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kernel.cfa@ 25d32e7

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Last change on this file since 25d32e7 was b93bf85, checked in by caparsons <caparson@…>, 2 years ago
fixed spurious channel close waituntil error case. Was caused by a race condition causing an exception to be thrown while another was in flight
Property mode set to `100644`
File size: 28.6 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
[f5f2768]	12	// Last Modified On : Mon Jan 9 08:42:05 2023
	13	// Update Count : 77
[8118303]	14	//
	15
[2026bb6]	16	#define __cforall_thread__
[43784ac]	17
[4069faad]	18	// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
[2026bb6]	19
[bfb9bf5]	20	#pragma GCC diagnostic push
	21	#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
	22
[8118303]	23	//C Includes
[214e8da]	24	#include <errno.h>
[9d944b2]	25	#include <stdio.h>
[445f984]	26	#include <string.h>
[58b6d1b]	27	#include <signal.h>
[9d944b2]	28	#include <unistd.h>
[bfb9bf5]	29
[dddb3dd0]	30	extern "C" {
	31	#include <sys/eventfd.h>
[d3605f8]	32	#include <sys/uio.h>
[dddb3dd0]	33	}
[8118303]	34
	35	//CFA Includes
[708ae38]	36	#include "kernel/private.hfa"
[73abe95]	37	#include "preemption.hfa"
[445f984]	38	#include "strstream.hfa"
	39	#include "device/cpu.hfa"
[7ef162b2]	40	#include "io/types.hfa"
[8118303]	41
	42	//Private includes
	43	#define __CFA_INVOKE_PRIVATE__
	44	#include "invoke.h"
[bfb9bf5]	45	#pragma GCC diagnostic pop
[8118303]	46
[89eff25]	47	#if !defined(__CFA_NO_STATISTICS__)
[c9c1c1cb]	48	#define __STATS_DEF( ...) __VA_ARGS__
[89eff25]	49	#else
[c9c1c1cb]	50	#define __STATS_DEF( ...)
[89eff25]	51	#endif
[4069faad]	52
[deca0f5]	53	//-----------------------------------------------------------------------------
	54	// Some assembly required
[1805b1b]	55	#if defined( __i386 )
[deca0f5]	56	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
	57	// fcw : X87 FPU control word (preserved across function calls)
	58	#define __x87_store \
	59	uint32_t __mxcr; \
	60	uint16_t __fcw; \
	61	__asm__ volatile ( \
	62	"stmxcsr %0\n" \
	63	"fnstcw %1\n" \
	64	: "=m" (__mxcr),\
	65	"=m" (__fcw) \
	66	)
	67
	68	#define __x87_load \
	69	__asm__ volatile ( \
	70	"fldcw %1\n" \
	71	"ldmxcsr %0\n" \
	72	::"m" (__mxcr),\
	73	"m" (__fcw) \
	74	)
	75
	76	#elif defined( __x86_64 )
	77	#define __x87_store \
	78	uint32_t __mxcr; \
	79	uint16_t __fcw; \
	80	__asm__ volatile ( \
	81	"stmxcsr %0\n" \
	82	"fnstcw %1\n" \
	83	: "=m" (__mxcr),\
	84	"=m" (__fcw) \
	85	)
	86
	87	#define __x87_load \
	88	__asm__ volatile ( \
	89	"fldcw %1\n" \
	90	"ldmxcsr %0\n" \
	91	:: "m" (__mxcr),\
	92	"m" (__fcw) \
	93	)
	94
[0190480]	95	#elif defined( __arm__ )
	96	#define __x87_store
	97	#define __x87_load
	98
	99	#elif defined( __aarch64__ )
[74f5c83]	100	#define __x87_store \
	101	uint32_t __fpcntl[2]; \
	102	__asm__ volatile ( \
	103	"mrs x9, FPCR\n" \
	104	"mrs x10, FPSR\n" \
	105	"stp x9, x10, %0\n" \
	106	: "=m" (__fpcntl) : : "x9", "x10" \
	107	)
	108
	109	#define __x87_load \
	110	__asm__ volatile ( \
	111	"ldp x9, x10, %0\n" \
	112	"msr FPSR, x10\n" \
	113	"msr FPCR, x9\n" \
	114	: "=m" (__fpcntl) : : "x9", "x10" \
	115	)
	116
[deca0f5]	117	#else
[0190480]	118	#error unsupported hardware architecture
[deca0f5]	119	#endif
	120
[e84ab3d]	121	extern thread$ * mainThread;
[e660761]	122	extern processor * mainProcessor;
[2ac095d]	123
[92e7631]	124	//-----------------------------------------------------------------------------
	125	// Kernel Scheduling logic
[e84ab3d]	126	static thread$ * __next_thread(cluster * this);
	127	static thread$ * __next_thread_slow(cluster * this);
[c9c1c1cb]	128	static thread$ * __next_thread_search(cluster * this);
[e84ab3d]	129	static inline bool __must_unpark( thread$ * thrd ) __attribute((nonnull(1)));
	130	static void __run_thread(processor * this, thread$ * dst);
[e873838]	131	static void __wake_one(cluster * cltr);
[1eb239e4]	132
[18f7858]	133	static void idle_sleep(processor * proc);
[5f5a729]	134	static bool mark_idle (__cluster_proc_list & idles, processor & proc);
