source: libcfa/src/concurrency/kernel.cfa @ 24e321c

ADTast-experimentalenumforall-pointer-decaypthread-emulationqualifiedEnum
Last change on this file since 24e321c was 24e321c, checked in by Thierry Delisle <tdelisle@…>, 3 years ago

Unpark now takes a hint on locality.

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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__
[43784ac]17#define _GNU_SOURCE
18
[4069faad]19// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
[2026bb6]20
[8118303]21//C Includes
[214e8da]22#include <errno.h>
[9d944b2]23#include <stdio.h>
[445f984]24#include <string.h>
[58b6d1b]25#include <signal.h>
[9d944b2]26#include <unistd.h>
[dddb3dd0]27extern "C" {
28        #include <sys/eventfd.h>
29}
[8118303]30
31//CFA Includes
[73abe95]32#include "kernel_private.hfa"
33#include "preemption.hfa"
[445f984]34#include "strstream.hfa"
35#include "device/cpu.hfa"
[8118303]36
37//Private includes
38#define __CFA_INVOKE_PRIVATE__
39#include "invoke.h"
40
[89eff25]41#if !defined(__CFA_NO_STATISTICS__)
42        #define __STATS( ...) __VA_ARGS__
43#else
44        #define __STATS( ...)
45#endif
[4069faad]46
[deca0f5]47//-----------------------------------------------------------------------------
48// Some assembly required
[1805b1b]49#if defined( __i386 )
[deca0f5]50        // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
51        // fcw  : X87 FPU control word (preserved across function calls)
52        #define __x87_store         \
53                uint32_t __mxcr;      \
54                uint16_t __fcw;       \
55                __asm__ volatile (    \
56                        "stmxcsr %0\n"  \
57                        "fnstcw  %1\n"  \
58                        : "=m" (__mxcr),\
59                                "=m" (__fcw)  \
60                )
61
62        #define __x87_load         \
63                __asm__ volatile (   \
64                        "fldcw  %1\n"  \
65                        "ldmxcsr %0\n" \
66                        ::"m" (__mxcr),\
67                                "m" (__fcw)  \
68                )
69
70#elif defined( __x86_64 )
71        #define __x87_store         \
72                uint32_t __mxcr;      \
73                uint16_t __fcw;       \
74                __asm__ volatile (    \
75                        "stmxcsr %0\n"  \
76                        "fnstcw  %1\n"  \
77                        : "=m" (__mxcr),\
78                                "=m" (__fcw)  \
79                )
80
81        #define __x87_load          \
82                __asm__ volatile (    \
83                        "fldcw  %1\n"   \
84                        "ldmxcsr %0\n"  \
85                        :: "m" (__mxcr),\
86                                "m" (__fcw)  \
87                )
88
[0190480]89#elif defined( __arm__ )
90        #define __x87_store
91        #define __x87_load
92
93#elif defined( __aarch64__ )
[74f5c83]94        #define __x87_store              \
95                uint32_t __fpcntl[2];    \
96                __asm__ volatile (    \
97                        "mrs x9, FPCR\n" \
98                        "mrs x10, FPSR\n"  \
99                        "stp x9, x10, %0\n"  \
100                        : "=m" (__fpcntl) : : "x9", "x10" \
101                )
102
103        #define __x87_load         \
104                __asm__ volatile (    \
105                        "ldp x9, x10, %0\n"  \
106                        "msr FPSR, x10\n"  \
107                        "msr FPCR, x9\n" \
108                : "=m" (__fpcntl) : : "x9", "x10" \
109                )
110
[deca0f5]111#else
[0190480]112        #error unsupported hardware architecture
[deca0f5]113#endif
114
[e84ab3d]115extern thread$ * mainThread;
[e660761]116extern processor * mainProcessor;
[2ac095d]117
[92e7631]118//-----------------------------------------------------------------------------
119// Kernel Scheduling logic
[e84ab3d]120static thread$ * __next_thread(cluster * this);
121static thread$ * __next_thread_slow(cluster * this);
122static inline bool __must_unpark( thread$ * thrd ) __attribute((nonnull(1)));
123static void __run_thread(processor * this, thread$ * dst);
[e873838]124static void __wake_one(cluster * cltr);
[1eb239e4]125
[6a9b12b]126static void mark_idle (__cluster_proc_list & idles, processor & proc);
127static void mark_awake(__cluster_proc_list & idles, processor & proc);
128static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list idles );
[1eb239e4]129
[dddb3dd0]130extern void __cfa_io_start( processor * );
[c1c95b1]131extern bool __cfa_io_drain( processor * );
[dddb3dd0]132extern void __cfa_io_flush( processor * );
133extern void __cfa_io_stop ( processor * );
[c1c95b1]134static inline bool __maybe_io_drain( processor * );
[dddb3dd0]135
136extern void __disable_interrupts_hard();
137extern void __enable_interrupts_hard();
[c84e80a]138
[a3821fa]139static inline void __disable_interrupts_checked() {
140        /* paranoid */ verify( __preemption_enabled() );
141        disable_interrupts();
142        /* paranoid */ verify( ! __preemption_enabled() );
143}
144
145static inline void __enable_interrupts_checked( bool poll = true ) {
146        /* paranoid */ verify( ! __preemption_enabled() );
147        enable_interrupts( poll );
148        /* paranoid */ verify( __preemption_enabled() );
149}
150
[75f3522]151//=============================================================================================
152// Kernel Scheduling logic
153//=============================================================================================
[8fcbb4c]154//Main of the processor contexts
[83a071f9]155void main(processorCtx_t & runner) {
[21184e3]156        // Because of a bug, we couldn't initialized the seed on construction
157        // Do it here
[8fc652e0]158        __cfaabi_tls.rand_seed ^= rdtscl();
159        __cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
