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kernel.cfa@ fa2e183

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ADT ast-experimental

Last change on this file since fa2e183 was 878cfcc, checked in by Thierry Delisle <tdelisle@…>, 3 years ago
Added extra check to make sure threads is never double executed
Property mode set to `100644`
File size: 29.0 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
[bfb9bf5]	21	#pragma GCC diagnostic push
	22	#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
	23
[8118303]	24	//C Includes
[214e8da]	25	#include <errno.h>
[9d944b2]	26	#include <stdio.h>
[445f984]	27	#include <string.h>
[58b6d1b]	28	#include <signal.h>
[9d944b2]	29	#include <unistd.h>
[bfb9bf5]	30
[dddb3dd0]	31	extern "C" {
	32	#include <sys/eventfd.h>
[d3605f8]	33	#include <sys/uio.h>
[dddb3dd0]	34	}
[8118303]	35
	36	//CFA Includes
[708ae38]	37	#include "kernel/private.hfa"
[73abe95]	38	#include "preemption.hfa"
[445f984]	39	#include "strstream.hfa"
	40	#include "device/cpu.hfa"
[7ef162b2]	41	#include "io/types.hfa"
[8118303]	42
	43	//Private includes
	44	#define __CFA_INVOKE_PRIVATE__
	45	#include "invoke.h"
[bfb9bf5]	46	#pragma GCC diagnostic pop
[8118303]	47
[89eff25]	48	#if !defined(__CFA_NO_STATISTICS__)
[c9c1c1cb]	49	#define __STATS_DEF( ...) __VA_ARGS__
[89eff25]	50	#else
[c9c1c1cb]	51	#define __STATS_DEF( ...)
[89eff25]	52	#endif
[4069faad]	53
[deca0f5]	54	//-----------------------------------------------------------------------------
	55	// Some assembly required
[1805b1b]	56	#if defined( __i386 )
[deca0f5]	57	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
	58	// fcw : X87 FPU control word (preserved across function calls)
	59	#define __x87_store \
	60	uint32_t __mxcr; \
	61	uint16_t __fcw; \
	62	__asm__ volatile ( \
	63	"stmxcsr %0\n" \
	64	"fnstcw %1\n" \
	65	: "=m" (__mxcr),\
	66	"=m" (__fcw) \
	67	)
	68
	69	#define __x87_load \
	70	__asm__ volatile ( \
	71	"fldcw %1\n" \
	72	"ldmxcsr %0\n" \
	73	::"m" (__mxcr),\
	74	"m" (__fcw) \
	75	)
	76
	77	#elif defined( __x86_64 )
	78	#define __x87_store \
	79	uint32_t __mxcr; \
	80	uint16_t __fcw; \
	81	__asm__ volatile ( \
	82	"stmxcsr %0\n" \
	83	"fnstcw %1\n" \
	84	: "=m" (__mxcr),\
	85	"=m" (__fcw) \
	86	)
	87
	88	#define __x87_load \
	89	__asm__ volatile ( \
	90	"fldcw %1\n" \
	91	"ldmxcsr %0\n" \
	92	:: "m" (__mxcr),\
	93	"m" (__fcw) \
	94	)
	95
[0190480]	96	#elif defined( __arm__ )
	97	#define __x87_store
	98	#define __x87_load
	99
	100	#elif defined( __aarch64__ )
[74f5c83]	101	#define __x87_store \
	102	uint32_t __fpcntl[2]; \
	103	__asm__ volatile ( \
	104	"mrs x9, FPCR\n" \
	105	"mrs x10, FPSR\n" \
	106	"stp x9, x10, %0\n" \
	107	: "=m" (__fpcntl) : : "x9", "x10" \
	108	)
	109
	110	#define __x87_load \
	111	__asm__ volatile ( \
	112	"ldp x9, x10, %0\n" \
	113	"msr FPSR, x10\n" \
	114	"msr FPCR, x9\n" \
	115	: "=m" (__fpcntl) : : "x9", "x10" \
	116	)
	117
[deca0f5]	118	#else
[0190480]	119	#error unsupported hardware architecture
[deca0f5]	120	#endif
	121
[e84ab3d]	122	extern thread$ * mainThread;
[e660761]	123	extern processor * mainProcessor;
[2ac095d]	124
[92e7631]	125	//-----------------------------------------------------------------------------
	126	// Kernel Scheduling logic
[e84ab3d]	127	static thread$ * __next_thread(cluster * this);
	128	static thread$ * __next_thread_slow(cluster * this);
[c9c1c1cb]	129	static thread$ * __next_thread_search(cluster * this);
[e84ab3d]	130	static inline bool __must_unpark( thread$ * thrd ) __attribute((nonnull(1)));
	131	static void __run_thread(processor * this, thread$ * dst);
[e873838]	132	static void __wake_one(cluster * cltr);
[1eb239e4]	133
[18f7858]	134	static void idle_sleep(processor * proc);
[5f5a729]	135	static bool mark_idle (__cluster_proc_list & idles, processor & proc);
[6a9b12b]	136	static void mark_awake(__cluster_proc_list & idles, processor & proc);
[1eb239e4]	137
[4479890]	138	extern bool __cfa_io_drain( processor * proc ) __attribute__((nonnull (1)));
[18f7858]	139	extern bool __cfa_io_flush( processor * ) __attribute__((nonnull (1)));