[6a9b12b]	135	static void mark_awake(__cluster_proc_list & idles, processor & proc);
[1eb239e4]	136
[4479890]	137	extern bool __cfa_io_drain( processor * proc ) __attribute__((nonnull (1)));
[18f7858]	138	extern bool __cfa_io_flush( processor * ) __attribute__((nonnull (1)));
[dddb3dd0]	139
[7ef162b2]	140
[dddb3dd0]	141	extern void __disable_interrupts_hard();
	142	extern void __enable_interrupts_hard();
[c84e80a]	143
[7ef162b2]	144
[75f3522]	145	//=============================================================================================
	146	// Kernel Scheduling logic
	147	//=============================================================================================
[8fcbb4c]	148	//Main of the processor contexts
[83a071f9]	149	void main(processorCtx_t & runner) {
[21184e3]	150	// Because of a bug, we couldn't initialized the seed on construction
	151	// Do it here
[dd46fd3]	152	PRNG_SET_SEED( __cfaabi_tls.random_state, rdtscl() );
[8fc652e0]	153	__cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
[f2384c9a]	154	__tls_rand_advance_bck();
[21184e3]	155
[83a071f9]	156	processor * this = runner.proc;
[094476d]	157	verify(this);
[c81ebf9]	158
[4069faad]	159	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]	160	#if !defined(__CFA_NO_STATISTICS__)
	161	if( this->print_halts ) {
[c993b15]	162	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->unique_id, this->name, (void*)this);
[28d73c1]	163	}
	164	#endif
[b798713]	165
[75f3522]	166	{
[c81ebf9]	167	// Setup preemption data
	168	preemption_scope scope = { this };
	169
[a5e7233]	170	// if we need to run some special setup, now is the time to do it.
	171	if(this->init.thrd) {
	172	this->init.thrd->curr_cluster = this->cltr;
	173	__run_thread(this, this->init.thrd);
	174	}
[325e6ea]	175
[4069faad]	176	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]	177
[e84ab3d]	178	thread$ * readyThread = 0p;
[1eb239e4]	179	MAIN_LOOP:
	180	for() {
[dddb3dd0]	181	// Check if there is pending io
[18f7858]	182	__cfa_io_drain( this );
[dddb3dd0]	183
[92e7631]	184	// Try to get the next thread
[8c50aed]	185	readyThread = __next_thread( this->cltr );
[75f3522]	186
[1eb239e4]	187	if( !readyThread ) {
[18f7858]	188	// there is no point in holding submissions if we are idle
[c9c1c1cb]	189	__IO_STATS__(true, io.flush.idle++; )
[18f7858]	190	__cfa_io_flush( this );
	191
	192	// drain again in case something showed up
	193	__cfa_io_drain( this );
[c33c2af]	194
[c9c1c1cb]	195	readyThread = __next_thread( this->cltr );
	196	}
	197
	198	if( !readyThread ) for(5) {
[1eb239e4]	199	readyThread = __next_thread_slow( this->cltr );
[c9c1c1cb]	200
	201	if( readyThread ) break;
	202
[18f7858]	203	// It's unlikely we still I/O to submit, but the arbiter could
	204	__IO_STATS__(true, io.flush.idle++; )
	205	__cfa_io_flush( this );
	206
	207	// drain again in case something showed up
	208	__cfa_io_drain( this );
[1eb239e4]	209	}
[4e6fb8e]	210
[1eb239e4]	211	HALT:
	212	if( !readyThread ) {
	213	// Don't block if we are done
	214	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	215
[1eb239e4]	216	// Push self to idle stack
[5f5a729]	217	if(!mark_idle(this->cltr->procs, * this)) continue MAIN_LOOP;
[398e8e9]	218
[1eb239e4]	219	// Confirm the ready-queue is empty
[c9c1c1cb]	220	readyThread = __next_thread_search( this->cltr );
[1eb239e4]	221	if( readyThread ) {
	222	// A thread was found, cancel the halt
[6a9b12b]	223	mark_awake(this->cltr->procs, * this);
[1eb239e4]	224
[c9c1c1cb]	225	__STATS__(true, ready.sleep.cancels++; )
[1eb239e4]	226
	227	// continue the mai loop
	228	break HALT;
	229	}
	230
[18f7858]	231	idle_sleep( this );
[1eb239e4]	232
	233	// We were woken up, remove self from idle
[6a9b12b]	234	mark_awake(this->cltr->procs, * this);
[1eb239e4]	235
	236	// DON'T just proceed, start looking again
	237	continue MAIN_LOOP;
[64a7146]	238	}
[1eb239e4]	239
	240	/* paranoid */ verify( readyThread );
	241
[dddb3dd0]	242	// Reset io dirty bit
	243	this->io.dirty = false;
	244
[1eb239e4]	245	// We found a thread run it
	246	__run_thread(this, readyThread);
	247
	248	// Are we done?
