source: libcfa/src/concurrency/kernel.cfa@ 89eff25

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since 89eff25 was 89eff25, checked in by Thierry Delisle <tdelisle@…>, 5 years ago

Some changes to stats and added back preferred
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File size: 29.0 KB
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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// 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#if !defined(__CFA_NO_STATISTICS__)
37 #define __STATS( ...) __VA_ARGS__
38#else
39 #define __STATS( ...)
40#endif
41
42//-----------------------------------------------------------------------------
43// Some assembly required
44#if defined( __i386 )
45 // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
46 // fcw : X87 FPU control word (preserved across function calls)
47 #define __x87_store \
48 uint32_t __mxcr; \
49 uint16_t __fcw; \
50 __asm__ volatile ( \
51 "stmxcsr %0\n" \
52 "fnstcw %1\n" \
53 : "=m" (__mxcr),\
54 "=m" (__fcw) \
55 )
56
57 #define __x87_load \
58 __asm__ volatile ( \
59 "fldcw %1\n" \
60 "ldmxcsr %0\n" \
61 ::"m" (__mxcr),\
62 "m" (__fcw) \
63 )
64
65#elif defined( __x86_64 )
66 #define __x87_store \
67 uint32_t __mxcr; \
68 uint16_t __fcw; \
69 __asm__ volatile ( \
70 "stmxcsr %0\n" \
71 "fnstcw %1\n" \
72 : "=m" (__mxcr),\
73 "=m" (__fcw) \
74 )
75
76 #define __x87_load \
77 __asm__ volatile ( \
78 "fldcw %1\n" \
79 "ldmxcsr %0\n" \
80 :: "m" (__mxcr),\
81 "m" (__fcw) \
82 )
83
84#elif defined( __arm__ )
85 #define __x87_store
86 #define __x87_load
87
88#elif defined( __aarch64__ )
89 #define __x87_store \
90 uint32_t __fpcntl[2]; \
91 __asm__ volatile ( \
92 "mrs x9, FPCR\n" \
93 "mrs x10, FPSR\n" \
94 "stp x9, x10, %0\n" \
95 : "=m" (__fpcntl) : : "x9", "x10" \
96 )
97
98 #define __x87_load \
99 __asm__ volatile ( \
100 "ldp x9, x10, %0\n" \
101 "msr FPSR, x10\n" \
102 "msr FPCR, x9\n" \
103 : "=m" (__fpcntl) : : "x9", "x10" \
104 )
105
106#else
107 #error unsupported hardware architecture
108#endif
109
110extern $thread * mainThread;
111extern processor * mainProcessor;
112
113//-----------------------------------------------------------------------------
114// Kernel Scheduling logic
115static $thread * __next_thread(cluster * this);
116static $thread * __next_thread_slow(cluster * this);
117static void __run_thread(processor * this, $thread * dst);
118static void __wake_one(cluster * cltr);
119
120static void mark_idle (__cluster_proc_list & idles, processor & proc);
121static void mark_awake(__cluster_proc_list & idles, processor & proc);
122static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list idles );
123
124extern void __cfa_io_start( processor * );
125extern bool __cfa_io_drain( processor * );
126extern void __cfa_io_flush( processor * );
127extern void __cfa_io_stop ( processor * );
128static inline bool __maybe_io_drain( processor * );
129
130extern void __disable_interrupts_hard();
131extern void __enable_interrupts_hard();
132
133//=============================================================================================
134// Kernel Scheduling logic
135//=============================================================================================
136//Main of the processor contexts
137void main(processorCtx_t & runner) {
138 // Because of a bug, we couldn't initialized the seed on construction
139 // Do it here
140 __cfaabi_tls.rand_seed ^= rdtscl();
141 __cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
142 __tls_rand_advance_bck();
143
144 processor * this = runner.proc;
145 verify(this);
146
147 __cfa_io_start( this );
148
149 __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
150 #if !defined(__CFA_NO_STATISTICS__)
151 if( this->print_halts ) {
152 __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
153 }
154 #endif
155
156 {
157 // Setup preemption data
158 preemption_scope scope = { this };
159
160 __STATS( unsigned long long last_tally = rdtscl(); )
161
162 // if we need to run some special setup, now is the time to do it.
