Merge pull request #3727 from stgraber/fixes

Split memory and swap cgroup2 checks and tweak validation

internal/server/cgroup/abstraction.go

@@ -153,7 +153,7 @@ func (cg *CGroup) GetProcessesUsage() (int64, error) {
 
 // SetMemorySwapLimit sets the hard limit for swap.
 func (cg *CGroup) SetMemorySwapLimit(limit int64) error {
-	if !cgControllers["memory"] {
+	if !cgControllers["memory.swap"] {
 		return ErrControllerMissing
 	}
 
@@ -314,7 +314,7 @@ func (cg *CGroup) SetMemorySwappiness(limit int64) error {
 
 // GetMemorySwapLimit returns the hard limit on swap usage.
 func (cg *CGroup) GetMemorySwapLimit() (int64, error) {
-	if !cgControllers["memory"] {
+	if !cgControllers["memory.swap"] {
 		return -1, ErrControllerMissing
 	}
 
@@ -337,7 +337,7 @@ func (cg *CGroup) GetMemorySwapLimit() (int64, error) {
 
 // GetMemorySwapUsage return current usage of swap.
 func (cg *CGroup) GetMemorySwapUsage() (int64, error) {
-	if !cgControllers["memory"] {
+	if !cgControllers["memory.swap"] {
 		return -1, ErrControllerMissing
 	}
 

internal/server/cgroup/init.go

@@ -11,6 +11,7 @@ import (
 	"github.com/lxc/incus/v7/internal/server/db/cluster"
 	"github.com/lxc/incus/v7/internal/server/db/warningtype"
 	"github.com/lxc/incus/v7/shared/logger"
+	"github.com/lxc/incus/v7/shared/util"
 )
 
 var cgControllers = map[string]bool{}
@@ -37,6 +38,9 @@ const (
 	// Memory resource control.
 	Memory
 
+	// MemorySwap resource control.
+	MemorySwap
+
 	// Pids resource control.
 	Pids
 )
@@ -54,6 +58,8 @@ func Supports(resource Resource) bool {
 		return cgControllers["io"]
 	case Memory:
 		return cgControllers["memory"]
+	case MemorySwap:
+		return cgControllers["memory.swap"]
 	case Pids:
 		return cgControllers["pids"]
 	}
@@ -98,6 +104,11 @@ func Warnings() []cluster.Warning {
 			TypeCode:    warningtype.MissingCGroupMemoryController,
 			LastMessage: "memory limits will be ignored",
 		})
+	} else if !Supports(MemorySwap) {
+		warnings = append(warnings, cluster.Warning{
+			TypeCode:    warningtype.MissingCGroupMemorySwapAccounting,
+			LastMessage: "swap limits will be ignored",
+		})
 	}
 
 	if !Supports(Pids) {
@@ -156,5 +167,15 @@ func Init() {
 		}
 
 		_ = controllers.Close()
+
+		// Check for swap accounting support (can be disabled through kernel arguments).
+		if cgControllers["memory"] {
+			for _, path := range []string{filepath.Join(cgPath, fields[2]), filepath.Join(cgPath, "init.scope")} {
+				if util.PathExists(filepath.Join(path, "memory.swap.current")) {
+					cgControllers["memory.swap"] = true
+					break
+				}
+			}
+		}
 	}
 }

internal/server/instance/drivers/driver_lxc.go

@@ -1192,7 +1192,10 @@ func (d *lxc) initLXC(config bool) (*liblxc.Container, error) {
 				if util.IsTrueOrEmpty(memorySwap) || util.IsFalse(memorySwap) {
 					err = cg.SetMemorySwapLimit(0)
 					if err != nil {
-						return nil, err
+						// Ignore missing swap accounting unless explicitly configured.
+						if memorySwap != "" || !errors.Is(err, cgroup.ErrControllerMissing) {
+							return nil, err
+						}
 					}
 				} else {
 					// Additional memory as swap.
@@ -5332,7 +5335,7 @@ func (d *lxc) Update(args db.InstanceArgs, userRequested bool) error {
 
