Changeset 4dad189 for src/libcfa/concurrency/preemption.c

Timestamp:

Feb 8, 2018, 1:59:03 PM (7 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

eb7f20c

Parents:

3d5f2ef1

Message:

Processor can no longer be destroyed from a thread that is running on said processor

File:

• src/libcfa/concurrency/preemption.c (modified) (3 diffs)

src/libcfa/concurrency/preemption.c

@@ -67 +67 @@
 }
 
+enum {
+        PREEMPT_NORMAL    = 0,
+        PREEMPT_TERMINATE = 1,
+};
+
 //=============================================================================================
 // Kernel Preemption logic
@@ -209 +214 @@
 // kill wrapper : signal a processor
 static void preempt( processor * this ) {
-        pthread_kill( this->kernel_thread, SIGUSR1 );
+        sigval_t value = { PREEMPT_NORMAL };
+        pthread_sigqueue( this->kernel_thread, SIGUSR1, value );
+}
+
+// kill wrapper : signal a processor
+void terminate(processor * this) {
+        this->do_terminate = true;
+        sigval_t value = { PREEMPT_TERMINATE };
+        pthread_sigqueue( this->kernel_thread, SIGUSR1, value );
 }
 
@@ -298 +311 @@
 void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ) {
         __cfaabi_dbg_debug_do( last_interrupt = (void *)(cxt->uc_mcontext.CFA_REG_IP); )
+
+        // SKULLDUGGERY: if a thread creates a processor and the immediately deletes it,
+        // the interrupt that is supposed to force the kernel thread to preempt might arrive
+        // before the kernel thread has even started running. When that happens an iterrupt
+        // we a null 'this_processor' will be caught, just ignore it.
+        if(!this_processor) return;
+
+        choose(sfp->si_value.sival_int) {
+                case PREEMPT_NORMAL   : ;// Normal case, nothing to do here
+                case PREEMPT_TERMINATE: verify(this_processor->do_terminate);
+                default:
+                        abortf( "internal error, signal value is %d", sfp->si_value.sival_int );
+        }
 
         // Check if it is safe to preempt here