc locks it, other thread blocks signals, gc sends stop
38  * request to other thread and waits, other thread blocks on lock. */
39 void check_sig_stop_for_gc_can_arrive_or_lose()
40 {
41     /* Get the current sigmask, by blocking the empty set. */
42     sigset_t empty,current;
43     sigemptyset(&empty);
44     thread_sigmask(SIG_BLOCK, &empty, &current);
45     if (sigismember(&current,SIG_STOP_FOR_GC))
46         lose("SIG_STOP_FOR_GC cannot arrive: it is blocked\n");
47     if (SymbolValue(GC_INHIBIT,arch_os_get_current_thread()) != NIL)
48         lose("SIG_STOP_FOR_GC cannot arrive: gc is inhibited\n");
49     if (arch_pseudo_atomic_atomic(NULL))
50         lose("SIG_STOP_FOR_GC cannot arrive: in pseudo atomic\n");
51 }
52
53 #define GET_ALL_THREADS_LOCK(name) \
54     { \
55         sigset_t _newset,_oldset; \
56         sigemptyset(&_newset); \
57         sigaddset_deferrable(&_newset); \
58         thread_sigmask(SIG_BLOCK, &_newset, &_oldset); \
59         check_sig_stop_for_gc_can_arrive_or_lose(); \
60         FSHOW_SIGNAL((stderr,"/%s:waiting on lock=%ld, thread=%lu\n",name, \
61                all_threads_lock,arch_os_get_current_thread()->os_thread)); \
62         get_spinlock(&all_threads_lock,(long)arch_os_get_current_thread()); \
63         FSHOW_SIGNAL((stderr,"/%s:got lock, thread=%lu\n", \
64                name,arch_os_get_current_thread()->os_thread));
65
66 #define RELEASE_ALL_THREADS_LOCK(name) \
67         FSHOW_SIGNAL((stderr,"/%s:released lock\n",name)); \
68         release_spinlock(&all_threads_lock); \
69         thread_sigmask(SIG_SETMASK,&_oldset,0); \
70     }
71 #endif
72
73
74 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
75 extern lispobj call_into_lisp_first_time(lispobj fun, lispobj *args, int nargs);
76 #endif
77
78 int
79 initial_thread_trampoline(struct thread *th)
80 {
81     lispobj function;
82 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
83     lispobj *args = NULL;
84 #endif
85     function = th->unbound_marker;
86     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
87     if(arch_os_thread_init(th)==0) return 1;
88
89     if(th->os_thread < 1) lose("th->os_thread not set up right");
90     th->state=STATE_RUNNING;
91 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
92     return call_into_lisp_first_time(function,args,0);
93 #else
94     return funcall0(function);
95 #endif
96 }
97
98 #ifdef LISP_FEATURE_SB_THREAD
99
100 /* this is the first thing that runs in the child (which is why the
101  * silly calling convention).  Basically it calls the user's requested
102  * lisp function after doing arch_os_thread_init and whatever other
103  * bookkeeping needs to be done
104  */
105 int
106 new_thread_trampoline(struct thread *th)
107 {
108     lispobj function;
109     int result;
110     function = th->unbound_marker;
111     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
112     if(arch_os_thread_init(th)==0) return 1;
113
114     /* wait here until our thread is linked into all_threads: see below */
115     while(th->os_thread<1) sched_yield();
116
117     th->state=STATE_RUNNING;
118     result = funcall0(function);
119     th->state=STATE_DEAD;
120     return result;
121 }
122 #endif /* LISP_FEATURE_SB_THREAD */
123
124 /* this is called from any other thread to create the new one, and
125  * initialize all parts of it that can be initialized from another
126  * thread
127  */
128
129 struct thread * create_thread_struct(lispobj initial_function) {
130     union per_thread_data *per_thread;
131     struct thread *th=0;        /*  subdue gcc */
132     void *spaces=0;
133
134     /* may as well allocate all the spaces at once: it saves us from
135      * having to decide what to do if only some of the allocations
136      * succeed */
137     spaces=os_validate(0,
138                        THREAD_CONTROL_STACK_SIZE+
139                        BINDING_STACK_SIZE+
140                        ALIEN_STACK_SIZE+
141                        dynamic_values_bytes+
142                        32*SIGSTKSZ);
143     if(!spaces)
144          return NULL;
145     per_thread=(union per_thread_data *)
146         (spaces+
147          THREAD_CONTROL_STACK_SIZE+
148          BINDING_STACK_SIZE+
149          ALIEN_STACK_SIZE);
150
151     if(all_threads) {
152         memcpy(per_thread,arch_os_get_current_thread(),
153                dynamic_values_bytes);
154     } else {
155 #ifdef LISP_FEATURE_SB_THREAD
156         int i;
157         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
158             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
159         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
160             SetSymbolValue