	140	extern void __cfa_io_idle( processor * ) __attribute__((nonnull (1)));
[dddb3dd0]	141
[d3605f8]	142	#if defined(CFA_WITH_IO_URING_IDLE)
	143	extern bool __kernel_read(processor * proc, io_future_t & future, iovec &, int fd);
[6ddef36]	144	#endif
[7ef162b2]	145
[dddb3dd0]	146	extern void __disable_interrupts_hard();
	147	extern void __enable_interrupts_hard();
[c84e80a]	148
[7ef162b2]	149
[75f3522]	150	//=============================================================================================
	151	// Kernel Scheduling logic
	152	//=============================================================================================
[8fcbb4c]	153	//Main of the processor contexts
[83a071f9]	154	void main(processorCtx_t & runner) {
[21184e3]	155	// Because of a bug, we couldn't initialized the seed on construction
	156	// Do it here
[8fc652e0]	157	__cfaabi_tls.rand_seed ^= rdtscl();
	158	__cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
[f2384c9a]	159	__tls_rand_advance_bck();
[21184e3]	160
[83a071f9]	161	processor * this = runner.proc;
[094476d]	162	verify(this);
[c81ebf9]	163
[22226e4]	164	/* paranoid */ verify( this->idle_wctx.ftr != 0p );
	165	/* paranoid */ verify( this->idle_wctx.rdbuf != 0p );
[7ef162b2]	166
[22226e4]	167	// used for idle sleep when io_uring is present
	168	// mark it as already fulfilled so we know if there is a pending request or not
	169	this->idle_wctx.ftr->self.ptr = 1p;
[dddb3dd0]	170
[4069faad]	171	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]	172	#if !defined(__CFA_NO_STATISTICS__)
	173	if( this->print_halts ) {
[c993b15]	174	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->unique_id, this->name, (void*)this);
[28d73c1]	175	}
	176	#endif
[b798713]	177
[75f3522]	178	{
[c81ebf9]	179	// Setup preemption data
	180	preemption_scope scope = { this };
	181
[a5e7233]	182	// if we need to run some special setup, now is the time to do it.
	183	if(this->init.thrd) {
	184	this->init.thrd->curr_cluster = this->cltr;
	185	__run_thread(this, this->init.thrd);
	186	}
[325e6ea]	187
[4069faad]	188	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]	189
[e84ab3d]	190	thread$ * readyThread = 0p;
[1eb239e4]	191	MAIN_LOOP:
	192	for() {
[dddb3dd0]	193	// Check if there is pending io
[18f7858]	194	__cfa_io_drain( this );
[dddb3dd0]	195
[92e7631]	196	// Try to get the next thread
[8c50aed]	197	readyThread = __next_thread( this->cltr );
[75f3522]	198
[1eb239e4]	199	if( !readyThread ) {
[18f7858]	200	// there is no point in holding submissions if we are idle
[c9c1c1cb]	201	__IO_STATS__(true, io.flush.idle++; )
[18f7858]	202	__cfa_io_flush( this );
	203
	204	// drain again in case something showed up
	205	__cfa_io_drain( this );
[c33c2af]	206
[c9c1c1cb]	207	readyThread = __next_thread( this->cltr );
	208	}
	209
	210	if( !readyThread ) for(5) {
[1eb239e4]	211	readyThread = __next_thread_slow( this->cltr );
[c9c1c1cb]	212
	213	if( readyThread ) break;
	214
[18f7858]	215	// It's unlikely we still I/O to submit, but the arbiter could
	216	__IO_STATS__(true, io.flush.idle++; )
	217	__cfa_io_flush( this );
	218
	219	// drain again in case something showed up
	220	__cfa_io_drain( this );
[1eb239e4]	221	}
[4e6fb8e]	222
[1eb239e4]	223	HALT:
	224	if( !readyThread ) {
	225	// Don't block if we are done
	226	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	227
[1eb239e4]	228	// Push self to idle stack
[5f5a729]	229	if(!mark_idle(this->cltr->procs, * this)) continue MAIN_LOOP;
[398e8e9]	230
[1eb239e4]	231	// Confirm the ready-queue is empty
[c9c1c1cb]	232	readyThread = __next_thread_search( this->cltr );
[1eb239e4]	233	if( readyThread ) {
	234	// A thread was found, cancel the halt
[6a9b12b]	235	mark_awake(this->cltr->procs, * this);
[1eb239e4]	236
[c9c1c1cb]	237	__STATS__(true, ready.sleep.cancels++; )
[1eb239e4]	238
	239	// continue the mai loop
	240	break HALT;
	241	}
	242
[18f7858]	243	idle_sleep( this );
[1eb239e4]	244
	245	// We were woken up, remove self from idle
[6a9b12b]	246	mark_awake(this->cltr->procs, * this);
[1eb239e4]	247
