Added a new method cgroups.GetStats() which will return a cgroups.Stats object which will contain all the available cgroup Stats.

Remove old Stats interface in libcontainers cgroups package.
Changed Stats to use unit64 instead of int64 to prevent integer overflow issues.
Updated unit tests.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)

libcontainer/cgroups/fs/stats_test_util.go

@@ -0,0 +1,73 @@
+package fs
+
+import (
+	"fmt"
+	"log"
+	"testing"
+
+	"github.com/dotcloud/docker/pkg/libcontainer/cgroups"
+)
+
+func blkioStatEntryEquals(expected, actual []cgroups.BlkioStatEntry) error {
+	if len(expected) != len(actual) {
+		return fmt.Errorf("blkioStatEntries length do not match")
+	}
+	for i, expValue := range expected {
+		actValue := actual[i]
+		if expValue != actValue {
+			return fmt.Errorf("Expected blkio stat entry %v but found %v", expValue, actValue)
+		}
+	}
+	return nil
+}
+
+func expectBlkioStatsEquals(t *testing.T, expected, actual cgroups.BlkioStats) {
+	if err := blkioStatEntryEquals(expected.IoServiceBytesRecursive, actual.IoServiceBytesRecursive); err != nil {
+		log.Printf("blkio IoServiceBytesRecursive do not match - %s\n", err)
+		t.Fail()
+	}
+
+	if err := blkioStatEntryEquals(expected.IoServicedRecursive, actual.IoServicedRecursive); err != nil {
+		log.Printf("blkio IoServicedRecursive do not match - %s\n", err)
+		t.Fail()
+	}
+
+	if err := blkioStatEntryEquals(expected.IoQueuedRecursive, actual.IoQueuedRecursive); err != nil {
+		log.Printf("blkio IoQueuedRecursive do not match - %s\n", err)
+		t.Fail()
+	}
+
+	if err := blkioStatEntryEquals(expected.SectorsRecursive, actual.SectorsRecursive); err != nil {
+		log.Printf("blkio SectorsRecursive do not match - %s\n", err)
+		t.Fail()
+	}
+}
+
+func expectThrottlingDataEquals(t *testing.T, expected, actual cgroups.ThrottlingData) {
+	if expected != actual {
+		log.Printf("Expected throttling data %v but found %v\n", expected, actual)
+		t.Fail()
+	}
+}
+
+func expectMemoryStatEquals(t *testing.T, expected, actual cgroups.MemoryStats) {
+	if expected.Usage != actual.Usage {
+		log.Printf("Expected memory usage %d but found %d\n", expected.Usage, actual.Usage)
+		t.Fail()
+	}
+	if expected.MaxUsage != actual.MaxUsage {
+		log.Printf("Expected memory max usage %d but found %d\n", expected.MaxUsage, actual.MaxUsage)
+		t.Fail()
+	}
+	for key, expValue := range expected.Stats {
+		actValue, ok := actual.Stats[key]
+		if !ok {
+			log.Printf("Expected memory stat key %s not found\n", key)
+			t.Fail()
+		}
+		if expValue != actValue {
+			log.Printf("Expected memory stat value %d but found %d\n", expValue, actValue)
+			t.Fail()
+		}
+	}
+}