163 if(this->init.thrd) {
164 this->init.thrd->curr_cluster = this->cltr;
165 __run_thread(this, this->init.thrd);
166 }
167
168 __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
169
170 $thread * readyThread = 0p;
171 MAIN_LOOP:
172 for() {
173 // Check if there is pending io
174 __maybe_io_drain( this );
175
176 // Try to get the next thread
177 readyThread = __next_thread( this->cltr );
178
179 if( !readyThread ) {
180 __cfa_io_flush( this );
181 readyThread = __next_thread_slow( this->cltr );
182 }
183
184 HALT:
185 if( !readyThread ) {
186 // Don't block if we are done
187 if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
188
189 #if !defined(__CFA_NO_STATISTICS__)
190 __tls_stats()->ready.sleep.halts++;
191 #endif
192
193 // Push self to idle stack
194 mark_idle(this->cltr->procs, * this);
195
196 // Confirm the ready-queue is empty
197 readyThread = __next_thread_slow( this->cltr );
198 if( readyThread ) {
199 // A thread was found, cancel the halt
200 mark_awake(this->cltr->procs, * this);
201
202 #if !defined(__CFA_NO_STATISTICS__)
203 __tls_stats()->ready.sleep.cancels++;
204 #endif
205
206 // continue the mai loop
207 break HALT;
208 }
209
210 #if !defined(__CFA_NO_STATISTICS__)
211 if(this->print_halts) {
212 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
213 }
214 #endif
215
216 __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
217
218 __disable_interrupts_hard();
219 eventfd_t val;
220 eventfd_read( this->idle, &val );
221 __enable_interrupts_hard();
222
223 #if !defined(__CFA_NO_STATISTICS__)
224 if(this->print_halts) {
225 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
226 }
227 #endif
228
229 // We were woken up, remove self from idle
230 mark_awake(this->cltr->procs, * this);
231
232 // DON'T just proceed, start looking again
233 continue MAIN_LOOP;
234 }
235
236 /* paranoid */ verify( readyThread );
237
238 // Reset io dirty bit
239 this->io.dirty = false;
240
241 // We found a thread run it
242 __run_thread(this, readyThread);
243
244 // Are we done?
245 if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
246
247 #if !defined(__CFA_NO_STATISTICS__)
248 unsigned long long curr = rdtscl();
249 if(curr > (last_tally + 500000000)) {
250 __tally_stats(this->cltr->stats, __cfaabi_tls.this_stats);
251 last_tally = curr;
252 }
253 #endif
254
255 if(this->io.pending && !this->io.dirty) {
256 __cfa_io_flush( this );
257 }
258
259 // SEARCH: {
260 // /* paranoid */ verify( ! __preemption_enabled() );
261 // /* paranoid */ verify( kernelTLS().this_proc_id );
262
263 // // First, lock the scheduler since we are searching for a thread
264
265 // // Try to get the next thread
266 // ready_schedule_lock();
267 // readyThread = pop_fast( this->cltr );
268 // ready_schedule_unlock();
269 // if(readyThread) { break SEARCH; }
270
271 // // If we can't find a thread, might as well flush any outstanding I/O
272 // if(this->io.pending) { __cfa_io_flush( this ); }
273
274 // // Spin a little on I/O, just in case
275 // for(25) {
276 // __maybe_io_drain( this );
277 // ready_schedule_lock();
278 // readyThread = pop_fast( this->cltr );
279 // ready_schedule_unlock();
280 // if(readyThread) { break SEARCH; }
281 // }
282
283 // // no luck, try stealing a few times
284 // for(25) {
285 // if( __maybe_io_drain( this ) ) {
286 // ready_schedule_lock();
287 // readyThread = pop_fast( this->cltr );
288 // } else {
289 // ready_schedule_lock();
290 // readyThread = pop_slow( this->cltr );
291 // }
292 // ready_schedule_unlock();
293 // if(readyThread) { break SEARCH; }
294 // }
295
296 // // still no luck, search for a thread
297 // ready_schedule_lock();
298 // readyThread = pop_search( this->cltr );
299 // ready_schedule_unlock();
300 // if(readyThread) { break SEARCH; }
301
302 // // Don't block if we are done
303 // if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
304
305 // __STATS( __tls_stats()->ready.sleep.halts++; )
306
307 // // Push self to idle stack
308 // mark_idle(this->cltr->procs, * this);
309
310 // // Confirm the ready-queue is empty
311 // __maybe_io_drain( this );
312 // ready_schedule_lock();
313 // readyThread = pop_search( this->cltr );
314 // ready_schedule_unlock();
315
316 // if( readyThread ) {
317 // // A thread was found, cancel the halt
318 // mark_awake(this->cltr->procs, * this);
319
320 // __STATS( __tls_stats()->ready.sleep.cancels++; )
321
322 // // continue the main loop
323 // break SEARCH;
324 // }
325
326 // __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl()); )
327 // __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
328
329 // // __disable_interrupts_hard();
330 // eventfd_t val;
331 // eventfd_read( this->idle, &val );
332 // // __enable_interrupts_hard();
333
334 // __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl()); )
335
336 // // We were woken up, remove self from idle
337 // mark_awake(this->cltr->procs, * this);
338
339 // // DON'T just proceed, start looking again
340 // continue MAIN_LOOP;
341 // }
342
343 // RUN_THREAD:
344 // /* paranoid */ verify( kernelTLS().this_proc_id );
345 // /* paranoid */ verify( ! __preemption_enabled() );
346 // /* paranoid */ verify( readyThread );
347
348 // // Reset io dirty bit
349 // this->io.dirty = false;
350
351 // // We found a thread run it
352 // __run_thread(this, readyThread);
353
354 // // Are we done?