	248	// DON'T just proceed, start looking again
	249	continue MAIN_LOOP;
[64a7146]	250	}
[1eb239e4]	251
	252	/* paranoid */ verify( readyThread );
	253
[dddb3dd0]	254	// Reset io dirty bit
	255	this->io.dirty = false;
	256
[1eb239e4]	257	// We found a thread run it
	258	__run_thread(this, readyThread);
	259
	260	// Are we done?
	261	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]	262
[d529ad0]	263	if(__atomic_load_n(&this->io.pending, __ATOMIC_RELAXED) && !__atomic_load_n(&this->io.dirty, __ATOMIC_RELAXED)) {
[c9c1c1cb]	264	__IO_STATS__(true, io.flush.dirty++; )
[18f7858]	265	__cfa_io_flush( this );
[dddb3dd0]	266	}
[c81ebf9]	267	}
	268
[4069faad]	269	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]	270	}
[8118303]	271
[454f478]	272	post( this->terminated );
[bdeba0b]	273
[28d73c1]	274	if(this == mainProcessor) {
[6a490b2]	275	// HACK : the coroutine context switch expects this_thread to be set
	276	// and it make sense for it to be set in all other cases except here
	277	// fake it
[8fc652e0]	278	__cfaabi_tls.this_thread = mainThread;
[6a490b2]	279	}
[7768b8d]	280
[4069faad]	281	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]	282	}
	283
[5c1a531]	284	static int * __volatile_errno() __attribute__((noinline));
	285	static int * __volatile_errno() { asm(""); return &errno; }
	286
[14a61b5]	287	// KERNEL ONLY
[1c273d0]	288	// runThread runs a thread by context switching
	289	// from the processor coroutine to the target thread
[e84ab3d]	290	static void __run_thread(processor * this, thread$ * thrd_dst) {
[8fc652e0]	291	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	292	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
	293	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
	294	__builtin_prefetch( thrd_dst->context.SP );
	295
[dddb3dd0]	296	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
	297
[e84ab3d]	298	coroutine$ * proc_cor = get_coroutine(this->runner);
[8fcbb4c]	299
[9f575ea]	300	// set state of processor coroutine to inactive
	301	verify(proc_cor->state == Active);
[ae7be7a]	302	proc_cor->state = Blocked;
[e8e457e]	303
[9f575ea]	304	// Actually run the thread
[3381ed7]	305	RUNNING: while(true) {
[ff79d5e]	306	thrd_dst->preempted = __NO_PREEMPTION;
[e8e457e]	307
[58d64a4]	308	// Update global state
[8fc652e0]	309	kernelTLS().this_thread = thrd_dst;
[75f3522]	310
[8bee858]	311	// Update the state after setting this_thread
	312	// so that the debugger can find all active threads
	313	// in tls storage
	314	thrd_dst->state = Active;
	315
[8fc652e0]	316	/* paranoid */ verify( ! __preemption_enabled() );
	317	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]	318	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]	319	/* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]	320	/* paranoid */ verify( thrd_dst->state != Halted );
[e84ab3d]	321	/* 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
	322	/* 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]	323	/* paranoid */ verify( __atomic_exchange_n( &thrd_dst->executing, this, __ATOMIC_SEQ_CST) == 0p );
[ac12f1f]	324	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]	325
[3381ed7]	326
[58d64a4]	327
[9f575ea]	328	// set context switch to the thread that the processor is executing
[c7a900a]	329	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
	330	// when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]	331
[50871b4]	332
	333
[ac12f1f]	334	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[878cfcc]	335	/* paranoid */ verify( __atomic_exchange_n( &thrd_dst->executing, 0p, __ATOMIC_SEQ_CST) == this );
[e84ab3d]	336	/* 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 );
	337	/* 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]	338	/* paranoid */ verify( thrd_dst->state != Halted );
[b4b63e8]	339	/* paranoid */ verify( thrd_dst->context.SP );
[8fc652e0]	340	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
	341	/* paranoid */ verify( ! __preemption_enabled() );
[75f3522]	342
[3381ed7]	343	// We just finished running a thread, there are a few things that could have happened.
