source: libcfa/src/concurrency/kernel.cfa @ dddb3dd0

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since dddb3dd0 was dddb3dd0, checked in by Thierry Delisle <tdelisle@…>, 8 months ago

Changed io to use ring per kernel threads.

  • Property mode set to 100644
File size: 23.9 KB
Line 
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// kernel.c --
8//
9// Author           : Thierry Delisle
10// Created On       : Tue Jan 17 12:27:26 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Mon Aug 31 07:08:20 2020
13// Update Count     : 71
14//
15
16#define __cforall_thread__
17// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
18
19//C Includes
20#include <errno.h>
21#include <stdio.h>
22#include <signal.h>
23#include <unistd.h>
24extern "C" {
25        #include <sys/eventfd.h>
26}
27
28//CFA Includes
29#include "kernel_private.hfa"
30#include "preemption.hfa"
31
32//Private includes
33#define __CFA_INVOKE_PRIVATE__
34#include "invoke.h"
35
36
37//-----------------------------------------------------------------------------
38// Some assembly required
39#if defined( __i386 )
40        // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
41        // fcw  : X87 FPU control word (preserved across function calls)
42        #define __x87_store         \
43                uint32_t __mxcr;      \
44                uint16_t __fcw;       \
45                __asm__ volatile (    \
46                        "stmxcsr %0\n"  \
47                        "fnstcw  %1\n"  \
48                        : "=m" (__mxcr),\
49                                "=m" (__fcw)  \
50                )
51
52        #define __x87_load         \
53                __asm__ volatile (   \
54                        "fldcw  %1\n"  \
55                        "ldmxcsr %0\n" \
56                        ::"m" (__mxcr),\
57                                "m" (__fcw)  \
58                )
59
60#elif defined( __x86_64 )
61        #define __x87_store         \
62                uint32_t __mxcr;      \
63                uint16_t __fcw;       \
64                __asm__ volatile (    \
65                        "stmxcsr %0\n"  \
66                        "fnstcw  %1\n"  \
67                        : "=m" (__mxcr),\
68                                "=m" (__fcw)  \
69                )
70
71        #define __x87_load          \
72                __asm__ volatile (    \
73                        "fldcw  %1\n"   \
74                        "ldmxcsr %0\n"  \
75                        :: "m" (__mxcr),\
76                                "m" (__fcw)  \
77                )
78
79#elif defined( __arm__ )
80        #define __x87_store
81        #define __x87_load
82
83#elif defined( __aarch64__ )
84        #define __x87_store              \
85                uint32_t __fpcntl[2];    \
86                __asm__ volatile (    \
87                        "mrs x9, FPCR\n" \
88                        "mrs x10, FPSR\n"  \
89                        "stp x9, x10, %0\n"  \
90                        : "=m" (__fpcntl) : : "x9", "x10" \
91                )
92
93        #define __x87_load         \
94                __asm__ volatile (    \
95                        "ldp x9, x10, %0\n"  \
96                        "msr FPSR, x10\n"  \
97                        "msr FPCR, x9\n" \
98                : "=m" (__fpcntl) : : "x9", "x10" \
99                )
100
101#else
102        #error unsupported hardware architecture
103#endif
104
105extern $thread * mainThread;
106extern processor * mainProcessor;
107
108//-----------------------------------------------------------------------------
109// Kernel Scheduling logic
110static $thread * __next_thread(cluster * this);
111static $thread * __next_thread_slow(cluster * this);
112static void __run_thread(processor * this, $thread * dst);
113static void __wake_one(cluster * cltr);
114
115static void push  (__cluster_idles & idles, processor & proc);
116static void remove(__cluster_idles & idles, processor & proc);
117static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
118
119extern void __cfa_io_start( processor * );
120extern void __cfa_io_drain( processor * );
121extern void __cfa_io_flush( processor * );
122extern void __cfa_io_stop ( processor * );
123static inline void __maybe_io_drain( processor * );
124
125extern void __disable_interrupts_hard();
126extern void __enable_interrupts_hard();
127
128//=============================================================================================
129// Kernel Scheduling logic
130//=============================================================================================
131//Main of the processor contexts
132void main(processorCtx_t & runner) {
133        // Because of a bug, we couldn't initialized the seed on construction
134        // Do it here
135        __cfaabi_tls.rand_seed ^= rdtscl();
136        __cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
137        __tls_rand_advance_bck();
138
139        processor * this = runner.proc;
140        verify(this);
141
142        __cfa_io_start( this );
143
144        __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
145        #if !defined(__CFA_NO_STATISTICS__)
146                if( this->print_halts ) {
147                        __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
148                }
149        #endif
150
151        {
152                // Setup preemption data
153                preemption_scope scope = { this };
154
155                #if !defined(__CFA_NO_STATISTICS__)
156                        unsigned long long last_tally = rdtscl();
157                #endif
158
159
160                __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
161
162                $thread * readyThread = 0p;
163                MAIN_LOOP:
164                for() {
165                        // Check if there is pending io
166                        __maybe_io_drain( this );
167
168                        // Try to get the next thread
169                        readyThread = __next_thread( this->cltr );
170
171                        if( !readyThread ) {
172                                __cfa_io_flush( this );
173                                readyThread = __next_thread_slow( this->cltr );
174                        }
175
176                        HALT:
177                        if( !readyThread ) {
178                                // Don't block if we are done
179                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
180
181                                #if !defined(__CFA_NO_STATISTICS__)
182                                        __tls_stats()->ready.sleep.halts++;
183                                #endif
184
185                                // Push self to idle stack