	249	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]	250
[d529ad0]	251	if(__atomic_load_n(&this->io.pending, __ATOMIC_RELAXED) && !__atomic_load_n(&this->io.dirty, __ATOMIC_RELAXED)) {
[c9c1c1cb]	252	__IO_STATS__(true, io.flush.dirty++; )
[18f7858]	253	__cfa_io_flush( this );
[dddb3dd0]	254	}
[c81ebf9]	255	}
	256
[4069faad]	257	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]	258	}
[8118303]	259
[26544f9]	260	__cfa_io_flush( this );
	261	__cfa_io_drain( this );
	262
[454f478]	263	post( this->terminated );
[bdeba0b]	264
[28d73c1]	265	if(this == mainProcessor) {
[6a490b2]	266	// HACK : the coroutine context switch expects this_thread to be set
	267	// and it make sense for it to be set in all other cases except here
	268	// fake it
[8fc652e0]	269	__cfaabi_tls.this_thread = mainThread;
[6a490b2]	270	}
[7768b8d]	271
[4069faad]	272	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]	273	}
	274
[5c1a531]	275	static int * __volatile_errno() __attribute__((noinline));
	276	static int * __volatile_errno() { asm(""); return &errno; }
	277
[14a61b5]	278	// KERNEL ONLY
[1c273d0]	279	// runThread runs a thread by context switching
	280	// from the processor coroutine to the target thread
[e84ab3d]	281	static void __run_thread(processor * this, thread$ * thrd_dst) {
[8fc652e0]	282	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	283	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
[15c93d8]	284	/* paranoid */ verifyf( thrd_dst->rdy_link.next == 0p, "Expected null got %p", thrd_dst->rdy_link.next );
[1eb239e4]	285	__builtin_prefetch( thrd_dst->context.SP );
	286
[dddb3dd0]	287	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
	288
[e84ab3d]	289	coroutine$ * proc_cor = get_coroutine(this->runner);
[8fcbb4c]	290
[9f575ea]	291	// set state of processor coroutine to inactive
	292	verify(proc_cor->state == Active);
[ae7be7a]	293	proc_cor->state = Blocked;
[e8e457e]	294
[9f575ea]	295	// Actually run the thread
[3381ed7]	296	RUNNING: while(true) {
[ff79d5e]	297	thrd_dst->preempted = __NO_PREEMPTION;
[e8e457e]	298
[58d64a4]	299	// Update global state
[8fc652e0]	300	kernelTLS().this_thread = thrd_dst;
[75f3522]	301
[8bee858]	302	// Update the state after setting this_thread
	303	// so that the debugger can find all active threads
	304	// in tls storage
	305	thrd_dst->state = Active;
	306
[8fc652e0]	307	/* paranoid */ verify( ! __preemption_enabled() );
	308	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]	309	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]	310	/* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]	311	/* paranoid */ verify( thrd_dst->state != Halted );
[e84ab3d]	312	/* 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
	313	/* 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
[878cfcc]	314	/* paranoid */ verify( __atomic_exchange_n( &thrd_dst->executing, this, __ATOMIC_SEQ_CST) == 0p );
[ac12f1f]	315	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]	316
[3381ed7]	317
[58d64a4]	318
[9f575ea]	319	// set context switch to the thread that the processor is executing
[c7a900a]	320	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
	321	// when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]	322
[50871b4]	323
	324
[ac12f1f]	325	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[878cfcc]	326	/* paranoid */ verify( __atomic_exchange_n( &thrd_dst->executing, 0p, __ATOMIC_SEQ_CST) == this );
[e84ab3d]	327	/* 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 );
	328	/* 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 );
[878cfcc]	329	/* paranoid */ verify( thrd_dst->state != Halted );
[b4b63e8]	330	/* paranoid */ verify( thrd_dst->context.SP );
[8fc652e0]	331	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
	332	/* paranoid */ verify( ! __preemption_enabled() );
[75f3522]	333
[3381ed7]	334	// We just finished running a thread, there are a few things that could have happened.
