Changeset 3d4b23fa for src/libcfa/concurrency/preemption.c

Timestamp:

Jul 13, 2017, 3:57:04 PM (8 years ago)

Author:

Rob Schluntz <rschlunt@…>

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:

0720e049, 9a1e509

Parents:

55a68c3 (diff), d6ff3ff (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'master' of plg.uwaterloo.ca:/u/cforall/software/cfa/cfa-cc

File:

• src/libcfa/concurrency/preemption.c (modified) (7 diffs)

src/libcfa/concurrency/preemption.c

@@ -15 +15 @@
 //
 
+#include "libhdr.h"
 #include "preemption.h"
 
 extern "C" {
+#include <errno.h>
+#include <execinfo.h>
+#define __USE_GNU
 #include <signal.h>
-}
-
-#define __CFA_DEFAULT_PREEMPTION__ 10
+#undef __USE_GNU
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+}
+
+
+#ifdef __USE_STREAM__
+#include "fstream"
+#endif
+
+#define __CFA_DEFAULT_PREEMPTION__ 10000
 
 __attribute__((weak)) unsigned int default_preemption() {
@@ -27 +40 @@
 }
 
+#define __CFA_SIGCXT__ ucontext_t *
+#define __CFA_SIGPARMS__ __attribute__((unused)) int sig, __attribute__((unused)) siginfo_t *sfp, __attribute__((unused)) __CFA_SIGCXT__ cxt
+
 static void preempt( processor   * this );
 static void timeout( thread_desc * this );
 
+void sigHandler_ctxSwitch( __CFA_SIGPARMS__ );
+void sigHandler_alarm    ( __CFA_SIGPARMS__ );
+void sigHandler_segv     ( __CFA_SIGPARMS__ );
+void sigHandler_abort    ( __CFA_SIGPARMS__ );
+
+static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags );
+LIB_DEBUG_DO( bool validate( alarm_list_t * this ); )
+
+#ifdef __x86_64__
+#define CFA_REG_IP REG_RIP
+#else
+#define CFA_REG_IP REG_EIP
+#endif
+
+
 //=============================================================================================
 // Kernel Preemption logic
 //=============================================================================================
 
-void kernel_start_preemption() {
-
-}
-
 void tick_preemption() {
+        // LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Ticking preemption\n" );
+
         alarm_list_t * alarms = &systemProcessor->alarms;
         __cfa_time_t currtime = __kernel_get_time();
         while( alarms->head && alarms->head->alarm < currtime ) {
                 alarm_node_t * node = pop(alarms);
+                // LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ticking %p\n", node );
+
                 if( node->kernel_alarm ) {
                         preempt( node->proc );
@@ -50 +81 @@
                 }
 
+                verify( validate( alarms ) );
+
                 if( node->period > 0 ) {
-                        node->alarm += node->period;
+                        node->alarm = currtime + node->period;
                         insert( alarms, node );
                 }
@@ -62 +95 @@
                 __kernel_set_timer( alarms->head->alarm - currtime );
         }
+
+        verify( validate( alarms ) );
+        // LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ticking preemption done\n" );
 }
 
 void update_preemption( processor * this, __cfa_time_t duration ) {
-        //     assert( THREAD_GETMEM( disableInt ) && THREAD_GETMEM( disableIntCnt ) == 1 );
+        LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Processor : %p updating preemption to %lu\n", this, duration );
+
         alarm_node_t * alarm = this->preemption_alarm;
+        duration *= 1000;
 
