source: src/libcfa/concurrency/preemption.c@ 1c273d0

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr new-env no_list persistent-indexer pthread-emulation qualifiedEnum resolv-new with_gc
Last change on this file since 1c273d0 was 1c273d0, checked in by Thierry Delisle <tdelisle@…>, 8 years ago

preemption works for threads
  • Property mode set to 100644
File size: 11.4 KB
Line 
1// -*- Mode: CFA -*-
2//
3// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
4//
5// The contents of this file are covered under the licence agreement in the
6// file "LICENCE" distributed with Cforall.
7//
8// signal.c --
9//
10// Author : Thierry Delisle
11// Created On : Mon Jun 5 14:20:42 2017
12// Last Modified By : Thierry Delisle
13// Last Modified On : --
14// Update Count : 0
15//
16
17#include "preemption.h"
18
19
20extern "C" {
21#include <errno.h>
22#include <execinfo.h>
23#define __USE_GNU
24#include <signal.h>
25#undef __USE_GNU
26#include <stdio.h>
27#include <string.h>
28#include <unistd.h>
29}
30
31
32#ifdef __USE_STREAM__
33#include "fstream"
34#endif
35#include "libhdr.h"
36
37#define __CFA_DEFAULT_PREEMPTION__ 10000
38
39__attribute__((weak)) unsigned int default_preemption() {
40 return __CFA_DEFAULT_PREEMPTION__;
41}
42
43#define __CFA_SIGCXT__ ucontext_t *
44#define __CFA_SIGPARMS__ __attribute__((unused)) int sig, __attribute__((unused)) siginfo_t *sfp, __attribute__((unused)) __CFA_SIGCXT__ cxt
45
46static void preempt( processor * this );
47static void timeout( thread_desc * this );
48
49void sigHandler_ctxSwitch( __CFA_SIGPARMS__ );
50void sigHandler_alarm ( __CFA_SIGPARMS__ );
51void sigHandler_segv ( __CFA_SIGPARMS__ );
52void sigHandler_abort ( __CFA_SIGPARMS__ );
53
54static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags );
55
56//=============================================================================================
57// Kernel Preemption logic
58//=============================================================================================
59
60void kernel_start_preemption() {
61 LIB_DEBUG_PRINT_SAFE("Kernel : Starting preemption\n");
62 __kernel_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO );
63 __kernel_sigaction( SIGALRM, sigHandler_alarm , SA_SIGINFO );
64 __kernel_sigaction( SIGSEGV, sigHandler_segv , SA_SIGINFO );
65 __kernel_sigaction( SIGBUS , sigHandler_segv , SA_SIGINFO );
66 // __kernel_sigaction( SIGABRT, sigHandler_abort , SA_SIGINFO );
67}
68
69void kernel_stop_preemption() {
70 //Block all signals, we are no longer in a position to handle them
71 sigset_t mask;
72 sigfillset( &mask );
73 sigprocmask( SIG_BLOCK, &mask, NULL );
74 LIB_DEBUG_PRINT_SAFE("Kernel : Preemption stopped\n");
75
76 // assert( !systemProcessor->alarms.head );
77 // assert( systemProcessor->alarms.tail == &systemProcessor->alarms.head );
78}
79
80LIB_DEBUG_DO( bool validate( alarm_list_t * this ); )
81
82void tick_preemption() {
83 // LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Ticking preemption\n" );
84
85 alarm_list_t * alarms = &systemProcessor->alarms;
86 __cfa_time_t currtime = __kernel_get_time();
87 while( alarms->head && alarms->head->alarm < currtime ) {
88 alarm_node_t * node = pop(alarms);
89 // LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ticking %p\n", node );
90
91 if( node->kernel_alarm ) {
92 preempt( node->proc );
93 }
94 else {
95 timeout( node->thrd );
96 }
97
98 verify( validate( alarms ) );
99
100 if( node->period > 0 ) {
101 node->alarm = currtime + node->period;
102 insert( alarms, node );
103 }
104 else {
105 node->set = false;
106 }
107 }
108
109 if( alarms->head ) {
110 __kernel_set_timer( alarms->head->alarm - currtime );
111 }
112
113 verify( validate( alarms ) );
114 // LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ticking preemption done\n" );
115}
116
117void update_preemption( processor * this, __cfa_time_t duration ) {
118 LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Processor : %p updating preemption to %lu\n", this, duration );
119
120 alarm_node_t * alarm = this->preemption_alarm;
121 duration *= 1000;
122
123 // Alarms need to be enabled
124 if ( duration > 0 && !alarm->set ) {
125 alarm->alarm = __kernel_get_time() + duration;
126 alarm->period = duration;
127 register_self( alarm );
128 }
129 // Zero duraction but alarm is set
130 else if ( duration == 0 && alarm->set ) {