	344	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
	345	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
	346	// 4 - Preempted
	347	// In case 1, we may have won a race so we can't write to the state again.
	348	// In case 2, we lost the race so we now own the thread.
	349
	350	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
[8bee858]	351	// Reset the this_thread now that we know
	352	// the state isn't active anymore
	353	kernelTLS().this_thread = 0p;
	354
[3381ed7]	355	// The thread was preempted, reschedule it and reset the flag
[24e321c]	356	schedule_thread$( thrd_dst, UNPARK_LOCAL );
[3381ed7]	357	break RUNNING;
	358	}
[75f3522]	359
[3ea8ad1]	360	if(unlikely(thrd_dst->state == Halting)) {
[8bee858]	361	// Reset the this_thread now that we know
	362	// the state isn't active anymore
	363	kernelTLS().this_thread = 0p;
	364
[ff79d5e]	365	// The thread has halted, it should never be scheduled/run again
[5afb49a]	366	// finish the thread
	367	__thread_finish( thrd_dst );
[ff79d5e]	368	break RUNNING;
	369	}
	370
	371	/* paranoid */ verify( thrd_dst->state == Active );
	372	thrd_dst->state = Blocked;
	373
[8bee858]	374	// Reset the this_thread now that we know
	375	// the state isn't active anymore
	376	kernelTLS().this_thread = 0p;
	377
[3381ed7]	378	// set state of processor coroutine to active and the thread to inactive
[ff79d5e]	379	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
	380	switch(old_ticket) {
[6a77224]	381	case TICKET_RUNNING:
[3381ed7]	382	// This is case 1, the regular case, nothing more is needed
	383	break RUNNING;
[6a77224]	384	case TICKET_UNBLOCK:
[c9c1c1cb]	385	__STATS__(true, ready.threads.threads++; )
[3381ed7]	386	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
	387	// In this case, just run it again.
	388	continue RUNNING;
	389	default:
	390	// This makes no sense, something is wrong abort
[ff79d5e]	391	abort();
[3381ed7]	392	}
[9f575ea]	393	}
[e8e457e]	394
[9f575ea]	395	// Just before returning to the processor, set the processor coroutine to active
[e8e457e]	396	proc_cor->state = Active;
[1eb239e4]	397
[dddb3dd0]	398	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
	399
[c9c1c1cb]	400	__STATS__(true, ready.threads.threads--; )
[ec43cf9]	401
[8fc652e0]	402	/* paranoid */ verify( ! __preemption_enabled() );
[82c948c]	403	}
	404
[14a61b5]	405	// KERNEL_ONLY
[c18bf9e]	406	static void returnToKernel() {
[8fc652e0]	407	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	408	coroutine$ * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
	409	thread$ * thrd_src = kernelTLS().this_thread;
[e8e457e]	410
[c9c1c1cb]	411	__STATS_DEF( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]	412
[9f575ea]	413	// Run the thread on this processor
	414	{
	415	int local_errno = *__volatile_errno();
	416	#if defined( __i386 ) \|\| defined( __x86_64 )
	417	__x87_store;
	418	#endif
[b4b63e8]	419	/* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]	420	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]	421	__cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]	422	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]	423	#if defined( __i386 ) \|\| defined( __x86_64 )
	424	__x87_load;
	425	#endif
	426	*__volatile_errno() = local_errno;
[8fcbb4c]	427	}
[deca0f5]	428
[29cb302]	429	#if !defined(__CFA_NO_STATISTICS__)
[89eff25]	430	/* paranoid */ verify( thrd_src->last_proc != 0p );
	431	if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]	432	__tls_stats()->ready.threads.migration++;
	433	}
	434	#endif
	435
[8fc652e0]	436	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	437	/* 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 );
	438	/* 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]	439	}
	440
[8def349]	441	//-----------------------------------------------------------------------------
	442	// Scheduler routines
[14a61b5]	443	// KERNEL ONLY
[24e321c]	444	static void __schedule_thread( thread$ * thrd, unpark_hint hint ) {
[8fc652e0]	445	/* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]	446	/* paranoid */ verify( ready_schedule_islocked());
[6a490b2]	447	/* paranoid */ verify( thrd );
	448	/* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]	449	/* paranoid */ verify( thrd->curr_cluster );
[3381ed7]	450	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]	451	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
	452	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]	453	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]	454	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]	455	/* paranoid */ #endif
[6a490b2]	456	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]	457	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]	458
[ae7be7a]	459	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]	460
[ec43cf9]	461	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
	462	struct cluster * cl = thrd->curr_cluster;
[c9c1c1cb]	463	__STATS_DEF(bool outside = hint == UNPARK_LOCAL && thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]	464
[254ad1b]	465	// push the thread to the cluster ready-queue
[24e321c]	466	push( cl, thrd, hint );
[32a8b61]	467
[254ad1b]	468	// variable thrd is no longer safe to use
[734908c]	469	thrd = 0xdeaddeaddeaddeadp;
[32a8b61]	470
[254ad1b]	471	// wake the cluster using the save variable.