	335	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
	336	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
	337	// 4 - Preempted
	338	// In case 1, we may have won a race so we can't write to the state again.
	339	// In case 2, we lost the race so we now own the thread.
	340
	341	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
[8bee858]	342	// Reset the this_thread now that we know
	343	// the state isn't active anymore
	344	kernelTLS().this_thread = 0p;
	345
[3381ed7]	346	// The thread was preempted, reschedule it and reset the flag
[24e321c]	347	schedule_thread$( thrd_dst, UNPARK_LOCAL );
[3381ed7]	348	break RUNNING;
	349	}
[75f3522]	350
[3ea8ad1]	351	if(unlikely(thrd_dst->state == Halting)) {
[8bee858]	352	// Reset the this_thread now that we know
	353	// the state isn't active anymore
	354	kernelTLS().this_thread = 0p;
	355
[ff79d5e]	356	// The thread has halted, it should never be scheduled/run again
[5afb49a]	357	// finish the thread
	358	__thread_finish( thrd_dst );
[ff79d5e]	359	break RUNNING;
	360	}
	361
	362	/* paranoid */ verify( thrd_dst->state == Active );
	363	thrd_dst->state = Blocked;
	364
[8bee858]	365	// Reset the this_thread now that we know
	366	// the state isn't active anymore
	367	kernelTLS().this_thread = 0p;
	368
[3381ed7]	369	// set state of processor coroutine to active and the thread to inactive
[ff79d5e]	370	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
	371	switch(old_ticket) {
[6a77224]	372	case TICKET_RUNNING:
[3381ed7]	373	// This is case 1, the regular case, nothing more is needed
	374	break RUNNING;
[6a77224]	375	case TICKET_UNBLOCK:
[c9c1c1cb]	376	__STATS__(true, ready.threads.threads++; )
[3381ed7]	377	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
	378	// In this case, just run it again.
	379	continue RUNNING;
	380	default:
	381	// This makes no sense, something is wrong abort
[ff79d5e]	382	abort();
[3381ed7]	383	}
[9f575ea]	384	}
[e8e457e]	385
[9f575ea]	386	// Just before returning to the processor, set the processor coroutine to active
[e8e457e]	387	proc_cor->state = Active;
[1eb239e4]	388
[dddb3dd0]	389	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
	390
[c9c1c1cb]	391	__STATS__(true, ready.threads.threads--; )
[ec43cf9]	392
[8fc652e0]	393	/* paranoid */ verify( ! __preemption_enabled() );
[82c948c]	394	}
	395
[14a61b5]	396	// KERNEL_ONLY
[c18bf9e]	397	static void returnToKernel() {
[8fc652e0]	398	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	399	coroutine$ * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
	400	thread$ * thrd_src = kernelTLS().this_thread;
[e8e457e]	401
[c9c1c1cb]	402	__STATS_DEF( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]	403
[9f575ea]	404	// Run the thread on this processor
	405	{
	406	int local_errno = *__volatile_errno();
	407	#if defined( __i386 ) \|\| defined( __x86_64 )
	408	__x87_store;
	409	#endif
[b4b63e8]	410	/* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]	411	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]	412	__cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]	413	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]	414	#if defined( __i386 ) \|\| defined( __x86_64 )
	415	__x87_load;
	416	#endif
	417	*__volatile_errno() = local_errno;
[8fcbb4c]	418	}
[deca0f5]	419
[29cb302]	420	#if !defined(__CFA_NO_STATISTICS__)
[89eff25]	421	/* paranoid */ verify( thrd_src->last_proc != 0p );
	422	if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]	423	__tls_stats()->ready.threads.migration++;
	424	}
	425	#endif
	426
[8fc652e0]	427	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	428	/* 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 );
	429	/* 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]	430	}
	431
[8def349]	432	//-----------------------------------------------------------------------------
	433	// Scheduler routines
[14a61b5]	434	// KERNEL ONLY
[24e321c]	435	static void __schedule_thread( thread$ * thrd, unpark_hint hint ) {
[8fc652e0]	436	/* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]	437	/* paranoid */ verify( ready_schedule_islocked());
[6a490b2]	438	/* paranoid */ verify( thrd );
	439	/* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]	440	/* paranoid */ verify( thrd->curr_cluster );
[3381ed7]	441	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]	442	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
	443	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]	444	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]	445	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]	446	/* paranoid */ #endif
[15c93d8]	447	/* paranoid */ verifyf( thrd->rdy_link.next == 0p, "Expected null got %p", thrd->rdy_link.next );
[ac12f1f]	448	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]	449
[ae7be7a]	450	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]	451
[ec43cf9]	452	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
	453	struct cluster * cl = thrd->curr_cluster;
[c9c1c1cb]	454	__STATS_DEF(bool outside = hint == UNPARK_LOCAL && thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]	455
[254ad1b]	456	// push the thread to the cluster ready-queue
[24e321c]	457	push( cl, thrd, hint );
[32a8b61]	458
[254ad1b]	459	// variable thrd is no longer safe to use
[734908c]	460	thrd = 0xdeaddeaddeaddeadp;
[32a8b61]	461
[254ad1b]	462	// wake the cluster using the save variable.