355 // if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
356
357 // #if !defined(__CFA_NO_STATISTICS__)
358 // unsigned long long curr = rdtscl();
359 // if(curr > (last_tally + 500000000)) {
360 // __tally_stats(this->cltr->stats, __cfaabi_tls.this_stats);
361 // last_tally = curr;
362 // }
363 // #endif
364
365 // if(this->io.pending && !this->io.dirty) {
366 // __cfa_io_flush( this );
367 // }
368
369 // // Check if there is pending io
370 // __maybe_io_drain( this );
371 }
372
373 __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
374 }
375
376 __cfa_io_stop( this );
377
378 post( this->terminated );
379
380
381 if(this == mainProcessor) {
382 // HACK : the coroutine context switch expects this_thread to be set
383 // and it make sense for it to be set in all other cases except here
384 // fake it
385 __cfaabi_tls.this_thread = mainThread;
386 }
387
388 __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
389}
390
391static int * __volatile_errno() __attribute__((noinline));
392static int * __volatile_errno() { asm(""); return &errno; }
393
394// KERNEL ONLY
395// runThread runs a thread by context switching
396// from the processor coroutine to the target thread
397static void __run_thread(processor * this, $thread * thrd_dst) {
398 /* paranoid */ verify( ! __preemption_enabled() );
399 /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
400 /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
401 __builtin_prefetch( thrd_dst->context.SP );
402
403 __cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
404
405 $coroutine * proc_cor = get_coroutine(this->runner);
406
407 // set state of processor coroutine to inactive
408 verify(proc_cor->state == Active);
409 proc_cor->state = Blocked;
410
411 // Actually run the thread
412 RUNNING: while(true) {
413 thrd_dst->preempted = __NO_PREEMPTION;
414 thrd_dst->state = Active;
415
416 // Update global state
417 kernelTLS().this_thread = thrd_dst;
418
419 /* paranoid */ verify( ! __preemption_enabled() );
420 /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
421 /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
422 /* paranoid */ verify( thrd_dst->context.SP );
423 /* paranoid */ verify( thrd_dst->state != Halted );
424 /* 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
425 /* 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
426 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
427
428
429
430 // set context switch to the thread that the processor is executing
431 __cfactx_switch( &proc_cor->context, &thrd_dst->context );
432 // when __cfactx_switch returns we are back in the processor coroutine
433
434 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
435 /* 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 );
436 /* 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 );
437 /* paranoid */ verify( thrd_dst->context.SP );
438 /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
439 /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
440 /* paranoid */ verify( ! __preemption_enabled() );
441
442 // Reset global state
443 kernelTLS().this_thread = 0p;
444
445 // We just finished running a thread, there are a few things that could have happened.
446 // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
447 // 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
448 // 4 - Preempted
449 // In case 1, we may have won a race so we can't write to the state again.
450 // In case 2, we lost the race so we now own the thread.
