What version of Go are you using (go version)?
$ go version
go version go1.17 darwin/amd64
Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (go env)?
go env Output
$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/hajimehoshi/Library/Caches/go-build"
GOENV="/Users/hajimehoshi/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/hajimehoshi/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/hajimehoshi/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.17"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/hajimehoshi/test/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/60/khbk2xqn1c5bml1byjn89dwc0000gn/T/go-build3631899530=/tmp/go-build -gno-record-gcc-switches -fno-common"
What did you do?
Run this and see the memory usage (I saw "Real Private Memory" on Activity on macOS):
package main
import (
"time"
"runtime"
)
var f func()
func foo(bs []byte) {
if f == nil {
copied := make([]byte, len(bs))
copy(copied, bs)
f = func() {
foo(copied)
}
return
}
println(len(bs))
}
func main() {
bs := make([]byte, 100*1024*1024)
foo(bs)
f()
f = nil
bs = nil
for {
runtime.GC()
time.Sleep(time.Second)
}
}What did you expect to see?
The private memory usage should be the same as this program (less than 10[MB] maybe):
func main() {
for {
runtime.GC()
time.Sleep(time.Second)
}
}What did you see instead?
The private memory usage keeps about 200[MB]
What version of Go are you using (
go version)?Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (
go env)?go envOutputWhat did you do?
Run this and see the memory usage (I saw "Real Private Memory" on Activity on macOS):
What did you expect to see?
The private memory usage should be the same as this program (less than 10[MB] maybe):
What did you see instead?
The private memory usage keeps about 200[MB]