source: libcfa/src/concurrency/kernel.cfa @ 96bfdde7

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-ast-unique-exprpthread-emulationqualifiedEnum
Last change on this file since 96bfdde7 was 96bfdde7, checked in by Thierry Delisle <tdelisle@…>, 3 years ago

Forgot to add symmetric change to last verify change

  • Property mode set to 100644
File size: 29.6 KB
RevLine 
[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
[ac12f1f]425                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[ab5baab]426                /* 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 );
427                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) || thrd_dst->corctx_flag, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
[b4b63e8]428                /* paranoid */ verify( thrd_dst->context.SP );
[9d6e1b8a]429                /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[8fc652e0]430                /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
431                /* paranoid */ verify( ! __preemption_enabled() );
[75f3522]432
[58d64a4]433                // Reset global state
[8fc652e0]434                kernelTLS().this_thread = 0p;
[3381ed7]435
436                // We just finished running a thread, there are a few things that could have happened.
437                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
438                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
439                // 4 - Preempted
440                // In case 1, we may have won a race so we can't write to the state again.
441                // In case 2, we lost the race so we now own the thread.
442
443                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
444                        // The thread was preempted, reschedule it and reset the flag
[254ad1b]445                        schedule_thread$( thrd_dst );
[3381ed7]446                        break RUNNING;
447                }
[75f3522]448
[3ea8ad1]449                if(unlikely(thrd_dst->state == Halting)) {
[ff79d5e]450                        // The thread has halted, it should never be scheduled/run again
[5afb49a]451                        // finish the thread
452                        __thread_finish( thrd_dst );
[ff79d5e]453                        break RUNNING;
454                }
455
456                /* paranoid */ verify( thrd_dst->state == Active );
457                thrd_dst->state = Blocked;
458
[3381ed7]459                // set state of processor coroutine to active and the thread to inactive
[ff79d5e]460                int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
461                switch(old_ticket) {
[6a77224]462                        case TICKET_RUNNING:
[3381ed7]463                                // This is case 1, the regular case, nothing more is needed
464                                break RUNNING;
[6a77224]465                        case TICKET_UNBLOCK:
[ec43cf9]466                                #if !defined(__CFA_NO_STATISTICS__)
467                                        __tls_stats()->ready.threads.threads++;
[73f4d08]468                                        __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]469                                #endif
[3381ed7]470                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
471                                // In this case, just run it again.
472                                continue RUNNING;
473                        default:
474                                // This makes no sense, something is wrong abort
[ff79d5e]475                                abort();
[3381ed7]476                }
[9f575ea]477        }
[e8e457e]478
[9f575ea]479        // Just before returning to the processor, set the processor coroutine to active
[e8e457e]480        proc_cor->state = Active;
[1eb239e4]481
[dddb3dd0]482        __cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
483
[ec43cf9]484        #if !defined(__CFA_NO_STATISTICS__)
485                __tls_stats()->ready.threads.threads--;
[73f4d08]486                __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]487        #endif
488
[8fc652e0]489        /* paranoid */ verify( ! __preemption_enabled() );
[82c948c]490}
491
[14a61b5]492// KERNEL_ONLY
[b0c7419]493void returnToKernel() {
[8fc652e0]494        /* paranoid */ verify( ! __preemption_enabled() );
495        $coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
496        $thread * thrd_src = kernelTLS().this_thread;
[e8e457e]497
[89eff25]498        __STATS( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]499
[9f575ea]500        // Run the thread on this processor
501        {
502                int local_errno = *__volatile_errno();
503                #if defined( __i386 ) || defined( __x86_64 )
504                        __x87_store;
505                #endif
[b4b63e8]506                /* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]507                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]508                __cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]509                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]510                #if defined( __i386 ) || defined( __x86_64 )
511                        __x87_load;
512                #endif
513                *__volatile_errno() = local_errno;
[8fcbb4c]514        }
[deca0f5]515
[29cb302]516        #if !defined(__CFA_NO_STATISTICS__)
[89eff25]517                /* paranoid */ verify( thrd_src->last_proc != 0p );
518                if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]519                        __tls_stats()->ready.threads.migration++;
520                }
521        #endif
522
[8fc652e0]523        /* paranoid */ verify( ! __preemption_enabled() );
[210b8b3]524        /* 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 );
525        /* 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 );
[c84e80a]526}
527
[8def349]528//-----------------------------------------------------------------------------
529// Scheduler routines
[14a61b5]530// KERNEL ONLY
[e9c0b4c]531static void __schedule_thread( $thread * thrd ) {
[8fc652e0]532        /* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]533        /* paranoid */ verify( ready_schedule_islocked());
[6a490b2]534        /* paranoid */ verify( thrd );
535        /* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]536        /* paranoid */ verify( thrd->curr_cluster );
[3381ed7]537        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]538        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
539                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]540        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]541                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]542        /* paranoid */ #endif
[6a490b2]543        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]544        /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]545
[b808625]546        const bool local = thrd->state != Start;
[ae7be7a]547        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]548
[ec43cf9]549        // Dereference the thread now because once we push it, there is not guaranteed it's still valid.