451
452 if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
453 // The thread was preempted, reschedule it and reset the flag
454 __schedule_thread( thrd_dst );
455 break RUNNING;
456 }
457
458 if(unlikely(thrd_dst->state == Halting)) {
459 // The thread has halted, it should never be scheduled/run again
460 // finish the thread
461 __thread_finish( thrd_dst );
462 break RUNNING;
463 }
464
465 /* paranoid */ verify( thrd_dst->state == Active );
466 thrd_dst->state = Blocked;
467
468 // set state of processor coroutine to active and the thread to inactive
469 int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
470 switch(old_ticket) {
471 case TICKET_RUNNING:
472 // This is case 1, the regular case, nothing more is needed
473 break RUNNING;
474 case TICKET_UNBLOCK:
475 #if !defined(__CFA_NO_STATISTICS__)
476 __tls_stats()->ready.threads.threads++;
477 __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
478 #endif
479 // This is case 2, the racy case, someone tried to run this thread before it finished blocking
480 // In this case, just run it again.
481 continue RUNNING;
482 default:
483 // This makes no sense, something is wrong abort
484 abort();
485 }
486 }
487
488 // Just before returning to the processor, set the processor coroutine to active
489 proc_cor->state = Active;
490
491 __cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
492
493 #if !defined(__CFA_NO_STATISTICS__)
494 __tls_stats()->ready.threads.threads--;
495 __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
496 #endif
497
498 /* paranoid */ verify( ! __preemption_enabled() );
499}
500
501// KERNEL_ONLY
502void returnToKernel() {
503 /* paranoid */ verify( ! __preemption_enabled() );
504 $coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
505 $thread * thrd_src = kernelTLS().this_thread;
506
507 __STATS( thrd_src->last_proc = kernelTLS().this_processor; )
508
509 // Run the thread on this processor
510 {
511 int local_errno = *__volatile_errno();
512 #if defined( __i386 ) || defined( __x86_64 )
513 __x87_store;
514 #endif
515 /* paranoid */ verify( proc_cor->context.SP );
516 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
517 __cfactx_switch( &thrd_src->context, &proc_cor->context );
518 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
519 #if defined( __i386 ) || defined( __x86_64 )
520 __x87_load;
521 #endif
522 *__volatile_errno() = local_errno;
523 }
524
525 #if !defined(__CFA_NO_STATISTICS__)
526 /* paranoid */ verify( thrd_src->last_proc != 0p );
527 if(thrd_src->last_proc != kernelTLS().this_processor) {
528 __tls_stats()->ready.threads.migration++;
529 }
530 #endif
531
532 /* paranoid */ verify( ! __preemption_enabled() );
533 /* 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 );
534 /* 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 );
535}
536
537//-----------------------------------------------------------------------------
538// Scheduler routines
539// KERNEL ONLY
540void __schedule_thread( $thread * thrd ) {
541 /* paranoid */ verify( ! __preemption_enabled() );
542 /* paranoid */ verify( kernelTLS().this_proc_id );
543 /* paranoid */ verify( thrd );
544 /* paranoid */ verify( thrd->state != Halted );
545 /* paranoid */ verify( thrd->curr_cluster );
546 /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
547 /* paranoid */ if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
548 "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
549 /* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
550 "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
551 /* paranoid */ #endif
552 /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
553 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
554
555
556 if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
557
558 // Dereference the thread now because once we push it, there is not guaranteed it's still valid.
559 struct cluster * cl = thrd->curr_cluster;
560 __STATS(bool outside = thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
561
562 ready_schedule_lock();
563 // push the thread to the cluster ready-queue
564 push( cl, thrd );
565
566 // variable thrd is no longer safe to use
567
568 // wake the cluster using the save variable.
