Merge the smp and threaded RTS ways

Now, the threaded RTS also includes SMP support.  The -smp flag is a
synonym for -threaded.  The performance implications of this are small
to negligible, and it results in a code cleanup and reduces the number
of combinations we have to test.

ghc/compiler/main/StaticFlags.hs

@@ -124,7 +124,7 @@ static_flags = [
   ,  ( "ticky"		, NoArg (addWay WayTicky) )
   ,  ( "parallel"	, NoArg (addWay WayPar) )
   ,  ( "gransim"	, NoArg (addWay WayGran) )
-  ,  ( "smp"		, NoArg (addWay WaySMP) )
+  ,  ( "smp"		, NoArg (addWay WayThreaded) ) -- backwards compat.
   ,  ( "debug"		, NoArg (addWay WayDebug) )
   ,  ( "ndp"		, NoArg (addWay WayNDP) )
   ,  ( "threaded"	, NoArg (addWay WayThreaded) )
@@ -416,7 +416,6 @@ data WayName
   | WayTicky
   | WayPar
   | WayGran
-  | WaySMP
   | WayNDP
   | WayUser_a
   | WayUser_b
@@ -554,16 +553,6 @@ way_details =
 	, "-optc-DGRAN"
 	, "-package concurrent" ]),
 
-    (WaySMP, Way  "s" True "SMP"
-	[ 
-#if !defined(mingw32_TARGET_OS)
-	  "-optc-pthread"
-#endif
-#if !defined(mingw32_TARGET_OS) && !defined(freebsd_TARGET_OS)
-	, "-optl-pthread"
-#endif
-	]),
-
     (WayNDP, Way  "ndp" False "Nested data parallelism"
 	[ "-fparr"
 	, "-fflatten"]),

ghc/includes/Closures.h

@@ -356,7 +356,7 @@ typedef struct {
   StgHeader                  header;
   StgClosure                *volatile current_value;
   StgTVarWaitQueue          *volatile first_wait_queue_entry;
-#if defined(SMP)
+#if defined(THREADED_RTS)
   StgInt                     volatile num_updates;
 #endif
 } StgTVar;
@@ -367,7 +367,7 @@ typedef struct {
   StgTVar                   *tvar;
   StgClosure                *expected_value;
   StgClosure                *new_value; 
-#if defined(SMP)
+#if defined(THREADED_RTS)
   StgInt                     num_updates;
 #endif
 } TRecEntry;

ghc/includes/Regs.h

@@ -25,7 +25,8 @@
 #include "gmp.h" // Needs MP_INT definition 
 
 /*
- * Spark pools: used to store pending sparks (SMP & PARALLEL_HASKELL only)
+ * Spark pools: used to store pending sparks 
+ *  (THREADED_RTS & PARALLEL_HASKELL only)
  * This is a circular buffer.  Invariants:
  *    - base <= hd < lim
  *    - base <= tl < lim
@@ -107,15 +108,16 @@ typedef struct StgRegTable_ {
   struct bdescr_ *rCurrentNursery; /* Hp/HpLim point into this block */
   struct bdescr_ *rCurrentAlloc;   /* for allocation using allocate() */
   StgWord         rHpAlloc;	/* number of *bytes* being allocated in heap */
-  // rmp_tmp1..rmp_result2 are only used in SMP builds to avoid per-thread temps
-  // in bss, but currently always incldue here so we just run mkDerivedConstants once
+  // rmp_tmp1..rmp_result2 are only used in THREADED_RTS builds to
+  // avoid per-thread temps in bss, but currently always incldue here
+  // so we just run mkDerivedConstants once
   StgInt          rmp_tmp_w;
   MP_INT          rmp_tmp1;      
   MP_INT          rmp_tmp2;      
   MP_INT          rmp_result1;
   MP_INT          rmp_result2;
   StgWord         rRet;  // holds the return code of the thread
-#if defined(SMP) || defined(PAR)
+#if defined(THREADED_RTS) || defined(PAR)
   StgSparkPool    rSparks;	/* per-task spark pool */
 #endif
 } StgRegTable;
@@ -330,10 +332,10 @@ struct PartCapability_ {
     StgRegTable r;
 };
 
-/* No such thing as a MainCapability under SMP - each thread must have
+/* No such thing as a MainCapability under THREADED_RTS - each thread must have
  * its own Capability.
  */
-#if IN_STG_CODE && !defined(SMP)
+#if IN_STG_CODE && !defined(THREADED_RTS)
 extern W_ MainCapability[];
 #endif
 
