On Wed, Oct 14, 2009 at 4:35 AM, vinit dhatrak <vinit.dhatrak@xxxxxxxxx> wrote: > On Wed, Oct 14, 2009 at 4:04 PM, Leonidas . <leonidas137@xxxxxxxxx> wrote: >> Hi, >> >> I am running Ubuntu Jaunty currently, with kernel version 2.6.28 kernel. >> I was assuming that, all the kernels above 2.6 will have CONFIG_PREEMPT >> =1 by default, but my default kernel does not have it set. >> >> Is that the norm? I can understand certain use cases which might require >> the kernel to be non pre-emptible but even a regular desktop distro does >> not have it set? Surprising? >> >> -Leo. >> >> -- >> To unsubscribe from this list: send an email with >> "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx >> Please read the FAQ at http://kernelnewbies.org/FAQ >> >> > > Hi Leo, > > I think this is just the config option set into your local source > code. This does not mean your running kernel is preempt disabled. You > can probably run this command to check whether your running kernel has > preemption feature. > > preemptive kernel :- > > vinitd@pe-lt271:~$ cat /proc/kallsyms | grep preempt > c0121550 T preempt_notifier_register > c0121580 T preempt_notifier_unregister > c012a350 t check_preempt_curr_idle > c012ab50 t check_preempt_curr_rt > c012ac50 t check_preempt_wakeup > c045a8f0 r __ksymtab_preempt_notifier_unregister > c045a8f8 r __ksymtab_preempt_notifier_register > c045ed3c r __kcrctab_preempt_notifier_unregister > c045ed40 r __kcrctab_preempt_notifier_register > c0460612 r __kstrtab_preempt_notifier_unregister > c046062e r __kstrtab_preempt_notifier_register > c0477824 D preempt_mark_thresh > f8fc8a68 d kvm_preempt_ops [kvm] > c0121550 u preempt_notifier_register [kvm] > c0121580 u preempt_notifier_unregister [kvm] > f8d46000 t lp_preempt [lp] > vinitd@pe-lt271:~$ > > > -Vinit > I am chekcing config in /boot, that is the config of the running kernel right? Another point is, I wrote a small piece of code which does if(preemptible()) print 1 else print 0, It always prints 0. And #define preemptible 0 if config_preempt is not set as per kernel headers. -Leo. -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
