some memory accesses are now explicitely atomic

... as far as I think this mostly is to keep the thread debuggers
happy

4 files changed, 25 insertions, 10 deletions

diff --git a/ChangeLog b/ChangeLog
index 6cbfcf70..e7de1c4d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -23,6 +23,7 @@ Version 4.5.0  [DEVEL] (rgerhards), 2009-??-??
   * $OMFileFlushOnTXEnd
   * $MainMsgQueueSyncQueueFiles
   * $ActionQueueSyncQueueFiles
+- done some memory accesses explicitely atomic
 ---------------------------------------------------------------------------
 Version 4.3.2  [beta] (rgerhards), 2009-06-24
 - removed long-obsoleted property UxTradMsg
diff --git a/runtime/atomic.h b/runtime/atomic.h
index fdf64214..f5ae9357 100644
--- a/runtime/atomic.h
+++ b/runtime/atomic.h
@@ -46,6 +46,11 @@
 #	define ATOMIC_DEC_AND_FETCH(data) __sync_sub_and_fetch(&(data), 1)
 #	define ATOMIC_FETCH_32BIT(data) ((unsigned) __sync_fetch_and_and(&(data), 0xffffffff))
 #	define ATOMIC_STORE_1_TO_32BIT(data) __sync_lock_test_and_set(&(data), 1)
+#	define ATOMIC_STORE_0_TO_INT(data) __sync_fetch_and_and(&(data), 0)
+#	define ATOMIC_STORE_1_TO_INT(data) __sync_fetch_and_or(&(data), 1)
+#	define ATOMIC_STORE_INT_TO_INT(data, val) __sync_fetch_and_or(&(data), (val))
+#	define ATOMIC_CAS(data, oldVal, newVal) __sync_bool_compare_and_swap(&(data), (oldVal), (newVal));
+#	define ATOMIC_CAS_VAL(data, oldVal, newVal) __sync_val_compare_and_swap(&(data), (oldVal), (newVal));
 #else
 	/* note that we gained parctical proof that theoretical problems DO occur
 	 * if we do not properly address them. See this blog post for details:
diff --git a/runtime/wti.c b/runtime/wti.c
index f20812f8..9de7c365 100644
--- a/runtime/wti.c
+++ b/runtime/wti.c
@@ -51,6 +51,7 @@
 #include "wti.h"
 #include "obj.h"
 #include "glbl.h"
+#include "atomic.h"
 
 /* static data */
 DEFobjStaticHelpers
@@ -106,6 +107,7 @@ rsRetVal
 wtiSetState(wti_t *pThis, qWrkCmd_t tCmd, int bActiveOnly, int bLockMutex)
 {
 	DEFiRet;
+	qWrkCmd_t tCurrCmd;
 	DEFVARS_mutexProtection;
 
 	ISOBJ_TYPE_assert(pThis, wti);
@@ -113,13 +115,14 @@ wtiSetState(wti_t *pThis, qWrkCmd_t tCmd, int bActiveOnly, int bLockMutex)
 
 	BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, bLockMutex);
 