[f2384c9a]160        __tls_rand_advance_bck();
[21184e3]161
[83a071f9]162        processor * this = runner.proc;
[094476d]163        verify(this);
[c81ebf9]164
[dddb3dd0]165        __cfa_io_start( this );
166
[4069faad]167        __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]168        #if !defined(__CFA_NO_STATISTICS__)
169                if( this->print_halts ) {
[c993b15]170                        __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->unique_id, this->name, (void*)this);
[28d73c1]171                }
172        #endif
[b798713]173
[75f3522]174        {
[c81ebf9]175                // Setup preemption data
176                preemption_scope scope = { this };
177
[a5e7233]178                // if we need to run some special setup, now is the time to do it.
179                if(this->init.thrd) {
180                        this->init.thrd->curr_cluster = this->cltr;
181                        __run_thread(this, this->init.thrd);
182                }
[325e6ea]183
[4069faad]184                __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]185
[e84ab3d]186                thread$ * readyThread = 0p;
[1eb239e4]187                MAIN_LOOP:
188                for() {
[57f70ab]189                        #define OLD_MAIN 1
190                        #if OLD_MAIN
[dddb3dd0]191                        // Check if there is pending io
192                        __maybe_io_drain( this );
193
[92e7631]194                        // Try to get the next thread
[8c50aed]195                        readyThread = __next_thread( this->cltr );
[75f3522]196
[1eb239e4]197                        if( !readyThread ) {
[dddb3dd0]198                                __cfa_io_flush( this );
[1eb239e4]199                                readyThread = __next_thread_slow( this->cltr );
200                        }
[4e6fb8e]201
[1eb239e4]202                        HALT:
203                        if( !readyThread ) {
204                                // Don't block if we are done
205                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]206
[1eb239e4]207                                #if !defined(__CFA_NO_STATISTICS__)
208                                        __tls_stats()->ready.sleep.halts++;
209                                #endif
[398e8e9]210
[1eb239e4]211                                // Push self to idle stack
[6a9b12b]212                                mark_idle(this->cltr->procs, * this);
[398e8e9]213
[1eb239e4]214                                // Confirm the ready-queue is empty
215                                readyThread = __next_thread_slow( this->cltr );
216                                if( readyThread ) {
217                                        // A thread was found, cancel the halt
[6a9b12b]218                                        mark_awake(this->cltr->procs, * this);
[1eb239e4]219
220                                        #if !defined(__CFA_NO_STATISTICS__)
221                                                __tls_stats()->ready.sleep.cancels++;
222                                        #endif
223
224                                        // continue the mai loop
225                                        break HALT;
226                                }
227
228                                #if !defined(__CFA_NO_STATISTICS__)
229                                        if(this->print_halts) {
[c993b15]230                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
[1eb239e4]231                                        }
232                                #endif
233
[dddb3dd0]234                                __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
235
[56e5b24]236                                {
237                                        eventfd_t val;
238                                        ssize_t ret = read( this->idle, &val, sizeof(val) );
239                                        if(ret < 0) {
240                                                switch((int)errno) {
241                                                case EAGAIN:
242                                                #if EAGAIN != EWOULDBLOCK
243                                                        case EWOULDBLOCK:
244                                                #endif
245                                                case EINTR:
246                                                        // No need to do anything special here, just assume it's a legitimate wake-up
247                                                        break;
248                                                default:
249                                                        abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
250                                                }
251                                        }
252                                }
[1eb239e4]253
254                                #if !defined(__CFA_NO_STATISTICS__)
255                                        if(this->print_halts) {
[c993b15]256                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
[1eb239e4]257                                        }
258                                #endif
259
260                                // We were woken up, remove self from idle
[6a9b12b]261                                mark_awake(this->cltr->procs, * this);
[1eb239e4]262
263                                // DON'T just proceed, start looking again
264                                continue MAIN_LOOP;
[64a7146]265                        }
[1eb239e4]266
267                        /* paranoid */ verify( readyThread );
268
[dddb3dd0]269                        // Reset io dirty bit
270                        this->io.dirty = false;
271
[1eb239e4]272                        // We found a thread run it
273                        __run_thread(this, readyThread);
274
275                        // Are we done?