161                 (FREE_TLS_INDEX,
162                  make_fixnum(MAX_INTERRUPTS+
163                              sizeof(struct thread)/sizeof(lispobj)),
164                  0);
165 #define STATIC_TLS_INIT(sym,field) \
166   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
167   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
168
169         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
170         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
171         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
172         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
173         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
174 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
175         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
176         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
177 #endif
178 #undef STATIC_TLS_INIT
179 #endif
180     }
181
182     th=&per_thread->thread;
183     th->control_stack_start = spaces;
184     th->binding_stack_start=
185         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
186     th->control_stack_end = th->binding_stack_start;
187     th->alien_stack_start=
188         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
189     th->binding_stack_pointer=th->binding_stack_start;
190     th->this=th;
191     th->os_thread=0;
192     th->interrupt_fun=NIL;
193     th->interrupt_fun_lock=0;
194     th->state=STATE_STARTING;
195 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
196     th->alien_stack_pointer=((void *)th->alien_stack_start
197                              + ALIEN_STACK_SIZE-N_WORD_BYTES);
198 #else
199     th->alien_stack_pointer=((void *)th->alien_stack_start);
200 #endif
201 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
202     th->pseudo_atomic_interrupted=0;
203     th->pseudo_atomic_atomic=0;
204 #endif
205 #ifdef LISP_FEATURE_GENCGC
206     gc_set_region_empty(&th->alloc_region);
207 #endif
208
209 #ifndef LISP_FEATURE_SB_THREAD
210     /* the tls-points-into-struct-thread trick is only good for threaded
211      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
212      * appropriate values from struct thread here, and make sure that
213      * we use the appropriate SymbolValue macros to access any of the
214      * variable quantities from the C runtime.  It's not quite OAOOM,
215      * it just feels like it */
216     SetSymbolValue(BINDING_STACK_START,(lispobj)th->binding_stack_start,th);
217     SetSymbolValue(CONTROL_STACK_START,(lispobj)th->control_stack_start,th);
218     SetSymbolValue(CONTROL_STACK_END,(lispobj)th->control_stack_end,th);
219 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
220     SetSymbolValue(BINDING_STACK_POINTER,(lispobj)th->binding_stack_pointer,th);
221     SetSymbolValue(ALIEN_STACK,(lispobj)th->alien_stack_pointer,th);
222     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,(lispobj)th->pseudo_atomic_atomic,th);
223     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
224 #else
225     current_binding_stack_pointer=th->binding_stack_pointer;
226     current_control_stack_pointer=th->control_stack_start;
227 #endif
228 #endif
229     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
230     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
231     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
232     bind_variable(INTERRUPT_PENDING, NIL,th);
233     bind_variable(INTERRUPTS_ENABLED,T,th);
234     bind_variable(GC_PENDING,NIL,th);
235 #ifdef LISP_FEATURE_SB_THREAD
236     bind_variable(STOP_FOR_GC_PENDING,NIL,th);
237 #endif
238
239     th->interrupt_data = (struct interrupt_data *)
240         os_validate(0,(sizeof (struct interrupt_data)));
241     if(all_threads)
242         memcpy(th->interrupt_data,
243                arch_os_get_current_thread()->interrupt_data,
244                sizeof (struct interrupt_data));
245     else
246         memcpy(th->interrupt_data,global_interrupt_data,
247                sizeof (struct interrupt_data));
248
249     th->unbound_marker=initial_function;
250     return th;
251 }
252
253 void link_thread(struct thread *th,os_thread_t kid_tid)
254 {
255     if (all_threads) all_threads->prev=th;
256     th->next=all_threads;
257     th->prev=0;
258     all_threads=th;
259     /* note that th->os_thread is 0 at this time.  We rely on
260      * all_threads_lock to ensure that we don't have >1 thread with
261      * os_thread=0 on the list at once
262      */
263     protect_control_stack_guard_page(th,1);
264     /* child will not start until this is set */
265     th->os_thread=kid_tid;
266 }
267
268 void create_initial_thread(lispobj initial_function) {
