source: libcfa/src/concurrency/monitor.cfa @ 760c88c

ast-experimental
Last change on this file since 760c88c was ed52dd5, checked in by Peter A. Buhr <pabuhr@…>, 21 months ago

remove comment about _GNU_SOURCE
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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// monitor.cfa --
8//
9// Author           : Thierry Delisle
10// Created On       : Thd Feb 23 12:27:26 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Sun Feb 19 17:00:59 2023
13// Update Count     : 12
14//
15
16#define __cforall_thread__
17
18#include "monitor.hfa"
19
20#include <stdlib.hfa>
21#include <inttypes.h>
22
23#include "kernel/private.hfa"
24
25#include "bits/algorithm.hfa"
26
27//-----------------------------------------------------------------------------
28// Forward declarations
29static inline void __set_owner ( monitor$ * this, thread$ * owner );
30static inline void __set_owner ( monitor$ * storage [], __lock_size_t count, thread$ * owner );
31static inline void set_mask  ( monitor$ * storage [], __lock_size_t count, const __waitfor_mask_t & mask );
32static inline void reset_mask( monitor$ * this );
33
34static inline thread$ * next_thread( monitor$ * this );
35static inline bool is_accepted( monitor$ * this, const __monitor_group_t & monitors );
36
37static inline void lock_all  ( __spinlock_t * locks [], __lock_size_t count );
38static inline void lock_all  ( monitor$ * source [], __spinlock_t * /*out*/ locks [], __lock_size_t count );
39static inline void unlock_all( __spinlock_t * locks [], __lock_size_t count );
40static inline void unlock_all( monitor$ * locks [], __lock_size_t count );
41
42static inline void save   ( monitor$ * ctx [], __lock_size_t count, __spinlock_t * locks [], unsigned int /*out*/ recursions [], __waitfor_mask_t /*out*/ masks [] );
43static inline void restore( monitor$ * ctx [], __lock_size_t count, __spinlock_t * locks [], unsigned int /*in */ recursions [], __waitfor_mask_t /*in */ masks [] );
44
45static inline void ?{}(__condition_node_t & this, thread$ * waiting_thread, __lock_size_t count, uintptr_t user_info );
46static inline void ?{}(__condition_criterion_t & this );
47static inline void ?{}(__condition_criterion_t & this, monitor$ * target, __condition_node_t * owner );
48
49static inline void init     ( __lock_size_t count, monitor$ * monitors [], __condition_node_t & waiter, __condition_criterion_t criteria [] );
50static inline void init_push( __lock_size_t count, monitor$ * monitors [], __condition_node_t & waiter, __condition_criterion_t criteria [] );
51
52static inline thread$ *        check_condition   ( __condition_criterion_t * );
53static inline void                 brand_condition   ( condition & );
54static inline [thread$ *, int] search_entry_queue( const __waitfor_mask_t &, monitor$ * monitors [], __lock_size_t count );
55
56forall(T & | sized( T ))
57static inline __lock_size_t insert_unique( T * array [], __lock_size_t & size, T * val );
58static inline __lock_size_t count_max    ( const __waitfor_mask_t & mask );
59static inline __lock_size_t aggregate    ( monitor$ * storage [], const __waitfor_mask_t & mask );
60
61//-----------------------------------------------------------------------------
62// Useful defines
63#define wait_ctx(thrd, user_info)                               /* Create the necessary information to use the signaller stack                         */ \
64        __condition_node_t waiter = { thrd, count, user_info };   /* Create the node specific to this wait operation                                     */ \
65        __condition_criterion_t criteria[count];                  /* Create the creteria this wait operation needs to wake up                            */ \
66        init( count, monitors, waiter, criteria );                /* Link everything together                                                            */ \
67
68#define wait_ctx_primed(thrd, user_info)                        /* Create the necessary information to use the signaller stack                         */ \
69        __condition_node_t waiter = { thrd, count, user_info };   /* Create the node specific to this wait operation                                     */ \
70        __condition_criterion_t criteria[count];                  /* Create the creteria this wait operation needs to wake up                            */ \
71        init_push( count, monitors, waiter, criteria );           /* Link everything together and push it to the AS-Stack                                */ \
72
73#define monitor_ctx( mons, cnt )                                /* Define that create the necessary struct for internal/external scheduling operations */ \
74        monitor$ ** monitors = mons;                          /* Save the targeted monitors                                                          */ \
75        __lock_size_t count = cnt;                                /* Save the count to a local variable                                                  */ \
76        unsigned int recursions[ count ];                         /* Save the current recursion levels to restore them later                             */ \
77        __waitfor_mask_t masks [ count ];                         /* Save the current waitfor masks to restore them later                                */ \
78        __spinlock_t *   locks [ count ];                         /* We need to pass-in an array of locks to BlockInternal                               */ \
79
80#define monitor_save    save   ( monitors, count, locks, recursions, masks )
81#define monitor_restore restore( monitors, count, locks, recursions, masks )
82
83
84//-----------------------------------------------------------------------------
85// Enter/Leave routines
86// Enter single monitor
87static void __enter( monitor$ * this, const __monitor_group_t & group ) {
