Context Navigation

kernel.cfa @ 9d8124f

ADTast-experimentalenumpthread-emulationqualifiedEnum

Last change on this file since 9d8124f was 708ae38, checked in by Thierry Delisle <tdelisle@…>, 2 years ago
Some more cleanup and grow/shrink now readjusts io timestamps. (They are still unused).
Property mode set to `100644`
File size: 28.9 KB

Line
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
10	// Created On : Tue Jan 17 12:27:26 2017
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Mon Aug 31 07:08:20 2020
13	// Update Count : 71
14	//
15
16	#define __cforall_thread__
17	#define _GNU_SOURCE
18
19	// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
20
21	#pragma GCC diagnostic push
22	#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
23
24	//C Includes
25	#include <errno.h>
26	#include <stdio.h>
27	#include <string.h>
28	#include <signal.h>
29	#include <unistd.h>
30
31	extern "C" {
32	#include <sys/eventfd.h>
33	#include <sys/uio.h>
34	}
35
36	//CFA Includes
37	#include "kernel/private.hfa"
38	#include "preemption.hfa"
39	#include "strstream.hfa"
40	#include "device/cpu.hfa"
41	#include "io/types.hfa"
42
43	//Private includes
44	#define __CFA_INVOKE_PRIVATE__
45	#include "invoke.h"
46	#pragma GCC diagnostic pop
47
48	#if !defined(__CFA_NO_STATISTICS__)
49	#define __STATS_DEF( ...) __VA_ARGS__
50	#else
51	#define __STATS_DEF( ...)
52	#endif
53
54	//-----------------------------------------------------------------------------
55	// Some assembly required
56	#if defined( __i386 )
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
96	#elif defined( __arm__ )
97	#define __x87_store
98	#define __x87_load
99
100	#elif defined( __aarch64__ )
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
118	#else
119	#error unsupported hardware architecture
120	#endif
121
122	extern thread$ * mainThread;
123	extern processor * mainProcessor;
124
125	//-----------------------------------------------------------------------------
126	// Kernel Scheduling logic
127	static thread$ * __next_thread(cluster * this);
128	static thread$ * __next_thread_slow(cluster * this);
129	static thread$ * __next_thread_search(cluster * this);
130	static inline bool __must_unpark( thread$ * thrd ) __attribute((nonnull(1)));
131	static void __run_thread(processor * this, thread$ * dst);
132	static void __wake_one(cluster * cltr);
133
134	static void idle_sleep(processor * proc, io_future_t & future, iovec & iov);
135	static bool mark_idle (__cluster_proc_list & idles, processor & proc);
136	static void mark_awake(__cluster_proc_list & idles, processor & proc);
137
138	extern void __cfa_io_start( processor * );
139	extern bool __cfa_io_drain( processor * );
140	extern bool __cfa_io_flush( processor *, int min_comp );
141	extern void __cfa_io_stop ( processor * );
142	static inline bool __maybe_io_drain( processor * );
143
144	#if defined(CFA_WITH_IO_URING_IDLE)
145	extern bool __kernel_read(processor * proc, io_future_t & future, iovec &, int fd);
146	#endif
147
148	extern void __disable_interrupts_hard();
149	extern void __enable_interrupts_hard();
150
151
152	//=============================================================================================
153	// Kernel Scheduling logic
154	//=============================================================================================
155	//Main of the processor contexts
156	void main(processorCtx_t & runner) {
157	// Because of a bug, we couldn't initialized the seed on construction
158	// Do it here
159	__cfaabi_tls.rand_seed ^= rdtscl();
160	__cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
161	__tls_rand_advance_bck();
162
163	processor * this = runner.proc;
164	verify(this);
165
166	io_future_t future; // used for idle sleep when io_uring is present
167	future.self.ptr = 1p; // mark it as already fulfilled so we know if there is a pending request or not
168	eventfd_t idle_val;
169	iovec idle_iovec = { &idle_val, sizeof(idle_val) };
170
171	__cfa_io_start( this );
172
173	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
174	#if !defined(__CFA_NO_STATISTICS__)
175	if( this->print_halts ) {
176	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->unique_id, this->name, (void*)this);
177	}
178	#endif
179
180	{
181	// Setup preemption data
182	preemption_scope scope = { this };
183
184	// if we need to run some special setup, now is the time to do it.