         // Alarms need to be enabled
@@ -89 +127 @@
 }
 
+//=============================================================================================
+// Kernel Signal Tools
+//=============================================================================================
+
+LIB_DEBUG_DO( static thread_local void * last_interrupt = 0; )
+
+extern "C" {
+        void disable_interrupts() {
+                __attribute__((unused)) unsigned short new_val = __atomic_add_fetch_2( &disable_preempt_count, 1, __ATOMIC_SEQ_CST );
+                verify( new_val < (unsigned short)65_000 );
+                verify( new_val != (unsigned short) 0 );
+        }
+
+        void enable_interrupts_noRF() {
+                __attribute__((unused)) unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST );
+                verify( prev != (unsigned short) 0 );
+        }
+
+        void enable_interrupts( DEBUG_CTX_PARAM ) {
+                processor * proc   = this_processor;
+                thread_desc * thrd = this_thread;
+                unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST );
+                verify( prev != (unsigned short) 0 );
+                if( prev == 1 && proc->pending_preemption ) {
+                        proc->pending_preemption = false;
+                        BlockInternal( thrd );
+                }
+
+                LIB_DEBUG_DO( proc->last_enable = caller; )
+        }
+}
+
+static inline void signal_unblock( int sig ) {
+        sigset_t mask;
+        sigemptyset( &mask );
+        sigaddset( &mask, sig );
+
+        if ( pthread_sigmask( SIG_UNBLOCK, &mask, NULL ) == -1 ) {
+            abortf( "internal error, pthread_sigmask" );
+        }
+}
+
+static inline void signal_block( int sig ) {
+        sigset_t mask;
+        sigemptyset( &mask );
+        sigaddset( &mask, sig );
+
+        if ( pthread_sigmask( SIG_BLOCK, &mask, NULL ) == -1 ) {
+            abortf( "internal error, pthread_sigmask" );
+        }
+}
+
+static inline bool preemption_ready() {
+        return disable_preempt_count == 0 && !preemption_in_progress;
+}
+
+static inline void defer_ctxSwitch() {
+        this_processor->pending_preemption = true;
+}
+
+static inline void defer_alarm() {
+        systemProcessor->pending_alarm = true;
+}
+
+static void preempt( processor * this ) {
+        pthread_kill( this->kernel_thread, SIGUSR1 );
+}
+
+static void timeout( thread_desc * this ) {
+        //TODO : implement waking threads
+}
+
+//=============================================================================================
+// Kernel Signal Startup/Shutdown logic
+//=============================================================================================
+
+static pthread_t alarm_thread;
+void * alarm_loop( __attribute__((unused)) void * args );
+
+void kernel_start_preemption() {
+        LIB_DEBUG_PRINT_SAFE("Kernel : Starting preemption\n");
+        __kernel_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO );
+        // __kernel_sigaction( SIGSEGV, sigHandler_segv     , SA_SIGINFO );
+        // __kernel_sigaction( SIGBUS , sigHandler_segv     , SA_SIGINFO );
+
+        signal_block( SIGALRM );
+
+        pthread_create( &alarm_thread, NULL, alarm_loop, NULL );
+}
+
+void kernel_stop_preemption() {
+        LIB_DEBUG_PRINT_SAFE("Kernel : Preemption stopping\n");
+
+        sigset_t mask;
+        sigfillset( &mask );
+        sigprocmask( SIG_BLOCK, &mask, NULL );
+
+        sigval val = { 1 };
+        pthread_sigqueue( alarm_thread, SIGALRM, val );
+        pthread_join( alarm_thread, NULL );
+        LIB_DEBUG_PRINT_SAFE("Kernel : Preemption stopped\n");
+}
+
 void ?{}( preemption_scope * this, processor * proc ) {
         (&this->alarm){ proc };
@@ -97 +238 @@
 
 void ^?{}( preemption_scope * this ) {
+        disable_interrupts();
+
         update_preemption( this->proc, 0 );
 }
 
 //=============================================================================================
-// Kernel Signal logic
-//=============================================================================================
-
-static inline bool preemption_ready() {
-        return this_processor->disable_preempt_count == 0;
-}
-
-static inline void defer_ctxSwitch() {
-        this_processor->pending_preemption = true;
-}
-
-static inline void defer_alarm() {
-        systemProcessor->pending_alarm = true;
-}
-
-void sigHandler_ctxSwitch( __attribute__((unused)) int sig ) {
+// Kernel Signal Handlers
+//=============================================================================================
+
+void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ) {
+        LIB_DEBUG_DO( last_interrupt = (void *)(cxt->uc_mcontext.gregs[CFA_REG_IP]); )
         if( preemption_ready() ) {
-                ScheduleInternal( this_processor->current_thread );
+                preemption_in_progress = true;
+                signal_unblock( SIGUSR1 );
+                this_processor->pending_preemption = false;
+                preemption_in_progress = false;
+                BlockInternal( (thread_desc*)this_thread );
         }
         else {
@@ -125 +261 @@
 }
 