88        thread$ * thrd = active_thread();
89
90        // Lock the monitor spinlock
91        lock( this->lock __cfaabi_dbg_ctx2 );
92
93        __cfaabi_dbg_print_safe( "Kernel : %10p Entering mon %p (%p)\n", thrd, this, this->owner);
94
95        if( unlikely(0 != (0x1 & (uintptr_t)this->owner)) ) {
96                abort( "Attempt by thread \"%.256s\" (%p) to access joined monitor %p.", thrd->self_cor.name, thrd, this );
97        }
98        else if( !this->owner ) {
99                // No one has the monitor, just take it
100                __set_owner( this, thrd );
101
102                __cfaabi_dbg_print_safe( "Kernel :  mon is free \n" );
103        }
104        else if( this->owner == thrd) {
105                // We already have the monitor, just note how many times we took it
106                this->recursion += 1;
107
108                __cfaabi_dbg_print_safe( "Kernel :  mon already owned \n" );
109        }
110        else if( is_accepted( this, group) ) {
111                // Some one was waiting for us, enter
112                __set_owner( this, thrd );
113
114                // Reset mask
115                reset_mask( this );
116
117                __cfaabi_dbg_print_safe( "Kernel :  mon accepts \n" );
118        }
119        else {
120                __cfaabi_dbg_print_safe( "Kernel :  blocking \n" );
121
122                // Some one else has the monitor, wait in line for it
123                /* paranoid */ verify( thrd->user_link.next == 0p );
124                append( this->entry_queue, thrd );
125                /* paranoid */ verify( thrd->user_link.next == 1p );
126
127                unlock( this->lock );
128                park();
129
130                __cfaabi_dbg_print_safe( "Kernel : %10p Entered  mon %p\n", thrd, this);
131
132                /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
133                return;
134        }
135
136        __cfaabi_dbg_print_safe( "Kernel : %10p Entered  mon %p\n", thrd, this);
137
138        /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
139        /* paranoid */ verify( this->lock.lock );
140
141        // Release the lock and leave
142        unlock( this->lock );
143        return;
144}
145
146static void __dtor_enter( monitor$ * this, fptr_t func, bool join ) {
147        thread$ * thrd = active_thread();
148        #if defined( __CFA_WITH_VERIFY__ )
149                bool is_thrd = this == &thrd->self_mon;
150        #endif
151
152        // Lock the monitor spinlock
153        lock( this->lock __cfaabi_dbg_ctx2 );
154
155        __cfaabi_dbg_print_safe( "Kernel : %10p Entering dtor for mon %p (%p)\n", thrd, this, this->owner);
156
157
158        if( !this->owner ) {
159                __cfaabi_dbg_print_safe( "Kernel : Destroying free mon %p\n", this);
160
161                // No one has the monitor, just take it
162                __set_owner( this, thrd );
163
164                /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
165                /* paranoid */ verify( !is_thrd || thrd->state == Halted || thrd->state == Cancelled );
166
167                unlock( this->lock );
168                return;
169        }
170        else if( this->owner == thrd && !join) {
171                // We already have the monitor... but where about to destroy it so the nesting will fail
172                // Abort!
173                abort( "Attempt to destroy monitor %p by thread \"%.256s\" (%p) in nested mutex.", this, thrd->self_cor.name, thrd );
174        }
175        // SKULLDUGGERY: join will act as a dtor so it would normally trigger to above check
176        // because join will not release the monitor after it executed.
177        // to avoid that it sets the owner to the special value thrd | 1p before exiting
178        else if( this->owner == (thread$*)(1 | (uintptr_t)thrd) ) {
179                // restore the owner and just return
180                __cfaabi_dbg_print_safe( "Kernel : Destroying free mon %p\n", this);
181
182                // No one has the monitor, just take it
183                __set_owner( this, thrd );
184
185                /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
186                /* paranoid */ verify( !is_thrd || thrd->state == Halted || thrd->state == Cancelled );
187
188                unlock( this->lock );
189                return;
190        }
191
192        // The monitor is busy, if this is a thread and the thread owns itself, it better be active
193        /* paranoid */ verify( !is_thrd || this->owner != thrd || (thrd->state != Halted && thrd->state != Cancelled) );
194
195        __lock_size_t count = 1;
196        monitor$ ** monitors = &this;
197        __monitor_group_t group = { &this, 1, func };
198        if( is_accepted( this, group) ) {
199                __cfaabi_dbg_print_safe( "Kernel :  mon accepts dtor, block and signal it \n" );
200
201                // Wake the thread that is waiting for this
202                __condition_criterion_t * urgent = pop( this->signal_stack );
203                /* paranoid */ verify( urgent );
204
205                // Reset mask
206                reset_mask( this );
207
208                // Create the node specific to this wait operation
209                wait_ctx_primed( thrd, 0 )
210
211                // Some one else has the monitor, wait for him to finish and then run
212                unlock( this->lock );
213
214                // Release the next thread
215                /* paranoid */ verifyf( urgent->owner->waiting_thread == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
216                unpark( urgent->owner->waiting_thread );
217
218                // Park current thread waiting
219                park();
220
221                // Some one was waiting for us, enter
222                /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
223
