integer limit = 20000; // <- bytes

Test()
{
    llSay(0, "Limited Memory " + (string)llGetMemoryLimit() +
              "\nUsed Memory " + (string)llGetUsedMemory() +
              "\nFree Memory " + (string)llGetFreeMemory());
}

default
{
    state_entry()
    {
        llSetMemoryLimit(limit);

        llScriptProfiler(PROFILE_SCRIPT_MEMORY);
        Test();
        llScriptProfiler(PROFILE_NONE);

        llSay(0,"This script used at most " + (string)llGetSPMaxMemory() + " bytes of memory during Test.");
    }
}