5 files changed, 28 insertions, 13 deletions

diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
index a593da486c..76945a28d4 100644
--- a/src/pkg/runtime/malloc.goc
+++ b/src/pkg/runtime/malloc.goc
@@ -19,6 +19,7 @@ package runtime
 // Mark mheap as 'no pointers', it does not contain interesting pointers but occupies ~45K.
 #pragma dataflag NOPTR
 MHeap runtime·mheap;
+MStats mstats;
 
 int32	runtime·checking;
 
@@ -417,7 +418,10 @@ runtime·purgecachedstats(MCache *c)
 	}
 }
 
-uintptr runtime·sizeof_C_MStats = sizeof(MStats);
+// Size of the trailing by_size array differs between Go and C,
+// NumSizeClasses was changed, but we can not change Go struct because of backward compatibility.
+// sizeof_C_MStats is what C thinks about size of Go struct.
+uintptr runtime·sizeof_C_MStats = sizeof(MStats) - (NumSizeClasses - 61) * sizeof(mstats.by_size[0]);
 
 #define MaxArena32 (2U<<30)
 
diff --git a/src/pkg/runtime/malloc.h b/src/pkg/runtime/malloc.h
index 52a23e391c..fc6c85e2c1 100644
--- a/src/pkg/runtime/malloc.h
+++ b/src/pkg/runtime/malloc.h
@@ -90,7 +90,7 @@ typedef struct GCStats	GCStats;
 
 enum
 {
-	PageShift	= 12,
+	PageShift	= 13,
 	PageSize	= 1<<PageShift,
 	PageMask	= PageSize - 1,
 };
@@ -103,7 +103,7 @@ enum
 	// size classes.  NumSizeClasses is that number.  It's needed here
 	// because there are static arrays of this length; when msize runs its
 	// size choosing algorithm it double-checks that NumSizeClasses agrees.
-	NumSizeClasses = 61,
+	NumSizeClasses = 67,
 
 	// Tunable constants.
 	MaxSmallSize = 32<<10,
@@ -259,7 +259,7 @@ struct MStats
 	} by_size[NumSizeClasses];
 };
 
-#define mstats runtime·memStats	/* name shared with Go */
+#define mstats runtime·memStats
 extern MStats mstats;
 
 // Size classes.  Computed and initialized by InitSizes.
diff --git a/src/pkg/runtime/mem.go b/src/pkg/runtime/mem.go
index dc735e4a62..fa308b5d96 100644
--- a/src/pkg/runtime/mem.go
+++ b/src/pkg/runtime/mem.go
@@ -60,9 +60,8 @@ type MemStats struct {
 
 var sizeof_C_MStats uintptr // filled in by malloc.goc
 
-var memStats MemStats
-
 func init() {
+	var memStats MemStats
 	if sizeof_C_MStats != unsafe.Sizeof(memStats) {
 		println(sizeof_C_MStats, unsafe.Sizeof(memStats))
 		panic("MStats vs MemStatsType size mismatch")
diff --git a/src/pkg/runtime/mgc0.c b/src/pkg/runtime/mgc0.c
index e21ad286da..dc2a8a99bb 100644
--- a/src/pkg/runtime/mgc0.c
+++ b/src/pkg/runtime/mgc0.c
@@ -25,6 +25,10 @@ enum {
 	wordsPerBitmapWord = sizeof(void*)*8/4,
 	bitShift = sizeof(void*)*8/4,
 
+	WorkbufSize	= 16*1024,
+	RootBlockSize	= 4*1024,
+	FinBlockSize	= 4*1024,
+
 	handoffThreshold = 4,
 	IntermediateBufferCapacity = 64,
 
@@ -154,11 +158,10 @@ struct Obj
 	uintptr	ti;	// type info
 };
 
-// The size of Workbuf is N*PageSize.
 typedef struct Workbuf Workbuf;
 struct Workbuf
 {
-#define SIZE (2*PageSize-sizeof(LFNode)-sizeof(uintptr))
+#define SIZE (WorkbufSize-sizeof(LFNode)-sizeof(uintptr))
 	LFNode  node; // must be first
 	uintptr nobj;
 	Obj     obj[SIZE/sizeof(Obj) - 1];
@@ -737,7 +740,7 @@ scanblock(Workbuf *wbuf, bool keepworking)
 	ChanType *chantype;
 	Obj *wp;
 
-	if(sizeof(Workbuf) % PageSize != 0)
+	if(sizeof(Workbuf) % WorkbufSize != 0)
 		runtime·throw("scanblock: size of Workbuf is suboptimal");
 
 	// Memory arena parameters.
@@ -1601,8 +1604,8 @@ runtime·queuefinalizer(byte *p, FuncVal *fn, uintptr nret, Type *fint, PtrType
 	runtime·lock(&finlock);
 	if(finq == nil || finq->cnt == finq->cap) {
 		if(finc == nil) {
-			finc = runtime·persistentalloc(PageSize, 0, &mstats.gc_sys);
-			finc->cap = (PageSize - sizeof(FinBlock)) / sizeof(Finalizer) + 1;
+			finc = runtime·persistentalloc(FinBlockSize, 0, &mstats.gc_sys);
+			finc->cap = (FinBlockSize - sizeof(FinBlock)) / sizeof(Finalizer) + 1;
 			finc->alllink = allfin;
 			allfin = finc;
 		}
@@ -2233,6 +2236,8 @@ gc(struct gc_args *args)
 	runtime·MProf_GC();
 }
 
+extern uintptr runtime·sizeof_C_MStats;
+
 void
 runtime·ReadMemStats(MStats *stats)
 {
@@ -2244,7 +2249,9 @@ runtime·ReadMemStats(MStats *stats)
 	m->gcing = 1;
 	runtime·stoptheworld();
 	updatememstats(nil);
-	*stats = mstats;
+	// Size of the trailing by_size array differs between Go and C,
+	// NumSizeClasses was changed, but we can not change Go struct because of backward compatibility.
+	runtime·memcopy(runtime·sizeof_C_MStats, stats, &mstats);
 	m->gcing = 0;
 	m->locks++;
 	runtime·semrelease(&runtime·worldsema);
diff --git a/src/pkg/runtime/netpoll.goc b/src/pkg/runtime/netpoll.goc
index 2830f882d8..81471dca5b 100644
--- a/src/pkg/runtime/netpoll.goc
+++ b/src/pkg/runtime/netpoll.goc
@@ -34,6 +34,11 @@ package net
 #define READY ((G*)1)
 #define WAIT  ((G*)2)
 
+enum
+{
+	PollBlockSize	= 4*1024,
+};
+
 struct PollDesc
 {
 	PollDesc* link;	// in pollcache, protected by pollcache.Lock
@@ -422,7 +427,7 @@ allocPollDesc(void)
 
 	runtime·lock(&pollcache);
 	if(pollcache.first == nil) {
-		n = PageSize/sizeof(*pd);
+		n = PollBlockSize/sizeof(*pd);
 		if(n == 0)
 			n = 1;
 		// Must be in non-GC memory because can be referenced