186                                push(this->cltr->idles, * this);
187
188                                // Confirm the ready-queue is empty
189                                readyThread = __next_thread_slow( this->cltr );
190                                if( readyThread ) {
191                                        // A thread was found, cancel the halt
192                                        remove(this->cltr->idles, * this);
193
194                                        #if !defined(__CFA_NO_STATISTICS__)
195                                                __tls_stats()->ready.sleep.cancels++;
196                                        #endif
197
198                                        // continue the mai loop
199                                        break HALT;
200                                }
201
202                                #if !defined(__CFA_NO_STATISTICS__)
203                                        if(this->print_halts) {
204                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
205                                        }
206                                #endif
207
208                                __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
209
210                                __disable_interrupts_hard();
211                                eventfd_t val;
212                                eventfd_read( this->idle, &val );
213                                __enable_interrupts_hard();
214
215                                #if !defined(__CFA_NO_STATISTICS__)
216                                        if(this->print_halts) {
217                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
218                                        }
219                                #endif
220
221                                // We were woken up, remove self from idle
222                                remove(this->cltr->idles, * this);
223
224                                // DON'T just proceed, start looking again
225                                continue MAIN_LOOP;
226                        }
227
228                        /* paranoid */ verify( readyThread );
229
230                        // Reset io dirty bit
231                        this->io.dirty = false;
232
233                        // We found a thread run it
234                        __run_thread(this, readyThread);
235
236                        // Are we done?
237                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
238
239                        #if !defined(__CFA_NO_STATISTICS__)
240                                unsigned long long curr = rdtscl();
241                                if(curr > (last_tally + 500000000)) {
242                                        __tally_stats(this->cltr->stats, __cfaabi_tls.this_stats);
243                                        last_tally = curr;
244                                }
245                        #endif
246
247                        if(this->io.pending && !this->io.dirty) {
248                                __cfa_io_flush( this );
249                        }
250                }
251
252                __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
253        }
254
255        __cfa_io_stop( this );
256
257        post( this->terminated );
258
259
260        if(this == mainProcessor) {
261                // HACK : the coroutine context switch expects this_thread to be set
262                // and it make sense for it to be set in all other cases except here
263                // fake it
264                __cfaabi_tls.this_thread = mainThread;
265        }
266
267        __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
268}
269
270static int * __volatile_errno() __attribute__((noinline));
271static int * __volatile_errno() { asm(""); return &errno; }
272
273// KERNEL ONLY
274// runThread runs a thread by context switching
275// from the processor coroutine to the target thread
276static void __run_thread(processor * this, $thread * thrd_dst) {
277        /* paranoid */ verify( ! __preemption_enabled() );
278        /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
279        /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
280        __builtin_prefetch( thrd_dst->context.SP );
281
282        __cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
283
284        $coroutine * proc_cor = get_coroutine(this->runner);
285
286        // set state of processor coroutine to inactive
287        verify(proc_cor->state == Active);
288        proc_cor->state = Blocked;
289
290        // Actually run the thread
291        RUNNING:  while(true) {
292                thrd_dst->preempted = __NO_PREEMPTION;
293                thrd_dst->state = Active;
294
295                // Update global state
296                kernelTLS().this_thread = thrd_dst;
297
298                /* paranoid */ verify( ! __preemption_enabled() );
299                /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
300                /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
301                /* paranoid */ verify( thrd_dst->context.SP );
302                /* paranoid */ verify( thrd_dst->state != Halted );
303                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) || thrd_dst->curr_cor == proc_cor, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst ); // add escape condition if we are setting up the processor
304                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit) || thrd_dst->curr_cor == proc_cor, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst ); // add escape condition if we are setting up the processor
305                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
306
307
308
309                // set context switch to the thread that the processor is executing
310                __cfactx_switch( &proc_cor->context, &thrd_dst->context );
311                // when __cfactx_switch returns we are back in the processor coroutine
312
313                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
314                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst );
315                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
316                /* paranoid */ verify( thrd_dst->context.SP );
317                /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
318                /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
319                /* paranoid */ verify( ! __preemption_enabled() );
320
321                // Reset global state
322                kernelTLS().this_thread = 0p;
323
324                // We just finished running a thread, there are a few things that could have happened.
