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ADT ast-experimental enum forall-pointer-decay pthread-emulation qualifiedEnum

Last change on this file since 7dd98b6 was c33c2af, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
Made some of the schedule locking more fine grain.
Property mode set to `100644`
File size: 30.5 KB

Rev	Line
[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]	27	extern "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]	115	extern thread$ * mainThread;
[e660761]	116	extern processor * mainProcessor;
[2ac095d]	117
[92e7631]	118	//-----------------------------------------------------------------------------
	119	// Kernel Scheduling logic
[e84ab3d]	120	static thread$ * __next_thread(cluster * this);
	121	static thread$ * __next_thread_slow(cluster * this);
	122	static inline bool __must_unpark( thread$ * thrd ) __attribute((nonnull(1)));
	123	static void __run_thread(processor * this, thread$ * dst);
[e873838]	124	static void __wake_one(cluster * cltr);
[1eb239e4]	125
[6a9b12b]	126	static void mark_idle (__cluster_proc_list & idles, processor & proc);
	127	static void mark_awake(__cluster_proc_list & idles, processor & proc);
	128	static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list idles );
[1eb239e4]	129
[dddb3dd0]	130	extern void __cfa_io_start( processor * );
[c1c95b1]	131	extern bool __cfa_io_drain( processor * );
[dddb3dd0]	132	extern void __cfa_io_flush( processor * );
	133	extern void __cfa_io_stop ( processor * );
[c1c95b1]	134	static inline bool __maybe_io_drain( processor * );
[dddb3dd0]	135
	136	extern void __disable_interrupts_hard();
	137	extern void __enable_interrupts_hard();
[c84e80a]	138
[a3821fa]	139	static inline void __disable_interrupts_checked() {
	140	/* paranoid */ verify( __preemption_enabled() );
	141	disable_interrupts();
	142	/* paranoid */ verify( ! __preemption_enabled() );
	143	}
	144
	145	static 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]	155	void 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 ) {
[c33c2af]	198	ready_schedule_lock();
[dddb3dd0]	199	__cfa_io_flush( this );
[c33c2af]	200	ready_schedule_unlock();
	201
[1eb239e4]	202	readyThread = __next_thread_slow( this->cltr );
	203	}
[4e6fb8e]	204
[1eb239e4]	205	HALT:
	206	if( !readyThread ) {
	207	// Don't block if we are done
	208	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	209
[1eb239e4]	210	#if !defined(__CFA_NO_STATISTICS__)
	211	__tls_stats()->ready.sleep.halts++;
	212	#endif
[398e8e9]	213
[1eb239e4]	214	// Push self to idle stack
[6a9b12b]	215	mark_idle(this->cltr->procs, * this);
[398e8e9]	216
[1eb239e4]	217	// Confirm the ready-queue is empty
	218	readyThread = __next_thread_slow( this->cltr );
	219	if( readyThread ) {
	220	// A thread was found, cancel the halt
[6a9b12b]	221	mark_awake(this->cltr->procs, * this);
[1eb239e4]	222
	223	#if !defined(__CFA_NO_STATISTICS__)
	224	__tls_stats()->ready.sleep.cancels++;
	225	#endif
	226
	227	// continue the mai loop
	228	break HALT;
	229	}
	230
	231	#if !defined(__CFA_NO_STATISTICS__)
	232	if(this->print_halts) {
[c993b15]	233	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
[1eb239e4]	234	}
	235	#endif
	236
[dddb3dd0]	237	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	238
[56e5b24]	239	{
	240	eventfd_t val;
	241	ssize_t ret = read( this->idle, &val, sizeof(val) );
	242	if(ret < 0) {
	243	switch((int)errno) {
	244	case EAGAIN:
	245	#if EAGAIN != EWOULDBLOCK
	246	case EWOULDBLOCK:
	247	#endif
	248	case EINTR:
	249	// No need to do anything special here, just assume it's a legitimate wake-up
	250	break;
	251	default:
	252	abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
	253	}
	254	}
	255	}
[1eb239e4]	256
	257	#if !defined(__CFA_NO_STATISTICS__)
	258	if(this->print_halts) {
[c993b15]	259	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
[1eb239e4]	260	}
	261	#endif
	262
	263	// We were woken up, remove self from idle
[6a9b12b]	264	mark_awake(this->cltr->procs, * this);
[1eb239e4]	265
	266	// DON'T just proceed, start looking again
	267	continue MAIN_LOOP;
[64a7146]	268	}
[1eb239e4]	269
	270	/* paranoid */ verify( readyThread );
	271
[dddb3dd0]	272	// Reset io dirty bit
	273	this->io.dirty = false;
	274
[1eb239e4]	275	// We found a thread run it
	276	__run_thread(this, readyThread);
	277
	278	// Are we done?
