source: libcfa/src/concurrency/kernel.cfa @ 733fd3d

ADTast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-ast-unique-exprpthread-emulationqualifiedEnum
Last change on this file since 733fd3d was 733fd3d, checked in by Thierry Delisle <tdelisle@…>, 3 years ago

Added missing corctx_flag in assertion

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File size: 29.7 KB
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[8118303]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
[75f3522]10// Created On       : Tue Jan 17 12:27:26 2017
[6b0b624]11// Last Modified By : Peter A. Buhr
[0190480]12// Last Modified On : Mon Aug 31 07:08:20 2020
13// Update Count     : 71
[8118303]14//
15
[2026bb6]16#define __cforall_thread__
[4069faad]17// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
[2026bb6]18
[8118303]19//C Includes
[214e8da]20#include <errno.h>
[9d944b2]21#include <stdio.h>
[58b6d1b]22#include <signal.h>
[9d944b2]23#include <unistd.h>
[dddb3dd0]24extern "C" {
25        #include <sys/eventfd.h>
26}
[8118303]27
28//CFA Includes
[73abe95]29#include "kernel_private.hfa"
30#include "preemption.hfa"
[8118303]31
32//Private includes
33#define __CFA_INVOKE_PRIVATE__
34#include "invoke.h"
35
[89eff25]36#if !defined(__CFA_NO_STATISTICS__)
37        #define __STATS( ...) __VA_ARGS__
38#else
39        #define __STATS( ...)
40#endif
[4069faad]41
[deca0f5]42//-----------------------------------------------------------------------------
43// Some assembly required
[1805b1b]44#if defined( __i386 )
[deca0f5]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
[0190480]84#elif defined( __arm__ )
85        #define __x87_store
86        #define __x87_load
87
88#elif defined( __aarch64__ )
[74f5c83]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
[deca0f5]106#else
[0190480]107        #error unsupported hardware architecture
[deca0f5]108#endif
109
[e660761]110extern $thread * mainThread;
111extern processor * mainProcessor;
[2ac095d]112
[92e7631]113//-----------------------------------------------------------------------------
114// Kernel Scheduling logic
115static $thread * __next_thread(cluster * this);
[1eb239e4]116static $thread * __next_thread_slow(cluster * this);
[c6c7e6c]117static inline bool __must_unpark( $thread * thrd ) __attribute((nonnull(1)));
[92e7631]118static void __run_thread(processor * this, $thread * dst);
[e873838]119static void __wake_one(cluster * cltr);
[1eb239e4]120
[6a9b12b]121static void mark_idle (__cluster_proc_list & idles, processor & proc);
122static void mark_awake(__cluster_proc_list & idles, processor & proc);
123static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list idles );
[1eb239e4]124
[dddb3dd0]125extern void __cfa_io_start( processor * );
[c1c95b1]126extern bool __cfa_io_drain( processor * );
[dddb3dd0]127extern void __cfa_io_flush( processor * );
128extern void __cfa_io_stop ( processor * );
[c1c95b1]129static inline bool __maybe_io_drain( processor * );
[dddb3dd0]130
131extern void __disable_interrupts_hard();
132extern void __enable_interrupts_hard();
[c84e80a]133
[a3821fa]134static inline void __disable_interrupts_checked() {
135        /* paranoid */ verify( __preemption_enabled() );
136        disable_interrupts();
137        /* paranoid */ verify( ! __preemption_enabled() );
138}
139
140static inline void __enable_interrupts_checked( bool poll = true ) {
141        /* paranoid */ verify( ! __preemption_enabled() );
142        enable_interrupts( poll );
143        /* paranoid */ verify( __preemption_enabled() );
144}
145
[75f3522]146//=============================================================================================
147// Kernel Scheduling logic
148//=============================================================================================
[8fcbb4c]149//Main of the processor contexts
[83a071f9]150void main(processorCtx_t & runner) {
[21184e3]151        // Because of a bug, we couldn't initialized the seed on construction
152        // Do it here
[8fc652e0]153        __cfaabi_tls.rand_seed ^= rdtscl();
154        __cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
[f2384c9a]155        __tls_rand_advance_bck();
[21184e3]156
[83a071f9]157        processor * this = runner.proc;
[094476d]158        verify(this);
[c81ebf9]159
[dddb3dd0]160        __cfa_io_start( this );
161
[4069faad]162        __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]163        #if !defined(__CFA_NO_STATISTICS__)
164                if( this->print_halts ) {
[c993b15]165                        __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->unique_id, this->name, (void*)this);
[28d73c1]166                }
167        #endif
[b798713]168
[75f3522]169        {
[c81ebf9]170                // Setup preemption data
171                preemption_scope scope = { this };
172
[a5e7233]173                // if we need to run some special setup, now is the time to do it.
