X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FCapability.h;h=0f61fad913ede2a688806f44efc522701397a3b7;hb=a11662957fa688997e6c4befff44e7efe94c2db8;hp=ba0695c8ee23ac7590626d77e81ed6997db3b8d8;hpb=164be7854f6de07bb4bc15f60af727ddb562cde7;p=ghc-hetmet.git

diff --git a/rts/Capability.h b/rts/Capability.h
index ba0695c..0f61fad 100644
--- a/rts/Capability.h
+++ b/rts/Capability.h
@@ -65,10 +65,12 @@ struct Capability_ {
     Task *suspended_ccalling_tasks;
 
     // One mutable list per generation, so we don't need to take any
-    // locks when updating an old-generation thunk.  These
-    // mini-mut-lists are moved onto the respective gen->mut_list at
-    // each GC.
+    // locks when updating an old-generation thunk.  This also lets us
+    // keep track of which closures this CPU has been mutating, so we
+    // can traverse them using the right thread during GC and avoid
+    // unnecessarily moving the data from one cache to another.
     bdescr **mut_lists;
+    bdescr **saved_mut_lists; // tmp use during GC
 
     // Context switch flag. We used to have one global flag, now one 
     // per capability. Locks required  : none (conflicts are harmless)
@@ -274,6 +276,7 @@ extern void grabCapability (Capability **pCap);
 
 // cause all capabilities to context switch as soon as possible.
 void setContextSwitches(void);
+INLINE_HEADER void contextSwitchCapability(Capability *cap);
 
 // Free all capabilities
 void freeCapabilities (void);
@@ -320,4 +323,16 @@ discardSparksCap (Capability *cap)
 { return discardSparks(cap->sparks); }
 #endif
 
+INLINE_HEADER void
+contextSwitchCapability (Capability *cap)
+{
+    // setting HpLim to NULL ensures that the next heap check will
+    // fail, and the thread will return to the scheduler.
+    cap->r.rHpLim = NULL;
+    // But just in case it didn't work (the target thread might be
+    // modifying HpLim at the same time), we set the end-of-block
+    // context-switch flag too:
+    cap->context_switch = 1;
+}
+
 #endif /* CAPABILITY_H */