	472	__wake_one( cl );
[1c273d0]	473
[ec43cf9]	474	#if !defined(__CFA_NO_STATISTICS__)
	475	if( kernelTLS().this_stats ) {
	476	__tls_stats()->ready.threads.threads++;
[89eff25]	477	if(outside) {
	478	__tls_stats()->ready.threads.extunpark++;
	479	}
[ec43cf9]	480	}
	481	else {
	482	__atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]	483	__atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[ec43cf9]	484	}
	485	#endif
	486
[254ad1b]	487	/* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]	488	/* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]	489	}
	490
[24e321c]	491	void schedule_thread$( thread$ * thrd, unpark_hint hint ) {
[254ad1b]	492	ready_schedule_lock();
[24e321c]	493	__schedule_thread( thrd, hint );
[254ad1b]	494	ready_schedule_unlock();
	495	}
	496
[14a61b5]	497	// KERNEL ONLY
[e84ab3d]	498	static inline thread$ * __next_thread(cluster * this) with( *this ) {
[8fc652e0]	499	/* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]	500
[e873838]	501	ready_schedule_lock();
[e84ab3d]	502	thread$ * thrd = pop_fast( this );
[e873838]	503	ready_schedule_unlock();
[7768b8d]	504
[8fc652e0]	505	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	506	return thrd;
[eb2e723]	507	}
	508
[64a7146]	509	// KERNEL ONLY
[e84ab3d]	510	static inline thread$ * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]	511	/* paranoid */ verify( ! __preemption_enabled() );
[64a7146]	512
[e873838]	513	ready_schedule_lock();
[c9c1c1cb]	514	thread$ * thrd = pop_slow( this );
	515	ready_schedule_unlock();
	516
	517	/* paranoid */ verify( ! __preemption_enabled() );
	518	return thrd;
	519	}
[fc59df78]	520
[c9c1c1cb]	521	// KERNEL ONLY
	522	static inline thread$ * __next_thread_search(cluster * this) with( *this ) {
	523	/* paranoid */ verify( ! __preemption_enabled() );
	524
	525	ready_schedule_lock();
	526	thread$ * thrd = pop_search( this );
[e873838]	527	ready_schedule_unlock();
[64a7146]	528
[8fc652e0]	529	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	530	return thrd;
[64a7146]	531	}
	532
[e84ab3d]	533	static inline bool __must_unpark( thread$ * thrd ) {
[ff79d5e]	534	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
	535	switch(old_ticket) {
[6a77224]	536	case TICKET_RUNNING:
[3381ed7]	537	// Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]	538	return false;
[6a77224]	539	case TICKET_BLOCKED:
[3381ed7]	540	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]	541	/* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]	542	return true;
[3381ed7]	543	default:
	544	// This makes no sense, something is wrong abort
[7ee8153]	545	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]	546	}
[eb2e723]	547	}
	548
[24e321c]	549	void __kernel_unpark( thread$ * thrd, unpark_hint hint ) {
[e9c0b4c]	550	/* paranoid */ verify( ! __preemption_enabled() );
	551	/* paranoid */ verify( ready_schedule_islocked());
	552
	553	if( !thrd ) return;
	554
	555	if(__must_unpark(thrd)) {
	556	// Wake lost the race,
[24e321c]	557	__schedule_thread( thrd, hint );
[e9c0b4c]	558	}
	559
	560	/* paranoid */ verify( ready_schedule_islocked());
	561	/* paranoid */ verify( ! __preemption_enabled() );
	562	}
	563
[c18bf9e]	564	void unpark( thread$ * thrd, unpark_hint hint ) libcfa_public {
[c6c7e6c]	565	if( !thrd ) return;
[0b33412]	566
[c6c7e6c]	567	if(__must_unpark(thrd)) {
	568	disable_interrupts();
[a3821fa]	569	// Wake lost the race,
[24e321c]	570	schedule_thread$( thrd, hint );
[a3821fa]	571	enable_interrupts(false);
[de6319f]	572	}
[eb2e723]	573	}
[0b33412]	574
[c18bf9e]	575	void park( void ) libcfa_public {
[a3821fa]	576	__disable_interrupts_checked();
	577	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
	578	returnToKernel();
	579	__enable_interrupts_checked();
[0c78741]	580
	581	}
[09800e9]	582
[5afb49a]	583	extern "C" {
	584	// Leave the thread monitor
	585	// last routine called by a thread.
