Allow default control values to be set for cgroupfs.

PiperOrigin-RevId: 366891806

1 files changed, 16 insertions, 2 deletions

diff --git a/pkg/sentry/fsimpl/cgroupfs/memory.go b/pkg/sentry/fsimpl/cgroupfs/memory.go
index eaf40a753..485c98376 100644
--- a/pkg/sentry/fsimpl/cgroupfs/memory.go
+++ b/pkg/sentry/fsimpl/cgroupfs/memory.go
@@ -17,7 +17,9 @@ package cgroupfs
 import (
 	"bytes"
 	"fmt"
+	"math"
 
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
@@ -28,12 +30,23 @@ import (
 // +stateify savable
 type memoryController struct {
 	controllerCommon
+
+	limitBytes int64
 }
 
 var _ controller = (*memoryController)(nil)
 
-func newMemoryController(fs *filesystem) *memoryController {
-	c := &memoryController{}
+func newMemoryController(fs *filesystem, defaults map[string]int64) *memoryController {
+	c := &memoryController{
+		// Linux sets this to (PAGE_COUNTER_MAX * PAGE_SIZE) by default, which
+		// is ~ 2**63 on a 64-bit system. So essentially, inifinity. The exact
+		// value isn't very important.
+		limitBytes: math.MaxInt64,
+	}
+	if val, ok := defaults["memory.limit_in_bytes"]; ok {
+		c.limitBytes = val
+		delete(defaults, "memory.limit_in_bytes")
+	}
 	c.controllerCommon.init(controllerMemory, fs)
 	return c
 }
@@ -41,6 +54,7 @@ func newMemoryController(fs *filesystem) *memoryController {
 // AddControlFiles implements controller.AddControlFiles.
 func (c *memoryController) AddControlFiles(ctx context.Context, creds *auth.Credentials, _ *cgroupInode, contents map[string]kernfs.Inode) {
 	contents["memory.usage_in_bytes"] = c.fs.newControllerFile(ctx, creds, &memoryUsageInBytesData{})
+	contents["memory.limit_in_bytes"] = c.fs.newStaticControllerFile(ctx, creds, linux.FileMode(0644), fmt.Sprintf("%d\n", c.limitBytes))
 }
 
 // +stateify savable