	279	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]	280
[dddb3dd0]	281	if(this->io.pending && !this->io.dirty) {
[c33c2af]	282	ready_schedule_lock();
[dddb3dd0]	283	__cfa_io_flush( this );
[c33c2af]	284	ready_schedule_unlock();
[dddb3dd0]	285	}
[89eff25]	286
[34b2796]	287	#else
[57f70ab]	288	#warning new kernel loop
[34b2796]	289	SEARCH: {
	290	/* paranoid */ verify( ! __preemption_enabled() );
	291
	292	// First, lock the scheduler since we are searching for a thread
	293	ready_schedule_lock();
	294
	295	// Try to get the next thread
	296	readyThread = pop_fast( this->cltr );
	297	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	298
	299	// If we can't find a thread, might as well flush any outstanding I/O
	300	if(this->io.pending) { __cfa_io_flush( this ); }
	301
	302	// Spin a little on I/O, just in case
[12daa43]	303	for(5) {
[34b2796]	304	__maybe_io_drain( this );
	305	readyThread = pop_fast( this->cltr );
	306	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	307	}
	308
	309	// no luck, try stealing a few times
[12daa43]	310	for(5) {
[34b2796]	311	if( __maybe_io_drain( this ) ) {
	312	readyThread = pop_fast( this->cltr );
	313	} else {
	314	readyThread = pop_slow( this->cltr );
	315	}
	316	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	317	}
	318
	319	// still no luck, search for a thread
	320	readyThread = pop_search( this->cltr );
	321	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	322
	323	// Don't block if we are done
[c33c2af]	324	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) {
	325	ready_schedule_unlock();
	326	break MAIN_LOOP;
	327	}
[34b2796]	328
	329	__STATS( __tls_stats()->ready.sleep.halts++; )
	330
	331	// Push self to idle stack
	332	ready_schedule_unlock();
	333	mark_idle(this->cltr->procs, * this);
	334	ready_schedule_lock();
	335
	336	// Confirm the ready-queue is empty
	337	__maybe_io_drain( this );
	338	readyThread = pop_search( this->cltr );
	339	ready_schedule_unlock();
	340
	341	if( readyThread ) {
	342	// A thread was found, cancel the halt
	343	mark_awake(this->cltr->procs, * this);
	344
	345	__STATS( __tls_stats()->ready.sleep.cancels++; )
	346
	347	// continue the main loop
	348	break SEARCH;
	349	}
	350
[abcae55]	351	__STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl()); )
[34b2796]	352	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	353
[ec421636]	354	{
	355	eventfd_t val;
	356	ssize_t ret = read( this->idle, &val, sizeof(val) );
	357	if(ret < 0) {
	358	switch((int)errno) {
	359	case EAGAIN:
	360	#if EAGAIN != EWOULDBLOCK
	361	case EWOULDBLOCK:
	362	#endif
	363	case EINTR:
	364	// No need to do anything special here, just assume it's a legitimate wake-up
	365	break;
	366	default:
	367	abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
	368	}
	369	}
	370	}
[34b2796]	371
[fb4ccdf]	372	__STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl()); )
[34b2796]	373
	374	// We were woken up, remove self from idle
	375	mark_awake(this->cltr->procs, * this);
	376
	377	// DON'T just proceed, start looking again
	378	continue MAIN_LOOP;
	379	}
	380
	381	RUN_THREAD:
	382	/* paranoid */ verify( ! __preemption_enabled() );
	383	/* paranoid */ verify( readyThread );
	384
	385	// Reset io dirty bit
	386	this->io.dirty = false;
	387
	388	// We found a thread run it
	389	__run_thread(this, readyThread);
	390
	391	// Are we done?
