Changeset eba74ba for src/libcfa/concurrency/preemption.c
- Timestamp:
- May 25, 2018, 2:51:06 PM (6 years ago)
- Branches:
- new-env, with_gc
- Children:
- cdc4d43
- Parents:
- 3ef35bd (diff), 58e822a (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
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src/libcfa/concurrency/preemption.c
r3ef35bd reba74ba 15 15 16 16 #include "preemption.h" 17 #include <assert.h> 17 18 18 19 extern "C" { … … 91 92 //Loop throught every thing expired 92 93 while( node = get_expired( alarms, currtime ) ) { 94 // __cfaabi_dbg_print_buffer_decl( " KERNEL: preemption tick.\n" ); 93 95 94 96 // Check if this is a kernel … … 103 105 Duration period = node->period; 104 106 if( period > 0 ) { 107 // __cfaabi_dbg_print_buffer_local( " KERNEL: alarm period is %lu.\n", period.tv ); 105 108 node->alarm = currtime + period; // Alarm is periodic, add currtime to it (used cached current time) 106 109 insert( alarms, node ); // Reinsert the node for the next time it triggers … … 112 115 113 116 // If there are still alarms pending, reset the timer 114 if( alarms->head ) { __kernel_set_timer( alarms->head->alarm - currtime ); } 117 if( alarms->head ) { 118 __cfaabi_dbg_print_buffer_decl( " KERNEL: @%lu(%lu) resetting alarm to %lu.\n", currtime.tv, __kernel_get_time().tv, (alarms->head->alarm - currtime).tv); 119 Duration delta = alarms->head->alarm - currtime; 120 Duration caped = max(delta, 50`us); 121 // itimerval tim = { caped }; 122 // __cfaabi_dbg_print_buffer_local( " Values are %lu, %lu, %lu %lu.\n", delta.tv, caped.tv, tim.it_value.tv_sec, tim.it_value.tv_usec); 123 124 __kernel_set_timer( caped ); 125 } 115 126 } 116 127 … … 150 161 void disable_interrupts() { 151 162 with( kernelTLS.preemption_state ) { 152 enabled = false; 163 static_assert(__atomic_always_lock_free(sizeof(enabled), &enabled), "Must be lock-free"); 164 165 // Set enabled flag to false 166 // should be atomic to avoid preemption in the middle of the operation. 167 // use memory order RELAXED since there is no inter-thread on this variable requirements 168 __atomic_store_n(&enabled, false, __ATOMIC_RELAXED); 169 170 // Signal the compiler that a fence is needed but only for signal handlers 171 __atomic_signal_fence(__ATOMIC_ACQUIRE); 172 153 173 __attribute__((unused)) unsigned short new_val = disable_count + 1; 154 174 disable_count = new_val; … … 160 180 // If counter reaches 0, execute any pending CtxSwitch 161 181 void enable_interrupts( __cfaabi_dbg_ctx_param ) { 162 processor * proc = kernelTLS.this_processor; // Cache the processor now since interrupts can start happening after the atomic add163 thread_desc * thrd = kernelTLS.this_thread; // Cache the thread now since interrupts can start happening after the atomic add182 processor * proc = kernelTLS.this_processor; // Cache the processor now since interrupts can start happening after the atomic store 183 thread_desc * thrd = kernelTLS.this_thread; // Cache the thread now since interrupts can start happening after the atomic store 164 184 165 185 with( kernelTLS.preemption_state ){ … … 170 190 // Check if we need to prempt the thread because an interrupt was missed 171 191 if( prev == 1 ) { 172 enabled = true; 192 static_assert(__atomic_always_lock_free(sizeof(enabled), &enabled), "Must be lock-free"); 193 194 // Set enabled flag to true 195 // should be atomic to avoid preemption in the middle of the operation. 196 // use memory order RELAXED since there is no inter-thread on this variable requirements 197 __atomic_store_n(&enabled, true, __ATOMIC_RELAXED); 198 199 // Signal the compiler that a fence is needed but only for signal handlers 200 __atomic_signal_fence(__ATOMIC_RELEASE); 173 201 if( proc->pending_preemption ) { 174 202 proc->pending_preemption = false; … … 189 217 verifyf( prev != 0u, "Incremented from %u\n", prev ); // If this triggers someone is enabled already enabled interrupts 190 218 if( prev == 1 ) { 191 kernelTLS.preemption_state.enabled = true; 219 static_assert(__atomic_always_lock_free(sizeof(kernelTLS.preemption_state.enabled), &kernelTLS.preemption_state.enabled), "Must be lock-free"); 220 // Set enabled flag to true 221 // should be atomic to avoid preemption in the middle of the operation. 222 // use memory order RELAXED since there is no inter-thread on this variable requirements 223 __atomic_store_n(&kernelTLS.preemption_state.enabled, true, __ATOMIC_RELAXED); 224 225 // Signal the compiler that a fence is needed but only for signal handlers 226 __atomic_signal_fence(__ATOMIC_RELEASE); 192 227 } 193 228 } … … 335 370 if( !preemption_ready() ) { return; } 336 371 337 __cfaabi_dbg_print_buffer_decl( " KERNEL: preempting core %p (%p ).\n", kernelTLS.this_processor, kernelTLS.this_thread);372 __cfaabi_dbg_print_buffer_decl( " KERNEL: preempting core %p (%p @ %p).\n", kernelTLS.this_processor, kernelTLS.this_thread, (void *)(cxt->uc_mcontext.CFA_REG_IP) ); 338 373 339 374 // Sync flag : prevent recursive calls to the signal handler 340 375 kernelTLS.preemption_state.in_progress = true; 341 376 342 // We are about to CtxSwitch out of the signal handler, let other handlers in 343 signal_unblock( SIGUSR1 ); 377 // Clear sighandler mask before context switching. 378 static_assert( sizeof( sigset_t ) == sizeof( cxt->uc_sigmask ), "Expected cxt->uc_sigmask to be of sigset_t" ); 379 if ( pthread_sigmask( SIG_SETMASK, (sigset_t *)&(cxt->uc_sigmask), NULL ) == -1 ) { 380 abort( "internal error, sigprocmask" ); 381 } 344 382 345 383 // TODO: this should go in finish action … … 377 415 case EAGAIN : 378 416 case EINTR : 417 {__cfaabi_dbg_print_buffer_decl( " KERNEL: Spurious wakeup %d.\n", err );} 379 418 continue; 380 419 case EINVAL : … … 424 463 sigset_t oldset; 425 464 int ret; 426 ret = sigprocmask(0, NULL, &oldset);465 ret = pthread_sigmask(0, NULL, &oldset); 427 466 if(ret != 0) { abort("ERROR sigprocmask returned %d", ret); } 428 467 429 468 ret = sigismember(&oldset, SIGUSR1); 430 469 if(ret < 0) { abort("ERROR sigismember returned %d", ret); } 431 432 470 if(ret == 1) { abort("ERROR SIGUSR1 is disabled"); } 471 472 ret = sigismember(&oldset, SIGALRM); 473 if(ret < 0) { abort("ERROR sigismember returned %d", ret); } 474 if(ret == 0) { abort("ERROR SIGALRM is enabled"); } 475 476 ret = sigismember(&oldset, SIGTERM); 477 if(ret < 0) { abort("ERROR sigismember returned %d", ret); } 478 if(ret == 1) { abort("ERROR SIGTERM is disabled"); } 433 479 } 434 480
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