224                __cfaabi_dbg_print_safe( "Kernel : Destroying %p\n", this);
225                return;
226        }
227        else {
228                __cfaabi_dbg_print_safe( "Kernel :  blocking \n" );
229
230                wait_ctx( thrd, 0 )
231                this->dtor_node = &waiter;
232
233                // Some one else has the monitor, wait in line for it
234                /* paranoid */ verify( thrd->user_link.next == 0p );
235                append( this->entry_queue, thrd );
236                /* paranoid */ verify( thrd->user_link.next == 1p );
237                unlock( this->lock );
238
239                // Park current thread waiting
240                park();
241
242                /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
243                return;
244        }
245}
246
247// Leave single monitor
248static void __leave( monitor$ * this ) {
249        // Lock the monitor spinlock
250        lock( this->lock __cfaabi_dbg_ctx2 );
251
252        __cfaabi_dbg_print_safe( "Kernel : %10p Leaving mon %p (%p)\n", active_thread(), this, this->owner);
253
254        /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
255
256        // Leaving a recursion level, decrement the counter
257        this->recursion -= 1;
258
259        // If we haven't left the last level of recursion
260        // it means we don't need to do anything
261        if( this->recursion != 0) {
262                __cfaabi_dbg_print_safe( "Kernel :  recursion still %d\n", this->recursion);
263                unlock( this->lock );
264                return;
265        }
266
267        // Get the next thread, will be null on low contention monitor
268        thread$ * new_owner = next_thread( this );
269
270        // Check the new owner is consistent with who we wake-up
271        // new_owner might be null even if someone owns the monitor when the owner is still waiting for another monitor
272        /* paranoid */ verifyf( !new_owner || new_owner == this->owner, "Expected owner to be %p, got %p (m: %p)", new_owner, this->owner, this );
273
274        // We can now let other threads in safely
275        unlock( this->lock );
276
277        //We need to wake-up the thread
278        /* paranoid */ verifyf( !new_owner || new_owner == this->owner, "Expected owner to be %p, got %p (m: %p)", new_owner, this->owner, this );
279        unpark( new_owner );
280}
281
282// Leave single monitor for the last time
283static void __dtor_leave( monitor$ * this, bool join ) {
284        __cfaabi_dbg_debug_do(
285                if( active_thread() != this->owner ) {
286                        abort( "Destroyed monitor %p has inconsistent owner, expected %p got %p.\n", this, active_thread(), this->owner);
287                }
288                if( this->recursion != 1  && !join ) {
289                        abort( "Destroyed monitor %p has %d outstanding nested calls.\n", this, this->recursion - 1);
290                }
291        )
292
293        this->owner = (thread$*)(1 | (uintptr_t)this->owner);
294}
295
296void __thread_finish( thread$ * thrd ) {
297        monitor$ * this = &thrd->self_mon;
298
299        // Lock the monitor now
300        /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
301        /* paranoid */ verify( this->lock.lock );
302        /* paranoid */ verify( thrd->context.SP );
303        /* paranoid */ verifyf( ((uintptr_t)thrd->context.SP) > ((uintptr_t)__get_stack(thrd->curr_cor)->limit), "ERROR : thread$ %p has been corrupted.\n StackPointer too large.\n", thrd );
304        /* paranoid */ verifyf( ((uintptr_t)thrd->context.SP) < ((uintptr_t)__get_stack(thrd->curr_cor)->base ), "ERROR : thread$ %p has been corrupted.\n StackPointer too small.\n", thrd );
305        /* paranoid */ verify( ! __preemption_enabled() );
306
307        /* paranoid */ verifyf( thrd == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", thrd, this->owner, this->recursion, this );
308        /* paranoid */ verify( thrd->state == Halting );
309        /* paranoid */ verify( this->recursion == 1 );
310
311        // Leaving a recursion level, decrement the counter
312        this->recursion -= 1;
313        this->owner = 0p;
314
315        // Fetch the next thread, can be null
316        thread$ * new_owner = next_thread( this );
317
318        // Mark the state as fully halted
319        thrd->state = Halted;
320
321        // Release the monitor lock
322        unlock( this->lock );
323
324        // Unpark the next owner if needed
325        /* paranoid */ verifyf( !new_owner || new_owner == this->owner, "Expected owner to be %p, got %p (m: %p)", new_owner, this->owner, this );
326        /* paranoid */ verify( ! __preemption_enabled() );
327        /* paranoid */ verify( thrd->state == Halted );
328        unpark( new_owner );
329}
330
331// Enter multiple monitor
332// relies on the monitor array being sorted
333static inline void enter( __monitor_group_t monitors ) {
334        for( __lock_size_t i = 0; i < monitors.size; i++) {
335                __enter( monitors[i], monitors );
336        }
337}
338
339// Leave multiple monitor
340// relies on the monitor array being sorted
341static inline void leave(monitor$ * monitors [], __lock_size_t count) {
342        for( __lock_size_t i = count - 1; i >= 0; i--) {
343                __leave( monitors[i] );
344        }
345}
346
347// Ctor for monitor guard
348// Sorts monitors before entering
349void ?{}( monitor_guard_t & this, monitor$ * m [], __lock_size_t count, fptr_t func ) libcfa_public {
350        thread$ * thrd = active_thread();
351
352        // Store current array
353        this.m = m;
354        this.count = count;
355
356        // Sort monitors based on address
357        __libcfa_small_sort(this.m, count);
358
359        // Save previous thread context
360        this.prev = thrd->monitors;
361