	463	__wake_one( cl );
[1c273d0]	464
[ec43cf9]	465	#if !defined(__CFA_NO_STATISTICS__)
	466	if( kernelTLS().this_stats ) {
	467	__tls_stats()->ready.threads.threads++;
[89eff25]	468	if(outside) {
	469	__tls_stats()->ready.threads.extunpark++;
	470	}
[ec43cf9]	471	}
	472	else {
	473	__atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]	474	__atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[ec43cf9]	475	}
	476	#endif
	477
[254ad1b]	478	/* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]	479	/* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]	480	}
	481
[24e321c]	482	void schedule_thread$( thread$ * thrd, unpark_hint hint ) {
[254ad1b]	483	ready_schedule_lock();
[24e321c]	484	__schedule_thread( thrd, hint );
[254ad1b]	485	ready_schedule_unlock();
	486	}
	487
[14a61b5]	488	// KERNEL ONLY
[e84ab3d]	489	static inline thread$ * __next_thread(cluster * this) with( *this ) {
[8fc652e0]	490	/* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]	491
[e873838]	492	ready_schedule_lock();
[e84ab3d]	493	thread$ * thrd = pop_fast( this );
[e873838]	494	ready_schedule_unlock();
[7768b8d]	495
[8fc652e0]	496	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	497	return thrd;
[eb2e723]	498	}
	499
[64a7146]	500	// KERNEL ONLY
[e84ab3d]	501	static inline thread$ * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]	502	/* paranoid */ verify( ! __preemption_enabled() );
[64a7146]	503
[e873838]	504	ready_schedule_lock();
[c9c1c1cb]	505	thread$ * thrd = pop_slow( this );
	506	ready_schedule_unlock();
	507
	508	/* paranoid */ verify( ! __preemption_enabled() );
	509	return thrd;
	510	}
[fc59df78]	511
[c9c1c1cb]	512	// KERNEL ONLY
	513	static inline thread$ * __next_thread_search(cluster * this) with( *this ) {
	514	/* paranoid */ verify( ! __preemption_enabled() );
	515
	516	ready_schedule_lock();
	517	thread$ * thrd = pop_search( this );
[e873838]	518	ready_schedule_unlock();
[64a7146]	519
[8fc652e0]	520	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	521	return thrd;
[64a7146]	522	}
	523
[e84ab3d]	524	static inline bool __must_unpark( thread$ * thrd ) {
[ff79d5e]	525	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
	526	switch(old_ticket) {
[6a77224]	527	case TICKET_RUNNING:
[3381ed7]	528	// Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]	529	return false;
[6a77224]	530	case TICKET_BLOCKED:
[3381ed7]	531	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]	532	/* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]	533	return true;
[3381ed7]	534	default:
	535	// This makes no sense, something is wrong abort
[7ee8153]	536	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]	537	}
[eb2e723]	538	}
	539
[24e321c]	540	void __kernel_unpark( thread$ * thrd, unpark_hint hint ) {
[e9c0b4c]	541	/* paranoid */ verify( ! __preemption_enabled() );
	542	/* paranoid */ verify( ready_schedule_islocked());
	543
	544	if( !thrd ) return;
	545
	546	if(__must_unpark(thrd)) {
	547	// Wake lost the race,
[24e321c]	548	__schedule_thread( thrd, hint );
[e9c0b4c]	549	}
	550
	551	/* paranoid */ verify( ready_schedule_islocked());
	552	/* paranoid */ verify( ! __preemption_enabled() );
	553	}
	554
[c18bf9e]	555	void unpark( thread$ * thrd, unpark_hint hint ) libcfa_public {
[c6c7e6c]	556	if( !thrd ) return;
[0b33412]	557
[c6c7e6c]	558	if(__must_unpark(thrd)) {
	559	disable_interrupts();
[a3821fa]	560	// Wake lost the race,
[24e321c]	561	schedule_thread$( thrd, hint );
[a3821fa]	562	enable_interrupts(false);
[de6319f]	563	}
[eb2e723]	564	}
[0b33412]	565
[c18bf9e]	566	void park( void ) libcfa_public {
[a3821fa]	567	__disable_interrupts_checked();
	568	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
	569	returnToKernel();
	570	__enable_interrupts_checked();
[0c78741]	571	}
[09800e9]	572
[5afb49a]	573	extern "C" {
	574	// Leave the thread monitor
	575	// last routine called by a thread.