+	tCurrCmd = pThis->tCurrCmd;
 	/* all worker states must be followed sequentially, only termination can be set in any state */
-	if(   (bActiveOnly && (pThis->tCurrCmd < eWRKTHRD_RUN_CREATED))
-	   || (pThis->tCurrCmd > tCmd && !(tCmd == eWRKTHRD_TERMINATING || tCmd == eWRKTHRD_STOPPED))) {
-		dbgprintf("%s: command %d can not be accepted in current %d processing state - ignored\n",
-			  wtiGetDbgHdr(pThis), tCmd, pThis->tCurrCmd);
+	if(   (bActiveOnly && (tCurrCmd < eWRKTHRD_RUN_CREATED))
+	   || (tCurrCmd > tCmd && !(tCmd == eWRKTHRD_TERMINATING || tCmd == eWRKTHRD_STOPPED))) {
+		DBGPRINTF("%s: command %d can not be accepted in current %d processing state - ignored\n",
+			  wtiGetDbgHdr(pThis), tCmd, tCurrCmd);
 	} else {
-		dbgprintf("%s: receiving command %d\n", wtiGetDbgHdr(pThis), tCmd);
+		DBGPRINTF("%s: receiving command %d\n", wtiGetDbgHdr(pThis), tCmd);
 		/* we could replace this with a simple if, but we leave the switch in in case we need
 		 * to add something at a later stage. -- rgerhards, 2008-09-30
 		 */
@@ -143,7 +146,12 @@ wtiSetState(wti_t *pThis, qWrkCmd_t tCmd, int bActiveOnly, int bLockMutex)
 				/* DO NOTHING */
 				break;
 		}
-		pThis->tCurrCmd = tCmd; /* apply the new state */
+		/* apply the new state */
+		unsigned val = ATOMIC_CAS_VAL(pThis->tCurrCmd, tCurrCmd, tCmd);
+		if(val != tCurrCmd) {
+			DBGPRINTF("wtiSetState PROBLEM, tCurrCmd %d overwritten with %d, wanted to set %d\n", tCurrCmd, val, tCmd);
+		}
+
 	}
 
 	END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
@@ -169,7 +177,7 @@ wtiCancelThrd(wti_t *pThis)
 		dbgoprint((obj_t*) pThis, "canceling worker thread\n");
 		pthread_cancel(pThis->thrdID);
 		wtiSetState(pThis, eWRKTHRD_TERMINATING, 0, MUTEX_ALREADY_LOCKED);
-		pThis->pWtp->bThrdStateChanged = 1; /* indicate change, so harverster will be called */
+		ATOMIC_STORE_1_TO_INT(pThis->pWtp->bThrdStateChanged); /* indicate change, so harverster will be called */
 	}
 
 	d_pthread_mutex_unlock(&pThis->mut);
@@ -318,7 +326,7 @@ wtiWorkerCancelCleanup(void *arg)
 	d_pthread_mutex_lock(&pWtp->mut);
 	wtiSetState(pThis, eWRKTHRD_TERMINATING, 0, MUTEX_ALREADY_LOCKED);
 	/* TODO: sync access? I currently think it is NOT needed -- rgerhards, 2008-01-28 */
-	pWtp->bThrdStateChanged = 1; /* indicate change, so harverster will be called */
+	ATOMIC_STORE_1_TO_INT(pWtp->bThrdStateChanged); /* indicate change, so harverster will be called */
 
 	d_pthread_mutex_unlock(&pWtp->mut);
 	pthread_setcancelstate(iCancelStateSave, NULL);
@@ -405,7 +413,7 @@ wtiWorker(wti_t *pThis)
 	pWtp->pfOnWorkerShutdown(pWtp->pUsr);
 
 	wtiSetState(pThis, eWRKTHRD_TERMINATING, 0, MUTEX_ALREADY_LOCKED);
-	pWtp->bThrdStateChanged = 1; /* indicate change, so harverster will be called */
+	ATOMIC_STORE_1_TO_INT(pWtp->bThrdStateChanged); /* indicate change, so harverster will be called */
 	d_pthread_mutex_unlock(&pThis->mut);
 	pthread_setcancelstate(iCancelStateSave, NULL);
 
diff --git a/runtime/wtp.c b/runtime/wtp.c
index 611b3f25..218a5db6 100644
--- a/runtime/wtp.c
+++ b/runtime/wtp.c
@@ -39,6 +39,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
+#include <atomic.h>
 
 #ifdef OS_SOLARIS
 #	include <sched.h>
@@ -214,7 +215,7 @@ wtpProcessThrdChanges(wtp_t *pThis)
 	 */
 	do {
 		/* reset the change marker */
-		pThis->bThrdStateChanged = 0;
+		ATOMIC_STORE_0_TO_INT(pThis->bThrdStateChanged);
 		/* go through all threads */
 		for(i = 0 ; i < pThis->iNumWorkerThreads ; ++i) {
 			wtiProcessThrdChanges(pThis->pWrkr[i], LOCK_MUTEX);