185	if(this->init.thrd) {
186	this->init.thrd->curr_cluster = this->cltr;
187	__run_thread(this, this->init.thrd);
188	}
189
190	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
191
192	thread$ * readyThread = 0p;
193	MAIN_LOOP:
194	for() {
195	// Check if there is pending io
196	__maybe_io_drain( this );
197
198	// Try to get the next thread
199	readyThread = __next_thread( this->cltr );
200
201	if( !readyThread ) {
202	__IO_STATS__(true, io.flush.idle++; )
203	__cfa_io_flush( this, 0 );
204
205	readyThread = __next_thread( this->cltr );
206	}
207
208	if( !readyThread ) for(5) {
209	__IO_STATS__(true, io.flush.idle++; )
210
211	readyThread = __next_thread_slow( this->cltr );
212
213	if( readyThread ) break;
214
215	__cfa_io_flush( this, 0 );
216	}
217
218	HALT:
219	if( !readyThread ) {
220	// Don't block if we are done
221	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
222
223	// Push self to idle stack
224	if(!mark_idle(this->cltr->procs, * this)) continue MAIN_LOOP;
225
226	// Confirm the ready-queue is empty
227	readyThread = __next_thread_search( this->cltr );
228	if( readyThread ) {
229	// A thread was found, cancel the halt
230	mark_awake(this->cltr->procs, * this);
231
232	__STATS__(true, ready.sleep.cancels++; )
233
234	// continue the mai loop
235	break HALT;
236	}
237
238	idle_sleep( this, future, idle_iovec );
239
240	// We were woken up, remove self from idle
241	mark_awake(this->cltr->procs, * this);
242
243	// DON'T just proceed, start looking again
244	continue MAIN_LOOP;
245	}
246
247	/* paranoid */ verify( readyThread );
248
249	// Reset io dirty bit
250	this->io.dirty = false;
251
252	// We found a thread run it
253	__run_thread(this, readyThread);
254
255	// Are we done?
256	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
257
258	if(__atomic_load_n(&this->io.pending, __ATOMIC_RELAXED) && !__atomic_load_n(&this->io.dirty, __ATOMIC_RELAXED)) {
259	__IO_STATS__(true, io.flush.dirty++; )
260	__cfa_io_flush( this, 0 );
261	}
262	}
263
264	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
265	}
266
267	for(int i = 0; !available(future); i++) {
268	if(i > 1000) __cfaabi_dbg_write( "ERROR: kernel has bin spinning on a flush after exit loop.\n", 60);
269	__cfa_io_flush( this, 1 );
270	}
271
272	__cfa_io_stop( this );
273
274	post( this->terminated );
275
276	if(this == mainProcessor) {
277	// HACK : the coroutine context switch expects this_thread to be set
278	// and it make sense for it to be set in all other cases except here
279	// fake it
280	__cfaabi_tls.this_thread = mainThread;
281	}
282
283	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
284	}
285
286	static int * __volatile_errno() __attribute__((noinline));
287	static int * __volatile_errno() { asm(""); return &errno; }
288
289	// KERNEL ONLY
290	// runThread runs a thread by context switching
291	// from the processor coroutine to the target thread
292	static void __run_thread(processor * this, thread$ * thrd_dst) {
293	/* paranoid */ verify( ! __preemption_enabled() );
294	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
295	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
296	__builtin_prefetch( thrd_dst->context.SP );
297
298	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
299
300	coroutine$ * proc_cor = get_coroutine(this->runner);
301
302	// set state of processor coroutine to inactive
303	verify(proc_cor->state == Active);
304	proc_cor->state = Blocked;
305
306	// Actually run the thread
307	RUNNING: while(true) {
308	thrd_dst->preempted = __NO_PREEMPTION;
309	thrd_dst->state = Active;
310
311	// Update global state
312	kernelTLS().this_thread = thrd_dst;
313
314	/* paranoid */ verify( ! __preemption_enabled() );
315	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
316	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
317	/* paranoid */ verify( thrd_dst->context.SP );
318	/* paranoid */ verify( thrd_dst->state != Halted );
319	/* 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
320	/* 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
321	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
322
323
324
325	// set context switch to the thread that the processor is executing
326	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
327	// when __cfactx_switch returns we are back in the processor coroutine
328
329
330
331	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
332	/* 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 );
333	/* 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 );
334	/* paranoid */ verify( thrd_dst->context.SP );
335	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
336	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
337	/* paranoid */ verify( ! __preemption_enabled() );
338
339	// Reset global state
340	kernelTLS().this_thread = 0p;
341
342	// We just finished running a thread, there are a few things that could have happened.