174                if(this->init.thrd) {
175                        this->init.thrd->curr_cluster = this->cltr;
176                        __run_thread(this, this->init.thrd);
177                }
[325e6ea]178
[4069faad]179                __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]180
[ac2b598]181                $thread * readyThread = 0p;
[1eb239e4]182                MAIN_LOOP:
183                for() {
[57f70ab]184                        #define OLD_MAIN 1
185                        #if OLD_MAIN
[dddb3dd0]186                        // Check if there is pending io
187                        __maybe_io_drain( this );
188
[92e7631]189                        // Try to get the next thread
[8c50aed]190                        readyThread = __next_thread( this->cltr );
[75f3522]191
[1eb239e4]192                        if( !readyThread ) {
[dddb3dd0]193                                __cfa_io_flush( this );
[1eb239e4]194                                readyThread = __next_thread_slow( this->cltr );
195                        }
[4e6fb8e]196
[1eb239e4]197                        HALT:
198                        if( !readyThread ) {
199                                // Don't block if we are done
200                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]201
[1eb239e4]202                                #if !defined(__CFA_NO_STATISTICS__)
203                                        __tls_stats()->ready.sleep.halts++;
204                                #endif
[398e8e9]205
[1eb239e4]206                                // Push self to idle stack
[6a9b12b]207                                mark_idle(this->cltr->procs, * this);
[398e8e9]208
[1eb239e4]209                                // Confirm the ready-queue is empty
210                                readyThread = __next_thread_slow( this->cltr );
211                                if( readyThread ) {
212                                        // A thread was found, cancel the halt
[6a9b12b]213                                        mark_awake(this->cltr->procs, * this);
[1eb239e4]214
215                                        #if !defined(__CFA_NO_STATISTICS__)
216                                                __tls_stats()->ready.sleep.cancels++;
217                                        #endif
218
219                                        // continue the mai loop
220                                        break HALT;
221                                }
222
223                                #if !defined(__CFA_NO_STATISTICS__)
224                                        if(this->print_halts) {
[c993b15]225                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
[1eb239e4]226                                        }
227                                #endif
228
[dddb3dd0]229                                __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
230
231                                __disable_interrupts_hard();
232                                eventfd_t val;
233                                eventfd_read( this->idle, &val );
234                                __enable_interrupts_hard();
[1eb239e4]235
236                                #if !defined(__CFA_NO_STATISTICS__)
237                                        if(this->print_halts) {
[c993b15]238                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
[1eb239e4]239                                        }
240                                #endif
241
242                                // We were woken up, remove self from idle
[6a9b12b]243                                mark_awake(this->cltr->procs, * this);
[1eb239e4]244
245                                // DON'T just proceed, start looking again
246                                continue MAIN_LOOP;
[64a7146]247                        }
[1eb239e4]248
249                        /* paranoid */ verify( readyThread );
250
[dddb3dd0]251                        // Reset io dirty bit
252                        this->io.dirty = false;
253
[1eb239e4]254                        // We found a thread run it
255                        __run_thread(this, readyThread);
256
257                        // Are we done?