@@ -349,8 +351,8 @@ extern W_ MainCapability[];
 GLOBAL_REG_DECL(StgRegTable *,BaseReg,REG_Base)
 #define ASSIGN_BaseReg(e) (BaseReg = (e))
 #else
-#ifdef SMP
-#error BaseReg must be in a register for SMP
+#ifdef THREADED_RTS
+#error BaseReg must be in a register for THREADED_RTS
 #endif
 #define BaseReg (&((struct PartCapability_ *)MainCapability)->r)
 #define ASSIGN_BaseReg(e) /*nothing*/
@@ -628,8 +630,8 @@ GLOBAL_REG_DECL(bdescr *,SparkLim,REG_SparkLim)
 #endif
 
 #ifdef CALLER_SAVES_Base
-#ifdef SMP
-#error "Can't have caller-saved BaseReg with SMP"
+#ifdef THREADED_RTS
+#error "Can't have caller-saved BaseReg with THREADED_RTS"
 #endif
 #define CALLER_SAVE_Base	/* nothing */
 #define CALLER_RESTORE_Base	BaseReg = &MainRegTable;

ghc/includes/Rts.h

@@ -70,14 +70,6 @@ extern void _assertFail (char *, unsigned int);
 
 #define doNothing() do { } while (0)
 
-#ifdef SMP
-#define USED_IF_SMP
-#define USED_IF_NOT_SMP STG_UNUSED
-#else
-#define USED_IF_SMP STG_UNUSED
-#define USED_IF_NOT_SMP
-#endif
-
 #ifdef DEBUG
 #define USED_IF_DEBUG
 #define USED_IF_NOT_DEBUG STG_UNUSED

ghc/includes/RtsConfig.h

@@ -39,7 +39,7 @@
 /* TICKY_TICKY needs EAGER_BLACKHOLING to verify no double-entries of
  * single-entry thunks.
  */
-/* #if defined(TICKY_TICKY) || defined(SMP) */
+/* #if defined(TICKY_TICKY) || defined(THREADED_RTS) */
 #if defined(TICKY_TICKY)
 #  define EAGER_BLACKHOLING
 #else

ghc/includes/RtsFlags.h

@@ -161,12 +161,12 @@ struct PAR_FLAGS {
 };
 #endif /* PAR */
 
-#ifdef SMP
+#ifdef THREADED_RTS
 struct PAR_FLAGS {
   nat            nNodes;         /* number of threads to run simultaneously */
   unsigned int	 maxLocalSparks;
 };
-#endif /* SMP */
+#endif /* THREADED_RTS */
 
 #ifdef GRAN
 struct GRAN_STATS_FLAGS {
@@ -240,7 +240,7 @@ struct GRAN_FLAGS {
   struct GRAN_COST_FLAGS Costs;          /* cost metric for simulation */
   struct GRAN_DEBUG_FLAGS Debug;         /* debugging options */
 
-  nat  maxThreads;              /* ToDo: share with SMP and GUM */
+  nat  maxThreads;              /* ToDo: share with THREADED_RTS and GUM */
   /* rtsBool labelling; */
   nat  packBufferSize;
   nat  packBufferSize_internal;
@@ -300,7 +300,7 @@ typedef struct _RTS_FLAGS {
     struct PROFILING_FLAGS   ProfFlags;
     struct TICKY_FLAGS	     TickyFlags;
 
-#if defined(SMP) || defined(PAR)
+#if defined(THREADED_RTS) || defined(PAR)
     struct PAR_FLAGS	ParFlags;
 #endif
 #ifdef GRAN

ghc/includes/SMP.h

@@ -2,25 +2,24 @@
  *
  * (c) The GHC Team, 2005
  *
- * Macros for SMP support
+ * Macros for THREADED_RTS support
  *
  * -------------------------------------------------------------------------- */
 
 #ifndef SMP_H
 #define SMP_H
 
-/* SMP is currently not compatible with the following options:
+/* THREADED_RTS is currently not compatible with the following options:
  *
- *      INTERPRETER
- *      PROFILING
+ *      PROFILING (but only 1 CPU supported)
  *      TICKY_TICKY
- *      and unregisterised builds.
+ *      Unregisterised builds are ok, but only 1 CPU supported.
  */
 
-#if defined(SMP)
+#if defined(THREADED_RTS)
 
-#if  defined(PROFILING)  || defined(TICKY_TICKY)
-#error Build options incompatible with SMP.
+#if  defined(TICKY_TICKY)
+#error Build options incompatible with THREADED_RTS.
 #endif
 
