How to Disable transparent huge page in Golang Code?

You can do it like shown below. You should test thoroughly to ensure there are no ill interactions with the go runtime.

package main

import (
    "fmt"
    "log"
    "os"
    "os/exec"
    "runtime"
    "syscall"
)

const (
    // https://filippo.io/linux-syscall-table/
    PRCTL_SYSCALL = 157

    // see /usr/include/linux/prctl.h
    PR_SET_THP_DISABLE = 41
    PR_GET_THP_DISABLE = 42
)

func disableTHP() {
    _, _, errno := syscall.RawSyscall6(uintptr(PRCTL_SYSCALL), uintptr(PR_SET_THP_DISABLE), uintptr(1), 0, 0, 0, 0)
    if errno != 0 {
        log.Fatalf("failed to disable THP: %v", errno)
    }
}
func isTHPDisabled() bool {
    s, _, errno := syscall.RawSyscall6(uintptr(PRCTL_SYSCALL), uintptr(PR_GET_THP_DISABLE), 0, 0, 0, 0, 0)
    if errno != 0 {
        log.Fatalf("failed get THP disable status: %v", errno)
    }
    return s == 1
}

func main() {
    if os.Getenv("X_IN_CHILD_PROC") == "" {
        runtime.LockOSThread()
        disableTHP()
        cmd := exec.Command(os.Args[0], os.Args...)
        cmd.Env = append(os.Environ(), fmt.Sprintf("X_IN_CHILD_PROC=yes"))
        cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
        _ = cmd.Run() // err discarded
        os.Exit(cmd.ProcessState.ExitCode())
    }

    // code below has THP disabled

    if !isTHPDisabled() { // sanity check
        log.Fatal("THP is somehow not disabled")
    }

    fmt.Println("THP is disabled")
    fmt.Println("hello world")
}