269     struct thread *th=create_thread_struct(initial_function);
270     os_thread_t kid_tid=thread_self();
271     if(th && kid_tid>0) {
272         link_thread(th,kid_tid);
273         initial_thread_trampoline(all_threads); /* no return */
274     } else lose("can't create initial thread");
275 }
276
277 #ifdef LISP_FEATURE_SB_THREAD
278
279 #ifndef __USE_XOPEN2K
280 extern int pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
281                                   size_t __stacksize);
282 #endif
283
284 boolean create_os_thread(struct thread *th,os_thread_t *kid_tid)
285 {
286     /* The new thread inherits the restrictive signal mask set here,
287      * and enables signals again when it is set up properly. */
288     pthread_attr_t attr;
289     sigset_t newset,oldset;
290     boolean r=1;
291     sigemptyset(&newset);
292     sigaddset_deferrable(&newset);
293     thread_sigmask(SIG_BLOCK, &newset, &oldset);
294
295     if((pthread_attr_init(&attr)) ||
296        (pthread_attr_setstack(&attr,th->control_stack_start,
297                               THREAD_CONTROL_STACK_SIZE-16)) ||
298        (pthread_create
299         (kid_tid,&attr,(void *(*)(void *))new_thread_trampoline,th)))
300         r=0;
301     thread_sigmask(SIG_SETMASK,&oldset,0);
302     return r;
303 }
304
305 struct thread *create_thread(lispobj initial_function) {
306     struct thread *th;
307     os_thread_t kid_tid=0;
308     boolean success;
309
310     if(linux_no_threads_p) return 0;
311
312     th=create_thread_struct(initial_function);
313     if(th==0) return 0;
314
315     /* we must not be interrupted here after a successful
316      * create_os_thread, because the kid will be waiting for its
317      * thread struct to be linked */
318     GET_ALL_THREADS_LOCK("create_thread")
319
320     success=create_os_thread(th,&kid_tid);
321     if (success)
322         link_thread(th,kid_tid);
323     else
324         os_invalidate((os_vm_address_t) th->control_stack_start,
325                       ((sizeof (lispobj))
326                        * (th->control_stack_end-th->control_stack_start)) +
327                       BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
328                       32*SIGSTKSZ);
329
330     RELEASE_ALL_THREADS_LOCK("create_thread")
331
332     if (success)
333         return th;
334     else
335         return 0;
336 }
337
338 /* called from lisp from the thread object finalizer */
339 void reap_dead_thread(struct thread *th)
340 {
341     if(th->state!=STATE_DEAD)
342         lose("thread %p is not joinable, state=%d\n",th,th->state);
343 #ifdef LISP_FEATURE_GENCGC
344     {
345         sigset_t newset,oldset;
346         sigemptyset(&newset);
347         sigaddset_blockable(&newset);
348         thread_sigmask(SIG_BLOCK, &newset, &oldset);
349         gc_alloc_update_page_tables(0, &th->alloc_region);
350         release_spinlock(&all_threads_lock);
351         thread_sigmask(SIG_SETMASK,&oldset,0);
352     }
353 #endif
354     GET_ALL_THREADS_LOCK("reap_dead_thread")
355     FSHOW((stderr,"/reap_dead_thread: reaping %lu\n",th->os_thread));
356     if(th->prev)
357         th->prev->next=th->next;
358     else all_threads=th->next;
359     if(th->next)
360         th->next->prev=th->prev;
361     RELEASE_ALL_THREADS_LOCK("reap_dead_thread")
362     if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
363     gc_assert(pthread_join(th->os_thread,NULL)==0);
364     os_invalidate((os_vm_address_t) th->control_stack_start,
365                   ((sizeof (lispobj))
366                    * (th->control_stack_end-th->control_stack_start)) +
367                   BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
368                   32*SIGSTKSZ);
369 }
370
371 int interrupt_thread(struct thread *th, lispobj function)
372 {
373     /* A thread may also become dead after this test. */
374     if ((th->state != STATE_DEAD)) {
375         /* In clone_threads, if A and B both interrupt C at
376          * approximately the same time, it does not matter: the
377          * second signal will be masked until the handler has
378          * returned from the first one.  In pthreads though, we
379          * can't put the knowledge of what function to call into
380          * the siginfo, so we have to store it in the destination
381          * thread, and do it in such a way that A won't clobber
382          * B's interrupt.  Hence this stupid linked list.
383          *
384          * This does depend on SIG_INTERRUPT_THREAD being queued
385          * (as POSIX RT signals are): we need to keep
386          * interrupt_fun data for exactly as many signals as are
387          * going to be received by the destination thread.