276                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]277
[dddb3dd0]278                        if(this->io.pending && !this->io.dirty) {
279                                __cfa_io_flush( this );
280                        }
[89eff25]281
[34b2796]282                        #else
[57f70ab]283                                #warning new kernel loop
[34b2796]284                        SEARCH: {
285                                /* paranoid */ verify( ! __preemption_enabled() );
286
287                                // First, lock the scheduler since we are searching for a thread
288                                ready_schedule_lock();
289
290                                // Try to get the next thread
291                                readyThread = pop_fast( this->cltr );
292                                if(readyThread) { ready_schedule_unlock(); break SEARCH; }
293
294                                // If we can't find a thread, might as well flush any outstanding I/O
295                                if(this->io.pending) { __cfa_io_flush( this ); }
296
297                                // Spin a little on I/O, just in case
[12daa43]298                                for(5) {
[34b2796]299                                        __maybe_io_drain( this );
300                                        readyThread = pop_fast( this->cltr );
301                                        if(readyThread) { ready_schedule_unlock(); break SEARCH; }
302                                }
303
304                                // no luck, try stealing a few times
[12daa43]305                                for(5) {
[34b2796]306                                        if( __maybe_io_drain( this ) ) {
307                                                readyThread = pop_fast( this->cltr );
308                                        } else {
309                                                readyThread = pop_slow( this->cltr );
310                                        }
311                                        if(readyThread) { ready_schedule_unlock(); break SEARCH; }
312                                }
313
314                                // still no luck, search for a thread
315                                readyThread = pop_search( this->cltr );
316                                if(readyThread) { ready_schedule_unlock(); break SEARCH; }
317
318                                // Don't block if we are done
319                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
320
321                                __STATS( __tls_stats()->ready.sleep.halts++; )
322
323                                // Push self to idle stack
324                                ready_schedule_unlock();
325                                mark_idle(this->cltr->procs, * this);
326                                ready_schedule_lock();
327
328                                // Confirm the ready-queue is empty
329                                __maybe_io_drain( this );
330                                readyThread = pop_search( this->cltr );
331                                ready_schedule_unlock();
332
333                                if( readyThread ) {
334                                        // A thread was found, cancel the halt
335                                        mark_awake(this->cltr->procs, * this);
336
337                                        __STATS( __tls_stats()->ready.sleep.cancels++; )
338
339                                        // continue the main loop
340                                        break SEARCH;
341                                }
342
[abcae55]343                                __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl()); )
[34b2796]344                                __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
345
[ec421636]346                                {
347                                        eventfd_t val;
348                                        ssize_t ret = read( this->idle, &val, sizeof(val) );
349                                        if(ret < 0) {
350                                                switch((int)errno) {
351                                                case EAGAIN:
352                                                #if EAGAIN != EWOULDBLOCK
353                                                        case EWOULDBLOCK:
354                                                #endif
355                                                case EINTR:
356                                                        // No need to do anything special here, just assume it's a legitimate wake-up
357                                                        break;
358                                                default:
359                                                        abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
360                                                }
361                                        }
362                                }
[34b2796]363
[fb4ccdf]364                                        __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl()); )
[34b2796]365
366                                // We were woken up, remove self from idle
367                                mark_awake(this->cltr->procs, * this);
368
369                                // DON'T just proceed, start looking again
370                                continue MAIN_LOOP;
371                        }
372
373                RUN_THREAD:
374                        /* paranoid */ verify( ! __preemption_enabled() );
375                        /* paranoid */ verify( readyThread );
376
377                        // Reset io dirty bit
378                        this->io.dirty = false;
379
380                        // We found a thread run it
381                        __run_thread(this, readyThread);
382
383                        // Are we done?
