1 files changed, 108 insertions, 0 deletions
diff --git a/src/runtime/mem.go b/src/runtime/mem.go
new file mode 100644
index 000000000..e6f1eb0e6
--- /dev/null
+++ b/src/runtime/mem.go
@@ -0,0 +1,108 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+import "unsafe"
+
+// Note: the MemStats struct should be kept in sync with
+// struct MStats in malloc.h
+
+// A MemStats records statistics about the memory allocator.
+type MemStats struct {
+	// General statistics.
+	Alloc      uint64 // bytes allocated and still in use
+	TotalAlloc uint64 // bytes allocated (even if freed)
+	Sys        uint64 // bytes obtained from system (sum of XxxSys below)
+	Lookups    uint64 // number of pointer lookups
+	Mallocs    uint64 // number of mallocs
+	Frees      uint64 // number of frees
+
+	// Main allocation heap statistics.
+	HeapAlloc    uint64 // bytes allocated and still in use
+	HeapSys      uint64 // bytes obtained from system
+	HeapIdle     uint64 // bytes in idle spans
+	HeapInuse    uint64 // bytes in non-idle span
+	HeapReleased uint64 // bytes released to the OS
+	HeapObjects  uint64 // total number of allocated objects
+
+	// Low-level fixed-size structure allocator statistics.
+	//	Inuse is bytes used now.
+	//	Sys is bytes obtained from system.
+	StackInuse  uint64 // bytes used by stack allocator
+	StackSys    uint64
+	MSpanInuse  uint64 // mspan structures
+	MSpanSys    uint64
+	MCacheInuse uint64 // mcache structures
+	MCacheSys   uint64
+	BuckHashSys uint64 // profiling bucket hash table
+	GCSys       uint64 // GC metadata
+	OtherSys    uint64 // other system allocations
+
+	// Garbage collector statistics.
+	NextGC       uint64 // next collection will happen when HeapAlloc ≥ this amount
+	LastGC       uint64 // end time of last collection (nanoseconds since 1970)
+	PauseTotalNs uint64
+	PauseNs      [256]uint64 // circular buffer of recent GC pause durations, most recent at [(NumGC+255)%256]
+	PauseEnd     [256]uint64 // circular buffer of recent GC pause end times
+	NumGC        uint32
+	EnableGC     bool
+	DebugGC      bool
+
+	// Per-size allocation statistics.
+	// 61 is NumSizeClasses in the C code.
+	BySize [61]struct {
+		Size    uint32
+		Mallocs uint64
+		Frees   uint64
+	}
+}
+
+var sizeof_C_MStats uintptr // filled in by malloc.goc
+
+func init() {
+	var memStats MemStats
+	if sizeof_C_MStats != unsafe.Sizeof(memStats) {
+		println(sizeof_C_MStats, unsafe.Sizeof(memStats))
+		gothrow("MStats vs MemStatsType size mismatch")
+	}
+}
+
+// ReadMemStats populates m with memory allocator statistics.
+func ReadMemStats(m *MemStats) {
+	// Have to acquire worldsema to stop the world,
+	// because stoptheworld can only be used by
+	// one goroutine at a time, and there might be
+	// a pending garbage collection already calling it.
+	semacquire(&worldsema, false)
+	gp := getg()
+	gp.m.gcing = 1
+	onM(stoptheworld)
+
+	gp.m.ptrarg[0] = noescape(unsafe.Pointer(m))
+	onM(readmemstats_m)
+
+	gp.m.gcing = 0
+	gp.m.locks++
+	semrelease(&worldsema)
+	onM(starttheworld)
+	gp.m.locks--
+}
+
+// Implementation of runtime/debug.WriteHeapDump
+func writeHeapDump(fd uintptr) {
+	semacquire(&worldsema, false)
+	gp := getg()
+	gp.m.gcing = 1
+	onM(stoptheworld)
+
+	gp.m.scalararg[0] = fd
+	onM(writeheapdump_m)
+
+	gp.m.gcing = 0
+	gp.m.locks++
+	semrelease(&worldsema)
+	onM(starttheworld)
+	gp.m.locks--
+}