	576	// Should never return
	577	void __cfactx_thrd_leave() {
[e84ab3d]	578	thread$ * thrd = active_thread();
	579	monitor$ * this = &thrd->self_mon;
[5afb49a]	580
	581	// Lock the monitor now
	582	lock( this->lock __cfaabi_dbg_ctx2 );
	583
	584	disable_interrupts();
	585
[9d6e1b8a]	586	/* paranoid */ verify( ! __preemption_enabled() );
	587	/* paranoid */ verify( thrd->state == Active );
	588	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
	589	/* paranoid */ verify( kernelTLS().this_thread == thrd );
	590	/* paranoid */ verify( thrd->context.SP );
[e84ab3d]	591	/* 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 );
	592	/* 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]	593
[58688bf]	594	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]	595	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
	596	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]	597
[28372f7]	598	thrd->state = Halting;
	599	thrd->ticket = TICKET_DEAD;
	600
[5afb49a]	601	// Leave the thread
	602	returnToKernel();
	603
	604	// Control flow should never reach here!
[9d6e1b8a]	605	abort();
[5afb49a]	606	}
[09800e9]	607	}
	608
[14a61b5]	609	// KERNEL ONLY
[c18bf9e]	610	bool force_yield( __Preemption_Reason reason ) libcfa_public {
[a3821fa]	611	__disable_interrupts_checked();
[e84ab3d]	612	thread$ * thrd = kernelTLS().this_thread;
[a3821fa]	613	/* paranoid */ verify(thrd->state == Active);
	614
	615	// SKULLDUGGERY: It is possible that we are preempting this thread just before
	616	// it was going to park itself. If that is the case and it is already using the
	617	// intrusive fields then we can't use them to preempt the thread
	618	// If that is the case, abandon the preemption.
	619	bool preempted = false;
[15c93d8]	620	if(thrd->rdy_link.next == 0p) {
[a3821fa]	621	preempted = true;
	622	thrd->preempted = reason;
	623	returnToKernel();
	624	}
	625	__enable_interrupts_checked( false );
[3381ed7]	626	return preempted;
[f2b12406]	627	}
	628
[14a61b5]	629	//=============================================================================================
[92e7631]	630	// Kernel Idle Sleep
[14a61b5]	631	//=============================================================================================
[64a7146]	632	// Wake a thread from the front if there are any
[e873838]	633	static void __wake_one(cluster * this) {
[7cf3b1d]	634	eventfd_t val;
	635
[8fc652e0]	636	/* paranoid */ verify( ! __preemption_enabled() );
[e873838]	637	/* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]	638
[64a7146]	639	// Check if there is a sleeping processor
[7cf3b1d]	640	struct __fd_waitctx * fdp = __atomic_load_n(&this->procs.fdw, __ATOMIC_SEQ_CST);
[14a61b5]	641
[7cf3b1d]	642	// If no one is sleeping: we are done
	643	if( fdp == 0p ) return;
[14a61b5]	644
[7cf3b1d]	645	int fd = 1;
[22226e4]	646	if( __atomic_load_n(&fdp->sem, __ATOMIC_SEQ_CST) != 1 ) {
	647	fd = __atomic_exchange_n(&fdp->sem, 1, __ATOMIC_RELAXED);
[7cf3b1d]	648	}
[14a61b5]	649
[7cf3b1d]	650	switch(fd) {
[4ccc150]	651	__attribute__((unused)) int ret;
[7cf3b1d]	652	case 0:
	653	// If the processor isn't ready to sleep then the exchange will already wake it up
	654	#if !defined(__CFA_NO_STATISTICS__)
	655	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.early++;
	656	} else { __atomic_fetch_add(&this->stats->ready.sleep.early, 1, __ATOMIC_RELAXED); }
	657	#endif
	658	break;
	659	case 1:
	660	// If someone else already said they will wake them: we are done
	661	#if !defined(__CFA_NO_STATISTICS__)
	662	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.seen++;
	663	} else { __atomic_fetch_add(&this->stats->ready.sleep.seen, 1, __ATOMIC_RELAXED); }