131 unregister_self( alarm );
132 alarm->alarm = 0;
133 alarm->period = 0;
134 }
135 // If alarm is different from previous, change it
136 else if ( duration > 0 && alarm->period != duration ) {
137 unregister_self( alarm );
138 alarm->alarm = __kernel_get_time() + duration;
139 alarm->period = duration;
140 register_self( alarm );
141 }
142}
143
144void ?{}( preemption_scope * this, processor * proc ) {
145 (&this->alarm){ proc };
146 this->proc = proc;
147 this->proc->preemption_alarm = &this->alarm;
148 update_preemption( this->proc, this->proc->preemption );
149}
150
151void ^?{}( preemption_scope * this ) {
152 disable_interrupts();
153
154 update_preemption( this->proc, 0 );
155}
156
157//=============================================================================================
158// Kernel Signal logic
159//=============================================================================================
160
161extern "C" {
162 void disable_interrupts() {
163 __attribute__((unused)) unsigned short new_val = __atomic_add_fetch_2( &disable_preempt_count, 1, __ATOMIC_SEQ_CST );
164 verify( new_val < (unsigned short)65_000 );
165 verify( new_val != (unsigned short) 0 );
166 }
167
168 void enable_interrupts_noRF() {
169 unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST );
170 verify( prev != (unsigned short) 0 );
171 }
172
173 void enable_interrupts( const char * func ) {
174 processor * proc = this_processor;
175 thread_desc * thrd = this_thread;
176 unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST );
177 verify( prev != (unsigned short) 0 );
178 if( prev == 1 && proc->pending_preemption ) {
179 proc->pending_preemption = false;
180 LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Executing deferred CtxSwitch on %p\n", this_processor );
181 BlockInternal( thrd );
182 LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Executing deferred back\n" );
183 }
184
185 proc->last_enable = func;
186 }
187}
188
189static inline void signal_unblock( int sig ) {
190 LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Processor : %p unblocking sig %i\n", this_processor, sig );
191
192 sigset_t mask;
193 sigemptyset( &mask );
194 sigaddset( &mask, sig );
195
196 if ( sigprocmask( SIG_UNBLOCK, &mask, NULL ) == -1 ) {
197 abortf( "internal error, sigprocmask" );
198 } // if
199}
200
201static inline bool preemption_ready() {
202 return disable_preempt_count == 0;
203}
204
205static inline void defer_ctxSwitch() {
206 this_processor->pending_preemption = true;
207}
208
209static inline void defer_alarm() {
210 systemProcessor->pending_alarm = true;
211}
212
213extern "C" {
214 __attribute__((noinline)) void __debug_break() {
215 pthread_kill( pthread_self(), SIGTRAP );
216 }
217}
218
219void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ) {
220 LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Ctx Switch IRH %p running %p @ %p\n", this_processor, this_thread, (void *)(cxt->uc_mcontext.gregs[REG_RIP]) );
221
222 if( preemption_ready() ) {
223 LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ctx Switch IRH : Blocking thread %p on %p\n", this_thread, this_processor );
224 signal_unblock( SIGUSR1 );
225 BlockInternal( (thread_desc*)this_thread );
226 LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ctx Switch IRH : Back\n\n");
227 }
228 else {
229 LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ctx Switch IRH : Defering\n" );
230 defer_ctxSwitch();
231 signal_unblock( SIGUSR1 );
232 }
233}
234
235void sigHandler_alarm( __CFA_SIGPARMS__ ) {
236 LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "\nAlarm IRH %p running %p @ %p\n", this_processor, this_thread, (void *)(cxt->uc_mcontext.gregs[REG_RIP]) );
237
238 // if( ((intptr_t)cxt->uc_mcontext.gregs[REG_RIP]) > 0xFFFFFF ) __debug_break();
239
240 if( try_lock( &systemProcessor->alarm_lock, __PRETTY_FUNCTION__ ) ) {
241 tick_preemption();
242 unlock( &systemProcessor->alarm_lock );
243 }
244 else {
245 defer_alarm();
246 }
247
248 signal_unblock( SIGALRM );
249
250 if( preemption_ready() && this_processor->pending_preemption ) {
251 LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Alarm IRH : Blocking thread %p on %p\n", this_thread, this_processor );
252 this_processor->pending_preemption = false;
253 BlockInternal( (thread_desc*)this_thread );