258                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]259
[dddb3dd0]260                        if(this->io.pending && !this->io.dirty) {
261                                __cfa_io_flush( this );
262                        }
[89eff25]263
[34b2796]264                        #else
[57f70ab]265                                #warning new kernel loop
[34b2796]266                        SEARCH: {
267                                /* paranoid */ verify( ! __preemption_enabled() );
268
269                                // First, lock the scheduler since we are searching for a thread
270                                ready_schedule_lock();
271
272                                // Try to get the next thread
273                                readyThread = pop_fast( this->cltr );
274                                if(readyThread) { ready_schedule_unlock(); break SEARCH; }
275
276                                // If we can't find a thread, might as well flush any outstanding I/O
277                                if(this->io.pending) { __cfa_io_flush( this ); }
278
279                                // Spin a little on I/O, just in case
[57f70ab]280                                        for(5) {
[34b2796]281                                        __maybe_io_drain( this );
282                                        readyThread = pop_fast( this->cltr );
283                                        if(readyThread) { ready_schedule_unlock(); break SEARCH; }
284                                }
285
286                                // no luck, try stealing a few times
[57f70ab]287                                        for(5) {
[34b2796]288                                        if( __maybe_io_drain( this ) ) {
289                                                readyThread = pop_fast( this->cltr );
290                                        } else {
291                                                readyThread = pop_slow( this->cltr );
292                                        }
293                                        if(readyThread) { ready_schedule_unlock(); break SEARCH; }
294                                }
295
296                                // still no luck, search for a thread
297                                readyThread = pop_search( this->cltr );
298                                if(readyThread) { ready_schedule_unlock(); break SEARCH; }
299
300                                // Don't block if we are done
301                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
302
303                                __STATS( __tls_stats()->ready.sleep.halts++; )
304
305                                // Push self to idle stack
306                                ready_schedule_unlock();
307                                mark_idle(this->cltr->procs, * this);
308                                ready_schedule_lock();
309
310                                // Confirm the ready-queue is empty
311                                __maybe_io_drain( this );
312                                readyThread = pop_search( this->cltr );
313                                ready_schedule_unlock();
314
315                                if( readyThread ) {
316                                        // A thread was found, cancel the halt
317                                        mark_awake(this->cltr->procs, * this);
318
319                                        __STATS( __tls_stats()->ready.sleep.cancels++; )
320
321                                        // continue the main loop
322                                        break SEARCH;
323                                }
324
[fb4ccdf]325                                        __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl()); )
[34b2796]326                                __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
327
328                                // __disable_interrupts_hard();
329                                eventfd_t val;
330                                eventfd_read( this->idle, &val );
331                                // __enable_interrupts_hard();
332
[fb4ccdf]333                                        __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl()); )
[34b2796]334
335                                // We were woken up, remove self from idle
336                                mark_awake(this->cltr->procs, * this);
337
338                                // DON'T just proceed, start looking again
339                                continue MAIN_LOOP;
340                        }
341
342                RUN_THREAD:
343                        /* paranoid */ verify( ! __preemption_enabled() );
344                        /* paranoid */ verify( readyThread );
345
346                        // Reset io dirty bit
347                        this->io.dirty = false;
348
349                        // We found a thread run it
350                        __run_thread(this, readyThread);
351
352                        // Are we done?