384                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
385
386                        if(this->io.pending && !this->io.dirty) {
387                                __cfa_io_flush( this );
388                        }
389
390                        ready_schedule_lock();
391                        __maybe_io_drain( this );
392                        ready_schedule_unlock();
393                        #endif
[c81ebf9]394                }
395
[4069faad]396                __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]397        }
[8118303]398
[dddb3dd0]399        __cfa_io_stop( this );
400
[454f478]401        post( this->terminated );
[bdeba0b]402
[28d73c1]403        if(this == mainProcessor) {
[6a490b2]404                // HACK : the coroutine context switch expects this_thread to be set
405                // and it make sense for it to be set in all other cases except here
406                // fake it
[8fc652e0]407                __cfaabi_tls.this_thread = mainThread;
[6a490b2]408        }
[7768b8d]409
[4069faad]410        __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]411}
412
[5c1a531]413static int * __volatile_errno() __attribute__((noinline));
414static int * __volatile_errno() { asm(""); return &errno; }
415
[14a61b5]416// KERNEL ONLY
[1c273d0]417// runThread runs a thread by context switching
418// from the processor coroutine to the target thread
[e84ab3d]419static void __run_thread(processor * this, thread$ * thrd_dst) {
[8fc652e0]420        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]421        /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
422        /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
423        __builtin_prefetch( thrd_dst->context.SP );
424
[dddb3dd0]425        __cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
426
[e84ab3d]427        coroutine$ * proc_cor = get_coroutine(this->runner);
[8fcbb4c]428
[9f575ea]429        // set state of processor coroutine to inactive
430        verify(proc_cor->state == Active);
[ae7be7a]431        proc_cor->state = Blocked;
[e8e457e]432
[9f575ea]433        // Actually run the thread
[3381ed7]434        RUNNING:  while(true) {
[ff79d5e]435                thrd_dst->preempted = __NO_PREEMPTION;
436                thrd_dst->state = Active;
[e8e457e]437
[58d64a4]438                // Update global state
[8fc652e0]439                kernelTLS().this_thread = thrd_dst;
[75f3522]440
[8fc652e0]441                /* paranoid */ verify( ! __preemption_enabled() );
442                /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]443                /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]444                /* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]445                /* paranoid */ verify( thrd_dst->state != Halted );
[e84ab3d]446                /* 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
447                /* 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]448                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]449
[3381ed7]450
[58d64a4]451
[9f575ea]452                // set context switch to the thread that the processor is executing
[c7a900a]453                __cfactx_switch( &proc_cor->context, &thrd_dst->context );
454                // when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]455
[50871b4]456
457
[ac12f1f]458                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[e84ab3d]459                /* 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 );
460                /* 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]461                /* paranoid */ verify( thrd_dst->context.SP );
[9d6e1b8a]462                /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[8fc652e0]463                /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
464                /* paranoid */ verify( ! __preemption_enabled() );
[75f3522]465
[58d64a4]466                // Reset global state
[8fc652e0]467                kernelTLS().this_thread = 0p;
[3381ed7]468
469                // We just finished running a thread, there are a few things that could have happened.
470                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
471                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
472                // 4 - Preempted
473                // In case 1, we may have won a race so we can't write to the state again.
474                // In case 2, we lost the race so we now own the thread.
