Changes in / [c659968:eb7f20c]

Location:

src/libcfa/concurrency

Files:

• kernel.c (modified) (1 diff)
• kernel_private.h (modified) (1 diff)
• preemption.c (modified) (3 diffs)

src/libcfa/concurrency/kernel.c

@@ -170 +170 @@
         if( ! do_terminate ) {
                 __cfaabi_dbg_print_safe("Kernel : core %p signaling termination\n", &this);
-                do_terminate = true;
+                terminate(&this);
                 P( terminated );
                 pthread_join( kernel_thread, NULL );

src/libcfa/concurrency/kernel_private.h

@@ -60 +60 @@
 void runThread(processor * this, thread_desc * dst);
 void finishRunning(processor * this);
+void terminate(processor * this);
 void spin(processor * this, unsigned int * spin_count);
 

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