	392	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
	393
	394	if(this->io.pending && !this->io.dirty) {
	395	__cfa_io_flush( this );
	396	}
	397
	398	ready_schedule_lock();
	399	__maybe_io_drain( this );
	400	ready_schedule_unlock();
	401	#endif
[c81ebf9]	402	}
	403
[4069faad]	404	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]	405	}
[8118303]	406
[dddb3dd0]	407	__cfa_io_stop( this );
	408
[454f478]	409	post( this->terminated );
[bdeba0b]	410
[28d73c1]	411	if(this == mainProcessor) {
[6a490b2]	412	// HACK : the coroutine context switch expects this_thread to be set
	413	// and it make sense for it to be set in all other cases except here
	414	// fake it
[8fc652e0]	415	__cfaabi_tls.this_thread = mainThread;
[6a490b2]	416	}
[7768b8d]	417
[4069faad]	418	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]	419	}
	420
[5c1a531]	421	static int * __volatile_errno() __attribute__((noinline));
	422	static int * __volatile_errno() { asm(""); return &errno; }
	423
[14a61b5]	424	// KERNEL ONLY
[1c273d0]	425	// runThread runs a thread by context switching
	426	// from the processor coroutine to the target thread
[e84ab3d]	427	static void __run_thread(processor * this, thread$ * thrd_dst) {
[8fc652e0]	428	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	429	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
	430	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
	431	__builtin_prefetch( thrd_dst->context.SP );
	432
[dddb3dd0]	433	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
	434
[e84ab3d]	435	coroutine$ * proc_cor = get_coroutine(this->runner);
[8fcbb4c]	436
[9f575ea]	437	// set state of processor coroutine to inactive
	438	verify(proc_cor->state == Active);
[ae7be7a]	439	proc_cor->state = Blocked;
[e8e457e]	440
[9f575ea]	441	// Actually run the thread
[3381ed7]	442	RUNNING: while(true) {
[ff79d5e]	443	thrd_dst->preempted = __NO_PREEMPTION;
	444	thrd_dst->state = Active;
[e8e457e]	445
[58d64a4]	446	// Update global state
[8fc652e0]	447	kernelTLS().this_thread = thrd_dst;
[75f3522]	448
[8fc652e0]	449	/* paranoid */ verify( ! __preemption_enabled() );
	450	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]	451	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]	452	/* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]	453	/* paranoid */ verify( thrd_dst->state != Halted );
[e84ab3d]	454	/* 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
	455	/* 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]	456	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]	457
[3381ed7]	458
[58d64a4]	459
[9f575ea]	460	// set context switch to the thread that the processor is executing
[c7a900a]	461	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
	462	// when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]	463
[50871b4]	464
	465
[ac12f1f]	466	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[e84ab3d]	467	/* 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 );
	468	/* 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]	469	/* paranoid */ verify( thrd_dst->context.SP );
[9d6e1b8a]	470	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[8fc652e0]	471	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
	472	/* paranoid */ verify( ! __preemption_enabled() );
[75f3522]	473
[58d64a4]	474	// Reset global state
[8fc652e0]	475	kernelTLS().this_thread = 0p;
[3381ed7]	476
	477	// We just finished running a thread, there are a few things that could have happened.
	478	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
	479	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
	480	// 4 - Preempted
	481	// In case 1, we may have won a race so we can't write to the state again.
	482	// In case 2, we lost the race so we now own the thread.
	483
	484	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
	485	// The thread was preempted, reschedule it and reset the flag
[24e321c]	486	schedule_thread$( thrd_dst, UNPARK_LOCAL );
[3381ed7]	487	break RUNNING;
	488	}
[75f3522]	489
[3ea8ad1]	490	if(unlikely(thrd_dst->state == Halting)) {
[ff79d5e]	491	// The thread has halted, it should never be scheduled/run again
[5afb49a]	492	// finish the thread
	493	__thread_finish( thrd_dst );
[ff79d5e]	494	break RUNNING;
	495	}
	496
	497	/* paranoid */ verify( thrd_dst->state == Active );
	498	thrd_dst->state = Blocked;
	499
[3381ed7]	500	// set state of processor coroutine to active and the thread to inactive
[ff79d5e]	501	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
	502	switch(old_ticket) {
[6a77224]	503	case TICKET_RUNNING:
[3381ed7]	504	// This is case 1, the regular case, nothing more is needed
	505	break RUNNING;
[6a77224]	506	case TICKET_UNBLOCK:
[ec43cf9]	507	#if !defined(__CFA_NO_STATISTICS__)
	508	__tls_stats()->ready.threads.threads++;
	509	#endif
[3381ed7]	510	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
	511	// In this case, just run it again.