362        // Update thread context (needed for conditions)
363        (thrd->monitors){m, count, func};
364
365        // __cfaabi_dbg_print_safe( "MGUARD : enter %d\n", count);
366
367        // Enter the monitors in order
368        __monitor_group_t group = {this.m, this.count, func};
369        enter( group );
370
371        // __cfaabi_dbg_print_safe( "MGUARD : entered\n" );
372}
373
374void ?{}( monitor_guard_t & this, monitor$ * m [], __lock_size_t count ) libcfa_public {
375        this{ m, count, 0p };
376}
377
378
379// Dtor for monitor guard
380void ^?{}( monitor_guard_t & this ) libcfa_public {
381        // __cfaabi_dbg_print_safe( "MGUARD : leaving %d\n", this.count);
382
383        // Leave the monitors in order
384        leave( this.m, this.count );
385
386        // __cfaabi_dbg_print_safe( "MGUARD : left\n" );
387
388        // Restore thread context
389        active_thread()->monitors = this.prev;
390}
391
392// Ctor for monitor guard
393// Sorts monitors before entering
394void ?{}( monitor_dtor_guard_t & this, monitor$ * m [], fptr_t func, bool join ) libcfa_public {
395        // optimization
396        thread$ * thrd = active_thread();
397
398        // Store current array
399        this.m = *m;
400
401        // Save previous thread context
402        this.prev = thrd->monitors;
403
404        // Save whether we are in a join or not
405        this.join = join;
406
407        // Update thread context (needed for conditions)
408        (thrd->monitors){m, 1, func};
409
410        __dtor_enter( this.m, func, join );
411}
412
413// Dtor for monitor guard
414void ^?{}( monitor_dtor_guard_t & this ) libcfa_public {
415        // Leave the monitors in order
416        __dtor_leave( this.m, this.join );
417
418        // Restore thread context
419        active_thread()->monitors = this.prev;
420}
421
422//-----------------------------------------------------------------------------
423// Internal scheduling types
424static void ?{}(__condition_node_t & this, thread$ * waiting_thread, __lock_size_t count, uintptr_t user_info ) {
425        this.waiting_thread = waiting_thread;
426        this.count = count;
427        this.next = 0p;
428        this.user_info = user_info;
429}
430
431static void ?{}(__condition_criterion_t & this ) with( this ) {
432        ready  = false;
433        target = 0p;
434        owner  = 0p;
435        next   = 0p;
436}
437
438static void ?{}(__condition_criterion_t & this, monitor$ * target, __condition_node_t & owner ) {
439        this.ready  = false;
440        this.target = target;
441        this.owner  = &owner;
442        this.next   = 0p;
443}
444
445//-----------------------------------------------------------------------------
446// Internal scheduling
447void wait( condition & this, uintptr_t user_info = 0 ) libcfa_public {
448        brand_condition( this );
449
450        // Check that everything is as expected
451        assertf( this.monitors != 0p, "Waiting with no monitors (%p)", this.monitors );
452        verifyf( this.monitor_count != 0, "Waiting with 0 monitors (%"PRIiFAST16")", this.monitor_count );
453        verifyf( this.monitor_count < 32u, "Excessive monitor count (%"PRIiFAST16")", this.monitor_count );
454
455        // Create storage for monitor context
456        monitor_ctx( this.monitors, this.monitor_count );
457
458        // Create the node specific to this wait operation
459        wait_ctx( active_thread(), user_info );
460
461        // Append the current wait operation to the ones already queued on the condition
462        // We don't need locks for that since conditions must always be waited on inside monitor mutual exclusion
463        /* paranoid */ verify( waiter.next == 0p );
464        append( this.blocked, &waiter );
465        /* paranoid */ verify( waiter.next == 1p );
466
467        // Lock all monitors (aggregates the locks as well)
468        lock_all( monitors, locks, count );
469
470        // Find the next thread(s) to run
471        __lock_size_t thread_count = 0;
472        thread$ * threads[ count ];
473        __builtin_memset( threads, 0, sizeof( threads ) );
474
475        // Save monitor states
476        monitor_save;
477
478        // Remove any duplicate threads
479        for( __lock_size_t i = 0; i < count; i++) {
480                thread$ * new_owner = next_thread( monitors[i] );
481                insert_unique( threads, thread_count, new_owner );
482        }
483
484        // Unlock the locks, we don't need them anymore
485        for(int i = 0; i < count; i++) {
486                unlock( *locks[i] );
487        }
488
489        // Wake the threads
490        for(int i = 0; i < thread_count; i++) {
491                unpark( threads[i] );
492        }
493
494        // Everything is ready to go to sleep
495        park();
496
497        // We are back, restore the owners and recursions
498        monitor_restore;
499}
500
501bool signal( condition & this ) libcfa_public {
502        if( is_empty( this ) ) { return false; }
503
504        //Check that everything is as expected
505        verify( this.monitors );
506        verify( this.monitor_count != 0 );
507
508        //Some more checking in debug
509        __cfaabi_dbg_debug_do(
510                thread$ * this_thrd = active_thread();
511                if ( this.monitor_count != this_thrd->monitors.size ) {
512                        abort( "Signal on condition %p made with different number of monitor(s), expected %zi got %zi", &this, this.monitor_count, this_thrd->monitors.size );
513                }
514
515                for(int i = 0; i < this.monitor_count; i++) {
516                        if ( this.monitors[i] != this_thrd->monitors[i] ) {
517                                abort( "Signal on condition %p made with different monitor, expected %p got %p", &this, this.monitors[i], this_thrd->monitors[i] );