	664	#endif
	665	break;
	666	default:
	667	// If the processor was ready to sleep, we need to wake it up with an actual write
	668	val = 1;
[4ccc150]	669	ret = eventfd_write( fd, val );
[77adaee]	670	/* paranoid */ verifyf( ret == 0, "Expected return to be 0, was %d\n", ret );
[7cf3b1d]	671
	672	#if !defined(__CFA_NO_STATISTICS__)
	673	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.wakes++;
	674	} else { __atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED); }
	675	#endif
	676	break;
	677	}
[1eb239e4]	678
[e873838]	679	/* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]	680	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	681
	682	return;
[64a7146]	683	}
[14a61b5]	684
[64a7146]	685	// Unconditionnaly wake a thread
[1eb239e4]	686	void __wake_proc(processor * this) {
[7d0ebd0]	687	/* paranoid */ verify( ! __preemption_enabled() );
	688
[64a7146]	689	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]	690
[22226e4]	691	this->idle_wctx.sem = 1;
[7cf3b1d]	692
[efa28d5]	693	this->idle_wctx.wake__time = rdtscl();
[262fafd9]	694
[7d0ebd0]	695	eventfd_t val;
	696	val = 1;
[d080549]	697	__attribute__((unused)) int ret = eventfd_write( this->idle_wctx.evfd, val );
[7d0ebd0]	698
[d080549]	699	/* paranoid */ verifyf( ret == 0, "Expected return to be 0, was %d\n", ret );
[7d0ebd0]	700	/* paranoid */ verify( ! __preemption_enabled() );
[92e7631]	701	}
	702
[18f7858]	703	static void idle_sleep(processor * this) {
[202c80b]	704	/* paranoid */ verify( this->idle_wctx.evfd != 1 );
	705	/* paranoid */ verify( this->idle_wctx.evfd != 2 );
	706
[7cf3b1d]	707	// Tell everyone we are ready to go do sleep
	708	for() {
[22226e4]	709	int expected = this->idle_wctx.sem;
[7cf3b1d]	710
	711	// Someone already told us to wake-up! No time for a nap.
	712	if(expected == 1) { return; }
	713
	714	// Try to mark that we are going to sleep
[22226e4]	715	if(__atomic_compare_exchange_n(&this->idle_wctx.sem, &expected, this->idle_wctx.evfd, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ) {
[7cf3b1d]	716	// Every one agreed, taking a nap
	717	break;
	718	}
	719	}
	720
	721
[a757ba1]	722	#if !defined(__CFA_NO_STATISTICS__)
	723	if(this->print_halts) {
	724	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
	725	}
	726	#endif
[1757f98]	727
[a757ba1]	728	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle_fd);
[1757f98]	729
[a757ba1]	730	{
	731	eventfd_t val;
	732	ssize_t ret = read( this->idle_wctx.evfd, &val, sizeof(val) );
	733	if(ret < 0) {
	734	switch((int)errno) {
	735	case EAGAIN:
	736	#if EAGAIN != EWOULDBLOCK
	737	case EWOULDBLOCK:
	738	#endif
	739	case EINTR:
	740	// No need to do anything special here, just assume it's a legitimate wake-up
	741	break;
	742	default:
	743	abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
[1757f98]	744	}
	745	}
[a757ba1]	746	}
[1757f98]	747
[a757ba1]	748	#if !defined(__CFA_NO_STATISTICS__)
	749	if(this->print_halts) {
	750	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
	751	}
[1757f98]	752	#endif
	753	}
	754
[5f5a729]	755	static bool mark_idle(__cluster_proc_list & this, processor & proc) {
[c9c1c1cb]	756	__STATS__(true, ready.sleep.halts++; )
[7cf3b1d]	757
[22226e4]	758	proc.idle_wctx.sem = 0;
[7cf3b1d]	759
[8fc652e0]	760	/* paranoid */ verify( ! __preemption_enabled() );
[5f5a729]	761	if(!try_lock( this )) return false;
[1eb239e4]	762	this.idle++;
	763	/* paranoid */ verify( this.idle <= this.total );
[fc59b580]	764	remove(proc);
[6a9b12b]	765	insert_first(this.idles, proc);
[34b8cb7]	766
[a757ba1]	767	// update the pointer to the head wait context, which should now point to this proc.