	512	continue RUNNING;
	513	default:
	514	// This makes no sense, something is wrong abort
[ff79d5e]	515	abort();
[3381ed7]	516	}
[9f575ea]	517	}
[e8e457e]	518
[9f575ea]	519	// Just before returning to the processor, set the processor coroutine to active
[e8e457e]	520	proc_cor->state = Active;
[1eb239e4]	521
[dddb3dd0]	522	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
	523
[ec43cf9]	524	#if !defined(__CFA_NO_STATISTICS__)
	525	__tls_stats()->ready.threads.threads--;
	526	#endif
	527
[8fc652e0]	528	/* paranoid */ verify( ! __preemption_enabled() );
[82c948c]	529	}
	530
[14a61b5]	531	// KERNEL_ONLY
[b0c7419]	532	void returnToKernel() {
[8fc652e0]	533	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	534	coroutine$ * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
	535	thread$ * thrd_src = kernelTLS().this_thread;
[e8e457e]	536
[89eff25]	537	__STATS( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]	538
[9f575ea]	539	// Run the thread on this processor
	540	{
	541	int local_errno = *__volatile_errno();
	542	#if defined( __i386 ) \|\| defined( __x86_64 )
	543	__x87_store;
	544	#endif
[b4b63e8]	545	/* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]	546	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]	547	__cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]	548	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]	549	#if defined( __i386 ) \|\| defined( __x86_64 )
	550	__x87_load;
	551	#endif
	552	*__volatile_errno() = local_errno;
[8fcbb4c]	553	}
[deca0f5]	554
[29cb302]	555	#if !defined(__CFA_NO_STATISTICS__)
[89eff25]	556	/* paranoid */ verify( thrd_src->last_proc != 0p );
	557	if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]	558	__tls_stats()->ready.threads.migration++;
	559	}
	560	#endif
	561
[8fc652e0]	562	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	563	/* 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 );
	564	/* 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]	565	}
	566
[8def349]	567	//-----------------------------------------------------------------------------
	568	// Scheduler routines
[14a61b5]	569	// KERNEL ONLY
[24e321c]	570	static void __schedule_thread( thread$ * thrd, unpark_hint hint ) {
[8fc652e0]	571	/* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]	572	/* paranoid */ verify( ready_schedule_islocked());
[6a490b2]	573	/* paranoid */ verify( thrd );
	574	/* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]	575	/* paranoid */ verify( thrd->curr_cluster );
[3381ed7]	576	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]	577	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
	578	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]	579	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]	580	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]	581	/* paranoid */ #endif
[6a490b2]	582	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]	583	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]	584
[b808625]	585	const bool local = thrd->state != Start;
[ae7be7a]	586	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]	587
[ec43cf9]	588	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
	589	struct cluster * cl = thrd->curr_cluster;
[24e321c]	590	__STATS(bool outside = hint == UNPARK_LOCAL && thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]	591
[254ad1b]	592	// push the thread to the cluster ready-queue
[24e321c]	593	push( cl, thrd, hint );
[32a8b61]	594
[254ad1b]	595	// variable thrd is no longer safe to use
[734908c]	596	thrd = 0xdeaddeaddeaddeadp;
[32a8b61]	597
[254ad1b]	598	// wake the cluster using the save variable.