475
476                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
477                        // The thread was preempted, reschedule it and reset the flag
[24e321c]478                        schedule_thread$( thrd_dst, UNPARK_LOCAL );
[3381ed7]479                        break RUNNING;
480                }
[75f3522]481
[3ea8ad1]482                if(unlikely(thrd_dst->state == Halting)) {
[ff79d5e]483                        // The thread has halted, it should never be scheduled/run again
[5afb49a]484                        // finish the thread
485                        __thread_finish( thrd_dst );
[ff79d5e]486                        break RUNNING;
487                }
488
489                /* paranoid */ verify( thrd_dst->state == Active );
490                thrd_dst->state = Blocked;
491
[3381ed7]492                // set state of processor coroutine to active and the thread to inactive
[ff79d5e]493                int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
494                switch(old_ticket) {
[6a77224]495                        case TICKET_RUNNING:
[3381ed7]496                                // This is case 1, the regular case, nothing more is needed
497                                break RUNNING;
[6a77224]498                        case TICKET_UNBLOCK:
[ec43cf9]499                                #if !defined(__CFA_NO_STATISTICS__)
500                                        __tls_stats()->ready.threads.threads++;
501                                #endif
[3381ed7]502                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
503                                // In this case, just run it again.
504                                continue RUNNING;
505                        default:
506                                // This makes no sense, something is wrong abort
[ff79d5e]507                                abort();
[3381ed7]508                }
[9f575ea]509        }
[e8e457e]510
[9f575ea]511        // Just before returning to the processor, set the processor coroutine to active
[e8e457e]512        proc_cor->state = Active;
[1eb239e4]513
[dddb3dd0]514        __cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
515
[ec43cf9]516        #if !defined(__CFA_NO_STATISTICS__)
517                __tls_stats()->ready.threads.threads--;
518        #endif
519
[8fc652e0]520        /* paranoid */ verify( ! __preemption_enabled() );
[82c948c]521}
522
[14a61b5]523// KERNEL_ONLY
[b0c7419]524void returnToKernel() {
[8fc652e0]525        /* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]526        coroutine$ * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
527        thread$ * thrd_src = kernelTLS().this_thread;
[e8e457e]528
[89eff25]529        __STATS( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]530
[9f575ea]531        // Run the thread on this processor
532        {
533                int local_errno = *__volatile_errno();
534                #if defined( __i386 ) || defined( __x86_64 )
535                        __x87_store;
536                #endif
[b4b63e8]537                /* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]538                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]539                __cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]540                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]541                #if defined( __i386 ) || defined( __x86_64 )
542                        __x87_load;
543                #endif
544                *__volatile_errno() = local_errno;
[8fcbb4c]545        }
[deca0f5]546
[29cb302]547        #if !defined(__CFA_NO_STATISTICS__)
[89eff25]548                /* paranoid */ verify( thrd_src->last_proc != 0p );
549                if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]550                        __tls_stats()->ready.threads.migration++;
551                }
552        #endif
553
[8fc652e0]554        /* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]555        /* 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 );
556        /* 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]557}
558
[8def349]559//-----------------------------------------------------------------------------
560// Scheduler routines
[14a61b5]561// KERNEL ONLY
[24e321c]562static void __schedule_thread( thread$ * thrd, unpark_hint hint ) {
[8fc652e0]563        /* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]564        /* paranoid */ verify( ready_schedule_islocked());
[6a490b2]565        /* paranoid */ verify( thrd );
566        /* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]567        /* paranoid */ verify( thrd->curr_cluster );
[3381ed7]568        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]569        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
570                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]571        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]572                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]573        /* paranoid */ #endif
[6a490b2]574        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]575        /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]576
[b808625]577        const bool local = thrd->state != Start;
[ae7be7a]578        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]579
[ec43cf9]580        // Dereference the thread now because once we push it, there is not guaranteed it's still valid.
581        struct cluster * cl = thrd->curr_cluster;
[24e321c]582        __STATS(bool outside = hint == UNPARK_LOCAL && thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]583
[254ad1b]584        // push the thread to the cluster ready-queue
[24e321c]585        push( cl, thrd, hint );
[32a8b61]586
[254ad1b]587        // variable thrd is no longer safe to use
[734908c]588        thrd = 0xdeaddeaddeaddeadp;
[32a8b61]589
[254ad1b]590        // wake the cluster using the save variable.