518                        }
519                }
520        );
521
522        __lock_size_t count = this.monitor_count;
523
524        // Lock all monitors
525        lock_all( this.monitors, 0p, count );
526
527        //Pop the head of the waiting queue
528        __condition_node_t * node = pop_head( this.blocked );
529
530        //Add the thread to the proper AS stack
531        for(int i = 0; i < count; i++) {
532                __condition_criterion_t * crit = &node->criteria[i];
533                assert( !crit->ready );
534                push( crit->target->signal_stack, crit );
535        }
536
537        //Release
538        unlock_all( this.monitors, count );
539
540        return true;
541}
542
543bool signal_block( condition & this ) libcfa_public {
544        if( !this.blocked.head ) { return false; }
545
546        //Check that everything is as expected
547        verifyf( this.monitors != 0p, "Waiting with no monitors (%p)", this.monitors );
548        verifyf( this.monitor_count != 0, "Waiting with 0 monitors (%"PRIiFAST16")", this.monitor_count );
549
550        // Create storage for monitor context
551        monitor_ctx( this.monitors, this.monitor_count );
552
553        // Lock all monitors (aggregates the locks them as well)
554        lock_all( monitors, locks, count );
555
556
557        // Create the node specific to this wait operation
558        wait_ctx_primed( active_thread(), 0 )
559
560        //save contexts
561        monitor_save;
562
563        //Find the thread to run
564        thread$ * signallee = pop_head( this.blocked )->waiting_thread;
565        __set_owner( monitors, count, signallee );
566
567        __cfaabi_dbg_print_buffer_decl( "Kernel : signal_block condition %p (s: %p)\n", &this, signallee );
568
569        // unlock all the monitors
570        unlock_all( locks, count );
571
572        // unpark the thread we signalled
573        unpark( signallee );
574
575        //Everything is ready to go to sleep
576        park();
577
578
579        // WE WOKE UP
580
581
582        __cfaabi_dbg_print_buffer_local( "Kernel :   signal_block returned\n" );
583
584        //We are back, restore the masks and recursions
585        monitor_restore;
586
587        return true;
588}
589
590// Access the user_info of the thread waiting at the front of the queue
591uintptr_t front( condition & this ) libcfa_public {
592        verifyf( !is_empty(this),
593                "Attempt to access user data on an empty condition.\n"
594                "Possible cause is not checking if the condition is empty before reading stored data."
595        );
596        return ((typeof(this.blocked.head))this.blocked.head)->user_info;
597}
598
599//-----------------------------------------------------------------------------
600// External scheduling
601// cases to handle :
602//      - target already there :
603//              block and wake
604//      - dtor already there
605//              put thread on signaller stack
606//      - non-blocking
607//              return else
608//      - timeout
609//              return timeout
610//      - block
611//              setup mask
612//              block
613void __waitfor_internal( const __waitfor_mask_t & mask, int duration ) libcfa_public {
614        // This statment doesn't have a contiguous list of monitors...
615        // Create one!
616        __lock_size_t max = count_max( mask );
617        monitor$ * mon_storage[max];
618        __builtin_memset( mon_storage, 0, sizeof( mon_storage ) );
619        __lock_size_t actual_count = aggregate( mon_storage, mask );
620
621        __cfaabi_dbg_print_buffer_decl( "Kernel : waitfor %"PRIdFAST16" (s: %"PRIdFAST16", m: %"PRIdFAST16")\n", actual_count, mask.size, (__lock_size_t)max);
622
623        if(actual_count == 0) return;
624
625        __cfaabi_dbg_print_buffer_local( "Kernel : waitfor internal proceeding\n" );
626
627        // Create storage for monitor context
628        monitor_ctx( mon_storage, actual_count );
629
630        // Lock all monitors (aggregates the locks as well)
631        lock_all( monitors, locks, count );
632
633        {
634                // Check if the entry queue
635                thread$ * next; int index;
636                [next, index] = search_entry_queue( mask, monitors, count );
637
638                if( next ) {
639                        *mask.accepted = index;
640                        __acceptable_t& accepted = mask[index];
641                        if( accepted.is_dtor ) {
642                                __cfaabi_dbg_print_buffer_local( "Kernel : dtor already there\n" );
643                                verifyf( accepted.size == 1,  "ERROR: Accepted dtor has more than 1 mutex parameter." );
644
645                                monitor$ * mon2dtor = accepted[0];
646                                verifyf( mon2dtor->dtor_node, "ERROR: Accepted monitor has no dtor_node." );
647
648                                __condition_criterion_t * dtor_crit = mon2dtor->dtor_node->criteria;
649                                push( mon2dtor->signal_stack, dtor_crit );
650
651                                unlock_all( locks, count );
652                        }
653                        else {
654                                __cfaabi_dbg_print_buffer_local( "Kernel : thread present, baton-passing\n" );
655
656                                // Create the node specific to this wait operation
657                                wait_ctx_primed( active_thread(), 0 );
658
659                                // Save monitor states
660                                monitor_save;
661
662                                __cfaabi_dbg_print_buffer_local( "Kernel :  baton of %"PRIdFAST16" monitors : ", count );
663                                #ifdef __CFA_DEBUG_PRINT__
664                                        for( int i = 0; i < count; i++) {
