mem: Add VirtualMemoryEx() and VirtualMemoryExWithContext()

mem/mem_linux.go

@@ -4,6 +4,7 @@ package mem
 
 import (
 	"context"
+	"encoding/json"
 	"math"
 	"os"
 	"strconv"
@@ -21,11 +22,36 @@ type VirtualMemoryExStat struct {
 	Unevictable  uint64 `json:"unevictable"`
 }
 
+func (v VirtualMemoryExStat) String() string {
+	s, _ := json.Marshal(v)
+	return string(s)
+}
+
 func VirtualMemory() (*VirtualMemoryStat, error) {
 	return VirtualMemoryWithContext(context.Background())
 }
 
 func VirtualMemoryWithContext(ctx context.Context) (*VirtualMemoryStat, error) {
+	vm, _, err := fillFromMeminfoWithContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return vm, nil
+}
+
+func VirtualMemoryEx() (*VirtualMemoryExStat, error) {
+	return VirtualMemoryExWithContext(context.Background())
+}
+
+func VirtualMemoryExWithContext(ctx context.Context) (*VirtualMemoryExStat, error) {
+	_, vmEx, err := fillFromMeminfoWithContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return vmEx, nil
+}
+
+func fillFromMeminfoWithContext(ctx context.Context) (*VirtualMemoryStat, *VirtualMemoryExStat, error) {
 	filename := common.HostProc("meminfo")
 	lines, _ := common.ReadLines(filename)
 
@@ -49,7 +75,7 @@ func VirtualMemoryWithContext(ctx context.Context) (*VirtualMemoryStat, error) {
 
 		t, err := strconv.ParseUint(value, 10, 64)
 		if err != nil {
-			return ret, err
+			return ret, retEx,err
 		}
 		switch key {
 		case "MemTotal":
@@ -144,7 +170,7 @@ func VirtualMemoryWithContext(ctx context.Context) (*VirtualMemoryStat, error) {
 	ret.Used = ret.Total - ret.Free - ret.Buffers - ret.Cached
 	ret.UsedPercent = float64(ret.Used) / float64(ret.Total) * 100.0
 
-	return ret, nil
+	return ret, retEx, nil
 }
 
 func SwapMemory() (*SwapMemoryStat, error) {