 /* 
@@ -113,7 +112,7 @@ unlockClosure(StgClosure *p, StgInfoTable *info)
 #endif
 }
 
-#else /* !SMP */
+#else /* !THREADED_RTS */
 
 #define wb() /* nothing */
 
@@ -125,6 +124,6 @@ xchg(StgPtr p, StgWord w)
     return old;
 }
 
-#endif /* !SMP */
+#endif /* !THREADED_RTS */
 
 #endif /* SMP_H */

ghc/includes/STM.h

@@ -33,7 +33,7 @@
 #ifndef STM_H
 #define STM_H
 
-#ifdef SMP
+#ifdef THREADED_RTS
 //#define STM_CG_LOCK
 #define STM_FG_LOCKS
 #else

ghc/includes/Storage.h

@@ -140,7 +140,7 @@ extern void exitStorage(void);
                                 via allocate() since the last GC.
 				Used in the reporting of statistics.
 
-   SMP: allocate and doYouWantToGC can be used from STG code, they are
+   THREADED_RTS: allocate and doYouWantToGC can be used from STG code, they are
    surrounded by a mutex.
    -------------------------------------------------------------------------- */
 
@@ -198,11 +198,11 @@ extern void GarbageCollect(void (*get_roots)(evac_fn),rtsBool force_major_gc);
 /*
  * Storage manager mutex
  */
-#if defined(SMP)
+#if defined(THREADED_RTS)
 extern Mutex sm_mutex;
 #endif
 
-#if defined(SMP)
+#if defined(THREADED_RTS)
 #define ACQUIRE_SM_LOCK   ACQUIRE_LOCK(&sm_mutex);
 #define RELEASE_SM_LOCK   RELEASE_LOCK(&sm_mutex);
 #define ASSERT_SM_LOCK()  ASSERT_LOCK_HELD(&sm_mutex);

ghc/rts/BlockAlloc.c

 /* -----------------------------------------------------------------------------
  *
- * (c) The GHC Team 1998-2000
+ * (c) The GHC Team 1998-2006
  * 
  * The block allocator and free list manager.
  *
@@ -29,8 +29,7 @@ static void    initMBlock(void *mblock);
 static bdescr *allocMegaGroup(nat mblocks);
 static void    freeMegaGroup(bdescr *bd);
 
-// In SMP mode, the free list is protected by sm_mutex.  In the
-// threaded RTS, it is protected by the Capability.
+// In THREADED_RTS mode, the free list is protected by sm_mutex.
 static bdescr *free_list = NULL;
 
 /* -----------------------------------------------------------------------------

ghc/rts/Capability.c

@@ -10,9 +10,9 @@
  * STG execution, a pointer to the capabilitity is kept in a
  * register (BaseReg; actually it is a pointer to cap->r).
  *
- * Only in an SMP build will there be multiple capabilities, for
- * the threaded RTS and other non-threaded builds, there is only
- * one global capability, namely MainCapability.
+ * Only in an THREADED_RTS build will there be multiple capabilities,
+ * for non-threaded builds there is only one global capability, namely
+ * MainCapability.
  *
  * --------------------------------------------------------------------------*/
 
@@ -26,9 +26,9 @@
 #include "Schedule.h"
 #include "Sparks.h"
 
-#if !defined(SMP)
-Capability MainCapability;     // for non-SMP, we have one global capability
-#endif
+// one global capability, this is the Capability for non-threaded
+// builds, and for +RTS -N1
+Capability MainCapability;
 
 nat n_capabilities;
 Capability *capabilities = NULL;
@@ -152,7 +152,7 @@ initCapability( Capability *cap, nat i )
 /* ---------------------------------------------------------------------------
  * Function:  initCapabilities()
  *
- * Purpose:   set up the Capability handling. For the SMP build,
+ * Purpose:   set up the Capability handling. For the THREADED_RTS build,
  *            we keep a table of them, the size of which is
  *            controlled by the user via the RTS flag -N.
  *
@@ -160,8 +160,8 @@ initCapability( Capability *cap, nat i )
 void
 initCapabilities( void )
 {
-#if defined(SMP)
-    nat i,n;
+#if defined(THREADED_RTS)
+    nat i;
 
 #ifndef REG_BaseReg
     // We can't support multiple CPUs if BaseReg is not a register
@@ -171,18 +171,31 @@ initCapabilities( void )
     }
 #endif
 
