X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FSchedule.c;h=8c254cc56a6d3011458d3502bee7ec0f530cf3e7;hb=66579ff945831c5fc9a17c58c722ff01f2268d76;hp=7f59f09155bd02e18c5dbe3ba6d5d7d468dbf53a;hpb=848dafe81b0b7e3564c09109a2f30b598235c555;p=ghc-hetmet.git

diff --git a/rts/Schedule.c b/rts/Schedule.c
index 7f59f09..8c254cc 100644
--- a/rts/Schedule.c
+++ b/rts/Schedule.c
@@ -89,11 +89,6 @@ StgTSO *blackhole_queue = NULL;
  */
 rtsBool blackholes_need_checking = rtsFalse;
 
-/* flag set by signal handler to precipitate a context switch
- * LOCK: none (just an advisory flag)
- */
-int context_switch = 0;
-
 /* flag that tracks whether we have done any execution in this time slice.
  * LOCK: currently none, perhaps we should lock (but needs to be
  * updated in the fast path of the scheduler).
@@ -504,7 +499,7 @@ schedule (Capability *initialCapability, Task *task)
      */
     if (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
 	&& !emptyThreadQueues(cap)) {
-	context_switch = 1;
+	cap->context_switch = 1;
     }
 	 
 run_thread:
@@ -1179,12 +1174,12 @@ scheduleHandleHeapOverflow( Capability *cap, StgTSO *t )
 	       "--<< thread %ld (%s) stopped: HeapOverflow",
 	       (long)t->id, whatNext_strs[t->what_next]);
 
-    if (context_switch) {
+    if (cap->context_switch) {
         // Sometimes we miss a context switch, e.g. when calling
         // primitives in a tight loop, MAYBE_GC() doesn't check the
         // context switch flag, and we end up waiting for a GC.
         // See #1984, and concurrent/should_run/1984
-        context_switch = 0;
+        cap->context_switch = 0;
         addToRunQueue(cap,t);
     } else {
         pushOnRunQueue(cap,t);
@@ -1234,7 +1229,7 @@ scheduleHandleYield( Capability *cap, StgTSO *t, nat prev_what_next )
     // the CPU because the tick always arrives during GC).  This way
     // penalises threads that do a lot of allocation, but that seems
     // better than the alternative.
-    context_switch = 0;
+    cap->context_switch = 0;
     
     /* put the thread back on the run queue.  Then, if we're ready to
      * GC, check whether this is the last task to stop.  If so, wake
@@ -1435,6 +1430,7 @@ scheduleDoGC (Capability *cap, Task *task USED_IF_THREADS, rtsBool force_major)
 	return cap;  // NOTE: task->cap might have changed here
     }
 
+    setContextSwitches();
     for (i=0; i < n_capabilities; i++) {
 	debugTrace(DEBUG_sched, "ready_to_gc, grabbing all the capabilies (%d/%d)", i, n_capabilities);
 	if (cap != &capabilities[i]) {
@@ -1445,7 +1441,6 @@ scheduleDoGC (Capability *cap, Task *task USED_IF_THREADS, rtsBool force_major)
 	    // all the Capabilities, but even so it's a slightly
 	    // unsavoury invariant.
 	    task->cap = pcap;
-	    context_switch = 1;
 	    waitForReturnCapability(&pcap, task);
 	    if (pcap != &capabilities[i]) {
 		barf("scheduleDoGC: got the wrong capability");
@@ -1912,7 +1907,7 @@ scheduleWaitThread (StgTSO* tso, /*[out]*/HaskellObj* ret, Capability *cap)
  * ------------------------------------------------------------------------- */
 
 #if defined(THREADED_RTS)
-void
+void OSThreadProcAttr
 workerStart(Task *task)
 {
     Capability *cap;
@@ -1954,7 +1949,6 @@ initScheduler(void)
 
   blackhole_queue   = END_TSO_QUEUE;
 
-  context_switch = 0;
   sched_state    = SCHED_RUNNING;
   recent_activity = ACTIVITY_YES;
 
@@ -2192,7 +2186,7 @@ static StgTSO *
 threadStackUnderflow (Task *task STG_UNUSED, StgTSO *tso)
 {
     bdescr *bd, *new_bd;
-    lnat new_tso_size_w, tso_size_w;
+    lnat free_w, tso_size_w;
     StgTSO *new_tso;
 
     tso_size_w = tso_sizeW(tso);
@@ -2207,19 +2201,19 @@ threadStackUnderflow (Task *task STG_UNUSED, StgTSO *tso)
     // while we are moving the TSO:
     lockClosure((StgClosure *)tso);
 
-    new_tso_size_w = round_to_mblocks(tso_size_w/2);
-
-    debugTrace(DEBUG_sched, "thread %ld: reducing TSO size from %lu words to %lu",
-               (long)tso->id, tso_size_w, new_tso_size_w);
+    // this is the number of words we'll free
+    free_w = round_to_mblocks(tso_size_w/2);
 
     bd = Bdescr((StgPtr)tso);
-    new_bd = splitLargeBlock(bd, new_tso_size_w / BLOCK_SIZE_W);
-    new_bd->free = bd->free;
+    new_bd = splitLargeBlock(bd, free_w / BLOCK_SIZE_W);
     bd->free = bd->start + TSO_STRUCT_SIZEW;
 
     new_tso = (StgTSO *)new_bd->start;
     memcpy(new_tso,tso,TSO_STRUCT_SIZE);
-    new_tso->stack_size = new_tso_size_w - TSO_STRUCT_SIZEW;
+    new_tso->stack_size = new_bd->free - new_tso->stack;
+
+    debugTrace(DEBUG_sched, "thread %ld: reducing TSO size from %lu words to %lu",
+               (long)tso->id, tso_size_w, tso_sizeW(new_tso));
 
     tso->what_next = ThreadRelocated;
     tso->_link = new_tso; // no write barrier reqd: same generation
@@ -2247,7 +2241,7 @@ void
 interruptStgRts(void)
 {
     sched_state = SCHED_INTERRUPTING;
-    context_switch = 1;
+    setContextSwitches();
     wakeUpRts();
 }