diff --git a/pkg/sentry/control/usage.go b/pkg/sentry/control/usage.go
index c3a838292..9e8fb389d 100644
--- a/pkg/sentry/control/usage.go
+++ b/pkg/sentry/control/usage.go
@@ -88,7 +88,7 @@ func (u *Usage) UsageFD(opts *MemoryUsageFileOpts, out *MemoryUsageFile) error {
 func (u *Usage) Collect(opts *MemoryUsageOpts, out *MemoryUsage) error {
 	if opts.Full {
 		// Ensure everything is up to date.
-		if err := u.Kernel.MemoryFile().UpdateUsage(0); err != nil {
+		if err := u.Kernel.MemoryFile().UpdateUsage(nil); err != nil {
 			return err
 		}
 
diff --git a/pkg/sentry/fsimpl/cgroupfs/memory.go b/pkg/sentry/fsimpl/cgroupfs/memory.go
index 0c8444f53..d48118712 100644
--- a/pkg/sentry/fsimpl/cgroupfs/memory.go
+++ b/pkg/sentry/fsimpl/cgroupfs/memory.go
@@ -121,13 +121,25 @@ type memoryCgroup struct {
 	*cgroupInode
 }
 
-func (memCg *memoryCgroup) collectMemoryUsage() uint64 {
-	_, totalBytes := usage.MemoryAccounting.CopyPerCg(memCg.ID())
-
+// Collects all the memory cgroup ids for the cgroup.
+func (memCg *memoryCgroup) collectMemCgIDs(memCgIDs map[uint32]struct{}) {
+	// Add ourselves.
+	memCgIDs[memCg.ID()] = struct{}{}
+	// Add our children.
 	memCg.forEachChildDir(func(d *dir) {
 		cg := memoryCgroup{d.cgi}
-		totalBytes += cg.collectMemoryUsage()
+		cg.collectMemCgIDs(memCgIDs)
 	})
+}
+
+// Returns the memory usage for all cgroup ids in memCgIDs.
+func getUsage(k *kernel.Kernel, memCgIDs map[uint32]struct{}) uint64 {
+	k.MemoryFile().UpdateUsage(memCgIDs)
+	var totalBytes uint64
+	for id := range memCgIDs {
+		_, bytes := usage.MemoryAccounting.CopyPerCg(id)
+		totalBytes += bytes
+	}
 	return totalBytes
 }
 
@@ -139,10 +151,10 @@ type memoryUsageInBytesData struct {
 // Generate implements vfs.DynamicBytesSource.Generate.
 func (d *memoryUsageInBytesData) Generate(ctx context.Context, buf *bytes.Buffer) error {
 	k := kernel.KernelFromContext(ctx)
-	mf := k.MemoryFile()
-	mf.UpdateUsage(d.memCg.ID())
 
-	totalBytes := d.memCg.collectMemoryUsage()
+	memCgIDs := make(map[uint32]struct{})
+	d.memCg.collectMemCgIDs(memCgIDs)
+	totalBytes := getUsage(k, memCgIDs)
 	fmt.Fprintf(buf, "%d\n", totalBytes)
 	return nil
 }
diff --git a/pkg/sentry/fsimpl/proc/tasks_files.go b/pkg/sentry/fsimpl/proc/tasks_files.go
index ca3e8dbbd..37bcff1f2 100644
--- a/pkg/sentry/fsimpl/proc/tasks_files.go
+++ b/pkg/sentry/fsimpl/proc/tasks_files.go
@@ -268,7 +268,7 @@ var _ dynamicInode = (*meminfoData)(nil)
 // Generate implements vfs.DynamicBytesSource.Generate.
 func (*meminfoData) Generate(ctx context.Context, buf *bytes.Buffer) error {
 	mf := kernel.KernelFromContext(ctx).MemoryFile()
-	_ = mf.UpdateUsage(0) // Best effort
+	_ = mf.UpdateUsage(nil) // Best effort
 	snapshot, totalUsage := usage.MemoryAccounting.Copy()
 	totalSize := usage.TotalMemory(mf.TotalSize(), totalUsage)
 	anon := snapshot.Anonymous + snapshot.Tmpfs
diff --git a/pkg/sentry/pgalloc/pgalloc.go b/pkg/sentry/pgalloc/pgalloc.go
index aa15963e9..8438fec42 100644
--- a/pkg/sentry/pgalloc/pgalloc.go
+++ b/pkg/sentry/pgalloc/pgalloc.go
@@ -1088,10 +1088,10 @@ func (f *MemoryFile) ShouldCacheEvictable() bool {
 }
 
