Hack:VHDFlush opt

Signed-off-by: John Howard <jhoward@microsoft.com>

daemon/start.go

@@ -3,6 +3,7 @@ package daemon // import "github.com/docker/docker/daemon"
 import (
 	"context"
 	"runtime"
+	"syscall"
 	"time"
 
 	"github.com/docker/docker/api/types"
@@ -195,11 +196,23 @@ func (daemon *Daemon) containerStart(container *container.Container, checkpoint
 		}
 	}
 
+	// Platform-specific processing between Create and Start
+	handle, err := postCreate(spec)
+	if err != nil {
+		if err2 := daemon.containerd.Delete(context.Background(), container.ID); err2 != nil {
+			logrus.WithError(err2).WithField("container", container.ID).Error("failed to delete failed post-create processing")
+		}
+		return err
+	}
+
 	// TODO(mlaventure): we need to specify checkpoint options here
 	pid, err := daemon.containerd.Start(context.Background(), container.ID, checkpointDir,
 		container.StreamConfig.Stdin() != nil || container.Config.Tty,
 		container.InitializeStdio)
 	if err != nil {
+		if handle != 0 {
+			syscall.CloseHandle(handle)
+		}
 		if err := daemon.containerd.Delete(context.Background(), container.ID); err != nil {
 			logrus.WithError(err).WithField("container", container.ID).
 				Error("failed to delete failed start container")
@@ -207,6 +220,9 @@ func (daemon *Daemon) containerStart(container *container.Container, checkpoint
 		return translateContainerdStartErr(container.Path, container.SetExitCode, err)
 	}
 
+	// Platform-specific processing after start
+	postStart(spec, handle)
+
 	container.SetRunning(pid, true)
 	container.HasBeenStartedBefore = true
 	daemon.setStateCounter(container)

daemon/start_unix.go

@@ -6,10 +6,12 @@ import (
 	"fmt"
 	"os/exec"
 	"path/filepath"
+	"syscall"
 
 	"github.com/containerd/containerd/runtime/linux/runctypes"
 	"github.com/docker/docker/container"
 	"github.com/docker/docker/errdefs"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 )
 
@@ -55,3 +57,13 @@ func (daemon *Daemon) getLibcontainerdCreateOptions(container *container.Contain
 
 	return opts, nil
 }
+
+// postCreate does platform-specific process after a container has been created,
+// but before it has been started.
+func postCreate(spec *specs.Spec) error {
+	return nil
+}
+
+// postStart does platform-specific process after a container has been started.
+func postStart(spec *specs.Spec, handle syscall.Handle) {
+}

daemon/start_windows.go

@@ -1,10 +1,18 @@
 package daemon // import "github.com/docker/docker/daemon"
 
 import (
+	"fmt"
+	"path/filepath"
+	"syscall"
+	"unsafe"
+
+	"github.com/Microsoft/go-winio/vhd"
 	"github.com/Microsoft/hcsshim/cmd/containerd-shim-runhcs-v1/options"
 	"github.com/Microsoft/opengcs/client"
 	"github.com/docker/docker/container"
 	"github.com/docker/docker/pkg/system"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
 )
 
 func (daemon *Daemon) getLibcontainerdCreateOptions(container *container.Container) (interface{}, error) {
@@ -46,3 +54,109 @@ func (daemon *Daemon) getLibcontainerdCreateOptions(container *container.Contain
 