550        struct cluster * cl = thrd->curr_cluster;
[89eff25]551        __STATS(bool outside = thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]552
[254ad1b]553        // push the thread to the cluster ready-queue
[b808625]554        push( cl, thrd, local );
[32a8b61]555
[254ad1b]556        // variable thrd is no longer safe to use
[734908c]557        thrd = 0xdeaddeaddeaddeadp;
[32a8b61]558
[254ad1b]559        // wake the cluster using the save variable.
560        __wake_one( cl );
[1c273d0]561
[ec43cf9]562        #if !defined(__CFA_NO_STATISTICS__)
563                if( kernelTLS().this_stats ) {
564                        __tls_stats()->ready.threads.threads++;
[89eff25]565                        if(outside) {
566                                __tls_stats()->ready.threads.extunpark++;
567                        }
[73f4d08]568                        __push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", kernelTLS().this_processor );
[ec43cf9]569                }
570                else {
571                        __atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]572                        __atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[73f4d08]573                        __push_stat( cl->stats, cl->stats->ready.threads.threads, true, "Cluster", cl );
[ec43cf9]574                }
575        #endif
576
[254ad1b]577        /* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]578        /* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]579}
580
[254ad1b]581void schedule_thread$( $thread * thrd ) {
582        ready_schedule_lock();
583                __schedule_thread( thrd );
584        ready_schedule_unlock();
585}
586
[14a61b5]587// KERNEL ONLY
[1eb239e4]588static inline $thread * __next_thread(cluster * this) with( *this ) {
[8fc652e0]589        /* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]590
[e873838]591        ready_schedule_lock();
[431cd4f]592                $thread * thrd = pop_fast( this );
[e873838]593        ready_schedule_unlock();
[7768b8d]594
[8fc652e0]595        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]596        return thrd;
[eb2e723]597}
598
[64a7146]599// KERNEL ONLY
[1eb239e4]600static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]601        /* paranoid */ verify( ! __preemption_enabled() );
[64a7146]602
[e873838]603        ready_schedule_lock();
[fc59df78]604                $thread * thrd;
605                for(25) {
606                        thrd = pop_slow( this );
607                        if(thrd) goto RET;
608                }
609                thrd = pop_search( this );
610
611                RET:
[e873838]612        ready_schedule_unlock();
[64a7146]613
[8fc652e0]614        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]615        return thrd;
[64a7146]616}
617
[c6c7e6c]618static inline bool __must_unpark( $thread * thrd ) {
[ff79d5e]619        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
620        switch(old_ticket) {
[6a77224]621                case TICKET_RUNNING:
[3381ed7]622                        // Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]623                        return false;
[6a77224]624                case TICKET_BLOCKED:
[3381ed7]625                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]626                        /* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]627                        return true;
[3381ed7]628                default:
629                        // This makes no sense, something is wrong abort
[7ee8153]630                        abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]631        }
[eb2e723]632}
633
[e9c0b4c]634void __kernel_unpark( $thread * thrd ) {
635        /* paranoid */ verify( ! __preemption_enabled() );
636        /* paranoid */ verify( ready_schedule_islocked());
637
638        if( !thrd ) return;
639
640        if(__must_unpark(thrd)) {
641                // Wake lost the race,
642                __schedule_thread( thrd );
643        }
644
645        /* paranoid */ verify( ready_schedule_islocked());
646        /* paranoid */ verify( ! __preemption_enabled() );
647}
648
[c6c7e6c]649void unpark( $thread * thrd ) {
650        if( !thrd ) return;
[0b33412]651
[c6c7e6c]652        if(__must_unpark(thrd)) {
653                disable_interrupts();
[a3821fa]654                        // Wake lost the race,
[254ad1b]655                        schedule_thread$( thrd );
[a3821fa]656                enable_interrupts(false);
[de6319f]657        }
[eb2e723]658}
[0b33412]659
[e235429]660void park( void ) {
[a3821fa]661        __disable_interrupts_checked();
662                /* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
663                returnToKernel();
664        __enable_interrupts_checked();
[0c78741]665
666}
[09800e9]667
[5afb49a]668extern "C" {
669        // Leave the thread monitor
670        // last routine called by a thread.