343	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
344	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
345	// 4 - Preempted
346	// In case 1, we may have won a race so we can't write to the state again.
347	// In case 2, we lost the race so we now own the thread.
348
349	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
350	// The thread was preempted, reschedule it and reset the flag
351	schedule_thread$( thrd_dst, UNPARK_LOCAL );
352	break RUNNING;
353	}
354
355	if(unlikely(thrd_dst->state == Halting)) {
356	// The thread has halted, it should never be scheduled/run again
357	// finish the thread
358	__thread_finish( thrd_dst );
359	break RUNNING;
360	}
361
362	/* paranoid */ verify( thrd_dst->state == Active );
363	thrd_dst->state = Blocked;
364
365	// set state of processor coroutine to active and the thread to inactive
366	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
367	switch(old_ticket) {
368	case TICKET_RUNNING:
369	// This is case 1, the regular case, nothing more is needed
370	break RUNNING;
371	case TICKET_UNBLOCK:
372	__STATS__(true, ready.threads.threads++; )
373	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
374	// In this case, just run it again.
375	continue RUNNING;
376	default:
377	// This makes no sense, something is wrong abort
378	abort();
379	}
380	}
381
382	// Just before returning to the processor, set the processor coroutine to active
383	proc_cor->state = Active;
384
385	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
386
387	__STATS__(true, ready.threads.threads--; )
388
389	/* paranoid */ verify( ! __preemption_enabled() );
390	}
391
392	// KERNEL_ONLY
393	void returnToKernel() {
394	/* paranoid */ verify( ! __preemption_enabled() );
395	coroutine$ * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
396	thread$ * thrd_src = kernelTLS().this_thread;
397
398	__STATS_DEF( thrd_src->last_proc = kernelTLS().this_processor; )
399
400	// Run the thread on this processor
401	{
402	int local_errno = *__volatile_errno();
403	#if defined( __i386 ) \|\| defined( __x86_64 )
404	__x87_store;
405	#endif
406	/* paranoid */ verify( proc_cor->context.SP );
407	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
408	__cfactx_switch( &thrd_src->context, &proc_cor->context );
409	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
410	#if defined( __i386 ) \|\| defined( __x86_64 )
411	__x87_load;
412	#endif
413	*__volatile_errno() = local_errno;
414	}
415
416	#if !defined(__CFA_NO_STATISTICS__)
417	/* paranoid */ verify( thrd_src->last_proc != 0p );
418	if(thrd_src->last_proc != kernelTLS().this_processor) {
419	__tls_stats()->ready.threads.migration++;
420	}
421	#endif
422
423	/* paranoid */ verify( ! __preemption_enabled() );
424	/* 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 );
425	/* 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 );
426	}
427
428	//-----------------------------------------------------------------------------
429	// Scheduler routines
430	// KERNEL ONLY
431	static void __schedule_thread( thread$ * thrd, unpark_hint hint ) {
432	/* paranoid */ verify( ! __preemption_enabled() );
433	/* paranoid */ verify( ready_schedule_islocked());
434	/* paranoid */ verify( thrd );
435	/* paranoid */ verify( thrd->state != Halted );
436	/* paranoid */ verify( thrd->curr_cluster );
437	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
438	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
439	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
440	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
441	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
442	/* paranoid */ #endif
443	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
444	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
445
446	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
447
448	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
449	struct cluster * cl = thrd->curr_cluster;
450	__STATS_DEF(bool outside = hint == UNPARK_LOCAL && thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
451
452	// push the thread to the cluster ready-queue
453	push( cl, thrd, hint );
454
455	// variable thrd is no longer safe to use
456	thrd = 0xdeaddeaddeaddeadp;
457
458	// wake the cluster using the save variable.