-    n_capabilities = n = RtsFlags.ParFlags.nNodes;
-    capabilities = stgMallocBytes(n * sizeof(Capability), "initCapabilities");
+    n_capabilities = RtsFlags.ParFlags.nNodes;
+
+    if (n_capabilities == 1) {
+	capabilities = &MainCapability;
+	// THREADED_RTS must work on builds that don't have a mutable
+	// BaseReg (eg. unregisterised), so in this case
+	// capabilities[0] must coincide with &MainCapability.
+    } else {
+	capabilities = stgMallocBytes(n_capabilities * sizeof(Capability),
+				      "initCapabilities");
+    }
 
-    for (i = 0; i < n; i++) {
+    for (i = 0; i < n_capabilities; i++) {
 	initCapability(&capabilities[i], i);
     }
 
-    IF_DEBUG(scheduler, sched_belch("allocated %d capabilities", n));
-#else
+    IF_DEBUG(scheduler, sched_belch("allocated %d capabilities", 
+				    n_capabilities));
+
+#else /* !THREADED_RTS */
+
     n_capabilities = 1;
     capabilities = &MainCapability;
     initCapability(&MainCapability, 0);
+
 #endif
 
     // There are no free capabilities to begin with.  We will start
@@ -263,15 +276,7 @@ releaseCapability_ (Capability* cap)
 	return;
     }
 
-    // If we have an unbound thread on the run queue, or if there's
-    // anything else to do, give the Capability to a worker thread.
-    if (!emptyRunQueue(cap) || !emptySparkPoolCap(cap) || globalWorkToDo()) {
-	if (cap->spare_workers) {
-	    giveCapabilityToTask(cap,cap->spare_workers);
-	    // The worker Task pops itself from the queue;
-	    return;
-	}
-
+    if (!cap->spare_workers) {
 	// Create a worker thread if we don't have one.  If the system
 	// is interrupted, we only create a worker task if there
 	// are threads that need to be completed.  If the system is
@@ -284,6 +289,16 @@ releaseCapability_ (Capability* cap)
 	}
     }
 
+    // If we have an unbound thread on the run queue, or if there's
+    // anything else to do, give the Capability to a worker thread.
+    if (!emptyRunQueue(cap) || !emptySparkPoolCap(cap) || globalWorkToDo()) {
+	if (cap->spare_workers) {
+	    giveCapabilityToTask(cap,cap->spare_workers);
+	    // The worker Task pops itself from the queue;
+	    return;
+	}
+    }
+
     last_free_capability = cap;
     IF_DEBUG(scheduler, sched_belch("freeing capability %d", cap->no));
 }
@@ -512,6 +527,7 @@ prodCapabilities(rtsBool all)
 	}
 	RELEASE_LOCK(&cap->lock);
     }
+    return;
 }
 
 void

ghc/rts/Capability.h

 /* ---------------------------------------------------------------------------
  *
- * (c) The GHC Team, 2001-2003
+ * (c) The GHC Team, 2001-2006
  *
  * Capabilities
  *
  * The notion of a capability is used when operating in multi-threaded
- * environments (which the SMP and Threads builds of the RTS do), to
+ * environments (which the THREADED_RTS build of the RTS does), to
  * hold all the state an OS thread/task needs to run Haskell code:
  * its STG registers, a pointer to its  TSO, a nursery etc. During
  * STG execution, a pointer to the capabilitity is kept in a 
  * register (BaseReg).
  *
- * Only in an SMP build will there be multiple capabilities, the threaded
- * RTS and other non-threaded builds, there is one global capability,
- * namely MainRegTable.
+ * Only in an THREADED_RTS build will there be multiple capabilities,
+ * in the non-threaded builds there is one global capability, namely
+ * MainCapability.
  *
  * This header file contains the functions for working with capabilities.
  * (the main, and only, consumer of this interface is the scheduler).
@@ -140,8 +140,8 @@ INLINE_HEADER void releaseCapability  (Capability* cap STG_UNUSED) {};
 INLINE_HEADER void releaseCapability_ (Capability* cap STG_UNUSED) {};
 #endif
 
-#if !IN_STG_CODE && !defined(SMP)
-// for non-SMP, we have one global capability
+#if !IN_STG_CODE
+// one global capability
 extern Capability MainCapability; 
 #endif
 

ghc/rts/GC.c

@@ -1154,7 +1154,9 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc )
   ACQUIRE_SM_LOCK;
   
