internal/debug: add debug_setMemoryLimit (ethereum#31441)

Author: georgehao

internal/debug/api.go

@@ -35,6 +35,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/hashicorp/go-bexpr"
 )
@@ -237,6 +238,24 @@ func (*HandlerT) SetGCPercent(v int) int {
 	return debug.SetGCPercent(v)
 }
 
+// SetMemoryLimit sets the GOMEMLIMIT for the process. It returns the previous limit.
+// Note:
+//
+//   - The input limit is provided as bytes. A negative input does not adjust the limit
+//
+//   - A zero limit or a limit that's lower than the amount of memory used by the Go
+//     runtime may cause the garbage collector to run nearly continuously. However,
+//     the application may still make progress.
+//
+//   - Setting the limit too low will cause Geth to become unresponsive.
+//
+//   - Geth also allocates memory off-heap, particularly for fastCache and Pebble,
+//     which can be non-trivial (a few gigabytes by default).
+func (*HandlerT) SetMemoryLimit(limit int64) int64 {
+	log.Info("Setting memory limit", "size", common.PrettyDuration(limit))
+	return debug.SetMemoryLimit(limit)
+}
+
 func writeProfile(name, file string) error {
 	p := pprof.Lookup(name)
 	log.Info("Writing profile records", "count", p.Count(), "type", name, "dump", file)

internal/web3ext/web3ext.go

@@ -269,6 +269,11 @@ web3._extend({
 			call: 'debug_setGCPercent',
 			params: 1,
 		}),
+		new web3._extend.Method({
+			name: 'setMemoryLimit',
+			call: 'debug_setMemoryLimit',
+			params: 1,
+		}),
 		new web3._extend.Method({
 			name: 'memStats',
 			call: 'debug_memStats',