Error out early if system does not support pre-copy checkpointing

CRIU's pre-copy migration support relies on the soft dirty page tracking
in the Linux kernel:

 https://www.kernel.org/doc/Documentation/vm/soft-dirty.txt

This functionality is not implemented for all architectures and it can
also be turned off in the kernel.

CRIU can check if the combination of architecture/kernel/CRIU supports
the soft dirty page tracking and exports this feature checking
functionality in go-criu.

This commit adds an early check if the user selects pre-copy
checkpointing to error out if the system does not support it.

Signed-off-by: Adrian Reber <areber@redhat.com>

2 files changed, 29 insertions, 0 deletions

diff --git a/pkg/criu/criu.go b/pkg/criu/criu.go
index 2a6805979..967da0dca 100644
--- a/pkg/criu/criu.go
+++ b/pkg/criu/criu.go
@@ -1,7 +1,12 @@
+// +build linux
+
 package criu
 
 import (
 	"github.com/checkpoint-restore/go-criu/v5"
+	"github.com/checkpoint-restore/go-criu/v5/rpc"
+
+	"google.golang.org/protobuf/proto"
 )
 
 // MinCriuVersion for Podman at least CRIU 3.11 is required
@@ -21,3 +26,20 @@ func CheckForCriu(version int) bool {
 	}
 	return result
 }
+
+func MemTrack() bool {
+	features, err := criu.MakeCriu().FeatureCheck(
+		&rpc.CriuFeatures{
+			MemTrack: proto.Bool(true),
+		},
+	)
+	if err != nil {
+		return false
+	}
+
+	if features == nil || features.MemTrack == nil {
+		return false
+	}
+
+	return *features.MemTrack
+}
diff --git a/pkg/criu/criu_unsupported.go b/pkg/criu/criu_unsupported.go
new file mode 100644
index 000000000..51cd0c1fd
--- /dev/null
+++ b/pkg/criu/criu_unsupported.go
@@ -0,0 +1,7 @@
+// +build !linux
+
+package criu
+
+func MemTrack() bool {
+	return false
+}