353                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
354
355                        if(this->io.pending && !this->io.dirty) {
356                                __cfa_io_flush( this );
357                        }
358
359                        ready_schedule_lock();
360                        __maybe_io_drain( this );
361                        ready_schedule_unlock();
362                        #endif
[c81ebf9]363                }
364
[4069faad]365                __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]366        }
[8118303]367
[dddb3dd0]368        __cfa_io_stop( this );
369
[454f478]370        post( this->terminated );
[bdeba0b]371
[28d73c1]372        if(this == mainProcessor) {
[6a490b2]373                // HACK : the coroutine context switch expects this_thread to be set
374                // and it make sense for it to be set in all other cases except here
375                // fake it
[8fc652e0]376                __cfaabi_tls.this_thread = mainThread;
[6a490b2]377        }
[7768b8d]378
[4069faad]379        __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]380}
381
[5c1a531]382static int * __volatile_errno() __attribute__((noinline));
383static int * __volatile_errno() { asm(""); return &errno; }
384
[14a61b5]385// KERNEL ONLY
[1c273d0]386// runThread runs a thread by context switching
387// from the processor coroutine to the target thread
[ac2b598]388static void __run_thread(processor * this, $thread * thrd_dst) {
[8fc652e0]389        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]390        /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
391        /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
392        __builtin_prefetch( thrd_dst->context.SP );
393
[dddb3dd0]394        __cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
395
[ac2b598]396        $coroutine * proc_cor = get_coroutine(this->runner);
[8fcbb4c]397
[9f575ea]398        // set state of processor coroutine to inactive
399        verify(proc_cor->state == Active);
[ae7be7a]400        proc_cor->state = Blocked;
[e8e457e]401
[9f575ea]402        // Actually run the thread
[3381ed7]403        RUNNING:  while(true) {
[ff79d5e]404                thrd_dst->preempted = __NO_PREEMPTION;
405                thrd_dst->state = Active;
[e8e457e]406
[58d64a4]407                // Update global state
[8fc652e0]408                kernelTLS().this_thread = thrd_dst;
[75f3522]409
[8fc652e0]410                /* paranoid */ verify( ! __preemption_enabled() );
411                /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]412                /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]413                /* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]414                /* paranoid */ verify( thrd_dst->state != Halted );
[96bfdde7]415                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) || thrd_dst->curr_cor == proc_cor || thrd_dst->corctx_flag, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst ); // add escape condition if we are setting up the processor
416                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit) || thrd_dst->curr_cor == proc_cor || thrd_dst->corctx_flag, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst ); // add escape condition if we are setting up the processor
[ac12f1f]417                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]418
[3381ed7]419
[58d64a4]420
[9f575ea]421                // set context switch to the thread that the processor is executing
[c7a900a]422                __cfactx_switch( &proc_cor->context, &thrd_dst->context );
423                // when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]424
[50871b4]425
426
[ac12f1f]427                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[ab5baab]428                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit) || thrd_dst->corctx_flag, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst );
429                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) || thrd_dst->corctx_flag, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
[b4b63e8]430                /* paranoid */ verify( thrd_dst->context.SP );
[9d6e1b8a]431                /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[8fc652e0]432                /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
433                /* paranoid */ verify( ! __preemption_enabled() );
[75f3522]434
[58d64a4]435                // Reset global state
[8fc652e0]436                kernelTLS().this_thread = 0p;
[3381ed7]437
438                // We just finished running a thread, there are a few things that could have happened.
439                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
440                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
441                // 4 - Preempted
442                // In case 1, we may have won a race so we can't write to the state again.
443                // In case 2, we lost the race so we now own the thread.
444
445                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
446                        // The thread was preempted, reschedule it and reset the flag
[254ad1b]447                        schedule_thread$( thrd_dst );
[3381ed7]448                        break RUNNING;
449                }
[75f3522]450
[3ea8ad1]451                if(unlikely(thrd_dst->state == Halting)) {
[ff79d5e]452                        // The thread has halted, it should never be scheduled/run again
[5afb49a]453                        // finish the thread
454                        __thread_finish( thrd_dst );
[ff79d5e]455                        break RUNNING;
456                }
457
458                /* paranoid */ verify( thrd_dst->state == Active );
459                thrd_dst->state = Blocked;
460
[3381ed7]461                // set state of processor coroutine to active and the thread to inactive
[ff79d5e]462                int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
463                switch(old_ticket) {
[6a77224]464                        case TICKET_RUNNING:
[3381ed7]465                                // This is case 1, the regular case, nothing more is needed
466                                break RUNNING;
[6a77224]467                        case TICKET_UNBLOCK:
[ec43cf9]468                                #if !defined(__CFA_NO_STATISTICS__)
469                                        __tls_stats()->ready.threads.threads++;
[73f4d08]470                                        __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]471                                #endif
[3381ed7]472                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
473                                // In this case, just run it again.