388          */
389         lispobj c=alloc_cons(function,NIL);
390         int kill_status;
391         /* interrupt_thread_handler locks this spinlock with
392          * interrupts blocked (it does so for the sake of
393          * arrange_return_to_lisp_function), so we must also block
394          * them or else SIG_STOP_FOR_GC and all_threads_lock will find
395          * a way to deadlock. */
396         sigset_t newset,oldset;
397         sigemptyset(&newset);
398         sigaddset_blockable(&newset);
399         thread_sigmask(SIG_BLOCK, &newset, &oldset);
400         get_spinlock(&th->interrupt_fun_lock,
401                      (long)arch_os_get_current_thread());
402         kill_status=thread_kill(th->os_thread,SIG_INTERRUPT_THREAD);
403         if(kill_status==0) {
404             ((struct cons *)native_pointer(c))->cdr=th->interrupt_fun;
405             th->interrupt_fun=c;
406         }
407         release_spinlock(&th->interrupt_fun_lock);
408         thread_sigmask(SIG_SETMASK,&oldset,0);
409         return (kill_status ? -1 : 0);
410     }
411     errno=EPERM; return -1;
412 }
413
414 /* stopping the world is a two-stage process.  From this thread we signal
415  * all the others with SIG_STOP_FOR_GC.  The handler for this signal does
416  * the usual pseudo-atomic checks (we don't want to stop a thread while
417  * it's in the middle of allocation) then waits for another SIG_STOP_FOR_GC.
418  */
419
420 /* To avoid deadlocks when gc stops the world all clients of each
421  * mutex must enable or disable SIG_STOP_FOR_GC for the duration of
422  * holding the lock, but they must agree on which. */
423 void gc_stop_the_world()
424 {
425     struct thread *p,*th=arch_os_get_current_thread();
426     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on lock, thread=%lu\n",
427                   th->os_thread));
428     /* keep threads from starting while the world is stopped. */
429     get_spinlock(&all_threads_lock,(long)th);
430     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got lock, thread=%lu\n",
431                   th->os_thread));
432     /* stop all other threads by sending them SIG_STOP_FOR_GC */
433     for(p=all_threads; p; p=p->next) {
434         while(p->state==STATE_STARTING) sched_yield();
435         if((p!=th) && (p->state==STATE_RUNNING)) {
436             FSHOW_SIGNAL((stderr, "/gc_stop_the_world: suspending %lu\n",
437                           p->os_thread));
438             if(thread_kill(p->os_thread,SIG_STOP_FOR_GC)==-1) {
439                 /* we can't kill the thread; assume because it died
440                  * since we last checked */
441                 p->state=STATE_DEAD;
442                 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:assuming %lu dead\n",
443                    p->os_thread));
444             }
445         }
446     }
447     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:signals sent\n"));
448     /* wait for the running threads to stop or finish */
449     for(p=all_threads;p;) {
450         gc_assert(p->os_thread!=0);
451         gc_assert(p->state!=STATE_STARTING);
452         if((p==th) || (p->state==STATE_SUSPENDED) ||
453            (p->state==STATE_DEAD)) {
454             p=p->next;
455         } else {
456             sched_yield();
457         }
458     }
459     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:end\n"));
460 }
461
462 void gc_start_the_world()
463 {
464     struct thread *p,*th=arch_os_get_current_thread();
465     /* if a resumed thread creates a new thread before we're done with
466      * this loop, the new thread will get consed on the front of
467      * all_threads, but it won't have been stopped so won't need
468      * restarting */
469     FSHOW_SIGNAL((stderr,"/gc_start_the_world:begin\n"));
470     for(p=all_threads;p;p=p->next) {
471         gc_assert(p->os_thread!=0);
472         if((p!=th) && (p->state!=STATE_DEAD)) {
473             if(p->state!=STATE_SUSPENDED) {
474                 lose("gc_start_the_world: wrong thread state is %d\n",
475                      fixnum_value(p->state));
476             }
477             FSHOW_SIGNAL((stderr, "/gc_start_the_world: resuming %lu\n",
478                           p->os_thread));
479             p->state=STATE_RUNNING;
480             thread_kill(p->os_thread,SIG_STOP_FOR_GC);
481         }
482     }
483     release_spinlock(&all_threads_lock);
484     FSHOW_SIGNAL((stderr,"/gc_start_the_world:end\n"));
485 }
486 #endif