665                                                __cfaabi_dbg_print_buffer_local( "%p %p ", monitors[i], monitors[i]->signal_stack.top );
666                                        }
667                                #endif
668                                __cfaabi_dbg_print_buffer_local( "\n" );
669
670                                // Set the owners to be the next thread
671                                __set_owner( monitors, count, next );
672
673                                // unlock all the monitors
674                                unlock_all( locks, count );
675
676                                // unpark the thread we signalled
677                                unpark( next );
678
679                                //Everything is ready to go to sleep
680                                park();
681
682                                // We are back, restore the owners and recursions
683                                monitor_restore;
684
685                                __cfaabi_dbg_print_buffer_local( "Kernel : thread present, returned\n" );
686                        }
687
688                        __cfaabi_dbg_print_buffer_local( "Kernel : accepted %d\n", *mask.accepted);
689                        return;
690                }
691        }
692
693
694        if( duration == 0 ) {
695                __cfaabi_dbg_print_buffer_local( "Kernel : non-blocking, exiting\n" );
696
697                unlock_all( locks, count );
698
699                __cfaabi_dbg_print_buffer_local( "Kernel : accepted %d\n", *mask.accepted);
700                return;
701        }
702
703
704        verifyf( duration < 0, "Timeout on waitfor statments not supported yet." );
705
706        __cfaabi_dbg_print_buffer_local( "Kernel : blocking waitfor\n" );
707
708        // Create the node specific to this wait operation
709        wait_ctx_primed( active_thread(), 0 );
710
711        monitor_save;
712        set_mask( monitors, count, mask );
713
714        for( __lock_size_t i = 0; i < count; i++) {
715                verify( monitors[i]->owner == active_thread() );
716        }
717
718        // unlock all the monitors
719        unlock_all( locks, count );
720
721        //Everything is ready to go to sleep
722        park();
723
724
725        // WE WOKE UP
726
727
728        //We are back, restore the masks and recursions
729        monitor_restore;
730
731        __cfaabi_dbg_print_buffer_local( "Kernel : exiting\n" );
732
733        __cfaabi_dbg_print_buffer_local( "Kernel : accepted %d\n", *mask.accepted);
734}
735
736//-----------------------------------------------------------------------------
737// Utilities
738
739static inline void __set_owner( monitor$ * this, thread$ * owner ) {
740        /* paranoid */ verify( this->lock.lock );
741
742        //Pass the monitor appropriately
743        this->owner = owner;
744
745        //We are passing the monitor to someone else, which means recursion level is not 0
746        this->recursion = owner ? 1 : 0;
747}
748
749static inline void __set_owner( monitor$ * monitors [], __lock_size_t count, thread$ * owner ) {
750        /* paranoid */ verify ( monitors[0]->lock.lock );
751        /* paranoid */ verifyf( monitors[0]->owner == active_thread(), "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), monitors[0]->owner, monitors[0]->recursion, monitors[0] );
752        monitors[0]->owner        = owner;
753        monitors[0]->recursion    = 1;
754        for( __lock_size_t i = 1; i < count; i++ ) {
755                /* paranoid */ verify ( monitors[i]->lock.lock );
756                /* paranoid */ verifyf( monitors[i]->owner == active_thread(), "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), monitors[i]->owner, monitors[i]->recursion, monitors[i] );
757                monitors[i]->owner        = owner;
758                monitors[i]->recursion    = 0;
759        }
760}
761
762static inline void set_mask( monitor$ * storage [], __lock_size_t count, const __waitfor_mask_t & mask ) {
763        for( __lock_size_t i = 0; i < count; i++) {
764                storage[i]->mask = mask;
765        }
766}
767
768static inline void reset_mask( monitor$ * this ) {
769        this->mask.accepted = 0p;
770        this->mask.data = 0p;
771        this->mask.size = 0;
772}
773
774static inline thread$ * next_thread( monitor$ * this ) {
775        //Check the signaller stack
776        __cfaabi_dbg_print_safe( "Kernel :  mon %p AS-stack top %p\n", this, this->signal_stack.top);
777        __condition_criterion_t * urgent = pop( this->signal_stack );
778        if( urgent ) {
779                //The signaller stack is not empty,
780                //regardless of if we are ready to baton pass,
781                //we need to set the monitor as in use
782                /* paranoid */ verifyf( !this->owner || active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
783                __set_owner( this,  urgent->owner->waiting_thread );
784
785                return check_condition( urgent );
786        }
787
788        // No signaller thread
789        // Get the next thread in the entry_queue
790        thread$ * new_owner = pop_head( this->entry_queue );
791        /* paranoid */ verifyf( !this->owner || active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
792        /* paranoid */ verify( !new_owner || new_owner->user_link.next == 0p );
793        __set_owner( this, new_owner );
794
795        return new_owner;
796}
797
798static inline bool is_accepted( monitor$ * this, const __monitor_group_t & group ) {
799        __acceptable_t * it = this->mask.data; // Optim
800        __lock_size_t count = this->mask.size;
801
802        // Check if there are any acceptable functions
803        if( !it ) return false;
804
805        // If this isn't the first monitor to test this, there is no reason to repeat the test.