	599	__wake_one( cl );
[1c273d0]	600
[ec43cf9]	601	#if !defined(__CFA_NO_STATISTICS__)
	602	if( kernelTLS().this_stats ) {
	603	__tls_stats()->ready.threads.threads++;
[89eff25]	604	if(outside) {
	605	__tls_stats()->ready.threads.extunpark++;
	606	}
[ec43cf9]	607	}
	608	else {
	609	__atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]	610	__atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[ec43cf9]	611	}
	612	#endif
	613
[254ad1b]	614	/* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]	615	/* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]	616	}
	617
[24e321c]	618	void schedule_thread$( thread$ * thrd, unpark_hint hint ) {
[254ad1b]	619	ready_schedule_lock();
[24e321c]	620	__schedule_thread( thrd, hint );
[254ad1b]	621	ready_schedule_unlock();
	622	}
	623
[14a61b5]	624	// KERNEL ONLY
[e84ab3d]	625	static inline thread$ * __next_thread(cluster * this) with( *this ) {
[8fc652e0]	626	/* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]	627
[e873838]	628	ready_schedule_lock();
[e84ab3d]	629	thread$ * thrd = pop_fast( this );
[e873838]	630	ready_schedule_unlock();
[7768b8d]	631
[8fc652e0]	632	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	633	return thrd;
[eb2e723]	634	}
	635
[64a7146]	636	// KERNEL ONLY
[e84ab3d]	637	static inline thread$ * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]	638	/* paranoid */ verify( ! __preemption_enabled() );
[64a7146]	639
[e873838]	640	ready_schedule_lock();
[e84ab3d]	641	thread$ * thrd;
[fc59df78]	642	for(25) {
	643	thrd = pop_slow( this );
	644	if(thrd) goto RET;
	645	}
	646	thrd = pop_search( this );
	647
	648	RET:
[e873838]	649	ready_schedule_unlock();
[64a7146]	650
[8fc652e0]	651	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	652	return thrd;
[64a7146]	653	}
	654
[e84ab3d]	655	static inline bool __must_unpark( thread$ * thrd ) {
[ff79d5e]	656	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
	657	switch(old_ticket) {
[6a77224]	658	case TICKET_RUNNING:
[3381ed7]	659	// Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]	660	return false;
[6a77224]	661	case TICKET_BLOCKED:
[3381ed7]	662	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]	663	/* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]	664	return true;
[3381ed7]	665	default:
	666	// This makes no sense, something is wrong abort
[7ee8153]	667	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]	668	}
[eb2e723]	669	}
	670
[24e321c]	671	void __kernel_unpark( thread$ * thrd, unpark_hint hint ) {
[e9c0b4c]	672	/* paranoid */ verify( ! __preemption_enabled() );
	673	/* paranoid */ verify( ready_schedule_islocked());
	674
	675	if( !thrd ) return;
	676
	677	if(__must_unpark(thrd)) {
	678	// Wake lost the race,
[24e321c]	679	__schedule_thread( thrd, hint );
[e9c0b4c]	680	}
	681
	682	/* paranoid */ verify( ready_schedule_islocked());
	683	/* paranoid */ verify( ! __preemption_enabled() );
	684	}
	685
[24e321c]	686	void unpark( thread$ * thrd, unpark_hint hint ) {
[c6c7e6c]	687	if( !thrd ) return;
[0b33412]	688
[c6c7e6c]	689	if(__must_unpark(thrd)) {
	690	disable_interrupts();
[a3821fa]	691	// Wake lost the race,
[24e321c]	692	schedule_thread$( thrd, hint );
[a3821fa]	693	enable_interrupts(false);
[de6319f]	694	}
[eb2e723]	695	}
[0b33412]	696
[e235429]	697	void park( void ) {
[a3821fa]	698	__disable_interrupts_checked();
	699	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
	700	returnToKernel();
	701	__enable_interrupts_checked();
[0c78741]	702
	703	}
[09800e9]	704
[5afb49a]	705	extern "C" {
	706	// Leave the thread monitor
	707	// last routine called by a thread.
	708	// Should never return
	709	void __cfactx_thrd_leave() {
[e84ab3d]	710	thread$ * thrd = active_thread();
	711	monitor$ * this = &thrd->self_mon;
[5afb49a]	712
	713	// Lock the monitor now
	714	lock( this->lock __cfaabi_dbg_ctx2 );
	715
	716	disable_interrupts();
	717
[9d6e1b8a]	718	/* paranoid */ verify( ! __preemption_enabled() );
	719	/* paranoid */ verify( thrd->state == Active );
	720	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
	721	/* paranoid */ verify( kernelTLS().this_thread == thrd );
	722	/* paranoid */ verify( thrd->context.SP );
[e84ab3d]	723	/* 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 );
	724	/* 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]	725
[3ea8ad1]	726	thrd->state = Halting;
[58688bf]	727	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]	728	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
	729	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]	730
	731	// Leave the thread
	732	returnToKernel();
	733
	734	// Control flow should never reach here!
[9d6e1b8a]	735	abort();
[5afb49a]	736	}
[09800e9]	737	}
	738
[14a61b5]	739	// KERNEL ONLY
[3381ed7]	740	bool force_yield( __Preemption_Reason reason ) {
[a3821fa]	741	__disable_interrupts_checked();
[e84ab3d]	742	thread$ * thrd = kernelTLS().this_thread;
[a3821fa]	743	/* paranoid */ verify(thrd->state == Active);
	744
	745	// SKULLDUGGERY: It is possible that we are preempting this thread just before
	746	// it was going to park itself. If that is the case and it is already using the
	747	// intrusive fields then we can't use them to preempt the thread
	748	// If that is the case, abandon the preemption.