591        __wake_one( cl );
[1c273d0]592
[ec43cf9]593        #if !defined(__CFA_NO_STATISTICS__)
594                if( kernelTLS().this_stats ) {
595                        __tls_stats()->ready.threads.threads++;
[89eff25]596                        if(outside) {
597                                __tls_stats()->ready.threads.extunpark++;
598                        }
[ec43cf9]599                }
600                else {
601                        __atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]602                        __atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[ec43cf9]603                }
604        #endif
605
[254ad1b]606        /* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]607        /* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]608}
609
[24e321c]610void schedule_thread$( thread$ * thrd, unpark_hint hint ) {
[254ad1b]611        ready_schedule_lock();
[24e321c]612                __schedule_thread( thrd, hint );
[254ad1b]613        ready_schedule_unlock();
614}
615
[14a61b5]616// KERNEL ONLY
[e84ab3d]617static inline thread$ * __next_thread(cluster * this) with( *this ) {
[8fc652e0]618        /* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]619
[e873838]620        ready_schedule_lock();
[e84ab3d]621                thread$ * thrd = pop_fast( this );
[e873838]622        ready_schedule_unlock();
[7768b8d]623
[8fc652e0]624        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]625        return thrd;
[eb2e723]626}
627
[64a7146]628// KERNEL ONLY
[e84ab3d]629static inline thread$ * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]630        /* paranoid */ verify( ! __preemption_enabled() );
[64a7146]631
[e873838]632        ready_schedule_lock();
[e84ab3d]633                thread$ * thrd;
[fc59df78]634                for(25) {
635                        thrd = pop_slow( this );
636                        if(thrd) goto RET;
637                }
638                thrd = pop_search( this );
639
640                RET:
[e873838]641        ready_schedule_unlock();
[64a7146]642
[8fc652e0]643        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]644        return thrd;
[64a7146]645}
646
[e84ab3d]647static inline bool __must_unpark( thread$ * thrd ) {
[ff79d5e]648        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
649        switch(old_ticket) {
[6a77224]650                case TICKET_RUNNING:
[3381ed7]651                        // Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]652                        return false;
[6a77224]653                case TICKET_BLOCKED:
[3381ed7]654                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]655                        /* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]656                        return true;
[3381ed7]657                default:
658                        // This makes no sense, something is wrong abort
[7ee8153]659                        abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]660        }
[eb2e723]661}
662
[24e321c]663void __kernel_unpark( thread$ * thrd, unpark_hint hint ) {
[e9c0b4c]664        /* paranoid */ verify( ! __preemption_enabled() );
665        /* paranoid */ verify( ready_schedule_islocked());
666
667        if( !thrd ) return;
668
669        if(__must_unpark(thrd)) {
670                // Wake lost the race,
[24e321c]671                __schedule_thread( thrd, hint );
[e9c0b4c]672        }
673
674        /* paranoid */ verify( ready_schedule_islocked());
675        /* paranoid */ verify( ! __preemption_enabled() );
676}
677
[24e321c]678void unpark( thread$ * thrd, unpark_hint hint ) {
[c6c7e6c]679        if( !thrd ) return;
[0b33412]680
[c6c7e6c]681        if(__must_unpark(thrd)) {
682                disable_interrupts();
[a3821fa]683                        // Wake lost the race,
[24e321c]684                        schedule_thread$( thrd, hint );
[a3821fa]685                enable_interrupts(false);
[de6319f]686        }
[eb2e723]687}
[0b33412]688
[e235429]689void park( void ) {
[a3821fa]690        __disable_interrupts_checked();
691                /* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
692                returnToKernel();
693        __enable_interrupts_checked();
[0c78741]694
695}
[09800e9]696
[5afb49a]697extern "C" {
698        // Leave the thread monitor
699        // last routine called by a thread.
700        // Should never return
701        void __cfactx_thrd_leave() {
[e84ab3d]702                thread$ * thrd = active_thread();
703                monitor$ * this = &thrd->self_mon;
[5afb49a]704
705                // Lock the monitor now
706                lock( this->lock __cfaabi_dbg_ctx2 );
707
708                disable_interrupts();
709
[9d6e1b8a]710                /* paranoid */ verify( ! __preemption_enabled() );
711                /* paranoid */ verify( thrd->state == Active );
712                /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
713                /* paranoid */ verify( kernelTLS().this_thread == thrd );
714                /* paranoid */ verify( thrd->context.SP );
[e84ab3d]715                /* 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 );
716                /* 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 );
[9d6e1b8a]717
[3ea8ad1]718                thrd->state = Halting;
[58688bf]719                if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]720                if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
721                if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]722
723                // Leave the thread
724                returnToKernel();
725
726                // Control flow should never reach here!
