X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FTask.c;h=9a8ebd69630b3864cb46bd27a7191e3328678509;hb=95ec750f94236c2ae127a147d7c9bebec036bcab;hp=c8cd9c4a2c19c2edf5e701c398149adf011502a3;hpb=48ff2a03397d744e4b24797d7b16fdaf6feb576a;p=ghc-hetmet.git

diff --git a/rts/Task.c b/rts/Task.c
index c8cd9c4..9a8ebd6 100644
--- a/rts/Task.c
+++ b/rts/Task.c
@@ -8,13 +8,13 @@
  * 
  * -------------------------------------------------------------------------*/
 
+#include "PosixSource.h"
 #include "Rts.h"
+
 #include "RtsUtils.h"
-#include "OSThreads.h"
 #include "Task.h"
 #include "Capability.h"
 #include "Stats.h"
-#include "RtsFlags.h"
 #include "Schedule.h"
 #include "Hash.h"
 #include "Trace.h"
@@ -28,10 +28,9 @@
 Task *all_tasks = NULL;
 static Task *task_free_list = NULL; // singly-linked
 static nat taskCount;
-#define DEFAULT_MAX_WORKERS 64
-static nat maxWorkers; // we won't create more workers than this
 static nat tasksRunning;
 static nat workerCount;
+static int tasksInitialized = 0;
 
 /* -----------------------------------------------------------------------------
  * Remembering the current thread's Task
@@ -52,31 +51,50 @@ Task *my_task;
 void
 initTaskManager (void)
 {
-    static int initialized = 0;
-
-    if (!initialized) {
+    if (!tasksInitialized) {
 	taskCount = 0;
 	workerCount = 0;
 	tasksRunning = 0;
-#if defined(THREADED_RTS)
-	maxWorkers = DEFAULT_MAX_WORKERS * RtsFlags.ParFlags.nNodes;
-#else
-	maxWorkers = DEFAULT_MAX_WORKERS;
-#endif
-	initialized = 1;
+	tasksInitialized = 1;
 #if defined(THREADED_RTS)
 	newThreadLocalKey(&currentTaskKey);
 #endif
     }
 }
 
-
-void
-stopTaskManager (void)
+nat
+freeTaskManager (void)
 {
-    debugTrace(DEBUG_sched, 
-	       "stopping task manager, %d tasks still running",
-	       tasksRunning);
+    Task *task, *next;
+
+    ASSERT_LOCK_HELD(&sched_mutex);
+
+    debugTrace(DEBUG_sched, "freeing task manager, %d tasks still running",
+               tasksRunning);
+
+    for (task = all_tasks; task != NULL; task = next) {
+        next = task->all_link;
+        if (task->stopped) {
+            // We only free resources if the Task is not in use.  A
+            // Task may still be in use if we have a Haskell thread in
+            // a foreign call while we are attempting to shut down the
+            // RTS (see conc059).
+#if defined(THREADED_RTS)
+            closeCondition(&task->cond);
+            closeMutex(&task->lock);
+#endif
+            stgFree(task);
+        }
+    }
+    all_tasks = NULL;
+    task_free_list = NULL;
+#if defined(THREADED_RTS)
+    freeThreadLocalKey(&currentTaskKey);
+#endif
+
+    tasksInitialized = 0;
+
+    return tasksRunning;
 }
 
 
@@ -88,7 +106,8 @@ newTask (void)
 #endif
     Task *task;
 
-    task = stgMallocBytes(sizeof(Task), "newTask");
+#define ROUND_TO_CACHE_LINE(x) ((((x)+63) / 64) * 64)
+    task = stgMallocBytes(ROUND_TO_CACHE_LINE(sizeof(Task)), "newTask");
     
     task->cap  = NULL;
     task->stopped = rtsFalse;
@@ -122,7 +141,6 @@ newTask (void)
     all_tasks = task;
 
     taskCount++;
-    workerCount++;
 
     return task;
 }
@@ -132,7 +150,17 @@ newBoundTask (void)
 {
     Task *task;
 