 // UpdateUsage ensures that the memory usage statistics in
-// usage.MemoryAccounting are up to date. If forceScan is true, the
-// UsageScanDuration is ignored and the memory file is scanned to get the
-// memory usage.
-func (f *MemoryFile) UpdateUsage(memCgID uint32) error {
+// usage.MemoryAccounting are up to date. If memCgIDs is nil, all the pages
+// will be scanned. Else only the pages which belong to the memory cgroup ids
+// in memCgIDs will be scanned and the memory usage will be updated.
+func (f *MemoryFile) UpdateUsage(memCgIDs map[uint32]struct{}) error {
 	f.mu.Lock()
 	defer f.mu.Unlock()
 
@@ -1120,10 +1120,10 @@ func (f *MemoryFile) UpdateUsage(memCgID uint32) error {
 		return nil
 	}
 
-	if memCgID == 0 {
+	if memCgIDs == nil {
 		f.usageLast = time.Now()
 	}
-	err = f.updateUsageLocked(currentUsage, memCgID, mincore)
+	err = f.updateUsageLocked(currentUsage, memCgIDs, mincore)
 	log.Debugf("UpdateUsage: currentUsage=%d, usageExpected=%d, usageSwapped=%d.",
 		currentUsage, f.usageExpected, f.usageSwapped)
 	log.Debugf("UpdateUsage: took %v.", time.Since(f.usageLast))
@@ -1136,7 +1136,7 @@ func (f *MemoryFile) UpdateUsage(memCgID uint32) error {
 //
 // Precondition: f.mu must be held; it may be unlocked and reacquired.
 // +checklocks:f.mu
-func (f *MemoryFile) updateUsageLocked(currentUsage uint64, memCgID uint32, checkCommitted func(bs []byte, committed []byte) error) error {
+func (f *MemoryFile) updateUsageLocked(currentUsage uint64, memCgIDs map[uint32]struct{}, checkCommitted func(bs []byte, committed []byte) error) error {
 	// Track if anything changed to elide the merge. In the common case, we
 	// expect all segments to be committed and no merge to occur.
 	changedAny := false
@@ -1183,10 +1183,12 @@ func (f *MemoryFile) updateUsageLocked(currentUsage uint64, memCgID uint32, chec
 		// Scan the pages of the given memCgID only. This will avoid scanning the
 		// whole memory file when the memory usage is required only for a specific
 		// cgroup. The total memory usage of all cgroups can be obtained when the
-		// memCgID is passed as zero.
-		if memCgID != 0 && seg.ValuePtr().memCgID != memCgID {
-			seg = seg.NextSegment()
-			continue
+		// memCgIDs is nil.
+		if memCgIDs != nil {
+			if _, ok := memCgIDs[seg.ValuePtr().memCgID]; !ok {
+				seg = seg.NextSegment()
+				continue
+			}
 		}
 
 		// Get the range for this segment. As we touch slices, the
diff --git a/pkg/sentry/pgalloc/save_restore.go b/pkg/sentry/pgalloc/save_restore.go
index 3d1785ada..cf17e4af7 100644
--- a/pkg/sentry/pgalloc/save_restore.go
+++ b/pkg/sentry/pgalloc/save_restore.go
@@ -50,7 +50,7 @@ func (f *MemoryFile) SaveTo(ctx context.Context, w wire.Writer) error {
 	// Ensure that all pages that contain data have knownCommitted set, since
 	// we only store knownCommitted pages below.
 	zeroPage := make([]byte, hostarch.PageSize)
-	err := f.updateUsageLocked(0, 0, func(bs []byte, committed []byte) error {
+	err := f.updateUsageLocked(0, nil, func(bs []byte, committed []byte) error {
 		for pgoff := 0; pgoff < len(bs); pgoff += hostarch.PageSize {
 			i := pgoff / hostarch.PageSize
 			pg := bs[pgoff : pgoff+hostarch.PageSize]
diff --git a/runsc/boot/events.go b/runsc/boot/events.go
index 342e3dd2f..f66864a2a 100644
--- a/runsc/boot/events.go
+++ b/runsc/boot/events.go
@@ -100,7 +100,7 @@ func (cm *containerManager) Event(cid *string, out *EventOut) error {
 
 	// Memory usage.
 	mem := cm.l.k.MemoryFile()
-	_ = mem.UpdateUsage(0) // best effort to update.
+	_ = mem.UpdateUsage(nil) // best effort to update.
 	_, totalUsage := usage.MemoryAccounting.Copy()
 	switch containers := cm.l.containerCount(); containers {
 	case 0: