[disk][linux] support new stats available with 4.18 and 5.5 kernels

https://www.kernel.org/doc/Documentation/ABI/testing/procfs-diskstats

disk/disk.go

@@ -30,20 +30,26 @@ type PartitionStat struct {
 }
 
 type IOCountersStat struct {
-	ReadCount        uint64 `json:"readCount"`
+	ReadCount             uint64 `json:"readCount"`
-	MergedReadCount  uint64 `json:"mergedReadCount"`
+	MergedReadCount       uint64 `json:"mergedReadCount"`
-	WriteCount       uint64 `json:"writeCount"`
+	WriteCount            uint64 `json:"writeCount"`
-	MergedWriteCount uint64 `json:"mergedWriteCount"`
+	MergedWriteCount      uint64 `json:"mergedWriteCount"`
-	ReadBytes        uint64 `json:"readBytes"`
+	ReadBytes             uint64 `json:"readBytes"`
-	WriteBytes       uint64 `json:"writeBytes"`
+	WriteBytes            uint64 `json:"writeBytes"`
-	ReadTime         uint64 `json:"readTime"`
+	ReadTime              uint64 `json:"readTime"`
-	WriteTime        uint64 `json:"writeTime"`
+	WriteTime             uint64 `json:"writeTime"`
-	IopsInProgress   uint64 `json:"iopsInProgress"`
+	IopsInProgress        uint64 `json:"iopsInProgress"`
-	IoTime           uint64 `json:"ioTime"`
+	IoTime                uint64 `json:"ioTime"`
-	WeightedIO       uint64 `json:"weightedIO"`
+	WeightedIO            uint64 `json:"weightedIO"`
-	Name             string `json:"name"`
+	DiscardCount          uint64 `json:"discardCount"`
-	SerialNumber     string `json:"serialNumber"`
+	MergedDiscardCount    uint64 `json:"mergedDiscardCount"`
-	Label            string `json:"label"`
+	SectorsDiscardedCount uint64 `json:"sectorsDiscardedCount"`
+	DiscardTime           uint64 `json:"discardTime"`
+	FlushCount            uint64 `json:"flushCount"`
+	FlushTime             uint64 `json:"flushTime"`
+	Name                  string `json:"name"`
+	SerialNumber          string `json:"serialNumber"`
+	Label                 string `json:"label"`
 }
 
 func (d UsageStat) String() string {

disk/disk_linux.go

@@ -417,18 +417,55 @@ func IOCountersWithContext(ctx context.Context, names ...string) (map[string]IOC
 		if err != nil {
 			return ret, err
 		}
+		var discardCount, mergedDiscardCount, sectorsDiscardedCount, discardTime, flushCount, flushTime uint64
+		if len(fields) >= 18 {
+			// kernel 4.18+
+			discardCount, err = strconv.ParseUint((fields[14]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			mergedDiscardCount, err = strconv.ParseUint((fields[15]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			sectorsDiscardedCount, err = strconv.ParseUint((fields[16]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			discardTime, err = strconv.ParseUint((fields[17]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			if len(fields) >= 20 {
+				// kernel 5.5+
+				flushCount, err = strconv.ParseUint((fields[18]), 10, 64)
+				if err != nil {
+					return ret, err
+				}
+				flushTime, err = strconv.ParseUint((fields[19]), 10, 64)
+				if err != nil {
+					return ret, err
+				}
+			}
+		}
 		d := IOCountersStat{
-			ReadBytes:        rbytes * sectorSize,
+			ReadBytes:             rbytes * sectorSize,
-			WriteBytes:       wbytes * sectorSize,
+			WriteBytes:            wbytes * sectorSize,
-			ReadCount:        reads,
+			ReadCount:             reads,
-			WriteCount:       writes,
+			WriteCount:            writes,
-			MergedReadCount:  mergedReads,
+			MergedReadCount:       mergedReads,
-			MergedWriteCount: mergedWrites,
+			MergedWriteCount:      mergedWrites,
-			ReadTime:         rtime,
+			ReadTime:              rtime,
-			WriteTime:        wtime,
+			WriteTime:             wtime,
-			IopsInProgress:   iopsInProgress,
+			IopsInProgress:        iopsInProgress,
-			IoTime:           iotime,
+			IoTime:                iotime,
-			WeightedIO:       weightedIO,
+			WeightedIO:            weightedIO,
+			DiscardCount:          discardCount,
+			MergedDiscardCount:    mergedDiscardCount,
+			SectorsDiscardedCount: sectorsDiscardedCount,
+			DiscardTime:           discardTime,
+			FlushCount:            flushCount,
+			FlushTime:             flushTime,
 		}
 		if d == empty {
 			continue

disk/disk_test.go

@@ -125,7 +125,7 @@ func TestDiskIOCountersStat_String(t *testing.T) {
 		WriteBytes:   400,
 		SerialNumber: "SERIAL",
 	}
-	e := `{"readCount":100,"mergedReadCount":0,"writeCount":200,"mergedWriteCount":0,"readBytes":300,"writeBytes":400,"readTime":0,"writeTime":0,"iopsInProgress":0,"ioTime":0,"weightedIO":0,"name":"sd01","serialNumber":"SERIAL","label":""}`
+	e := `{"readCount":100,"mergedReadCount":0,"writeCount":200,"mergedWriteCount":0,"readBytes":300,"writeBytes":400,"readTime":0,"writeTime":0,"iopsInProgress":0,"ioTime":0,"weightedIO":0,"discardCount":0,"mergedDiscardCount":0,"sectorsDiscardedCount":0,"discardTime":0,"flushCount":0,"flushTime":0,"name":"sd01","serialNumber":"SERIAL","label":""}`
 	if e != fmt.Sprintf("%v", v) {
 		t.Errorf("DiskUsageStat string is invalid: %v", v)
 	}