On Mon, 25 Aug 2008, Linus Torvalds wrote: > > But I'll look at your vmlinux, see what stands out. Oops. I already see the problem. Your .config has soem _huge_ CPU count, doesn't it? checkstack.pl shows these things as the top problems: 0xffffffff80266234 smp_call_function_mask [vmlinux]: 2736 0xffffffff80234747 __build_sched_domains [vmlinux]: 2232 0xffffffff8023523f __build_sched_domains [vmlinux]: 2232 0xffffffff8021e884 setup_IO_APIC_irq [vmlinux]: 1616 0xffffffff8021ee24 arch_setup_ht_irq [vmlinux]: 1600 0xffffffff8021f144 arch_setup_msi_irq [vmlinux]: 1600 0xffffffff8021e3b0 __assign_irq_vector [vmlinux]: 1592 0xffffffff8021e626 __assign_irq_vector [vmlinux]: 1592 0xffffffff8023257e move_task_off_dead_cpu [vmlinux]: 1592 0xffffffff802326e8 move_task_off_dead_cpu [vmlinux]: 1592 0xffffffff8025dbc5 tick_handle_oneshot_broadcast [vmlinux]:1544 0xffffffff8025dcb4 tick_handle_oneshot_broadcast [vmlinux]:1544 0xffffffff803f3dc4 store_scaling_governor [vmlinux]: 1376 0xffffffff80279ef4 cpuset_write_resmask [vmlinux]: 1360 0xffffffff803f465d cpufreq_add_dev [vmlinux]: 1352 0xffffffff803f495b cpufreq_add_dev [vmlinux]: 1352 0xffffffff803f3fc4 store_scaling_max_freq [vmlinux]: 1328 0xffffffff803f4064 store_scaling_min_freq [vmlinux]: 1328 0xffffffff803f44c4 cpufreq_update_policy [vmlinux]: 1328 .. and sys_init_module is actually way way down the list. I bet the only reason it showed up at all was because dynamically it was such a deep callchain, and part of that callchain probably called some of those really nasty things. Anyway, the reason smp_call_function_mask and friends have such _huge_ stack usages for you is that they contain a 'cpumask_t' on the stack. For example, for me, usign a sane NR_CPU, the size of the stack frame for smp_call_function_mask is under 200 bytes. For you, it's 2736 bytes. How about you make CONFIG_NR_CPU's something _sane_? Like 16? Or do you really have four thousand CPU's in that system? Oh, I guess you have the MAXSMP config enabled? I really think that was a bit too aggressive. Linus -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
