cmd/utils: allow file descriptor limit to be set via CLI (ethereum#24477)

Author: gzliudan

cmd/XDC/main.go

@@ -93,6 +93,7 @@ var (
 		//utils.CacheDatabaseFlag,
 		//utils.CacheGCFlag,
 		//utils.TrieCacheGenFlag,
+		utils.FDLimitFlag,
 		utils.ListenPortFlag,
 		utils.MaxPeersFlag,
 		utils.MaxPendingPeersFlag,

cmd/XDC/usage.go

@@ -123,15 +123,16 @@ var AppHelpFlagGroups = []flagGroup{
 	//		utils.TxPoolLifetimeFlag,
 	//	},
 	//},
-	//{
-	//	Name: "PERFORMANCE TUNING",
-	//	Flags: []cli.Flag{
-	//		utils.CacheFlag,
-	//		utils.CacheDatabaseFlag,
-	//		utils.CacheGCFlag,
-	//		utils.TrieCacheGenFlag,
-	//	},
-	//},
+	{
+		Name: "PERFORMANCE TUNING",
+		Flags: []cli.Flag{
+			// utils.CacheFlag,
+			// utils.CacheDatabaseFlag,
+			// utils.CacheGCFlag,
+			// utils.TrieCacheGenFlag,
+			utils.FDLimitFlag,
+		},
+	},
 	{
 		Name: "ACCOUNT",
 		Flags: []cli.Flag{

cmd/gc/main.go

@@ -52,7 +52,7 @@ type ResultProcessNode struct {
 
 func main() {
 	flag.Parse()
-	db, _ := leveldb.New(*dir, ethconfig.Defaults.DatabaseCache, utils.MakeDatabaseHandles(), "")
+	db, _ := leveldb.New(*dir, ethconfig.Defaults.DatabaseCache, utils.MakeDatabaseHandles(0), "")
 	lddb := rawdb.NewDatabase(db)
 	head := core.GetHeadBlockHash(lddb)
 	currentHeader := core.GetHeader(lddb, head, core.GetBlockNumber(lddb, head))

cmd/utils/flags.go

@@ -313,6 +313,10 @@ var (
 		Usage: "Percentage of cache memory allowance to use for trie pruning",
 		Value: 25,
 	}
+	FDLimitFlag = cli.IntFlag{
+		Name:  "fdlimit",
+		Usage: "Raise the open file descriptor resource limit (default = system fd limit)",
+	}
 	// Miner settings
 	StakingEnabledFlag = cli.BoolFlag{
 		Name:  "mine",
@@ -816,11 +820,24 @@ func setPrefix(ctx *cli.Context, cfg *node.Config) {
 
 // MakeDatabaseHandles raises out the number of allowed file handles per process
 // for XDC and returns half of the allowance to assign to the database.
-func MakeDatabaseHandles() int {
+func MakeDatabaseHandles(max int) int {
 	limit, err := fdlimit.Maximum()
 	if err != nil {
 		Fatalf("Failed to retrieve file descriptor allowance: %v", err)
 	}
+	switch {
+	case max == 0:
+		// User didn't specify a meaningful value, use system limits
+	case max < 128:
+		// User specified something unhealthy, just use system defaults
+		log.Error("File descriptor limit invalid (<128)", "had", max, "updated", limit)
+	case max > limit:
+		// User requested more than the OS allows, notify that we can't allocate it
+		log.Warn("Requested file descriptors denied by OS", "req", max, "limit", limit)
+	default:
+		// User limit is meaningful and within allowed range, use that
+		limit = max
+	}
 	raised, err := fdlimit.Raise(uint64(limit))
 	if err != nil {
 		Fatalf("Failed to raise file descriptor allowance: %v", err)
@@ -1178,7 +1195,7 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	if ctx.GlobalIsSet(CacheFlag.Name) || ctx.GlobalIsSet(CacheDatabaseFlag.Name) {
 		cfg.DatabaseCache = ctx.GlobalInt(CacheFlag.Name) * ctx.GlobalInt(CacheDatabaseFlag.Name) / 100
 	}
-	cfg.DatabaseHandles = MakeDatabaseHandles()
+	cfg.DatabaseHandles = MakeDatabaseHandles(ctx.GlobalInt(FDLimitFlag.Name))
 
 	if gcmode := ctx.GlobalString(GCModeFlag.Name); gcmode != "full" && gcmode != "archive" {
 		Fatalf("--%s must be either 'full' or 'archive'", GCModeFlag.Name)
@@ -1267,7 +1284,7 @@ func SetupNetwork(ctx *cli.Context) {
 func MakeChainDatabase(ctx *cli.Context, stack *node.Node) ethdb.Database {
 	var (
 		cache   = ctx.GlobalInt(CacheFlag.Name) * ctx.GlobalInt(CacheDatabaseFlag.Name) / 100
-		handles = MakeDatabaseHandles()
+		handles = MakeDatabaseHandles(ctx.GlobalInt(FDLimitFlag.Name))
 	)
 	name := "chaindata"
 	if ctx.GlobalBool(LightModeFlag.Name) {