	749	bool preempted = false;
	750	if(thrd->link.next == 0p) {
	751	preempted = true;
	752	thrd->preempted = reason;
	753	returnToKernel();
	754	}
	755	__enable_interrupts_checked( false );
[3381ed7]	756	return preempted;
[f2b12406]	757	}
	758
[14a61b5]	759	//=============================================================================================
[92e7631]	760	// Kernel Idle Sleep
[14a61b5]	761	//=============================================================================================
[64a7146]	762	// Wake a thread from the front if there are any
[e873838]	763	static void __wake_one(cluster * this) {
[8fc652e0]	764	/* paranoid */ verify( ! __preemption_enabled() );
[e873838]	765	/* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]	766
[64a7146]	767	// Check if there is a sleeping processor
[1eb239e4]	768	processor * p;
	769	unsigned idle;
	770	unsigned total;
[6a9b12b]	771	[idle, total, p] = query_idles(this->procs);
[14a61b5]	772
[64a7146]	773	// If no one is sleeping, we are done
[1eb239e4]	774	if( idle == 0 ) return;
[14a61b5]	775
[64a7146]	776	// We found a processor, wake it up
[dddb3dd0]	777	eventfd_t val;
	778	val = 1;
	779	eventfd_write( p->idle, val );
[14a61b5]	780
[1eb239e4]	781	#if !defined(__CFA_NO_STATISTICS__)
[5cb51502]	782	if( kernelTLS().this_stats ) {
	783	__tls_stats()->ready.sleep.wakes++;
	784	}
	785	else {
	786	__atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
	787	}
[1eb239e4]	788	#endif
	789
[e873838]	790	/* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]	791	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	792
	793	return;
[64a7146]	794	}
[14a61b5]	795
[64a7146]	796	// Unconditionnaly wake a thread
[1eb239e4]	797	void __wake_proc(processor * this) {
[64a7146]	798	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]	799
[a3821fa]	800	__disable_interrupts_checked();
[8fc652e0]	801	/* paranoid */ verify( ! __preemption_enabled() );
[dddb3dd0]	802	eventfd_t val;
	803	val = 1;
[55d6affb]	804	eventfd_write( this->idle, val );
[a3821fa]	805	__enable_interrupts_checked();
[92e7631]	806	}
	807
[6a9b12b]	808	static void mark_idle(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	809	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	810	lock( this );
	811	this.idle++;
	812	/* paranoid */ verify( this.idle <= this.total );
[fc59b580]	813	remove(proc);
[6a9b12b]	814	insert_first(this.idles, proc);
[1eb239e4]	815	unlock( this );
[8fc652e0]	816	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	817	}
[8e16177]	818
[6a9b12b]	819	static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	820	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	821	lock( this );
	822	this.idle--;
	823	/* paranoid */ verify( this.idle >= 0 );
	824	remove(proc);
[fc59b580]	825	insert_last(this.actives, proc);
[1eb239e4]	826	unlock( this );
[8fc652e0]	827	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	828	}
[c34ebf2]	829
[6a9b12b]	830	static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
	831	/* paranoid */ verify( ! __preemption_enabled() );
	832	/* paranoid */ verify( ready_schedule_islocked() );
	833
[1eb239e4]	834	for() {
	835	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
	836	if( 1 == (l % 2) ) { Pause(); continue; }
	837	unsigned idle = this.idle;
	838	unsigned total = this.total;
[6a9b12b]	839	processor * proc = &this.idles`first;
[7fdae38]	840	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
	841	asm volatile("": : :"memory");
[1eb239e4]	842	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
	843	return [idle, total, proc];
	844	}
[6a9b12b]	845
	846	/* paranoid */ verify( ready_schedule_islocked() );
	847	/* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]	848	}
	849
[dbe9b08]	850	//=============================================================================================
	851	// Unexpected Terminating logic
	852	//=============================================================================================
[92bfda0]	853	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
[e84ab3d]	854	thread$ * thrd = __cfaabi_tls.this_thread;
[9d944b2]	855
[de94a60]	856	if(thrd) {
	857	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]	858	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	859
[212c2187]	860	if ( &thrd->self_cor != thrd->curr_cor ) {