 				// Store the old values for revert
 				oldMemswLimit := int64(-1)
-				if cgroup.Supports(cgroup.Memory) {
+				if cgroup.Supports(cgroup.MemorySwap) {
 					oldMemswLimit, err = cg.GetMemorySwapLimit()
 					if err != nil {
 						oldMemswLimit = -1
@@ -5363,7 +5366,7 @@ func (d *lxc) Update(args db.InstanceArgs, userRequested bool) error {
 				}
 
 				// Reset everything
-				if cgroup.Supports(cgroup.Memory) {
+				if cgroup.Supports(cgroup.MemorySwap) {
 					err = cg.SetMemorySwapLimit(-1)
 					if err != nil {
 						revertMemory()
@@ -5398,26 +5401,27 @@ func (d *lxc) Update(args db.InstanceArgs, userRequested bool) error {
 						return err
 					}
 
-					if cgroup.Supports(cgroup.Memory) {
-						if util.IsTrueOrEmpty(memorySwap) || util.IsFalse(memorySwap) {
-							err = cg.SetMemorySwapLimit(0)
-							if err != nil {
-								revertMemory()
-								return err
-							}
-						} else {
-							// Additional memory as swap.
-							swapInt, err := units.ParseByteSizeString(memorySwap)
-							if err != nil {
+					if util.IsTrueOrEmpty(memorySwap) || util.IsFalse(memorySwap) {
+						err = cg.SetMemorySwapLimit(0)
+						if err != nil {
+							// Ignore missing swap accounting unless explicitly configured.
+							if memorySwap != "" || !errors.Is(err, cgroup.ErrControllerMissing) {
 								revertMemory()
 								return err
 							}
+						}
+					} else {
+						// Additional memory as swap.
+						swapInt, err := units.ParseByteSizeString(memorySwap)
+						if err != nil {
+							revertMemory()
+							return err
+						}
 
-							err = cg.SetMemorySwapLimit(swapInt)
-							if err != nil {
-								revertMemory()
-								return err
-							}
+						err = cg.SetMemorySwapLimit(swapInt)
+						if err != nil {
+							revertMemory()
+							return err
 						}
 					}
 				}
@@ -5441,8 +5445,11 @@ func (d *lxc) Update(args db.InstanceArgs, userRequested bool) error {
 
 						// Maximum priority (10) should be default swappiness (60).
 						err = cg.SetMemorySwappiness(int64(70 - priority))
-						if err != nil && !errors.Is(err, cgroup.ErrControllerMissing) {
-							return err
+						if err != nil {
+							// Ignore missing swappiness support unless explicitly configured.
+							if memorySwapPriority != "" || !errors.Is(err, cgroup.ErrControllerMissing) {
+								return err
+							}
 						}
 					}
 				}
@@ -9370,7 +9377,7 @@ func (d *lxc) Metrics(hostInterfaces []net.Interface) (*metrics.MetricSet, error
 	out.AddSamples(metrics.MemoryOOMKillsTotal, metrics.Sample{Value: float64(oomKills)})
 
 	// Handle swap.
-	if cgroup.Supports(cgroup.Memory) {
+	if cgroup.Supports(cgroup.MemorySwap) {
 		swapUsage, err := cg.GetMemorySwapUsage()
 		if err != nil {
 			d.logger.Warn("Failed to get swap usage", logger.Ctx{"err": err})

internal/server/seccomp/seccomp.go

@@ -1797,7 +1797,7 @@ func (srv *Server) HandleSysinfoSyscall(c Instance, siov *Iovec) int {
 	instMetrics.Freeram = instMetrics.Totalram - uint64(memoryUsage) - instMetrics.Bufferram
 
 	// Get instance swap info.
-	if cgroup.Supports(cgroup.Memory) {
+	if cgroup.Supports(cgroup.MemorySwap) {
 		swapLimit, err := cg.GetMemorySwapLimit()
 		if err != nil {
 			l.Warn("Failed getting swap limit", logger.Ctx{"err": err})