806        if( this != group[0] ) return group[0]->mask.accepted >= 0;
807
808        // For all acceptable functions check if this is the current function.
809        for( __lock_size_t i = 0; i < count; i++, it++ ) {
810                if( *it == group ) {
811                        *this->mask.accepted = i;
812                        return true;
813                }
814        }
815
816        // No function matched
817        return false;
818}
819
820static inline void init( __lock_size_t count, monitor$ * monitors [], __condition_node_t & waiter, __condition_criterion_t criteria [] ) {
821        for( __lock_size_t i = 0; i < count; i++) {
822                (criteria[i]){ monitors[i], waiter };
823        }
824
825        waiter.criteria = criteria;
826}
827
828static inline void init_push( __lock_size_t count, monitor$ * monitors [], __condition_node_t & waiter, __condition_criterion_t criteria [] ) {
829        for( __lock_size_t i = 0; i < count; i++) {
830                (criteria[i]){ monitors[i], waiter };
831                __cfaabi_dbg_print_safe( "Kernel :  target %p = %p\n", criteria[i].target, &criteria[i] );
832                push( criteria[i].target->signal_stack, &criteria[i] );
833        }
834
835        waiter.criteria = criteria;
836}
837
838static inline void lock_all( __spinlock_t * locks [], __lock_size_t count ) {
839        for( __lock_size_t i = 0; i < count; i++ ) {
840                lock( *locks[i] __cfaabi_dbg_ctx2 );
841        }
842}
843
844static inline void lock_all( monitor$ * source [], __spinlock_t * /*out*/ locks [], __lock_size_t count ) {
845        for( __lock_size_t i = 0; i < count; i++ ) {
846                __spinlock_t * l = &source[i]->lock;
847                lock( *l __cfaabi_dbg_ctx2 );
848                if(locks) locks[i] = l;
849        }
850}
851
852static inline void unlock_all( __spinlock_t * locks [], __lock_size_t count ) {
853        for( __lock_size_t i = 0; i < count; i++ ) {
854                unlock( *locks[i] );
855        }
856}
857
858static inline void unlock_all( monitor$ * locks [], __lock_size_t count ) {
859        for( __lock_size_t i = 0; i < count; i++ ) {
860                unlock( locks[i]->lock );
861        }
862}
863
864static inline void save(
865        monitor$ * ctx [],
866        __lock_size_t count,
867        __attribute((unused)) __spinlock_t * locks [],
868        unsigned int /*out*/ recursions [],
869        __waitfor_mask_t /*out*/ masks []
870) {
871        for( __lock_size_t i = 0; i < count; i++ ) {
872                recursions[i] = ctx[i]->recursion;
873                masks[i]      = ctx[i]->mask;
874        }
875}
876
877static inline void restore(
878        monitor$ * ctx [],
879        __lock_size_t count,
880        __spinlock_t * locks [],
881        unsigned int /*out*/ recursions [],
882        __waitfor_mask_t /*out*/ masks []
883) {
884        lock_all( locks, count );
885        for( __lock_size_t i = 0; i < count; i++ ) {
886                ctx[i]->recursion = recursions[i];
887                ctx[i]->mask      = masks[i];
888        }
889        unlock_all( locks, count );
890}
891
892// Function has 2 different behavior
893// 1 - Marks a monitors as being ready to run
894// 2 - Checks if all the monitors are ready to run
895//     if so return the thread to run
896static inline thread$ * check_condition( __condition_criterion_t * target ) {
897        __condition_node_t * node = target->owner;
898        unsigned short count = node->count;
899        __condition_criterion_t * criteria = node->criteria;
900
901        bool ready2run = true;
902
903        for(    int i = 0; i < count; i++ ) {
904
905                // __cfaabi_dbg_print_safe( "Checking %p for %p\n", &criteria[i], target );
906                if( &criteria[i] == target ) {
907                        criteria[i].ready = true;
908                        // __cfaabi_dbg_print_safe( "True\n" );
909                }
910
911                ready2run = criteria[i].ready && ready2run;
912        }
913
914        __cfaabi_dbg_print_safe( "Kernel :  Runing %i (%p)\n", ready2run, ready2run ? (thread*)node->waiting_thread : (thread*)0p );
915        return ready2run ? node->waiting_thread : 0p;
916}
917
918static inline void brand_condition( condition & this ) {
919        thread$ * thrd = active_thread();
920        if( !this.monitors ) {
921                // __cfaabi_dbg_print_safe( "Branding\n" );
922                assertf( thrd->monitors.data != 0p, "No current monitor to brand condition %p", thrd->monitors.data );
923                this.monitor_count = thrd->monitors.size;
924
925                this.monitors = (monitor$ **)malloc( this.monitor_count * sizeof( *this.monitors ) );
926                for( int i = 0; i < this.monitor_count; i++ ) {
927                        this.monitors[i] = thrd->monitors[i];
928                }
929        }
930}
931
932static inline [thread$ *, int] search_entry_queue( const __waitfor_mask_t & mask, monitor$ * monitors [], __lock_size_t count ) {
933
934        __queue_t(thread$) & entry_queue = monitors[0]->entry_queue;
935
936        #if defined( __CFA_WITH_VERIFY__ )
937                thread$ * last = 0p;
938        #endif
939        // For each thread in the entry-queue