325                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
326                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
327                // 4 - Preempted
328                // In case 1, we may have won a race so we can't write to the state again.
329                // In case 2, we lost the race so we now own the thread.
330
331                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
332                        // The thread was preempted, reschedule it and reset the flag
333                        __schedule_thread( thrd_dst );
334                        break RUNNING;
335                }
336
337                if(unlikely(thrd_dst->state == Halting)) {
338                        // The thread has halted, it should never be scheduled/run again
339                        // finish the thread
340                        __thread_finish( thrd_dst );
341                        break RUNNING;
342                }
343
344                /* paranoid */ verify( thrd_dst->state == Active );
345                thrd_dst->state = Blocked;
346
347                // set state of processor coroutine to active and the thread to inactive
348                int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
349                switch(old_ticket) {
350                        case TICKET_RUNNING:
351                                // This is case 1, the regular case, nothing more is needed
352                                break RUNNING;
353                        case TICKET_UNBLOCK:
354                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
355                                // In this case, just run it again.
356                                continue RUNNING;
357                        default:
358                                // This makes no sense, something is wrong abort
359                                abort();
360                }
361        }
362
363        // Just before returning to the processor, set the processor coroutine to active
364        proc_cor->state = Active;
365
366        __cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
367
368        /* paranoid */ verify( ! __preemption_enabled() );
369}
370
371// KERNEL_ONLY
372void returnToKernel() {
373        /* paranoid */ verify( ! __preemption_enabled() );
374        $coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
375        $thread * thrd_src = kernelTLS().this_thread;
376
377        #if !defined(__CFA_NO_STATISTICS__)
378                struct processor * last_proc = kernelTLS().this_processor;
379        #endif
380
381        // Run the thread on this processor
382        {
383                int local_errno = *__volatile_errno();
384                #if defined( __i386 ) || defined( __x86_64 )
385                        __x87_store;
386                #endif
387                /* paranoid */ verify( proc_cor->context.SP );
388                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
389                __cfactx_switch( &thrd_src->context, &proc_cor->context );
390                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
391                #if defined( __i386 ) || defined( __x86_64 )
392                        __x87_load;
393                #endif
394                *__volatile_errno() = local_errno;
395        }
396
397        #if !defined(__CFA_NO_STATISTICS__)
398                if(last_proc != kernelTLS().this_processor) {
399                        __tls_stats()->ready.threads.migration++;
400                }
401        #endif
402
403        /* paranoid */ verify( ! __preemption_enabled() );
404        /* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) < ((uintptr_t)__get_stack(thrd_src->curr_cor)->base ), "ERROR : Returning $thread %p has been corrupted.\n StackPointer too small.\n", thrd_src );
405        /* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) > ((uintptr_t)__get_stack(thrd_src->curr_cor)->limit), "ERROR : Returning $thread %p has been corrupted.\n StackPointer too large.\n", thrd_src );
406}
407
408//-----------------------------------------------------------------------------
409// Scheduler routines
410// KERNEL ONLY
411void __schedule_thread( $thread * thrd ) {
412        /* paranoid */ verify( ! __preemption_enabled() );
413        /* paranoid */ verify( kernelTLS().this_proc_id );
414        /* paranoid */ verify( thrd );
415        /* paranoid */ verify( thrd->state != Halted );
416        /* paranoid */ verify( thrd->curr_cluster );
417        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
418        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
419                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
420        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
421                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
422        /* paranoid */ #endif
423        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
424        /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
425
426
427        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
428
429        ready_schedule_lock();
430                // Dereference the thread now because once we push it, there is not guaranteed it's still valid.
431                struct cluster * cl = thrd->curr_cluster;
432
433                // push the thread to the cluster ready-queue
434                push( cl, thrd );
435
436                // variable thrd is no longer safe to use
437
438                // wake the cluster using the save variable.