671        // Should never return
672        void __cfactx_thrd_leave() {
[8fc652e0]673                $thread * thrd = active_thread();
[5afb49a]674                $monitor * this = &thrd->self_mon;
675
676                // Lock the monitor now
677                lock( this->lock __cfaabi_dbg_ctx2 );
678
679                disable_interrupts();
680
[9d6e1b8a]681                /* paranoid */ verify( ! __preemption_enabled() );
682                /* paranoid */ verify( thrd->state == Active );
683                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
684                /* paranoid */ verify( kernelTLS().this_thread == thrd );
685                /* paranoid */ verify( thrd->context.SP );
686                /* 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 );
687                /* 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 );
688
[3ea8ad1]689                thrd->state = Halting;
[58688bf]690                if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]691                if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
692                if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]693
694                // Leave the thread
695                returnToKernel();
696
697                // Control flow should never reach here!
[9d6e1b8a]698                abort();
[5afb49a]699        }
[09800e9]700}
701
[14a61b5]702// KERNEL ONLY
[3381ed7]703bool force_yield( __Preemption_Reason reason ) {
[a3821fa]704        __disable_interrupts_checked();
705                $thread * thrd = kernelTLS().this_thread;
706                /* paranoid */ verify(thrd->state == Active);
707
708                // SKULLDUGGERY: It is possible that we are preempting this thread just before
709                // it was going to park itself. If that is the case and it is already using the
710                // intrusive fields then we can't use them to preempt the thread
711                // If that is the case, abandon the preemption.
712                bool preempted = false;
713                if(thrd->link.next == 0p) {
714                        preempted = true;
715                        thrd->preempted = reason;
716                        returnToKernel();
717                }
718        __enable_interrupts_checked( false );
[3381ed7]719        return preempted;
[f2b12406]720}
721
[14a61b5]722//=============================================================================================
[92e7631]723// Kernel Idle Sleep
[14a61b5]724//=============================================================================================
[64a7146]725// Wake a thread from the front if there are any
[e873838]726static void __wake_one(cluster * this) {
[8fc652e0]727        /* paranoid */ verify( ! __preemption_enabled() );
[e873838]728        /* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]729
[64a7146]730        // Check if there is a sleeping processor
[1eb239e4]731        processor * p;
732        unsigned idle;
733        unsigned total;
[6a9b12b]734        [idle, total, p] = query_idles(this->procs);
[14a61b5]735
[64a7146]736        // If no one is sleeping, we are done
[1eb239e4]737        if( idle == 0 ) return;
[14a61b5]738
[64a7146]739        // We found a processor, wake it up
[dddb3dd0]740        eventfd_t val;
741        val = 1;
742        eventfd_write( p->idle, val );
[14a61b5]743
[1eb239e4]744        #if !defined(__CFA_NO_STATISTICS__)
[5cb51502]745                if( kernelTLS().this_stats ) {
746                        __tls_stats()->ready.sleep.wakes++;
747                }
748                else {
749                        __atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
750                }
[1eb239e4]751        #endif
752
[e873838]753        /* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]754        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]755
756        return;
[64a7146]757}
[14a61b5]758
[64a7146]759// Unconditionnaly wake a thread
[1eb239e4]760void __wake_proc(processor * this) {
[64a7146]761        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]762
[a3821fa]763        __disable_interrupts_checked();
[8fc652e0]764                /* paranoid */ verify( ! __preemption_enabled() );
[dddb3dd0]765                eventfd_t val;
766                val = 1;
[55d6affb]767                eventfd_write( this->idle, val );
[a3821fa]768        __enable_interrupts_checked();
[92e7631]769}
770
[6a9b12b]771static void mark_idle(__cluster_proc_list & this, processor & proc) {
[8fc652e0]772        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]773        lock( this );
774                this.idle++;
775                /* paranoid */ verify( this.idle <= this.total );
[fc59b580]776                remove(proc);
[6a9b12b]777                insert_first(this.idles, proc);
[1eb239e4]778        unlock( this );
[8fc652e0]779        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]780}
[8e16177]781
[6a9b12b]782static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]783        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]784        lock( this );
785                this.idle--;
786                /* paranoid */ verify( this.idle >= 0 );
787                remove(proc);
[fc59b580]788                insert_last(this.actives, proc);
[1eb239e4]789        unlock( this );
[8fc652e0]790        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]791}
[c34ebf2]792
[6a9b12b]793static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
794        /* paranoid */ verify( ! __preemption_enabled() );
795        /* paranoid */ verify( ready_schedule_islocked() );
796
[1eb239e4]797        for() {
798                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
799                if( 1 == (l % 2) ) { Pause(); continue; }
800                unsigned idle    = this.idle;
801                unsigned total   = this.total;