-void sigHandler_alarm( __attribute__((unused)) int sig ) {
-        if( try_lock( &systemProcessor->alarm_lock ) ) {
-                tick_preemption();
-                unlock( &systemProcessor->alarm_lock );
-        }
-        else {
-                defer_alarm();
-        }
-}
-
-static void preempt( processor * this ) {
-        pthread_kill( this->kernel_thread, SIGUSR1 );
-}
-
-static void timeout( thread_desc * this ) {
-        //TODO : implement waking threads
-}
+void * alarm_loop( __attribute__((unused)) void * args ) {
+        sigset_t mask;
+        sigemptyset( &mask );
+        sigaddset( &mask, SIGALRM );
+
+        if ( pthread_sigmask( SIG_BLOCK, &mask, NULL ) == -1 ) {
+            abortf( "internal error, pthread_sigmask" );
+        }
+
+        while( true ) {
+                siginfo_t info;
+                int sig = sigwaitinfo( &mask, &info );
+                if( sig < 0 ) {
+                        abortf( "internal error, sigwait" );
+                }
+                else if( sig == SIGALRM )
+                {
+                        LIB_DEBUG_PRINT_SAFE("Kernel : Caught signal %d (%d)\n", sig, info.si_value.sival_int );
+                        if( info.si_value.sival_int == 0 )
+                        {
+                                LIB_DEBUG_PRINT_SAFE("Kernel : Preemption thread tick\n");
+                                lock( &systemProcessor->alarm_lock DEBUG_CTX2 );
+                                tick_preemption();
+                                unlock( &systemProcessor->alarm_lock );
+                        }
+                        else if( info.si_value.sival_int == 1 )
+                        {
+                                break;
+                        }
+                }
+                else
+                {
+                        LIB_DEBUG_PRINT_SAFE("Kernel : Unexpected signal %d (%d)\n", sig, info.si_value.sival_int);
+                }
+        }
+
+        LIB_DEBUG_PRINT_SAFE("Kernel : Preemption thread stopping\n");
+        return NULL;
+}
+
+static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags ) {
+        struct sigaction act;
+
+        act.sa_sigaction = (void (*)(int, siginfo_t *, void *))handler;
+        act.sa_flags = flags;
+
+        if ( sigaction( sig, &act, NULL ) == -1 ) {
+                LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO,
+                        " __kernel_sigaction( sig:%d, handler:%p, flags:%d ), problem installing signal handler, error(%d) %s.\n",
+                        sig, handler, flags, errno, strerror( errno )
+                );
+                _exit( EXIT_FAILURE );
+        }
+}
+
+typedef void (*sa_handler_t)(int);
+
+static void __kernel_sigdefault( int sig ) {
+        struct sigaction act;
+
+        // act.sa_handler = SIG_DFL;
+        act.sa_flags = 0;
+        sigemptyset( &act.sa_mask );
+
+        if ( sigaction( sig, &act, NULL ) == -1 ) {
+                LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO,
+                        " __kernel_sigdefault( sig:%d ), problem reseting signal handler, error(%d) %s.\n",
+                        sig, errno, strerror( errno )
+                );
+                _exit( EXIT_FAILURE );
+        }
+}
+
+//=============================================================================================
+// Terminating Signals logic
+//=============================================================================================
+
+LIB_DEBUG_DO(
+        static void __kernel_backtrace( int start ) {
+                // skip first N stack frames
+
+                enum { Frames = 50 };
+                void * array[Frames];
+                int size = backtrace( array, Frames );
+                char ** messages = backtrace_symbols( array, size );
+
+                // find executable name
+                *index( messages[0], '(' ) = '\0';
+                #ifdef __USE_STREAM__
+                serr | "Stack back trace for:" | messages[0] | endl;
+                #else
+                fprintf( stderr, "Stack back trace for: %s\n", messages[0]);
+                #endif
+
+                // skip last 2 stack frames after main
+                for ( int i = start; i < size && messages != NULL; i += 1 ) {
+                        char * name = NULL;
+                        char * offset_begin = NULL;
+                        char * offset_end = NULL;
+
+                        for ( char *p = messages[i]; *p; ++p ) {
+                                // find parantheses and +offset
+                                if ( *p == '(' ) {
+                                        name = p;
+                                }
+                                else if ( *p == '+' ) {
+                                        offset_begin = p;
+                                }
+                                else if ( *p == ')' ) {
+                                        offset_end = p;
+                                        break;
+                                }
+                        }
+
+                        // if line contains symbol print it
+                        int frameNo = i - start;
+                        if ( name && offset_begin && offset_end && name < offset_begin ) {
+                                // delimit strings
+                                *name++ = '\0';
+                                *offset_begin++ = '\0';
+                                *offset_end++ = '\0';
+
+                                #ifdef __USE_STREAM__
+                                serr    | "("  | frameNo | ")" | messages[i] | ":"
+                                        | name | "+" | offset_begin | offset_end | endl;
+                                #else
+                                fprintf( stderr, "(%i) %s : %s + %s %s\n", frameNo, messages[i], name, offset_begin, offset_end);
+                                #endif
+                        }
+                        // otherwise, print the whole line
+                        else {
+                                #ifdef __USE_STREAM__
+                                serr | "(" | frameNo | ")" | messages[i] | endl;
+                                #else
+                                fprintf( stderr, "(%i) %s\n", frameNo, messages[i] );
+                                #endif
+                        }
+                }
+
+                free( messages );
+        }
+)
+
+// void sigHandler_segv( __CFA_SIGPARMS__ ) {
+//      LIB_DEBUG_DO(
+//              #ifdef __USE_STREAM__
+//              serr    | "*CFA runtime error* program cfa-cpp terminated with"
+//                      | (sig == SIGSEGV ? "segment fault." : "bus error.")
+//                      | endl;
+//              #else
+//              fprintf( stderr, "*CFA runtime error* program cfa-cpp terminated with %s\n", sig == SIGSEGV ? "segment fault." : "bus error." );
+//              #endif
+
+//              // skip first 2 stack frames
+//              __kernel_backtrace( 1 );
+//      )
+//      exit( EXIT_FAILURE );
+// }
+
+// void sigHandler_abort( __CFA_SIGPARMS__ ) {
+//      // skip first 6 stack frames
+//      LIB_DEBUG_DO( __kernel_backtrace( 6 ); )
+
+//      // reset default signal handler
+//      __kernel_sigdefault( SIGABRT );
+
+//      raise( SIGABRT );
+// }