void set_jemalloc_bg_thread(int enable) {
    /* let jemalloc do purging asynchronously, required when there's no traffic 
     * after flushdb */
    char val = !!enable;
    je_mallctl("background_thread", NULL, 0, &val, 1);
}
void set_jemalloc_bg_thread(int enable) {
     
    char val = !!enable;
    je_mallctl("background_thread", NULL, 0, &val, 1);
}