	586	// Should never return
	587	void __cfactx_thrd_leave() {
[e84ab3d]	588	thread$ * thrd = active_thread();
	589	monitor$ * this = &thrd->self_mon;
[5afb49a]	590
	591	// Lock the monitor now
	592	lock( this->lock __cfaabi_dbg_ctx2 );
	593
	594	disable_interrupts();
	595
[9d6e1b8a]	596	/* paranoid */ verify( ! __preemption_enabled() );
	597	/* paranoid */ verify( thrd->state == Active );
	598	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
	599	/* paranoid */ verify( kernelTLS().this_thread == thrd );
	600	/* paranoid */ verify( thrd->context.SP );
[e84ab3d]	601	/* 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 );
	602	/* 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]	603
[3ea8ad1]	604	thrd->state = Halting;
[58688bf]	605	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]	606	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
	607	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]	608
	609	// Leave the thread
	610	returnToKernel();
	611
	612	// Control flow should never reach here!
[9d6e1b8a]	613	abort();
[5afb49a]	614	}
[09800e9]	615	}
	616
[14a61b5]	617	// KERNEL ONLY
[c18bf9e]	618	bool force_yield( __Preemption_Reason reason ) libcfa_public {
[a3821fa]	619	__disable_interrupts_checked();
[e84ab3d]	620	thread$ * thrd = kernelTLS().this_thread;
[a3821fa]	621	/* paranoid */ verify(thrd->state == Active);
	622
	623	// SKULLDUGGERY: It is possible that we are preempting this thread just before
	624	// it was going to park itself. If that is the case and it is already using the
	625	// intrusive fields then we can't use them to preempt the thread
	626	// If that is the case, abandon the preemption.
	627	bool preempted = false;
	628	if(thrd->link.next == 0p) {
	629	preempted = true;
	630	thrd->preempted = reason;
	631	returnToKernel();
	632	}
	633	__enable_interrupts_checked( false );
[3381ed7]	634	return preempted;
[f2b12406]	635	}
	636
[14a61b5]	637	//=============================================================================================
[92e7631]	638	// Kernel Idle Sleep
[14a61b5]	639	//=============================================================================================
[64a7146]	640	// Wake a thread from the front if there are any
[e873838]	641	static void __wake_one(cluster * this) {
[7cf3b1d]	642	eventfd_t val;
	643
[8fc652e0]	644	/* paranoid */ verify( ! __preemption_enabled() );
[e873838]	645	/* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]	646
[64a7146]	647	// Check if there is a sleeping processor
[7cf3b1d]	648	struct __fd_waitctx * fdp = __atomic_load_n(&this->procs.fdw, __ATOMIC_SEQ_CST);
[14a61b5]	649
[7cf3b1d]	650	// If no one is sleeping: we are done
	651	if( fdp == 0p ) return;
[14a61b5]	652
[7cf3b1d]	653	int fd = 1;
[22226e4]	654	if( __atomic_load_n(&fdp->sem, __ATOMIC_SEQ_CST) != 1 ) {
	655	fd = __atomic_exchange_n(&fdp->sem, 1, __ATOMIC_RELAXED);
[7cf3b1d]	656	}
[14a61b5]	657
[7cf3b1d]	658	switch(fd) {
[4ccc150]	659	__attribute__((unused)) int ret;
[7cf3b1d]	660	case 0:
	661	// If the processor isn't ready to sleep then the exchange will already wake it up
	662	#if !defined(__CFA_NO_STATISTICS__)
	663	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.early++;
	664	} else { __atomic_fetch_add(&this->stats->ready.sleep.early, 1, __ATOMIC_RELAXED); }
	665	#endif
	666	break;
	667	case 1:
	668	// If someone else already said they will wake them: we are done
	669	#if !defined(__CFA_NO_STATISTICS__)
	670	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.seen++;
	671	} else { __atomic_fetch_add(&this->stats->ready.sleep.seen, 1, __ATOMIC_RELAXED); }
	672	#endif
	673	break;
	674	default:
	675	// If the processor was ready to sleep, we need to wake it up with an actual write
	676	val = 1;
[4ccc150]	677	ret = eventfd_write( fd, val );
[77adaee]	678	/* paranoid */ verifyf( ret == 0, "Expected return to be 0, was %d\n", ret );
[7cf3b1d]	679
	680	#if !defined(__CFA_NO_STATISTICS__)
	681	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.wakes++;