 	return nil, nil
 }
+
+// postCreate does platform-specific process after a container has been created,
+// but before it has been started.
+func postCreate(spec *specs.Spec) (syscall.Handle, error) {
+
+	// Check if any action is needed first.
+	if !postCreateStartActionNeeded(spec) {
+		return 0, nil
+	}
+
+	// Operating on the scratch disk
+	path := filepath.Join(spec.Windows.LayerFolders[len(spec.Windows.LayerFolders)-1], "sandbox.vhdx")
+
+	if spec.Windows.HyperV == nil {
+		// Argon (WCOW)
+		handle, err := vhd.OpenVirtualDisk(path, vhd.VirtualDiskAccessNone, vhd.OpenVirtualDiskFlagParentCachedIO|vhd.OpenVirtualDiskFlagIgnoreRelativeParentLocator)
+		if err != nil {
+			syscall.CloseHandle(handle)
+			return 0, errors.Wrap(err, fmt.Sprintf("failed to open %s", path))
+		}
+		if err := setVhdWriteCacheMode(handle, WriteCacheModeDisableFlushing); err != nil {
+			syscall.CloseHandle(handle)
+			return 0, errors.Wrap(err, fmt.Sprintf("failed to disable flushing on %s", path))
+		}
+		return handle, nil
+	}
+
+	// TODO Xenon (WCOW)
+	return 0, nil
+}
+
+// postStart does platform-specific process after a container has been started.
+func postStart(spec *specs.Spec, handle syscall.Handle) {
+	if handle == 0 {
+		return
+	}
+
+	if !postCreateStartActionNeeded(spec) {
+		return
+	}
+
+	setVhdWriteCacheMode(handle, WriteCacheModeCacheMetadata)
+	syscall.CloseHandle(handle)
+}
+
+// postCreateStartActionNeeded determines if there is something that needs
+// to be done in the postCreate or postStart functions.
+func postCreateStartActionNeeded(spec *specs.Spec) bool {
+	// No-op if not using containerd runtime
+	if !system.ContainerdRuntimeSupported() {
+		return false
+	}
+
+	// No-op pre-RS5 or post-18855. Pre-RS5 doesn't use v2. Post 18855 has
+	// these optimisations in the platform for v2 callers.
+	osv := system.GetOSVersion()
+	fmt.Println(osv)
+	if osv.Build < 17763 || osv.Build >= 18855 {
+		return false
+	}
+
+	// No-op if we're not optimising, or LCOW.
+	if spec == nil || spec.Windows == nil || !spec.Windows.IgnoreFlushesDuringBoot || spec.Linux != nil {
+		return false
+	}
+	return true
+}
+
+type WriteCacheMode uint16
+
+const (
+	// Write Cache Mode for a VHD.
+	WriteCacheModeCacheMetadata         WriteCacheMode = 0
+	WriteCacheModeWriteInternalMetadata WriteCacheMode = 1
+	WriteCacheModeWriteMetadata         WriteCacheMode = 2
+	WriteCacheModeCommitAll             WriteCacheMode = 3
+	WriteCacheModeDisableFlushing       WriteCacheMode = 4
+)
+
+// setVhdWriteCacheMode sets the WriteCacheMode for a VHD. The handle
+// to the VHD should be opened with Access: None, Flags: ParentCachedIO |
+// IgnoreRelativeParentLocator. Use DisableFlushing for optimisation during
+// first boot, and CacheMetadata following container start
+func setVhdWriteCacheMode(handle syscall.Handle, wcm WriteCacheMode) error {
+	type storageSetSurfaceCachePolicyRequest struct {
+		RequestLevel uint32
+		CacheMode    uint16
+		pad          uint16 // For 4-byte alignment
+	}
+	const ioctlSetSurfaceCachePolicy uint32 = 0x2d1a10
+	request := storageSetSurfaceCachePolicyRequest{
+		RequestLevel: 1,
+		CacheMode:    uint16(wcm),
+		pad:          0,
+	}
+	var bytesReturned uint32
+	return syscall.DeviceIoControl(
+		handle,
+		ioctlSetSurfaceCachePolicy,
+		(*byte)(unsafe.Pointer(&request)),
+		uint32(unsafe.Sizeof(request)),
+		nil,
+		0,
+		&bytesReturned,
+		nil)
+}

libcontainerd/remote/client.go

@@ -283,6 +283,7 @@ func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin
 		return -1, errors.Wrap(err, "failed to retrieve spec")
 	}
 	uid, gid := getSpecUser(spec)
+
 	t, err = ctr.ctr.NewTask(ctx,
 		func(id string) (cio.IO, error) {
 			fifos := newFIFOSet(ctr.bundleDir, libcontainerdtypes.InitProcessName, withStdin, spec.Process.Terminal)