	861	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]	862	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	863	}
	864	else {
[1c40091]	865	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]	866	}
[1c273d0]	867	}
[9d944b2]	868	else {
[de94a60]	869	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]	870	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]	871	}
	872	}
	873
[92bfda0]	874	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
	875	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]	876	}
	877
[de94a60]	878	static __spinlock_t kernel_debug_lock;
	879
[9d944b2]	880	extern "C" {
[1c40091]	881	void __cfaabi_bits_acquire() {
[36982fc]	882	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]	883	}
	884
[1c40091]	885	void __cfaabi_bits_release() {
[ea7d2b0]	886	unlock( kernel_debug_lock );
[9d944b2]	887	}
[8118303]	888	}
	889
[fa21ac9]	890	//=============================================================================================
	891	// Kernel Utilities
	892	//=============================================================================================
[dddb3dd0]	893	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	894	#include "io/types.hfa"
	895	#endif
	896
[c1c95b1]	897	static inline bool __maybe_io_drain( processor * proc ) {
[e9c0b4c]	898	bool ret = false;
[dddb3dd0]	899	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	900	__cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
	901
	902	// Check if we should drain the queue
	903	$io_context * ctx = proc->io.ctx;
	904	unsigned head = *ctx->cq.head;
	905	unsigned tail = *ctx->cq.tail;
[c1c95b1]	906	if(head == tail) return false;
[57f70ab]	907	#if OLD_MAIN
[b7fd2db6]	908	ready_schedule_lock();
[e9c0b4c]	909	ret = __cfa_io_drain( proc );
[b7fd2db6]	910	ready_schedule_unlock();
[57f70ab]	911	#else
	912	ret = __cfa_io_drain( proc );
	913	#endif
[dddb3dd0]	914	#endif
[e9c0b4c]	915	return ret;
[dddb3dd0]	916	}
	917
[de94a60]	918	//-----------------------------------------------------------------------------
	919	// Debug
	920	__cfaabi_dbg_debug_do(
[1997b4e]	921	extern "C" {
[ae66348]	922	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]	923	this.prev_name = prev_name;
[8fc652e0]	924	this.prev_thrd = kernelTLS().this_thread;
[1997b4e]	925	}
[9181f1d]	926	}
[f7d6bb0]	927	)
[2026bb6]	928
	929	//-----------------------------------------------------------------------------
	930	// Debug
[8c50aed]	931	bool threading_enabled(void) __attribute__((const)) {
[2026bb6]	932	return true;
	933	}
[c34ebf2]	934
	935	//-----------------------------------------------------------------------------
	936	// Statistics
	937	#if !defined(__CFA_NO_STATISTICS__)
	938	void print_halts( processor & this ) {
	939	this.print_halts = true;
	940	}
[58688bf]	941
[69914cbc]	942	static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
[8464edf]	943	/* paranoid */ verify( cltr->stats );
	944
	945	processor * it = &list`first;
	946	for(unsigned i = 0; i < count; i++) {
	947	/* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
	948	/* paranoid */ verify( it->local_data->this_stats );
[c33c2af]	949	// __print_stats( it->local_data->this_stats, cltr->print_stats, "Processor", it->name, (void*)it );
[8464edf]	950	__tally_stats( cltr->stats, it->local_data->this_stats );
	951	it = &(*it)`next;
	952	}
	953	}
	954
	955	void crawl_cluster_stats( cluster & this ) {
	956	// Stop the world, otherwise stats could get really messed-up
	957	// this doesn't solve all problems but does solve many
	958	// so it's probably good enough
[c33c2af]	959	disable_interrupts();
[8464edf]	960	uint_fast32_t last_size = ready_mutate_lock();
	961
	962	crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
	963	crawl_list(&this, this.procs.idles , this.procs.idle );
	964
	965	// Unlock the RWlock
	966	ready_mutate_unlock( last_size );
[c33c2af]	967	enable_interrupts();
[8464edf]	968	}
	969
	970
[58688bf]	971	void print_stats_now( cluster & this, int flags ) {
[8464edf]	972	crawl_cluster_stats( this );
[1b033b8]	973	__print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
	974	}
[c34ebf2]	975	#endif
[8118303]	976	// Local Variables: //
	977	// mode: c //
	978	// tab-width: 4 //
	979	// End: //

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