439                __wake_one( cl );
440        ready_schedule_unlock();
441
442        /* paranoid */ verify( ! __preemption_enabled() );
443}
444
445// KERNEL ONLY
446static inline $thread * __next_thread(cluster * this) with( *this ) {
447        /* paranoid */ verify( ! __preemption_enabled() );
448        /* paranoid */ verify( kernelTLS().this_proc_id );
449
450        ready_schedule_lock();
451                $thread * thrd = pop( this );
452        ready_schedule_unlock();
453
454        /* paranoid */ verify( kernelTLS().this_proc_id );
455        /* paranoid */ verify( ! __preemption_enabled() );
456        return thrd;
457}
458
459// KERNEL ONLY
460static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
461        /* paranoid */ verify( ! __preemption_enabled() );
462        /* paranoid */ verify( kernelTLS().this_proc_id );
463
464        ready_schedule_lock();
465                $thread * thrd = pop_slow( this );
466        ready_schedule_unlock();
467
468        /* paranoid */ verify( kernelTLS().this_proc_id );
469        /* paranoid */ verify( ! __preemption_enabled() );
470        return thrd;
471}
472
473void unpark( $thread * thrd ) {
474        if( !thrd ) return;
475
476        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
477        switch(old_ticket) {
478                case TICKET_RUNNING:
479                        // Wake won the race, the thread will reschedule/rerun itself
480                        break;
481                case TICKET_BLOCKED:
482                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
483                        /* paranoid */ verify( thrd->state == Blocked );
484
485                        {
486                                /* paranoid */ verify( publicTLS_get(this_proc_id) );
487                                bool full = publicTLS_get(this_proc_id)->full_proc;
488                                if(full) disable_interrupts();
489
490                                /* paranoid */ verify( ! __preemption_enabled() );
491
492                                // Wake lost the race,
493                                __schedule_thread( thrd );
494
495                                /* paranoid */ verify( ! __preemption_enabled() );
496
497                                if(full) enable_interrupts( __cfaabi_dbg_ctx );
498                                /* paranoid */ verify( publicTLS_get(this_proc_id) );
499                        }
500
501                        break;
502                default:
503                        // This makes no sense, something is wrong abort
504                        abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
505        }
506}
507
508void park( void ) {
509        /* paranoid */ verify( __preemption_enabled() );
510        disable_interrupts();
511        /* paranoid */ verify( ! __preemption_enabled() );
512        /* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
513
514        returnToKernel();
515
516        /* paranoid */ verify( ! __preemption_enabled() );
517        enable_interrupts( __cfaabi_dbg_ctx );
518        /* paranoid */ verify( __preemption_enabled() );
519
520}
521
522extern "C" {
523        // Leave the thread monitor
524        // last routine called by a thread.
525        // Should never return
526        void __cfactx_thrd_leave() {
527                $thread * thrd = active_thread();
528                $monitor * this = &thrd->self_mon;
529
530                // Lock the monitor now
531                lock( this->lock __cfaabi_dbg_ctx2 );
532
533                disable_interrupts();
534
535                /* paranoid */ verify( ! __preemption_enabled() );
536                /* paranoid */ verify( thrd->state == Active );
537                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
538                /* paranoid */ verify( kernelTLS().this_thread == thrd );
539                /* paranoid */ verify( thrd->context.SP );
540                /* 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 );
541                /* 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 );
542
543                thrd->state = Halting;
544                if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
545                if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
546                if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
547
548                // Leave the thread
549                returnToKernel();
550
551                // Control flow should never reach here!
552                abort();
553        }
554}
555
556// KERNEL ONLY
557bool force_yield( __Preemption_Reason reason ) {
558        /* paranoid */ verify( __preemption_enabled() );
559        disable_interrupts();
560        /* paranoid */ verify( ! __preemption_enabled() );
561
562        $thread * thrd = kernelTLS().this_thread;
563        /* paranoid */ verify(thrd->state == Active);
564
565        // SKULLDUGGERY: It is possible that we are preempting this thread just before
566        // it was going to park itself. If that is the case and it is already using the
567        // intrusive fields then we can't use them to preempt the thread
568        // If that is the case, abandon the preemption.