[9d6e1b8a]727                abort();
[5afb49a]728        }
[09800e9]729}
730
[14a61b5]731// KERNEL ONLY
[3381ed7]732bool force_yield( __Preemption_Reason reason ) {
[a3821fa]733        __disable_interrupts_checked();
[e84ab3d]734                thread$ * thrd = kernelTLS().this_thread;
[a3821fa]735                /* paranoid */ verify(thrd->state == Active);
736
737                // SKULLDUGGERY: It is possible that we are preempting this thread just before
738                // it was going to park itself. If that is the case and it is already using the
739                // intrusive fields then we can't use them to preempt the thread
740                // If that is the case, abandon the preemption.
741                bool preempted = false;
742                if(thrd->link.next == 0p) {
743                        preempted = true;
744                        thrd->preempted = reason;
745                        returnToKernel();
746                }
747        __enable_interrupts_checked( false );
[3381ed7]748        return preempted;
[f2b12406]749}
750
[14a61b5]751//=============================================================================================
[92e7631]752// Kernel Idle Sleep
[14a61b5]753//=============================================================================================
[64a7146]754// Wake a thread from the front if there are any
[e873838]755static void __wake_one(cluster * this) {
[8fc652e0]756        /* paranoid */ verify( ! __preemption_enabled() );
[e873838]757        /* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]758
[64a7146]759        // Check if there is a sleeping processor
[1eb239e4]760        processor * p;
761        unsigned idle;
762        unsigned total;
[6a9b12b]763        [idle, total, p] = query_idles(this->procs);
[14a61b5]764
[64a7146]765        // If no one is sleeping, we are done
[1eb239e4]766        if( idle == 0 ) return;
[14a61b5]767
[64a7146]768        // We found a processor, wake it up
[dddb3dd0]769        eventfd_t val;
770        val = 1;
771        eventfd_write( p->idle, val );
[14a61b5]772
[1eb239e4]773        #if !defined(__CFA_NO_STATISTICS__)
[5cb51502]774                if( kernelTLS().this_stats ) {
775                        __tls_stats()->ready.sleep.wakes++;
776                }
777                else {
778                        __atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
779                }
[1eb239e4]780        #endif
781
[e873838]782        /* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]783        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]784
785        return;
[64a7146]786}
[14a61b5]787
[64a7146]788// Unconditionnaly wake a thread
[1eb239e4]789void __wake_proc(processor * this) {
[64a7146]790        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]791
[a3821fa]792        __disable_interrupts_checked();
[8fc652e0]793                /* paranoid */ verify( ! __preemption_enabled() );
[dddb3dd0]794                eventfd_t val;
795                val = 1;
[55d6affb]796                eventfd_write( this->idle, val );
[a3821fa]797        __enable_interrupts_checked();
[92e7631]798}
799
[6a9b12b]800static void mark_idle(__cluster_proc_list & this, processor & proc) {
[8fc652e0]801        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]802        lock( this );
803                this.idle++;
804                /* paranoid */ verify( this.idle <= this.total );
[fc59b580]805                remove(proc);
[6a9b12b]806                insert_first(this.idles, proc);
[1eb239e4]807        unlock( this );
[8fc652e0]808        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]809}
[8e16177]810
[6a9b12b]811static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]812        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]813        lock( this );
814                this.idle--;
815                /* paranoid */ verify( this.idle >= 0 );
816                remove(proc);
[fc59b580]817                insert_last(this.actives, proc);
[1eb239e4]818        unlock( this );
[8fc652e0]819        /* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]820}
[c34ebf2]821
[6a9b12b]822static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
823        /* paranoid */ verify( ! __preemption_enabled() );
824        /* paranoid */ verify( ready_schedule_islocked() );
825
[1eb239e4]826        for() {
827                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
828                if( 1 == (l % 2) ) { Pause(); continue; }
829                unsigned idle    = this.idle;
830                unsigned total   = this.total;
[6a9b12b]831                processor * proc = &this.idles`first;
[7fdae38]832                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
833                asm volatile("": : :"memory");
[1eb239e4]834                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
835                return [idle, total, proc];
836        }
[6a9b12b]837
838        /* paranoid */ verify( ready_schedule_islocked() );
839        /* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]840}
841
[dbe9b08]842//=============================================================================================
843// Unexpected Terminating logic