474                                continue RUNNING;
475                        default:
476                                // This makes no sense, something is wrong abort
[ff79d5e]477                                abort();
[3381ed7]478                }
[9f575ea]479        }
[e8e457e]480
[9f575ea]481        // Just before returning to the processor, set the processor coroutine to active
[e8e457e]482        proc_cor->state = Active;
[1eb239e4]483
[dddb3dd0]484        __cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
485
[ec43cf9]486        #if !defined(__CFA_NO_STATISTICS__)
487                __tls_stats()->ready.threads.threads--;
[73f4d08]488                __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]489        #endif
490
[8fc652e0]491        /* paranoid */ verify( ! __preemption_enabled() );
[82c948c]492}
493
[14a61b5]494// KERNEL_ONLY
[b0c7419]495void returnToKernel() {
[8fc652e0]496        /* paranoid */ verify( ! __preemption_enabled() );
497        $coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
498        $thread * thrd_src = kernelTLS().this_thread;
[e8e457e]499
[89eff25]500        __STATS( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]501
[9f575ea]502        // Run the thread on this processor
503        {
504                int local_errno = *__volatile_errno();
505                #if defined( __i386 ) || defined( __x86_64 )
506                        __x87_store;
507                #endif
[b4b63e8]508                /* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]509                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]510                __cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]511                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]512                #if defined( __i386 ) || defined( __x86_64 )
513                        __x87_load;
514                #endif
515                *__volatile_errno() = local_errno;
[8fcbb4c]516        }
[deca0f5]517
[29cb302]518        #if !defined(__CFA_NO_STATISTICS__)
[89eff25]519                /* paranoid */ verify( thrd_src->last_proc != 0p );
520                if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]521                        __tls_stats()->ready.threads.migration++;
522                }
523        #endif
524
[8fc652e0]525        /* paranoid */ verify( ! __preemption_enabled() );
[733fd3d]526        /* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) < ((uintptr_t)__get_stack(thrd_src->curr_cor)->base ) || thrd_src->corctx_flag, "ERROR : Returning $thread %p has been corrupted.\n StackPointer too small.\n", thrd_src );
527        /* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) > ((uintptr_t)__get_stack(thrd_src->curr_cor)->limit) || thrd_src->corctx_flag, "ERROR : Returning $thread %p has been corrupted.\n StackPointer too large.\n", thrd_src );
[c84e80a]528}
529
[8def349]530//-----------------------------------------------------------------------------
531// Scheduler routines
[14a61b5]532// KERNEL ONLY
[e9c0b4c]533static void __schedule_thread( $thread * thrd ) {
[8fc652e0]534        /* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]535        /* paranoid */ verify( ready_schedule_islocked());
[6a490b2]536        /* paranoid */ verify( thrd );
537        /* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]538        /* paranoid */ verify( thrd->curr_cluster );
[3381ed7]539        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]540        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
541                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]542        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]543                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]544        /* paranoid */ #endif
[6a490b2]545        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]546        /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]547
[b808625]548        const bool local = thrd->state != Start;
[ae7be7a]549        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]550
[ec43cf9]551        // Dereference the thread now because once we push it, there is not guaranteed it's still valid.
552        struct cluster * cl = thrd->curr_cluster;
[89eff25]553        __STATS(bool outside = thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]554
[254ad1b]555        // push the thread to the cluster ready-queue
[b808625]556        push( cl, thrd, local );
[32a8b61]557
[254ad1b]558        // variable thrd is no longer safe to use
[734908c]559        thrd = 0xdeaddeaddeaddeadp;
[32a8b61]560
[254ad1b]561        // wake the cluster using the save variable.