	682	} else { __atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED); }
	683	#endif
	684	break;
	685	}
[1eb239e4]	686
[e873838]	687	/* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]	688	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	689
	690	return;
[64a7146]	691	}
[14a61b5]	692
[64a7146]	693	// Unconditionnaly wake a thread
[1eb239e4]	694	void __wake_proc(processor * this) {
[7d0ebd0]	695	/* paranoid */ verify( ! __preemption_enabled() );
	696
[64a7146]	697	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]	698
[22226e4]	699	this->idle_wctx.sem = 1;
[7cf3b1d]	700
[efa28d5]	701	this->idle_wctx.wake__time = rdtscl();
[262fafd9]	702
[7d0ebd0]	703	eventfd_t val;
	704	val = 1;
[d080549]	705	__attribute__((unused)) int ret = eventfd_write( this->idle_wctx.evfd, val );
[7d0ebd0]	706
[d080549]	707	/* paranoid */ verifyf( ret == 0, "Expected return to be 0, was %d\n", ret );
[7d0ebd0]	708	/* paranoid */ verify( ! __preemption_enabled() );
[92e7631]	709	}
	710
[18f7858]	711	static void idle_sleep(processor * this) {
[202c80b]	712	/* paranoid */ verify( this->idle_wctx.evfd != 1 );
	713	/* paranoid */ verify( this->idle_wctx.evfd != 2 );
	714
[7cf3b1d]	715	// Tell everyone we are ready to go do sleep
	716	for() {
[22226e4]	717	int expected = this->idle_wctx.sem;
[7cf3b1d]	718
	719	// Someone already told us to wake-up! No time for a nap.
	720	if(expected == 1) { return; }
	721
	722	// Try to mark that we are going to sleep
[22226e4]	723	if(__atomic_compare_exchange_n(&this->idle_wctx.sem, &expected, this->idle_wctx.evfd, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ) {
[7cf3b1d]	724	// Every one agreed, taking a nap
	725	break;
	726	}
	727	}
	728
	729
[d3605f8]	730	#if !defined(CFA_WITH_IO_URING_IDLE)
[7ef162b2]	731	#if !defined(__CFA_NO_STATISTICS__)
	732	if(this->print_halts) {
	733	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
	734	}
	735	#endif
[1757f98]	736
[7ef162b2]	737	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle_fd);
[1757f98]	738
[7ef162b2]	739	{
	740	eventfd_t val;
[22226e4]	741	ssize_t ret = read( this->idle_wctx.evfd, &val, sizeof(val) );
[7ef162b2]	742	if(ret < 0) {
	743	switch((int)errno) {
	744	case EAGAIN:
	745	#if EAGAIN != EWOULDBLOCK
	746	case EWOULDBLOCK:
	747	#endif
	748	case EINTR:
	749	// No need to do anything special here, just assume it's a legitimate wake-up
	750	break;
	751	default:
	752	abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
	753	}
[1757f98]	754	}
	755	}
	756
[7ef162b2]	757	#if !defined(__CFA_NO_STATISTICS__)
	758	if(this->print_halts) {
	759	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
	760	}
	761	#endif
	762	#else
[18f7858]	763	__cfa_io_idle( this );
[1757f98]	764	#endif
	765	}
	766
[5f5a729]	767	static bool mark_idle(__cluster_proc_list & this, processor & proc) {
[c9c1c1cb]	768	__STATS__(true, ready.sleep.halts++; )
[7cf3b1d]	769
[22226e4]	770	proc.idle_wctx.sem = 0;
[7cf3b1d]	771
[8fc652e0]	772	/* paranoid */ verify( ! __preemption_enabled() );
[5f5a729]	773	if(!try_lock( this )) return false;
[1eb239e4]	774	this.idle++;
	775	/* paranoid */ verify( this.idle <= this.total );
[fc59b580]	776	remove(proc);
[6a9b12b]	777	insert_first(this.idles, proc);
[34b8cb7]	778
[7cf3b1d]	779	__atomic_store_n(&this.fdw, &proc.idle_wctx, __ATOMIC_SEQ_CST);
[1eb239e4]	780	unlock( this );
[8fc652e0]	781	/* paranoid */ verify( ! __preemption_enabled() );
[5f5a729]	782
	783	return true;
[1eb239e4]	784	}
[8e16177]	785
[6a9b12b]	786	static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	787	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	788	lock( this );
	789	this.idle--;
	790	/* paranoid */ verify( this.idle >= 0 );
	791	remove(proc);
[fc59b580]	792	insert_last(this.actives, proc);
[6a9b12b]	793
[a633f6f]	794	{
[7cf3b1d]	795	struct __fd_waitctx * wctx = 0;
	796	if(!this.idles`isEmpty) wctx = &this.idles`first.idle_wctx;
	797	__atomic_store_n(&this.fdw, wctx, __ATOMIC_SEQ_CST);
[a633f6f]	798	}
	799