254 LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Alarm Switch IRH : Back\n\n");
255 }
256}
257
258static void preempt( processor * this ) {
259 // LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Processor : signalling %p\n", this );
260
261 if( this != systemProcessor ) {
262 pthread_kill( this->kernel_thread, SIGUSR1 );
263 }
264 else {
265 defer_ctxSwitch();
266 }
267}
268
269static void timeout( thread_desc * this ) {
270 //TODO : implement waking threads
271}
272
273static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags ) {
274 struct sigaction act;
275
276 act.sa_sigaction = (void (*)(int, siginfo_t *, void *))handler;
277 act.sa_flags = flags;
278
279 // disabled during signal handler
280 sigemptyset( &act.sa_mask );
281 sigaddset( &act.sa_mask, sig );
282
283 if ( sigaction( sig, &act, NULL ) == -1 ) {
284 LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO,
285 " __kernel_sigaction( sig:%d, handler:%p, flags:%d ), problem installing signal handler, error(%d) %s.\n",
286 sig, handler, flags, errno, strerror( errno )
287 );
288 _exit( EXIT_FAILURE );
289 }
290}
291
292typedef void (*sa_handler_t)(int);
293
294static void __kernel_sigdefault( int sig ) {
295 struct sigaction act;
296
297 // act.sa_handler = SIG_DFL;
298 act.sa_flags = 0;
299 sigemptyset( &act.sa_mask );
300
301 if ( sigaction( sig, &act, NULL ) == -1 ) {
302 LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO,
303 " __kernel_sigdefault( sig:%d ), problem reseting signal handler, error(%d) %s.\n",
304 sig, errno, strerror( errno )
305 );
306 _exit( EXIT_FAILURE );
307 }
308}
309
310//=============================================================================================
311// Terminating Signals logic
312//=============================================================================================
313
314LIB_DEBUG_DO(
315 static void __kernel_backtrace( int start ) {
316 // skip first N stack frames
317
318 enum { Frames = 50 };
319 void * array[Frames];
320 int size = backtrace( array, Frames );
321 char ** messages = backtrace_symbols( array, size );
322
323 // find executable name
324 *index( messages[0], '(' ) = '\0';
325 #ifdef __USE_STREAM__
326 serr | "Stack back trace for:" | messages[0] | endl;
327 #else
328 fprintf( stderr, "Stack back trace for: %s\n", messages[0]);
329 #endif
330
331 // skip last 2 stack frames after main
332 for ( int i = start; i < size && messages != NULL; i += 1 ) {
333 char * name = NULL;
334 char * offset_begin = NULL;
335 char * offset_end = NULL;
336
337 for ( char *p = messages[i]; *p; ++p ) {
338 // find parantheses and +offset
339 if ( *p == '(' ) {
340 name = p;
341 }
342 else if ( *p == '+' ) {
343 offset_begin = p;
344 }
345 else if ( *p == ')' ) {
346 offset_end = p;
347 break;
348 }
349 }
350
351 // if line contains symbol print it
352 int frameNo = i - start;
353 if ( name && offset_begin && offset_end && name < offset_begin ) {
354 // delimit strings
355 *name++ = '\0';
356 *offset_begin++ = '\0';
357 *offset_end++ = '\0';
358
359 #ifdef __USE_STREAM__
360 serr | "(" | frameNo | ")" | messages[i] | ":"
361 | name | "+" | offset_begin | offset_end | endl;
362 #else
363 fprintf( stderr, "(%i) %s : %s + %s %s\n", frameNo, messages[i], name, offset_begin, offset_end);
364 #endif
365 }
366 // otherwise, print the whole line
367 else {
368 #ifdef __USE_STREAM__
369 serr | "(" | frameNo | ")" | messages[i] | endl;
370 #else
371 fprintf( stderr, "(%i) %s\n", frameNo, messages[i] );
372 #endif
373 }
374 }
375
376 free( messages );
377 }
378)
379
380void sigHandler_segv( __CFA_SIGPARMS__ ) {
381 LIB_DEBUG_DO(
382 #ifdef __USE_STREAM__
383 serr | "*CFA runtime error* program cfa-cpp terminated with"
384 | (sig == SIGSEGV ? "segment fault." : "bus error.")
385 | endl;
386 #else
387 fprintf( stderr, "*CFA runtime error* program cfa-cpp terminated with %s\n", sig == SIGSEGV ? "segment fault." : "bus error." );
388 #endif
389
390 // skip first 2 stack frames
391 __kernel_backtrace( 1 );
392 )
393 exit( EXIT_FAILURE );
394}
395
396// void sigHandler_abort( __CFA_SIGPARMS__ ) {
397// // skip first 6 stack frames
398// LIB_DEBUG_DO( __kernel_backtrace( 6 ); )
399
400// // reset default signal handler
401// __kernel_sigdefault( SIGABRT );
402
403// raise( SIGABRT );
404// }
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