[7cf3b1d]	768	__atomic_store_n(&this.fdw, &proc.idle_wctx, __ATOMIC_SEQ_CST);
[1eb239e4]	769	unlock( this );
[8fc652e0]	770	/* paranoid */ verify( ! __preemption_enabled() );
[5f5a729]	771
	772	return true;
[1eb239e4]	773	}
[8e16177]	774
[6a9b12b]	775	static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	776	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	777	lock( this );
	778	this.idle--;
	779	/* paranoid */ verify( this.idle >= 0 );
	780	remove(proc);
[fc59b580]	781	insert_last(this.actives, proc);
[6a9b12b]	782
[a633f6f]	783	{
[a757ba1]	784	// update the pointer to the head wait context
[7cf3b1d]	785	struct __fd_waitctx * wctx = 0;
	786	if(!this.idles`isEmpty) wctx = &this.idles`first.idle_wctx;
	787	__atomic_store_n(&this.fdw, wctx, __ATOMIC_SEQ_CST);
[a633f6f]	788	}
	789
[34b8cb7]	790	unlock( this );
[6a9b12b]	791	/* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]	792	}
	793
[dbe9b08]	794	//=============================================================================================
	795	// Unexpected Terminating logic
	796	//=============================================================================================
[92bfda0]	797	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
[e84ab3d]	798	thread$ * thrd = __cfaabi_tls.this_thread;
[9d944b2]	799
[de94a60]	800	if(thrd) {
	801	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]	802	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	803
[212c2187]	804	if ( &thrd->self_cor != thrd->curr_cor ) {
	805	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]	806	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	807	}
	808	else {
[1c40091]	809	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]	810	}
[1c273d0]	811	}
[9d944b2]	812	else {
[de94a60]	813	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]	814	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]	815	}
	816	}
	817
[92bfda0]	818	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
	819	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]	820	}
	821
[de94a60]	822	static __spinlock_t kernel_debug_lock;
	823
[9d944b2]	824	extern "C" {
[1c40091]	825	void __cfaabi_bits_acquire() {
[36982fc]	826	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]	827	}
	828
[1c40091]	829	void __cfaabi_bits_release() {
[ea7d2b0]	830	unlock( kernel_debug_lock );
[9d944b2]	831	}
[8118303]	832	}
	833
[fa21ac9]	834	//=============================================================================================
	835	// Kernel Utilities
	836	//=============================================================================================
[dddb3dd0]	837	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	838	#include "io/types.hfa"
	839	#endif
	840
[2026bb6]	841	//-----------------------------------------------------------------------------
	842	// Debug
[c18bf9e]	843	bool threading_enabled(void) __attribute__((const)) libcfa_public {
[2026bb6]	844	return true;
	845	}
[c34ebf2]	846
	847	//-----------------------------------------------------------------------------
	848	// Statistics
	849	#if !defined(__CFA_NO_STATISTICS__)
[c18bf9e]	850	void print_halts( processor & this ) libcfa_public {
[c34ebf2]	851	this.print_halts = true;
	852	}
[58688bf]	853
[69914cbc]	854	static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
[8464edf]	855	/* paranoid */ verify( cltr->stats );
	856
	857	processor * it = &list`first;
	858	for(unsigned i = 0; i < count; i++) {
	859	/* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
	860	/* paranoid */ verify( it->local_data->this_stats );
[c33c2af]	861	// __print_stats( it->local_data->this_stats, cltr->print_stats, "Processor", it->name, (void*)it );
[8464edf]	862	__tally_stats( cltr->stats, it->local_data->this_stats );
	863	it = &(*it)`next;
	864	}
	865	}
	866
[c18bf9e]	867	static void crawl_cluster_stats( cluster & this ) {
[8464edf]	868	// Stop the world, otherwise stats could get really messed-up
	869	// this doesn't solve all problems but does solve many
	870	// so it's probably good enough
[c33c2af]	871	disable_interrupts();
[8464edf]	872	uint_fast32_t last_size = ready_mutate_lock();
	873
	874	crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
	875	crawl_list(&this, this.procs.idles , this.procs.idle );
	876
	877	// Unlock the RWlock
	878	ready_mutate_unlock( last_size );
[c33c2af]	879	enable_interrupts();
[8464edf]	880	}
	881
	882
[c18bf9e]	883	void print_stats_now( cluster & this, int flags ) libcfa_public {
[8464edf]	884	crawl_cluster_stats( this );
[202c80b]	885	__print_stats( this.stats, flags, "Cluster", this.name, (void*)&this );
[1b033b8]	886	}
[c34ebf2]	887	#endif
[8118303]	888	// Local Variables: //
	889	// mode: c //
	890	// tab-width: 4 //
	891	// End: //

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