844//=============================================================================================
[92bfda0]845void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
[e84ab3d]846        thread$ * thrd = __cfaabi_tls.this_thread;
[9d944b2]847
[de94a60]848        if(thrd) {
849                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]850                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]851
[212c2187]852                if ( &thrd->self_cor != thrd->curr_cor ) {
853                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]854                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]855                }
856                else {
[1c40091]857                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]858                }
[1c273d0]859        }
[9d944b2]860        else {
[de94a60]861                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]862                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]863        }
864}
865
[92bfda0]866int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
867        return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]868}
869
[de94a60]870static __spinlock_t kernel_debug_lock;
871
[9d944b2]872extern "C" {
[1c40091]873        void __cfaabi_bits_acquire() {
[36982fc]874                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]875        }
876
[1c40091]877        void __cfaabi_bits_release() {
[ea7d2b0]878                unlock( kernel_debug_lock );
[9d944b2]879        }
[8118303]880}
881
[fa21ac9]882//=============================================================================================
883// Kernel Utilities
884//=============================================================================================
[dddb3dd0]885#if defined(CFA_HAVE_LINUX_IO_URING_H)
886#include "io/types.hfa"
887#endif
888
[c1c95b1]889static inline bool __maybe_io_drain( processor * proc ) {
[e9c0b4c]890        bool ret = false;
[dddb3dd0]891        #if defined(CFA_HAVE_LINUX_IO_URING_H)
892                __cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
893
894                // Check if we should drain the queue
895                $io_context * ctx = proc->io.ctx;
896                unsigned head = *ctx->cq.head;
897                unsigned tail = *ctx->cq.tail;
[c1c95b1]898                if(head == tail) return false;
[57f70ab]899                #if OLD_MAIN
[b7fd2db6]900                ready_schedule_lock();
[e9c0b4c]901                ret = __cfa_io_drain( proc );
[b7fd2db6]902                ready_schedule_unlock();
[57f70ab]903                #else
904                        ret = __cfa_io_drain( proc );
905        #endif
[dddb3dd0]906        #endif
[e9c0b4c]907        return ret;
[dddb3dd0]908}
909
[de94a60]910//-----------------------------------------------------------------------------
911// Debug
912__cfaabi_dbg_debug_do(
[1997b4e]913        extern "C" {
[ae66348]914                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]915                        this.prev_name = prev_name;
[8fc652e0]916                        this.prev_thrd = kernelTLS().this_thread;
[1997b4e]917                }
[9181f1d]918        }
[f7d6bb0]919)
[2026bb6]920
921//-----------------------------------------------------------------------------
922// Debug
[8c50aed]923bool threading_enabled(void) __attribute__((const)) {
[2026bb6]924        return true;
925}
[c34ebf2]926
927//-----------------------------------------------------------------------------
928// Statistics
929#if !defined(__CFA_NO_STATISTICS__)
930        void print_halts( processor & this ) {
931                this.print_halts = true;
932        }
[58688bf]933
[69914cbc]934        static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
[8464edf]935                /* paranoid */ verify( cltr->stats );
936
937                processor * it = &list`first;
938                for(unsigned i = 0; i < count; i++) {
939                        /* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
940                        /* paranoid */ verify( it->local_data->this_stats );
941                        __tally_stats( cltr->stats, it->local_data->this_stats );
942                        it = &(*it)`next;
943                }
944        }
945
946        void crawl_cluster_stats( cluster & this ) {
947                // Stop the world, otherwise stats could get really messed-up
948                // this doesn't solve all problems but does solve many
949                // so it's probably good enough
950                uint_fast32_t last_size = ready_mutate_lock();
951
952                        crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
953                        crawl_list(&this, this.procs.idles  , this.procs.idle );
954
955                // Unlock the RWlock
956                ready_mutate_unlock( last_size );
957        }
958
959
[58688bf]960        void print_stats_now( cluster & this, int flags ) {
[8464edf]961                crawl_cluster_stats( this );
[1b033b8]962                __print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
963        }
[c34ebf2]964#endif
[8118303]965// Local Variables: //
966// mode: c //
967// tab-width: 4 //
968// End: //
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