-    ASSERT_LOCK_HELD(&sched_mutex);
+    if (!tasksInitialized) {
+        errorBelch("newBoundTask: RTS is not initialised; call hs_init() first");
+        stg_exit(EXIT_FAILURE);
+    }
+
+    // ToDo: get rid of this lock in the common case.  We could store
+    // a free Task in thread-local storage, for example.  That would
+    // leave just one lock on the path into the RTS: cap->lock when
+    // acquiring the Capability.
+    ACQUIRE_LOCK(&sched_mutex);
+
     if (task_free_list == NULL) {
 	task = newTask();
     } else {
@@ -151,6 +179,8 @@ newBoundTask (void)
 
     taskEnter(task);
 
+    RELEASE_LOCK(&sched_mutex);
+
     debugTrace(DEBUG_sched, "new task (taskCount: %d)", taskCount);
     return task;
 }
@@ -158,6 +188,7 @@ newBoundTask (void)
 void
 boundTaskExiting (Task *task)
 {
+    task->tso = NULL;
     task->stopped = rtsTrue;
     task->cap = NULL;
 
@@ -189,9 +220,13 @@ discardTask (Task *task)
 {
     ASSERT_LOCK_HELD(&sched_mutex);
     if (!task->stopped) {
-	debugTrace(DEBUG_sched, "discarding task %ld", TASK_ID(task));
+	debugTrace(DEBUG_sched, "discarding task %ld", (long)TASK_ID(task));
 	task->cap = NULL;
-	task->tso = NULL;
+        if (task->tso == NULL) {
+            workerCount--;
+        } else {
+            task->tso = NULL;
+        }
 	task->stopped = rtsTrue;
 	tasksRunning--;
 	task->next = task_free_list;
@@ -222,28 +257,30 @@ taskTimeStamp (Task *task USED_IF_THREADS)
 #endif
 }
 
+#if defined(THREADED_RTS)
+
 void
 workerTaskStop (Task *task)
 {
-#if defined(THREADED_RTS)
     OSThreadId id;
     id = osThreadId();
     ASSERT(task->id == id);
     ASSERT(myTask() == task);
-#endif
 
+    task->cap = NULL;
     taskTimeStamp(task);
     task->stopped = rtsTrue;
     tasksRunning--;
-}
+    workerCount--;
 
-void
-resetTaskManagerAfterFork (void)
-{
-    // TODO!
-    taskCount = 0;
+    ACQUIRE_LOCK(&sched_mutex);
+    task->next = task_free_list;
+    task_free_list = task;
+    RELEASE_LOCK(&sched_mutex);
 }
 
+#endif
+
 #if defined(THREADED_RTS)
 
 void
@@ -254,9 +291,6 @@ startWorkerTask (Capability *cap,
   OSThreadId tid;
   Task *task;
 
-  if (workerCount >= maxWorkers) {
-      barf("too many workers; runaway worker creation?");
-  }
   workerCount++;
 
   // A worker always gets a fresh Task structure.
@@ -279,7 +313,8 @@ startWorkerTask (Capability *cap,
 
   r = createOSThread(&tid, (OSThreadProc *)taskStart, task);
   if (r != 0) {
-    barf("startTask: Can't create new task");
+    sysErrorBelch("failed to create OS thread");
+    stg_exit(EXIT_FAILURE);
   }
 
   debugTrace(DEBUG_sched, "new worker task (taskCount: %d)", taskCount);
@@ -316,7 +351,7 @@ printAllTasks(void)
 		debugBelch("on capability %d, ", task->cap->no);
 	    }
 	    if (task->tso) {
-		debugBelch("bound to thread %d", task->tso->id);
+	      debugBelch("bound to thread %lu", (unsigned long)task->tso->id);
 	    } else {
 		debugBelch("worker");
 	    }