562        __wake_one( cl );
[1c273d0]563
[ec43cf9]564        #if !defined(__CFA_NO_STATISTICS__)
565                if( kernelTLS().this_stats ) {
566                        __tls_stats()->ready.threads.threads++;
[89eff25]567                        if(outside) {
568                                __tls_stats()->ready.threads.extunpark++;
569                        }
[73f4d08]570                        __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", kernelTLS().this_processor );
[ec43cf9]571                }
572                else {
573                        __atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]574                        __atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[73f4d08]575                        __push_stat( cl->stats, cl->stats->ready.threads.threads, true, "Cluster", cl );
[ec43cf9]576                }
577        #endif
578
[254ad1b]579        /* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]580        /* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]581}
582
[254ad1b]583void schedule_thread$( $thread * thrd ) {
584        ready_schedule_lock();
585                __schedule_thread( thrd );
586        ready_schedule_unlock();
587}
588
[14a61b5]589// KERNEL ONLY
[1eb239e4]590static inline $thread * __next_thread(cluster * this) with( *this ) {
[8fc652e0]591        /* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]592
[e873838]593        ready_schedule_lock();
[431cd4f]594                $thread * thrd = pop_fast( this );
[e873838]595        ready_schedule_unlock();
[7768b8d]596
[8fc652e0]597        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]598        return thrd;
[eb2e723]599}
600
[64a7146]601// KERNEL ONLY
[1eb239e4]602static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]603        /* paranoid */ verify( ! __preemption_enabled() );
[64a7146]604
[e873838]605        ready_schedule_lock();
[fc59df78]606                $thread * thrd;
607                for(25) {
608                        thrd = pop_slow( this );
609                        if(thrd) goto RET;
610                }
611                thrd = pop_search( this );
612
613                RET:
[e873838]614        ready_schedule_unlock();
[64a7146]615
[8fc652e0]616        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]617        return thrd;
[64a7146]618}
619
[c6c7e6c]620static inline bool __must_unpark( $thread * thrd ) {
[ff79d5e]621        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
622        switch(old_ticket) {
[6a77224]623                case TICKET_RUNNING:
[3381ed7]624                        // Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]625                        return false;
[6a77224]626                case TICKET_BLOCKED:
[3381ed7]627                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]628                        /* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]629                        return true;
[3381ed7]630                default:
631                        // This makes no sense, something is wrong abort
[7ee8153]632                        abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]633        }
[eb2e723]634}
635
[e9c0b4c]636void __kernel_unpark( $thread * thrd ) {
637        /* paranoid */ verify( ! __preemption_enabled() );
638        /* paranoid */ verify( ready_schedule_islocked());
639
640        if( !thrd ) return;
641
642        if(__must_unpark(thrd)) {
643                // Wake lost the race,
644                __schedule_thread( thrd );
645        }
646
647        /* paranoid */ verify( ready_schedule_islocked());
648        /* paranoid */ verify( ! __preemption_enabled() );
649}
650
[c6c7e6c]651void unpark( $thread * thrd ) {
652        if( !thrd ) return;
[0b33412]653
[c6c7e6c]654        if(__must_unpark(thrd)) {
655                disable_interrupts();
[a3821fa]656                        // Wake lost the race,
[254ad1b]657                        schedule_thread$( thrd );
[a3821fa]658                enable_interrupts(false);
[de6319f]659        }
[eb2e723]660}
[0b33412]661
[e235429]662void park( void ) {
[a3821fa]663        __disable_interrupts_checked();
664                /* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
665                returnToKernel();
666        __enable_interrupts_checked();
[0c78741]667
668}
[09800e9]669
[5afb49a]670extern "C" {
671        // Leave the thread monitor
672        // last routine called by a thread.
673        // Should never return
674        void __cfactx_thrd_leave() {
[8fc652e0]675                $thread * thrd = active_thread();
[5afb49a]676                $monitor * this = &thrd->self_mon;
677
678                // Lock the monitor now
679                lock( this->lock __cfaabi_dbg_ctx2 );
680
681                disable_interrupts();
682
[9d6e1b8a]683                /* paranoid */ verify( ! __preemption_enabled() );
684                /* paranoid */ verify( thrd->state == Active );
685                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
686                /* paranoid */ verify( kernelTLS().this_thread == thrd );
687                /* paranoid */ verify( thrd->context.SP );
688                /* 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 );
689                /* 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 );
690
[3ea8ad1]691                thrd->state = Halting;
[58688bf]692                if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]693                if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
694                if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]695
696                // Leave the thread
697                returnToKernel();
698
699                // Control flow should never reach here!
