common: controllerHandler.Apply replaced by fs2.NewManager

The Update() function previously iterated through handlers calling their
Apply() methods. With cgroups v1 removed, all handlers' Apply()
implementations were identical - they all called fs2.NewManager().Set().

This commit removes the redundant handler Apply() methods and has Update()
call fs2.NewManager().Set() directly. The Update() method now performs the
same function more efficiently without the handler indirection.

Signed-off-by: Lokesh Mandvekar <[email protected]>

Author: lsm5

common/pkg/cgroups/blkio_linux.go

@@ -3,13 +3,11 @@
 package cgroups
 
 import (
-	"path/filepath"
 	"strconv"
 	"strings"
 
 	"github.com/opencontainers/cgroups"
 	"github.com/opencontainers/cgroups/fs"
-	"github.com/opencontainers/cgroups/fs2"
 )
 
 type linuxBlkioHandler struct {
@@ -20,15 +18,6 @@ func getBlkioHandler() *linuxBlkioHandler {
 	return &linuxBlkioHandler{}
 }
 
-// Apply set the specified constraints.
-func (c *linuxBlkioHandler) Apply(ctr *CgroupControl, res *cgroups.Resources) error {
-	man, err := fs2.NewManager(ctr.config, filepath.Join(cgroupRoot, ctr.config.Path))
-	if err != nil {
-		return err
-	}
-	return man.Set(res)
-}
-
 // Stat fills a metrics structure with usage stats for the controller.
 func (c *linuxBlkioHandler) Stat(ctr *CgroupControl, m *cgroups.Stats) error {
 	var ioServiceBytesRecursive []cgroups.BlkioStatEntry

common/pkg/cgroups/cgroups_linux.go

@@ -20,6 +20,7 @@ import (
 	systemdDbus "github.com/coreos/go-systemd/v22/dbus"
 	"github.com/godbus/dbus/v5"
 	"github.com/opencontainers/cgroups"
+	"github.com/opencontainers/cgroups/fs2"
 	"go.podman.io/storage/pkg/fileutils"
 	"go.podman.io/storage/pkg/unshare"
 	"golang.org/x/sys/unix"
@@ -42,7 +43,6 @@ type CgroupControl struct {
 }
 
 type controllerHandler interface {
-	Apply(*CgroupControl, *cgroups.Resources) error
 	Stat(*CgroupControl, *cgroups.Stats) error
 }
 
@@ -306,12 +306,11 @@ func (c *CgroupControl) DeleteByPath(path string) error {
 
 // Update updates the cgroups.
 func (c *CgroupControl) Update(resources *cgroups.Resources) error {
-	for _, h := range handlers {
-		if err := h.Apply(c, resources); err != nil {
-			return err
-		}
+	man, err := fs2.NewManager(c.config, filepath.Join(cgroupRoot, c.config.Path))
+	if err != nil {
+		return err
 	}
-	return nil
+	return man.Set(resources)
 }
 
 // Stat returns usage statistics for the cgroup.

common/pkg/cgroups/cpu_linux.go

@@ -3,12 +3,10 @@
 package cgroups
 
 import (
-	"path/filepath"
 	"strconv"
 
 	"github.com/opencontainers/cgroups"
 	"github.com/opencontainers/cgroups/fs"
-	"github.com/opencontainers/cgroups/fs2"
 )
 
 type linuxCPUHandler struct {
@@ -19,15 +17,6 @@ func getCPUHandler() *linuxCPUHandler {
 	return &linuxCPUHandler{}
 }
 
-// Apply set the specified constraints.
-func (c *linuxCPUHandler) Apply(ctr *CgroupControl, res *cgroups.Resources) error {
-	man, err := fs2.NewManager(ctr.config, filepath.Join(cgroupRoot, ctr.config.Path))
-	if err != nil {
-		return err
-	}
-	return man.Set(res)
-}
-
 // Stat fills a metrics structure with usage stats for the controller.
 func (c *linuxCPUHandler) Stat(ctr *CgroupControl, m *cgroups.Stats) error {
 	cpu := cgroups.CpuStats{}

common/pkg/cgroups/cpuset_linux.go

@@ -3,11 +3,8 @@
 package cgroups
 
 import (
-	"path/filepath"
-
 	"github.com/opencontainers/cgroups"
 	"github.com/opencontainers/cgroups/fs"
-	"github.com/opencontainers/cgroups/fs2"
 )
 
 type linuxCpusetHandler struct {
@@ -18,15 +15,6 @@ func getCpusetHandler() *linuxCpusetHandler {
 	return &linuxCpusetHandler{}
 }
 
-// Apply set the specified constraints.
-func (c *linuxCpusetHandler) Apply(ctr *CgroupControl, res *cgroups.Resources) error {
-	man, err := fs2.NewManager(ctr.config, filepath.Join(cgroupRoot, ctr.config.Path))
-	if err != nil {
-		return err
-	}
-	return man.Set(res)
-}
-
 // Stat fills a metrics structure with usage stats for the controller.
 func (c *linuxCpusetHandler) Stat(_ *CgroupControl, _ *cgroups.Stats) error {
 	return nil

common/pkg/cgroups/memory_linux.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/opencontainers/cgroups"
 	"github.com/opencontainers/cgroups/fs"
-	"github.com/opencontainers/cgroups/fs2"
 )
 
 type linuxMemHandler struct {
@@ -18,15 +17,6 @@ func getMemoryHandler() *linuxMemHandler {
 	return &linuxMemHandler{}
 }
 
-// Apply set the specified constraints.
-func (c *linuxMemHandler) Apply(ctr *CgroupControl, res *cgroups.Resources) error {
-	man, err := fs2.NewManager(ctr.config, filepath.Join(cgroupRoot, ctr.config.Path))
-	if err != nil {
-		return err
-	}
-	return man.Set(res)
-}
-
 // Stat fills a metrics structure with usage stats for the controller.
 func (c *linuxMemHandler) Stat(ctr *CgroupControl, m *cgroups.Stats) error {
 	var err error

common/pkg/cgroups/pids_linux.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/opencontainers/cgroups"
 	"github.com/opencontainers/cgroups/fs"
-	"github.com/opencontainers/cgroups/fs2"
 )
 
 type linuxPidHandler struct {
@@ -18,15 +17,6 @@ func getPidsHandler() *linuxPidHandler {
 	return &linuxPidHandler{}
 }
 
-// Apply set the specified constraints.
-func (c *linuxPidHandler) Apply(ctr *CgroupControl, res *cgroups.Resources) error {
-	man, err := fs2.NewManager(ctr.config, filepath.Join(cgroupRoot, ctr.config.Path))
-	if err != nil {
-		return err
-	}
-	return man.Set(res)
-}
-
 // Stat fills a metrics structure with usage stats for the controller.
 func (c *linuxPidHandler) Stat(ctr *CgroupControl, m *cgroups.Stats) error {
 	if ctr.config.Path == "" {