569 __wake_one( cl );
570 ready_schedule_unlock();
571
572 #if !defined(__CFA_NO_STATISTICS__)
573 if( kernelTLS().this_stats ) {
574 __tls_stats()->ready.threads.threads++;
575 if(outside) {
576 __tls_stats()->ready.threads.extunpark++;
577 }
578 __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", kernelTLS().this_processor );
579 }
580 else {
581 __atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
582 __atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
583 __push_stat( cl->stats, cl->stats->ready.threads.threads, true, "Cluster", cl );
584 }
585 #endif
586
587 /* paranoid */ verify( ! __preemption_enabled() );
588}
589
590// KERNEL ONLY
591static inline $thread * __next_thread(cluster * this) with( *this ) {
592 /* paranoid */ verify( ! __preemption_enabled() );
593 /* paranoid */ verify( kernelTLS().this_proc_id );
594
595 ready_schedule_lock();
596 $thread * thrd = pop_fast( this );
597 ready_schedule_unlock();
598
599 /* paranoid */ verify( kernelTLS().this_proc_id );
600 /* paranoid */ verify( ! __preemption_enabled() );
601 return thrd;
602}
603
604// KERNEL ONLY
605static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
606 /* paranoid */ verify( ! __preemption_enabled() );
607 /* paranoid */ verify( kernelTLS().this_proc_id );
608
609 ready_schedule_lock();
610 $thread * thrd;
611 for(25) {
612 thrd = pop_slow( this );
613 if(thrd) goto RET;
614 }
615 thrd = pop_search( this );
616
617 RET:
618 ready_schedule_unlock();
619
620 /* paranoid */ verify( kernelTLS().this_proc_id );
621 /* paranoid */ verify( ! __preemption_enabled() );
622 return thrd;
623}
624
625void unpark( $thread * thrd ) {
626 if( !thrd ) return;
627
628 int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
629 switch(old_ticket) {
630 case TICKET_RUNNING:
631 // Wake won the race, the thread will reschedule/rerun itself
632 break;
633 case TICKET_BLOCKED:
634 /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
635 /* paranoid */ verify( thrd->state == Blocked );
636
637 {
638 /* paranoid */ verify( publicTLS_get(this_proc_id) );
639 disable_interrupts();
640
641 /* paranoid */ verify( ! __preemption_enabled() );
642
643 // Wake lost the race,
644 __schedule_thread( thrd );
645
646 /* paranoid */ verify( ! __preemption_enabled() );
647
648 enable_interrupts_noPoll();
649 /* paranoid */ verify( publicTLS_get(this_proc_id) );
650 }
651
652 break;
653 default:
654 // This makes no sense, something is wrong abort
655 abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
656 }
657}
658
659void park( void ) {
660 /* paranoid */ verify( __preemption_enabled() );
661 disable_interrupts();
662 /* paranoid */ verify( ! __preemption_enabled() );
663 /* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
664
665 returnToKernel();
666
667 /* paranoid */ verify( ! __preemption_enabled() );
668 enable_interrupts( __cfaabi_dbg_ctx );
669 /* paranoid */ verify( __preemption_enabled() );
670
671}
672
673extern "C" {
674 // Leave the thread monitor
675 // last routine called by a thread.
676 // Should never return
677 void __cfactx_thrd_leave() {
678 $thread * thrd = active_thread();
679 $monitor * this = &thrd->self_mon;
680
681 // Lock the monitor now
682 lock( this->lock __cfaabi_dbg_ctx2 );
683
684 disable_interrupts();
685
686 /* paranoid */ verify( ! __preemption_enabled() );
687 /* paranoid */ verify( thrd->state == Active );
688 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
689 /* paranoid */ verify( kernelTLS().this_thread == thrd );
690 /* paranoid */ verify( thrd->context.SP );
691 /* 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 );
692 /* 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 );
693
694 thrd->state = Halting;
695 if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
696 if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
697 if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
698
699 // Leave the thread
700 returnToKernel();
701
702 // Control flow should never reach here!
703 abort();
704 }
705}
706
707// KERNEL ONLY
708bool force_yield( __Preemption_Reason reason ) {
709 /* paranoid */ verify( __preemption_enabled() );
710 disable_interrupts();
711 /* paranoid */ verify( ! __preemption_enabled() );
712
713 $thread * thrd = kernelTLS().this_thread;
714 /* paranoid */ verify(thrd->state == Active);
715
716 // SKULLDUGGERY: It is possible that we are preempting this thread just before
717 // it was going to park itself. If that is the case and it is already using the
718 // intrusive fields then we can't use them to preempt the thread
719 // If that is the case, abandon the preemption.