459	__wake_one( cl );
460
461	#if !defined(__CFA_NO_STATISTICS__)
462	if( kernelTLS().this_stats ) {
463	__tls_stats()->ready.threads.threads++;
464	if(outside) {
465	__tls_stats()->ready.threads.extunpark++;
466	}
467	}
468	else {
469	__atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
470	__atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
471	}
472	#endif
473
474	/* paranoid */ verify( ready_schedule_islocked());
475	/* paranoid */ verify( ! __preemption_enabled() );
476	}
477
478	void schedule_thread$( thread$ * thrd, unpark_hint hint ) {
479	ready_schedule_lock();
480	__schedule_thread( thrd, hint );
481	ready_schedule_unlock();
482	}
483
484	// KERNEL ONLY
485	static inline thread$ * __next_thread(cluster * this) with( *this ) {
486	/* paranoid */ verify( ! __preemption_enabled() );
487
488	ready_schedule_lock();
489	thread$ * thrd = pop_fast( this );
490	ready_schedule_unlock();
491
492	/* paranoid */ verify( ! __preemption_enabled() );
493	return thrd;
494	}
495
496	// KERNEL ONLY
497	static inline thread$ * __next_thread_slow(cluster * this) with( *this ) {
498	/* paranoid */ verify( ! __preemption_enabled() );
499
500	ready_schedule_lock();
501	thread$ * thrd = pop_slow( this );
502	ready_schedule_unlock();
503
504	/* paranoid */ verify( ! __preemption_enabled() );
505	return thrd;
506	}
507
508	// KERNEL ONLY
509	static inline thread$ * __next_thread_search(cluster * this) with( *this ) {
510	/* paranoid */ verify( ! __preemption_enabled() );
511
512	ready_schedule_lock();
513	thread$ * thrd = pop_search( this );
514	ready_schedule_unlock();
515
516	/* paranoid */ verify( ! __preemption_enabled() );
517	return thrd;
518	}
519
520	static inline bool __must_unpark( thread$ * thrd ) {
521	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
522	switch(old_ticket) {
523	case TICKET_RUNNING:
524	// Wake won the race, the thread will reschedule/rerun itself
525	return false;
526	case TICKET_BLOCKED:
527	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
528	/* paranoid */ verify( thrd->state == Blocked );
529	return true;
530	default:
531	// This makes no sense, something is wrong abort
532	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
533	}
534	}
535
536	void __kernel_unpark( thread$ * thrd, unpark_hint hint ) {
537	/* paranoid */ verify( ! __preemption_enabled() );
538	/* paranoid */ verify( ready_schedule_islocked());
539
540	if( !thrd ) return;
541
542	if(__must_unpark(thrd)) {
543	// Wake lost the race,
544	__schedule_thread( thrd, hint );
545	}
546
547	/* paranoid */ verify( ready_schedule_islocked());
548	/* paranoid */ verify( ! __preemption_enabled() );
549	}
550
551	void unpark( thread$ * thrd, unpark_hint hint ) {
552	if( !thrd ) return;
553
554	if(__must_unpark(thrd)) {
555	disable_interrupts();
556	// Wake lost the race,
557	schedule_thread$( thrd, hint );
558	enable_interrupts(false);
559	}
560	}
561
562	void park( void ) {
563	__disable_interrupts_checked();
564	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
565	returnToKernel();
566	__enable_interrupts_checked();
567
568	}
569
570	extern "C" {
571	// Leave the thread monitor
572	// last routine called by a thread.
573	// Should never return
574	void __cfactx_thrd_leave() {
575	thread$ * thrd = active_thread();
576	monitor$ * this = &thrd->self_mon;
577
578	// Lock the monitor now
579	lock( this->lock __cfaabi_dbg_ctx2 );
580
581	disable_interrupts();
582
583	/* paranoid */ verify( ! __preemption_enabled() );
584	/* paranoid */ verify( thrd->state == Active );
585	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
586	/* paranoid */ verify( kernelTLS().this_thread == thrd );
587	/* paranoid */ verify( thrd->context.SP );
588	/* 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 );
589	/* 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 );
590
591	thrd->state = Halting;
592	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
593	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
594	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
595
596	// Leave the thread
597	returnToKernel();
598
599	// Control flow should never reach here!
600	abort();
601	}
602	}
603
604	// KERNEL ONLY
605	bool force_yield( __Preemption_Reason reason ) {
606	__disable_interrupts_checked();
607	thread$ * thrd = kernelTLS().this_thread;
608	/* paranoid */ verify(thrd->state == Active);
609
610	// SKULLDUGGERY: It is possible that we are preempting this thread just before
611	// it was going to park itself. If that is the case and it is already using the
612	// intrusive fields then we can't use them to preempt the thread
613	// If that is the case, abandon the preemption.