569        bool preempted = false;
570        if(thrd->link.next == 0p) {
571                preempted = true;
572                thrd->preempted = reason;
573                returnToKernel();
574        }
575
576        /* paranoid */ verify( ! __preemption_enabled() );
577        enable_interrupts_noPoll();
578        /* paranoid */ verify( __preemption_enabled() );
579
580        return preempted;
581}
582
583//=============================================================================================
584// Kernel Idle Sleep
585//=============================================================================================
586// Wake a thread from the front if there are any
587static void __wake_one(cluster * this) {
588        /* paranoid */ verify( ! __preemption_enabled() );
589        /* paranoid */ verify( ready_schedule_islocked() );
590
591        // Check if there is a sleeping processor
592        processor * p;
593        unsigned idle;
594        unsigned total;
595        [idle, total, p] = query(this->idles);
596
597        // If no one is sleeping, we are done
598        if( idle == 0 ) return;
599
600        // We found a processor, wake it up
601        eventfd_t val;
602        val = 1;
603        eventfd_write( p->idle, val );
604
605        #if !defined(__CFA_NO_STATISTICS__)
606                __tls_stats()->ready.sleep.wakes++;
607        #endif
608
609        /* paranoid */ verify( ready_schedule_islocked() );
610        /* paranoid */ verify( ! __preemption_enabled() );
611
612        return;
613}
614
615// Unconditionnaly wake a thread
616void __wake_proc(processor * this) {
617        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
618
619        disable_interrupts();
620                /* paranoid */ verify( ! __preemption_enabled() );
621                eventfd_t val;
622                val = 1;
623                eventfd_read( this->idle, &val );
624        enable_interrupts( __cfaabi_dbg_ctx );
625}
626
627static void push  (__cluster_idles & this, processor & proc) {
628        /* paranoid */ verify( ! __preemption_enabled() );
629        lock( this );
630                this.idle++;
631                /* paranoid */ verify( this.idle <= this.total );
632
633                insert_first(this.list, proc);
634        unlock( this );
635        /* paranoid */ verify( ! __preemption_enabled() );
636}
637
638static void remove(__cluster_idles & this, processor & proc) {
639        /* paranoid */ verify( ! __preemption_enabled() );
640        lock( this );
641                this.idle--;
642                /* paranoid */ verify( this.idle >= 0 );
643
644                remove(proc);
645        unlock( this );
646        /* paranoid */ verify( ! __preemption_enabled() );
647}
648
649static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
650        for() {
651                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
652                if( 1 == (l % 2) ) { Pause(); continue; }
653                unsigned idle    = this.idle;
654                unsigned total   = this.total;
655                processor * proc = &this.list`first;
656                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
657                asm volatile("": : :"memory");
658                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
659                return [idle, total, proc];
660        }
661}
662
663//=============================================================================================
664// Unexpected Terminating logic
665//=============================================================================================
666void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
667        $thread * thrd = __cfaabi_tls.this_thread;
668
669        if(thrd) {
670                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
671                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
672
673                if ( &thrd->self_cor != thrd->curr_cor ) {
674                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
675                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
676                }
677                else {
678                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
679                }
680        }
681        else {
682                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
683                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
684        }
685}
686
687int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
688        return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
689}
690
691static __spinlock_t kernel_debug_lock;
692
693extern "C" {
694        void __cfaabi_bits_acquire() {
695                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
696        }
697
698        void __cfaabi_bits_release() {
699                unlock( kernel_debug_lock );
700        }
701}
702
703//=============================================================================================
704// Kernel Utilities
705//=============================================================================================
706#if defined(CFA_HAVE_LINUX_IO_URING_H)
707#include "io/types.hfa"
708#endif
709
710static inline void __maybe_io_drain( processor * proc ) {
711        #if defined(CFA_HAVE_LINUX_IO_URING_H)
712                __cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
713
714                // Check if we should drain the queue
715                $io_context * ctx = proc->io.ctx;
716                unsigned head = *ctx->cq.head;
717                unsigned tail = *ctx->cq.tail;
718                if(head != tail) __cfa_io_drain( proc );
719        #endif
720}
721
722//-----------------------------------------------------------------------------
723// Debug
724__cfaabi_dbg_debug_do(
725        extern "C" {
726                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
727                        this.prev_name = prev_name;
728                        this.prev_thrd = kernelTLS().this_thread;
729                }
730        }
731)
732
733//-----------------------------------------------------------------------------
734// Debug
735bool threading_enabled(void) __attribute__((const)) {
736        return true;
737}
738
739//-----------------------------------------------------------------------------
740// Statistics
741#if !defined(__CFA_NO_STATISTICS__)
742        void print_halts( processor & this ) {
743                this.print_halts = true;
744        }
745
746        void print_stats_now( cluster & this, int flags ) {
747                __print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
748        }
749
750        extern int __print_alarm_stats;
751        void print_alarm_stats() {
752                __print_alarm_stats = -1;
753        }
754#endif
755// Local Variables: //
756// mode: c //
757// tab-width: 4 //
758// End: //
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