   // send exceptions to any threads which were about to die 
+  RELEASE_SM_LOCK;
   resurrectThreads(resurrected_threads);
+  ACQUIRE_SM_LOCK;
 
   // Update the stable pointer hash table.
   updateStablePtrTable(major_gc);

ghc/rts/RtsFlags.c

@@ -217,7 +217,7 @@ void initRtsFlagsDefaults(void)
 
     RtsFlags.ConcFlags.ctxtSwitchTime	= CS_MIN_MILLISECS;  /* In milliseconds */
 
-#ifdef SMP
+#ifdef THREADED_RTS
     RtsFlags.ParFlags.nNodes	        = 1;
 #endif
 
@@ -244,9 +244,9 @@ void initRtsFlagsDefaults(void)
     RtsFlags.ParFlags.fishDelay         = FISH_DELAY;
 #endif
 
-#if defined(PAR) || defined(SMP)
+#if defined(PAR) || defined(THREADED_RTS)
     RtsFlags.ParFlags.maxLocalSparks	= 4096;
-#endif /* PAR || SMP */
+#endif /* PAR || THREADED_RTS */
 
 #if defined(GRAN)
     /* ToDo: check defaults for GranSim and GUM */
@@ -435,10 +435,10 @@ usage_text[] = {
 "  -Dz  DEBUG: stack squezing",
 "",
 #endif /* DEBUG */
-#if defined(SMP)
+#if defined(THREADED_RTS)
 "  -N<n>     Use <n> OS threads (default: 1)",
 #endif
-#if defined(SMP) || defined(PAR)
+#if defined(THREADED_RTS) || defined(PAR)
 "  -e<size>  Size of spark pools (default 100)",
 #endif
 #if defined(PAR)
@@ -448,7 +448,7 @@ usage_text[] = {
 "  -qd       Turn on PVM-ish debugging",
 "  -qO       Disable output for performance measurement",
 #endif
-#if defined(SMP) || defined(PAR)
+#if defined(THREADED_RTS) || defined(PAR)
 "  -e<n>     Maximum number of outstanding local sparks (default: 4096)",
 #endif
 #if defined(PAR)
@@ -611,14 +611,6 @@ errorBelch("not built for: -prof"); \
 error = rtsTrue;
 #endif
 
-#ifdef SMP
-# define SMP_BUILD_ONLY(x)      x
-#else
-# define SMP_BUILD_ONLY(x) \
-errorBelch("not built for: -smp"); \
-error = rtsTrue;
-#endif
-
 #ifdef PAR
 # define PAR_BUILD_ONLY(x)      x
 #else
@@ -627,10 +619,18 @@ errorBelch("not built for: -parallel"); \
 error = rtsTrue;
 #endif
 
-#if defined(SMP) || defined(PAR)
-# define PAR_OR_SMP_BUILD_ONLY(x)      x
+#ifdef THREADED_RTS
+# define THREADED_BUILD_ONLY(x)      x
+#else
+# define THREADED_BUILD_ONLY(x) \
+errorBelch("not built for: -smp"); \
+error = rtsTrue;
+#endif
+
+#if defined(THREADED_RTS) || defined(PAR)
+# define PAR_OR_THREADED_BUILD_ONLY(x)      x
 #else
-# define PAR_OR_SMP_BUILD_ONLY(x) \
+# define PAR_OR_THREADED_BUILD_ONLY(x) \
 errorBelch("not built for: -parallel or -smp"); \
 error = rtsTrue;
 #endif
@@ -1037,9 +1037,9 @@ error = rtsTrue;
 		}
     	    	break;
 
-#ifdef SMP
+#ifdef THREADED_RTS
 	      case 'N':
-		SMP_BUILD_ONLY(
+		THREADED_BUILD_ONLY(
 		if (rts_argv[arg][2] != '\0') {
 		    RtsFlags.ParFlags.nNodes
 		      = strtol(rts_argv[arg]+2, (char **) NULL, 10);
@@ -1052,7 +1052,7 @@ error = rtsTrue;
 #endif
 	      /* =========== PARALLEL =========================== */
 	      case 'e':
-		PAR_OR_SMP_BUILD_ONLY(
+		PAR_OR_THREADED_BUILD_ONLY(
 		if (rts_argv[arg][2] != '\0') {
 		    RtsFlags.ParFlags.maxLocalSparks
 		      = strtol(rts_argv[arg]+2, (char **) NULL, 10);