614	bool preempted = false;
615	if(thrd->link.next == 0p) {
616	preempted = true;
617	thrd->preempted = reason;
618	returnToKernel();
619	}
620	__enable_interrupts_checked( false );
621	return preempted;
622	}
623
624	//=============================================================================================
625	// Kernel Idle Sleep
626	//=============================================================================================
627	// Wake a thread from the front if there are any
628	static void __wake_one(cluster * this) {
629	eventfd_t val;
630
631	/* paranoid */ verify( ! __preemption_enabled() );
632	/* paranoid */ verify( ready_schedule_islocked() );
633
634	// Check if there is a sleeping processor
635	struct __fd_waitctx * fdp = __atomic_load_n(&this->procs.fdw, __ATOMIC_SEQ_CST);
636
637	// If no one is sleeping: we are done
638	if( fdp == 0p ) return;
639
640	int fd = 1;
641	if( __atomic_load_n(&fdp->fd, __ATOMIC_SEQ_CST) != 1 ) {
642	fd = __atomic_exchange_n(&fdp->fd, 1, __ATOMIC_RELAXED);
643	}
644
645	switch(fd) {
646	case 0:
647	// If the processor isn't ready to sleep then the exchange will already wake it up
648	#if !defined(__CFA_NO_STATISTICS__)
649	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.early++;
650	} else { __atomic_fetch_add(&this->stats->ready.sleep.early, 1, __ATOMIC_RELAXED); }
651	#endif
652	break;
653	case 1:
654	// If someone else already said they will wake them: we are done
655	#if !defined(__CFA_NO_STATISTICS__)
656	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.seen++;
657	} else { __atomic_fetch_add(&this->stats->ready.sleep.seen, 1, __ATOMIC_RELAXED); }
658	#endif
659	break;
660	default:
661	// If the processor was ready to sleep, we need to wake it up with an actual write
662	val = 1;
663	eventfd_write( fd, val );
664
665	#if !defined(__CFA_NO_STATISTICS__)
666	if( kernelTLS().this_stats ) { __tls_stats()->ready.sleep.wakes++;
667	} else { __atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED); }
668	#endif
669	break;
670	}
671
672	/* paranoid */ verify( ready_schedule_islocked() );
673	/* paranoid */ verify( ! __preemption_enabled() );
674
675	return;
676	}
677
678	// Unconditionnaly wake a thread
679	void __wake_proc(processor * this) {
680	/* paranoid */ verify( ! __preemption_enabled() );
681
682	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
683
684	this->idle_wctx.fd = 1;
685
686	eventfd_t val;
687	val = 1;
688	eventfd_write( this->idle_fd, val );
689
690	/* paranoid */ verify( ! __preemption_enabled() );
691	}
692
693	static void idle_sleep(processor * this, io_future_t & future, iovec & iov) {
694	// Tell everyone we are ready to go do sleep
695	for() {
696	int expected = this->idle_wctx.fd;
697
698	// Someone already told us to wake-up! No time for a nap.
699	if(expected == 1) { return; }
700
701	// Try to mark that we are going to sleep
702	if(__atomic_compare_exchange_n(&this->idle_wctx.fd, &expected, this->idle_fd, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ) {
703	// Every one agreed, taking a nap
704	break;
705	}
706	}
707
708
709	#if !defined(CFA_WITH_IO_URING_IDLE)
710	#if !defined(__CFA_NO_STATISTICS__)
711	if(this->print_halts) {
712	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
713	}
714	#endif
715
716	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle_fd);
717
718	{
719	eventfd_t val;
720	ssize_t ret = read( this->idle_fd, &val, sizeof(val) );
721	if(ret < 0) {
722	switch((int)errno) {
723	case EAGAIN:
724	#if EAGAIN != EWOULDBLOCK
725	case EWOULDBLOCK:
726	#endif
727	case EINTR:
728	// No need to do anything special here, just assume it's a legitimate wake-up
729	break;
730	default:
731	abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
732	}
733	}
734	}
735
736	#if !defined(__CFA_NO_STATISTICS__)
737	if(this->print_halts) {
738	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
739	}
740	#endif
741	#else
742	// Do we already have a pending read
743	if(available(future)) {
744	// There is no pending read, we need to add one
745	reset(future);
746
747	__kernel_read(this, future, iov, this->idle_fd );
748	}
749
750	__cfa_io_flush( this, 1 );
751	#endif
752	}
753
754	static bool mark_idle(__cluster_proc_list & this, processor & proc) {
755	__STATS__(true, ready.sleep.halts++; )
756
757	proc.idle_wctx.fd = 0;
758
759	/* paranoid */ verify( ! __preemption_enabled() );
760	if(!try_lock( this )) return false;
761	this.idle++;
762	/* paranoid */ verify( this.idle <= this.total );
763	remove(proc);
764	insert_first(this.idles, proc);
765
766	__atomic_store_n(&this.fdw, &proc.idle_wctx, __ATOMIC_SEQ_CST);
767	unlock( this );
768	/* paranoid */ verify( ! __preemption_enabled() );
769
770	return true;