[6a9b12b]802                processor * proc = &this.idles`first;
[7fdae38]803                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
804                asm volatile("": : :"memory");
[1eb239e4]805                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
806                return [idle, total, proc];
807        }
[6a9b12b]808
809        /* paranoid */ verify( ready_schedule_islocked() );
810        /* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]811}
812
[dbe9b08]813//=============================================================================================
814// Unexpected Terminating logic
815//=============================================================================================
[92bfda0]816void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
817        $thread * thrd = __cfaabi_tls.this_thread;
[9d944b2]818
[de94a60]819        if(thrd) {
820                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]821                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]822
[212c2187]823                if ( &thrd->self_cor != thrd->curr_cor ) {
824                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]825                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]826                }
827                else {
[1c40091]828                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]829                }
[1c273d0]830        }
[9d944b2]831        else {
[de94a60]832                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]833                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]834        }
835}
836
[92bfda0]837int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
838        return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]839}
840
[de94a60]841static __spinlock_t kernel_debug_lock;
842
[9d944b2]843extern "C" {
[1c40091]844        void __cfaabi_bits_acquire() {
[36982fc]845                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]846        }
847
[1c40091]848        void __cfaabi_bits_release() {
[ea7d2b0]849                unlock( kernel_debug_lock );
[9d944b2]850        }
[8118303]851}
852
[fa21ac9]853//=============================================================================================
854// Kernel Utilities
855//=============================================================================================
[dddb3dd0]856#if defined(CFA_HAVE_LINUX_IO_URING_H)
857#include "io/types.hfa"
858#endif
859
[c1c95b1]860static inline bool __maybe_io_drain( processor * proc ) {
[e9c0b4c]861        bool ret = false;
[dddb3dd0]862        #if defined(CFA_HAVE_LINUX_IO_URING_H)
863                __cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
864
865                // Check if we should drain the queue
866                $io_context * ctx = proc->io.ctx;
867                unsigned head = *ctx->cq.head;
868                unsigned tail = *ctx->cq.tail;
[c1c95b1]869                if(head == tail) return false;
[57f70ab]870                #if OLD_MAIN
[b7fd2db6]871                ready_schedule_lock();
[e9c0b4c]872                ret = __cfa_io_drain( proc );
[b7fd2db6]873                ready_schedule_unlock();
[57f70ab]874                #else
875                        ret = __cfa_io_drain( proc );
876        #endif
[dddb3dd0]877        #endif
[e9c0b4c]878        return ret;
[dddb3dd0]879}
880
[de94a60]881//-----------------------------------------------------------------------------
882// Debug
883__cfaabi_dbg_debug_do(
[1997b4e]884        extern "C" {
[ae66348]885                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]886                        this.prev_name = prev_name;
[8fc652e0]887                        this.prev_thrd = kernelTLS().this_thread;
[1997b4e]888                }
[9181f1d]889        }
[f7d6bb0]890)
[2026bb6]891
892//-----------------------------------------------------------------------------
893// Debug
[8c50aed]894bool threading_enabled(void) __attribute__((const)) {
[2026bb6]895        return true;
896}
[c34ebf2]897
898//-----------------------------------------------------------------------------
899// Statistics
900#if !defined(__CFA_NO_STATISTICS__)
901        void print_halts( processor & this ) {
902                this.print_halts = true;
903        }
[58688bf]904
[69914cbc]905        static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
[8464edf]906                /* paranoid */ verify( cltr->stats );
907
908                processor * it = &list`first;
909                for(unsigned i = 0; i < count; i++) {
910                        /* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
911                        /* paranoid */ verify( it->local_data->this_stats );
912                        __tally_stats( cltr->stats, it->local_data->this_stats );
913                        it = &(*it)`next;
914                }
915        }
916
917        void crawl_cluster_stats( cluster & this ) {
918                // Stop the world, otherwise stats could get really messed-up
919                // this doesn't solve all problems but does solve many
920                // so it's probably good enough
921                uint_fast32_t last_size = ready_mutate_lock();
922
923                        crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
924                        crawl_list(&this, this.procs.idles  , this.procs.idle );
925
926                // Unlock the RWlock
927                ready_mutate_unlock( last_size );
928        }
929
930
[58688bf]931        void print_stats_now( cluster & this, int flags ) {
[8464edf]932                crawl_cluster_stats( this );
[1b033b8]933                __print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
934        }
[c34ebf2]935#endif
[8118303]936// Local Variables: //
937// mode: c //
938// tab-width: 4 //
939// End: //
Note: See TracBrowser for help on using the repository browser.