720 bool preempted = false;
721 if(thrd->link.next == 0p) {
722 preempted = true;
723 thrd->preempted = reason;
724 returnToKernel();
725 }
726
727 /* paranoid */ verify( ! __preemption_enabled() );
728 enable_interrupts_noPoll();
729 /* paranoid */ verify( __preemption_enabled() );
730
731 return preempted;
732}
733
734//=============================================================================================
735// Kernel Idle Sleep
736//=============================================================================================
737// Wake a thread from the front if there are any
738static void __wake_one(cluster * this) {
739 /* paranoid */ verify( ! __preemption_enabled() );
740 /* paranoid */ verify( ready_schedule_islocked() );
741
742 // Check if there is a sleeping processor
743 processor * p;
744 unsigned idle;
745 unsigned total;
746 [idle, total, p] = query_idles(this->procs);
747
748 // If no one is sleeping, we are done
749 if( idle == 0 ) return;
750
751 // We found a processor, wake it up
752 eventfd_t val;
753 val = 1;
754 eventfd_write( p->idle, val );
755
756 #if !defined(__CFA_NO_STATISTICS__)
757 if( kernelTLS().this_stats ) {
758 __tls_stats()->ready.sleep.wakes++;
759 }
760 else {
761 __atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
762 }
763 #endif
764
765 /* paranoid */ verify( ready_schedule_islocked() );
766 /* paranoid */ verify( ! __preemption_enabled() );
767
768 return;
769}
770
771// Unconditionnaly wake a thread
772void __wake_proc(processor * this) {
773 __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
774
775 disable_interrupts();
776 /* paranoid */ verify( ! __preemption_enabled() );
777 eventfd_t val;
778 val = 1;
779 eventfd_write( this->idle, val );
780 enable_interrupts( __cfaabi_dbg_ctx );
781}
782
783static void mark_idle(__cluster_proc_list & this, processor & proc) {
784 /* paranoid */ verify( ! __preemption_enabled() );
785 lock( this );
786 this.idle++;
787 /* paranoid */ verify( this.idle <= this.total );
788 remove(proc);
789 insert_first(this.idles, proc);
790 unlock( this );
791 /* paranoid */ verify( ! __preemption_enabled() );
792}
793
794static void mark_awake(__cluster_proc_list & this, processor & proc) {
795 /* paranoid */ verify( ! __preemption_enabled() );
796 lock( this );
797 this.idle--;
798 /* paranoid */ verify( this.idle >= 0 );
799 remove(proc);
800 insert_last(this.actives, proc);
801 unlock( this );
802 /* paranoid */ verify( ! __preemption_enabled() );
803}
804
805static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
806 /* paranoid */ verify( ! __preemption_enabled() );
807 /* paranoid */ verify( ready_schedule_islocked() );
808
809 for() {
810 uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
811 if( 1 == (l % 2) ) { Pause(); continue; }
812 unsigned idle = this.idle;
813 unsigned total = this.total;
814 processor * proc = &this.idles`first;
815 // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
816 asm volatile("": : :"memory");
817 if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
818 return [idle, total, proc];
819 }
820
821 /* paranoid */ verify( ready_schedule_islocked() );
822 /* paranoid */ verify( ! __preemption_enabled() );
823}
824
825//=============================================================================================
826// Unexpected Terminating logic
827//=============================================================================================
828void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
829 $thread * thrd = __cfaabi_tls.this_thread;
830
831 if(thrd) {
832 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
833 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
834
835 if ( &thrd->self_cor != thrd->curr_cor ) {
836 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
837 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
838 }
839 else {
840 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
841 }
842 }
843 else {
844 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
845 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
846 }
847}
848
849int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
850 return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
851}
852
853static __spinlock_t kernel_debug_lock;
854
855extern "C" {
856 void __cfaabi_bits_acquire() {
857 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
858 }
859
860 void __cfaabi_bits_release() {
861 unlock( kernel_debug_lock );
862 }
863}
864
865//=============================================================================================
866// Kernel Utilities
867//=============================================================================================
868#if defined(CFA_HAVE_LINUX_IO_URING_H)
869#include "io/types.hfa"
870#endif
871
872static inline bool __maybe_io_drain( processor * proc ) {
873 #if defined(CFA_HAVE_LINUX_IO_URING_H)
874 __cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
875
876 // Check if we should drain the queue
877 $io_context * ctx = proc->io.ctx;
878 unsigned head = *ctx->cq.head;
879 unsigned tail = *ctx->cq.tail;
880 if(head == tail) return false;
881 return __cfa_io_drain( proc );
882 #endif
883}
884
885//-----------------------------------------------------------------------------
886// Debug
887__cfaabi_dbg_debug_do(
888 extern "C" {
889 void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
890 this.prev_name = prev_name;
891 this.prev_thrd = kernelTLS().this_thread;
892 }
893 }
894)
895
896//-----------------------------------------------------------------------------
897// Debug
898bool threading_enabled(void) __attribute__((const)) {
899 return true;
900}
901
902//-----------------------------------------------------------------------------
903// Statistics
904#if !defined(__CFA_NO_STATISTICS__)
905 void print_halts( processor & this ) {
906 this.print_halts = true;
907 }
908
909 void print_stats_now( cluster & this, int flags ) {
910 __print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
911 }
912#endif
913// Local Variables: //
914// mode: c //
915// tab-width: 4 //
916// End: //
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