[9d6e1b8a]700                abort();
[5afb49a]701        }
[09800e9]702}
703
[14a61b5]704// KERNEL ONLY
[3381ed7]705bool force_yield( __Preemption_Reason reason ) {
[a3821fa]706        __disable_interrupts_checked();
707                $thread * thrd = kernelTLS().this_thread;
708                /* paranoid */ verify(thrd->state == Active);
709
710                // SKULLDUGGERY: It is possible that we are preempting this thread just before
711                // it was going to park itself. If that is the case and it is already using the
712                // intrusive fields then we can't use them to preempt the thread
713                // If that is the case, abandon the preemption.
714                bool preempted = false;
715                if(thrd->link.next == 0p) {
716                        preempted = true;
717                        thrd->preempted = reason;
718                        returnToKernel();
719                }
720        __enable_interrupts_checked( false );
[3381ed7]721        return preempted;
[f2b12406]722}
723
[14a61b5]724//=============================================================================================
[92e7631]725// Kernel Idle Sleep
[14a61b5]726//=============================================================================================
[64a7146]727// Wake a thread from the front if there are any
[e873838]728static void __wake_one(cluster * this) {
[8fc652e0]729        /* paranoid */ verify( ! __preemption_enabled() );
[e873838]730        /* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]731
[64a7146]732        // Check if there is a sleeping processor
[1eb239e4]733        processor * p;
734        unsigned idle;
735        unsigned total;
[6a9b12b]736        [idle, total, p] = query_idles(this->procs);
[14a61b5]737
[64a7146]738        // If no one is sleeping, we are done
[1eb239e4]739        if( idle == 0 ) return;
[14a61b5]740
[64a7146]741        // We found a processor, wake it up
[dddb3dd0]742        eventfd_t val;
743        val = 1;
744        eventfd_write( p->idle, val );
[14a61b5]745
[1eb239e4]746        #if !defined(__CFA_NO_STATISTICS__)
[5cb51502]747                if( kernelTLS().this_stats ) {
748                        __tls_stats()->ready.sleep.wakes++;
749                }
750                else {
751                        __atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
752                }
[1eb239e4]753        #endif
754
[e873838]755        /* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]756        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]757
758        return;
[64a7146]759}
[14a61b5]760
[64a7146]761// Unconditionnaly wake a thread
[1eb239e4]762void __wake_proc(processor * this) {
[64a7146]763        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]764
[a3821fa]765        __disable_interrupts_checked();
[8fc652e0]766                /* paranoid */ verify( ! __preemption_enabled() );
[dddb3dd0]767                eventfd_t val;
768                val = 1;
[55d6affb]769                eventfd_write( this->idle, val );
[a3821fa]770        __enable_interrupts_checked();
[92e7631]771}
772
[6a9b12b]773static void mark_idle(__cluster_proc_list & this, processor & proc) {
[8fc652e0]774        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]775        lock( this );
776                this.idle++;
777                /* paranoid */ verify( this.idle <= this.total );
[fc59b580]778                remove(proc);
[6a9b12b]779                insert_first(this.idles, proc);
[1eb239e4]780        unlock( this );
[8fc652e0]781        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]782}
[8e16177]783
[6a9b12b]784static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]785        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]786        lock( this );
787                this.idle--;
788                /* paranoid */ verify( this.idle >= 0 );
789                remove(proc);
[fc59b580]790                insert_last(this.actives, proc);
[1eb239e4]791        unlock( this );
[8fc652e0]792        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]793}
[c34ebf2]794
[6a9b12b]795static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
796        /* paranoid */ verify( ! __preemption_enabled() );
797        /* paranoid */ verify( ready_schedule_islocked() );
798
[1eb239e4]799        for() {
800                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
801                if( 1 == (l % 2) ) { Pause(); continue; }
802                unsigned idle    = this.idle;
803                unsigned total   = this.total;
[6a9b12b]804                processor * proc = &this.idles`first;
[7fdae38]805                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
806                asm volatile("": : :"memory");
[1eb239e4]807                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
808                return [idle, total, proc];
809        }
[6a9b12b]810
811        /* paranoid */ verify( ready_schedule_islocked() );
812        /* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]813}
814
[dbe9b08]815//=============================================================================================
816// Unexpected Terminating logic