ghc/rts/RtsStartup.c

@@ -17,6 +17,7 @@
 #include "Stats.h"      /* initStats */
 #include "STM.h"        /* initSTM */
 #include "Signals.h"
+#include "RtsSignals.h"
 #include "Timer.h"      /* startTimer, stopTimer */
 #include "Weak.h"
 #include "Ticky.h"
@@ -275,12 +276,8 @@ void
 hs_add_root(void (*init_root)(void))
 {
     bdescr *bd;
-#ifdef SMP
-    Capability cap;
-#else
-#define cap MainCapability
-#endif
     nat init_sp;
+    Capability *cap = &MainCapability;
 
     if (hs_init_count <= 0) {
 	barf("hs_add_root() must be called after hs_init()");
@@ -296,8 +293,8 @@ hs_add_root(void (*init_root)(void))
 	init_stack[--init_sp] = (F_)init_root;
     }
     
-    cap.r.rSp = (P_)(init_stack + init_sp);
-    StgRun((StgFunPtr)stg_init, &cap.r);
+    cap->r.rSp = (P_)(init_stack + init_sp);
+    StgRun((StgFunPtr)stg_init, &cap->r);
 
     freeGroup_lock(bd);
 

ghc/rts/STM.c

@@ -28,7 +28,7 @@
  * in STM.h:
  * 
  * STM_UNIPROC assumes that the caller serialises invocations on the STM interface.
- * In the Haskell RTS this means it is suitable only for non-SMP builds.
+ * In the Haskell RTS this means it is suitable only for non-THREADED_RTS builds.
  *
  * STM_CG_LOCK uses coarse-grained locking -- a single 'stm lock' is acquired during
  * an invocation on the STM interface.  Note that this does not mean that 
@@ -97,8 +97,8 @@
 #define TRUE 1
 #define FALSE 0
 
-// ACQ_ASSERT is used for assertions which are only required for SMP builds with
-// fine-grained locking. 
+// ACQ_ASSERT is used for assertions which are only required for
+// THREADED_RTS builds with fine-grained locking.
 
 #if defined(STM_FG_LOCKS)
 #define ACQ_ASSERT(_X) ASSERT(_X)
@@ -794,7 +794,7 @@ static volatile StgInt64 max_commits = 0;
 
 static volatile StgBool token_locked = FALSE;
 
-#if defined(SMP)
+#if defined(THREADED_RTS)
 static void getTokenBatch(Capability *cap) {
   while (cas(&token_locked, FALSE, TRUE) == TRUE) { /* nothing */ }
   max_commits += TOKEN_BATCH_SIZE;
@@ -1252,7 +1252,7 @@ StgTVar *stmNewTVar(Capability *cap,
   SET_HDR (result, &stg_TVAR_info, CCS_SYSTEM);
   result -> current_value = new_value;
   result -> first_wait_queue_entry = END_STM_WAIT_QUEUE;
-#if defined(SMP)
+#if defined(THREADED_RTS)
   result -> num_updates = 0;
 #endif
   return result;

ghc/rts/Sanity.c

@@ -549,7 +549,7 @@ checkHeap(bdescr *bd)
 {
     StgPtr p;
 
-#if defined(SMP)
+#if defined(THREADED_RTS)
     // heap sanity checking doesn't work with SMP, because we can't
     // zero the slop (see Updates.h).
     return;

ghc/rts/Schedule.c

@@ -175,7 +175,7 @@ rtsBool shutting_down_scheduler = rtsFalse;
 
 /*
  * This mutex protects most of the global scheduler data in
- * the THREADED_RTS and (inc. SMP) runtime.
+ * the THREADED_RTS runtime.
  */
 #if defined(THREADED_RTS)
 Mutex sched_mutex;
@@ -199,7 +199,7 @@ static Capability *schedule (Capability *initialCapability, Task *task);
 // scheduler clearer.
 //
 static void schedulePreLoop (void);
-#if defined(SMP)
+#if defined(THREADED_RTS)
 static void schedulePushWork(Capability *cap, Task *task);
 #endif
 static void scheduleStartSignalHandlers (Capability *cap);
@@ -227,7 +227,8 @@ static void scheduleHandleThreadBlocked( StgTSO *t );
 static rtsBool scheduleHandleThreadFinished( Capability *cap, Task *task,
 					     StgTSO *t );
 static rtsBool scheduleDoHeapProfile(rtsBool ready_to_gc);
-static void scheduleDoGC(Capability *cap, Task *task, rtsBool force_major);
+static void scheduleDoGC(Capability *cap, Task *task, rtsBool force_major,
+			 void (*get_roots)(evac_fn));