Fix LRU cache usage

ebpf/event_handler.go

@@ -13,7 +13,7 @@ import (
 
  "github.com/cilium/ebpf/ringbuf"
  "github.com/go-delve/delve/pkg/proc"
- lru "github.com/hashicorp/golang-lru/v2"
+ "github.com/hashicorp/golang-lru/v2/expirable"
  "github.com/keisku/gmon/bininfo"
 )
 
@@ -26,7 +26,17 @@ type eventHandler struct {
 
 func (h *eventHandler) run(ctx context.Context) {
  var event bpfEvent
- stackIdCache, _ := lru.New[int32, struct{}](16)
+ // To delete stack_addresses that is not used recently.
+ stackIdCache := expirable.NewLRU[int32, struct{}](
+ 32, // cache size
+ func(key int32, _ struct{}) {
+ slog.Debug("delete stack_addresses", slog.Int("stack_id", int(key)))
+ if err := h.objs.StackAddresses.Delete(key); err != nil {
+ slog.Debug("Failed to delete stack_addresses", slog.Any("error", err))
+ }
+ },
+ time.Minute, // TTL of each cache entry
+ )
  for {
  if err := h.readRecord(ctx, &event); err != nil {
  if errors.Is(err, ringbuf.ErrClosed) {
@@ -47,13 +57,7 @@ func (h *eventHandler) run(ctx context.Context) {
  Stack: stack,
  Exit: event.Exit,
  })
- contains, _ := stackIdCache.ContainsOrAdd(event.StackId, struct{}{})
- if !contains {
- slog.Debug("delete stack_addresses", slog.Int("stack_id", int(event.StackId)))
- if err := h.objs.StackAddresses.Delete(event.StackId); err != nil {
- slog.Debug("Failed to delete stack_addresses", slog.Any("error", err))
- }
- }
+ _ = stackIdCache.Add(event.StackId, struct{}{})
  }
 }