File: issue15277.go

package info (click to toggle)
gcc-arm-none-eabi 15%3A12.2.rel1-1
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 959,712 kB
  • sloc: cpp: 3,275,382; ansic: 2,061,766; ada: 840,956; f90: 208,513; makefile: 76,132; asm: 73,433; xml: 50,448; exp: 34,146; sh: 32,436; objc: 15,637; fortran: 14,012; python: 11,991; pascal: 6,787; awk: 4,779; perl: 3,054; yacc: 338; ml: 285; lex: 201; haskell: 122
file content (40 lines) | stat: -rw-r--r-- 849 bytes parent folder | download | duplicates (17) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
 
// run

// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build amd64

package main

import "runtime"

type big [10 << 20]byte

func f(x *big, start int64) {
	if delta := inuse() - start; delta < 9<<20 {
		println("after alloc: expected delta at least 9MB, got: ", delta)
	}
	runtime.KeepAlive(x)
	x = nil
	if delta := inuse() - start; delta > 1<<20 {
		println("after drop: expected delta below 1MB, got: ", delta)
	}
	x = new(big)
	if delta := inuse() - start; delta < 9<<20 {
		println("second alloc: expected delta at least 9MB, got: ", delta)
	}
	runtime.KeepAlive(x)
}

func main() {
	x := inuse()
	f(new(big), x)
}

func inuse() int64 {
	runtime.GC()
	var st runtime.MemStats
	runtime.ReadMemStats(&st)
	return int64(st.Alloc)
}