817//=============================================================================================
[92bfda0]818void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
819        $thread * thrd = __cfaabi_tls.this_thread;
[9d944b2]820
[de94a60]821        if(thrd) {
822                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]823                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]824
[212c2187]825                if ( &thrd->self_cor != thrd->curr_cor ) {
826                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]827                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]828                }
829                else {
[1c40091]830                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]831                }
[1c273d0]832        }
[9d944b2]833        else {
[de94a60]834                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]835                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]836        }
837}
838
[92bfda0]839int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
840        return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]841}
842
[de94a60]843static __spinlock_t kernel_debug_lock;
844
[9d944b2]845extern "C" {
[1c40091]846        void __cfaabi_bits_acquire() {
[36982fc]847                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]848        }
849
[1c40091]850        void __cfaabi_bits_release() {
[ea7d2b0]851                unlock( kernel_debug_lock );
[9d944b2]852        }
[8118303]853}
854
[fa21ac9]855//=============================================================================================
856// Kernel Utilities
857//=============================================================================================
[dddb3dd0]858#if defined(CFA_HAVE_LINUX_IO_URING_H)
859#include "io/types.hfa"
860#endif
861
[c1c95b1]862static inline bool __maybe_io_drain( processor * proc ) {
[e9c0b4c]863        bool ret = false;
[dddb3dd0]864        #if defined(CFA_HAVE_LINUX_IO_URING_H)
865                __cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
866
867                // Check if we should drain the queue
868                $io_context * ctx = proc->io.ctx;
869                unsigned head = *ctx->cq.head;
870                unsigned tail = *ctx->cq.tail;
[c1c95b1]871                if(head == tail) return false;
[57f70ab]872                #if OLD_MAIN
[b7fd2db6]873                ready_schedule_lock();
[e9c0b4c]874                ret = __cfa_io_drain( proc );
[b7fd2db6]875                ready_schedule_unlock();
[57f70ab]876                #else
877                        ret = __cfa_io_drain( proc );
878        #endif
[dddb3dd0]879        #endif
[e9c0b4c]880        return ret;
[dddb3dd0]881}
882
[de94a60]883//-----------------------------------------------------------------------------
884// Debug
885__cfaabi_dbg_debug_do(
[1997b4e]886        extern "C" {
[ae66348]887                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]888                        this.prev_name = prev_name;
[8fc652e0]889                        this.prev_thrd = kernelTLS().this_thread;
[1997b4e]890                }
[9181f1d]891        }
[f7d6bb0]892)
[2026bb6]893
894//-----------------------------------------------------------------------------
895// Debug
[8c50aed]896bool threading_enabled(void) __attribute__((const)) {
[2026bb6]897        return true;
898}
[c34ebf2]899
900//-----------------------------------------------------------------------------
901// Statistics
902#if !defined(__CFA_NO_STATISTICS__)
903        void print_halts( processor & this ) {
904                this.print_halts = true;
905        }
[58688bf]906
[69914cbc]907        static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
[8464edf]908                /* paranoid */ verify( cltr->stats );
909
910                processor * it = &list`first;
911                for(unsigned i = 0; i < count; i++) {
912                        /* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
913                        /* paranoid */ verify( it->local_data->this_stats );
914                        __tally_stats( cltr->stats, it->local_data->this_stats );
915                        it = &(*it)`next;
916                }
917        }
918
919        void crawl_cluster_stats( cluster & this ) {
920                // Stop the world, otherwise stats could get really messed-up
921                // this doesn't solve all problems but does solve many
922                // so it's probably good enough
923                uint_fast32_t last_size = ready_mutate_lock();
924
925                        crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
926                        crawl_list(&this, this.procs.idles  , this.procs.idle );
927
928                // Unlock the RWlock
929                ready_mutate_unlock( last_size );
930        }
931
932
[58688bf]933        void print_stats_now( cluster & this, int flags ) {
[8464edf]934                crawl_cluster_stats( this );
[1b033b8]935                __print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
936        }
[c34ebf2]937#endif
[8118303]938// Local Variables: //
939// mode: c //
940// tab-width: 4 //
941// End: //
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