940        for(    thread$ ** thrd_it = &entry_queue.head;
941                (*thrd_it) != 1p;
942                thrd_it = &get_next(**thrd_it)
943        ) {
944                thread$ * curr = *thrd_it;
945
946                /* paranoid */ verifyf( !last || last->user_link.next == curr, "search not making progress, from %p (%p) to %p", last, last->user_link.next, curr );
947                /* paranoid */ verifyf( curr != last, "search not making progress, from %p to %p", last, curr );
948
949                // For each acceptable check if it matches
950                int i = 0;
951                __acceptable_t * end   = end  (mask);
952                __acceptable_t * begin = begin(mask);
953                for( __acceptable_t * it = begin; it != end; it++, i++ ) {
954                        // Check if we have a match
955                        if( *it == curr->monitors ) {
956
957                                // If we have a match return it
958                                // after removeing it from the entry queue
959                                return [remove( entry_queue, thrd_it ), i];
960                        }
961                }
962
963                #if defined( __CFA_WITH_VERIFY__ )
964                        last = curr;
965                #endif
966        }
967
968        return [0, -1];
969}
970
971forall(T & | sized( T ))
972static inline __lock_size_t insert_unique( T * array [], __lock_size_t & size, T * val ) {
973        if( !val ) return size;
974
975        for( __lock_size_t i = 0; i <= size; i++) {
976                if( array[i] == val ) return size;
977        }
978
979        array[size] = val;
980        size = size + 1;
981        return size;
982}
983
984static inline __lock_size_t count_max( const __waitfor_mask_t & mask ) {
985        __lock_size_t max = 0;
986        for( __lock_size_t i = 0; i < mask.size; i++ ) {
987                __acceptable_t & accepted = mask[i];
988                max += accepted.size;
989        }
990        return max;
991}
992
993static inline __lock_size_t aggregate( monitor$ * storage [], const __waitfor_mask_t & mask ) {
994        __lock_size_t size = 0;
995        for( __lock_size_t i = 0; i < mask.size; i++ ) {
996                __acceptable_t & accepted = mask[i];
997                __libcfa_small_sort( accepted.data, accepted.size );
998                for( __lock_size_t j = 0; j < accepted.size; j++) {
999                        insert_unique( storage, size, accepted[j] );
1000                }
1001        }
1002        // TODO insertion sort instead of this
1003        __libcfa_small_sort( storage, size );
1004        return size;
1005}
1006
1007//-----------------------------------------------------------------------------
1008// Enter routine for mutex stmt
1009// Can't be accepted since a mutex stmt is effectively an anonymous routine
1010// Thus we do not need a monitor group
1011void lock( monitor$ * this ) libcfa_public {
1012        thread$ * thrd = active_thread();
1013
1014        // Lock the monitor spinlock
1015        lock( this->lock __cfaabi_dbg_ctx2 );
1016
1017        __cfaabi_dbg_print_safe( "Kernel : %10p Entering mon %p (%p)\n", thrd, this, this->owner);
1018
1019        if( unlikely(0 != (0x1 & (uintptr_t)this->owner)) ) {
1020                abort( "Attempt by thread \"%.256s\" (%p) to access joined monitor %p.", thrd->self_cor.name, thrd, this );
1021        }
1022        else if( !this->owner ) {
1023                // No one has the monitor, just take it
1024                __set_owner( this, thrd );
1025
1026                __cfaabi_dbg_print_safe( "Kernel :  mon is free \n" );
1027        }
1028        else if( this->owner == thrd) {
1029                // We already have the monitor, just note how many times we took it
1030                this->recursion += 1;
1031
1032                __cfaabi_dbg_print_safe( "Kernel :  mon already owned \n" );
1033        }
1034        else {
1035                __cfaabi_dbg_print_safe( "Kernel :  blocking \n" );
1036
1037                // Some one else has the monitor, wait in line for it
1038                /* paranoid */ verify( thrd->user_link.next == 0p );
1039                append( this->entry_queue, thrd );
1040                /* paranoid */ verify( thrd->user_link.next == 1p );
1041
1042                unlock( this->lock );
1043                park();
1044
1045                __cfaabi_dbg_print_safe( "Kernel : %10p Entered  mon %p\n", thrd, this);
1046
1047                /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
1048                return;
1049        }
1050
1051        __cfaabi_dbg_print_safe( "Kernel : %10p Entered  mon %p\n", thrd, this);
1052
1053        /* paranoid */ verifyf( active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
1054        /* paranoid */ verify( this->lock.lock );
1055
1056        // Release the lock and leave
1057        unlock( this->lock );
1058        return;
1059}
1060
1061// Leave routine for mutex stmt
1062// Is just a wrapper around __leave for the is_lock trait to see
1063void unlock( monitor$ * this ) libcfa_public { __leave( this ); }
1064
1065// Local Variables: //
1066// mode: c //
1067// tab-width: 4 //
1068// End: //
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