Sungju's Slow Life

Personal journal

What happens if numa=off is provided in kernel parameter?

If “numa=off” is in kernel boot parameter, it will mark ‘numa_off’ global variable which will be checked during initialization function which is ‘x86_numa_init()’ in x86_64. This will make it not call ‘numa_init’ if numa_off is 1.

static __init int numa_setup(char *opt)
    if (!opt)
        return -EINVAL;
    if (!strncmp(opt, "off", 3))
        numa_off = 1;
    if (!strncmp(opt, "fake=", 5))
        numa_emu_cmdline(opt + 5);
    if (!strncmp(opt, "noacpi", 6))
        acpi_numa = -1;
    return 0;
early_param("numa", numa_setup);

 * x86_numa_init - Initialize NUMA
 * Try each configured NUMA initialization method until one succeeds.  The
 * last fallback is dummy single node config encomapssing whole memory and
 * never fails.
void __init x86_numa_init(void)
    if (!numa_off) {
        if (!numa_init(numaq_numa_init))


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About Me

A software engineer who loves any technologies that makes life easier. That’s why I love Linux and Mac at the same time.


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