771	}
772
773	static void mark_awake(__cluster_proc_list & this, processor & proc) {
774	/* paranoid */ verify( ! __preemption_enabled() );
775	lock( this );
776	this.idle--;
777	/* paranoid */ verify( this.idle >= 0 );
778	remove(proc);
779	insert_last(this.actives, proc);
780
781	{
782	struct __fd_waitctx * wctx = 0;
783	if(!this.idles`isEmpty) wctx = &this.idles`first.idle_wctx;
784	__atomic_store_n(&this.fdw, wctx, __ATOMIC_SEQ_CST);
785	}
786
787	unlock( this );
788	/* paranoid */ verify( ! __preemption_enabled() );
789	}
790
791	//=============================================================================================
792	// Unexpected Terminating logic
793	//=============================================================================================
794	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
795	thread$ * thrd = __cfaabi_tls.this_thread;
796
797	if(thrd) {
798	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
799	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
800
801	if ( &thrd->self_cor != thrd->curr_cor ) {
802	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
803	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
804	}
805	else {
806	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
807	}
808	}
809	else {
810	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
811	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
812	}
813	}
814
815	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
816	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
817	}
818
819	static __spinlock_t kernel_debug_lock;
820
821	extern "C" {
822	void __cfaabi_bits_acquire() {
823	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
824	}
825
826	void __cfaabi_bits_release() {
827	unlock( kernel_debug_lock );
828	}
829	}
830
831	//=============================================================================================
832	// Kernel Utilities
833	//=============================================================================================
834	#if defined(CFA_HAVE_LINUX_IO_URING_H)
835	#include "io/types.hfa"
836	#endif
837
838	static inline bool __maybe_io_drain( processor * proc ) {
839	bool ret = false;
840	#if defined(CFA_HAVE_LINUX_IO_URING_H)
841	__cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
842
843	// Check if we should drain the queue
844	$io_context * ctx = proc->io.ctx;
845	unsigned head = *ctx->cq.head;
846	unsigned tail = *ctx->cq.tail;
847	if(head == tail) return false;
848	ready_schedule_lock();
849	ret = __cfa_io_drain( proc );
850	ready_schedule_unlock();
851	#endif
852	return ret;
853	}
854
855	//-----------------------------------------------------------------------------
856	// Debug
857	__cfaabi_dbg_debug_do(
858	extern "C" {
859	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
860	this.prev_name = prev_name;
861	this.prev_thrd = kernelTLS().this_thread;
862	}
863	}
864	)
865
866	//-----------------------------------------------------------------------------
867	// Debug
868	bool threading_enabled(void) __attribute__((const)) {
869	return true;
870	}
871
872	//-----------------------------------------------------------------------------
873	// Statistics
874	#if !defined(__CFA_NO_STATISTICS__)
875	void print_halts( processor & this ) {
876	this.print_halts = true;
877	}
878
879	static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
880	/* paranoid */ verify( cltr->stats );
881
882	processor * it = &list`first;
883	for(unsigned i = 0; i < count; i++) {
884	/* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
885	/* paranoid */ verify( it->local_data->this_stats );
886	// __print_stats( it->local_data->this_stats, cltr->print_stats, "Processor", it->name, (void*)it );
887	__tally_stats( cltr->stats, it->local_data->this_stats );
888	it = &(*it)`next;
889	}
890	}
891
892	void crawl_cluster_stats( cluster & this ) {
893	// Stop the world, otherwise stats could get really messed-up
894	// this doesn't solve all problems but does solve many
895	// so it's probably good enough
896	disable_interrupts();
897	uint_fast32_t last_size = ready_mutate_lock();
898
899	crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
900	crawl_list(&this, this.procs.idles , this.procs.idle );
901
902	// Unlock the RWlock
903	ready_mutate_unlock( last_size );
904	enable_interrupts();
905	}
906
907
908	void print_stats_now( cluster & this, int flags ) {
909	crawl_cluster_stats( this );
910	__print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
911	}
912	#endif
913	// Local Variables: //
914	// mode: c //
915	// tab-width: 4 //
916	// End: //

Note: See TracBrowser for help on using the repository browser.

Download in other formats:

Original Format