[34b8cb7]	800	unlock( this );
[6a9b12b]	801	/* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]	802	}
	803
[dbe9b08]	804	//=============================================================================================
	805	// Unexpected Terminating logic
	806	//=============================================================================================
[92bfda0]	807	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
[e84ab3d]	808	thread$ * thrd = __cfaabi_tls.this_thread;
[9d944b2]	809
[de94a60]	810	if(thrd) {
	811	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]	812	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	813
[212c2187]	814	if ( &thrd->self_cor != thrd->curr_cor ) {
	815	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]	816	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	817	}
	818	else {
[1c40091]	819	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]	820	}
[1c273d0]	821	}
[9d944b2]	822	else {
[de94a60]	823	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]	824	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]	825	}
	826	}
	827
[92bfda0]	828	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
	829	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]	830	}
	831
[de94a60]	832	static __spinlock_t kernel_debug_lock;
	833
[9d944b2]	834	extern "C" {
[1c40091]	835	void __cfaabi_bits_acquire() {
[36982fc]	836	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]	837	}
	838
[1c40091]	839	void __cfaabi_bits_release() {
[ea7d2b0]	840	unlock( kernel_debug_lock );
[9d944b2]	841	}
[8118303]	842	}
	843
[fa21ac9]	844	//=============================================================================================
	845	// Kernel Utilities
	846	//=============================================================================================
[dddb3dd0]	847	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	848	#include "io/types.hfa"
	849	#endif
	850
[2026bb6]	851	//-----------------------------------------------------------------------------
	852	// Debug
[c18bf9e]	853	bool threading_enabled(void) __attribute__((const)) libcfa_public {
[2026bb6]	854	return true;
	855	}
[c34ebf2]	856
	857	//-----------------------------------------------------------------------------
	858	// Statistics
	859	#if !defined(__CFA_NO_STATISTICS__)
[c18bf9e]	860	void print_halts( processor & this ) libcfa_public {
[c34ebf2]	861	this.print_halts = true;
	862	}
[58688bf]	863
[69914cbc]	864	static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
[8464edf]	865	/* paranoid */ verify( cltr->stats );
	866
	867	processor * it = &list`first;
	868	for(unsigned i = 0; i < count; i++) {
	869	/* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
	870	/* paranoid */ verify( it->local_data->this_stats );
[c33c2af]	871	// __print_stats( it->local_data->this_stats, cltr->print_stats, "Processor", it->name, (void*)it );
[8464edf]	872	__tally_stats( cltr->stats, it->local_data->this_stats );
	873	it = &(*it)`next;
	874	}
	875	}
	876
[c18bf9e]	877	static void crawl_cluster_stats( cluster & this ) {
[8464edf]	878	// Stop the world, otherwise stats could get really messed-up
	879	// this doesn't solve all problems but does solve many
	880	// so it's probably good enough
[c33c2af]	881	disable_interrupts();
[8464edf]	882	uint_fast32_t last_size = ready_mutate_lock();
	883
	884	crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
	885	crawl_list(&this, this.procs.idles , this.procs.idle );
	886
	887	// Unlock the RWlock
	888	ready_mutate_unlock( last_size );
[c33c2af]	889	enable_interrupts();
[8464edf]	890	}
	891
	892
[c18bf9e]	893	void print_stats_now( cluster & this, int flags ) libcfa_public {
[8464edf]	894	crawl_cluster_stats( this );
[202c80b]	895	__print_stats( this.stats, flags, "Cluster", this.name, (void*)&this );
[1b033b8]	896	}
[c34ebf2]	897	#endif
[8118303]	898	// Local Variables: //
	899	// mode: c //
	900	// tab-width: 4 //
	901	// End: //

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