On Wednesday 13 May 2015 02:24 AM, Steven Rostedt wrote: > On Tue, 12 May 2015 13:36:01 -0700 > Andrew Morton <a...@linux-foundation.org> wrote: > >> On Tue, 12 May 2015 16:03:51 -0400 Steven Rostedt <rost...@goodmis.org> >> wrote: >> >>> On Tue, 12 May 2015 12:59:26 +0530 >>> Shreyas B Prabhu <shre...@linux.vnet.ibm.com> wrote: >>> >>>> Hi Steven, >>>> On closer look, there is no particular maintainer who picks changes to >>>> this file. Can you please pick these up? >>> >>> Perhaps Andrew Morton? >>> >>> No problem, I can take these too. >>> >> >> I grabbed them, thanks. >>
Thanks Andrew. >>> + TP_CONDITION(cpu_online(smp_processor_id())), >> >> Are we sure these can't generate check_preemption_disabled() warnings? >> Is there some reason why all these calls always occur with preemption >> disabled? > > Good catch. I don't think the code does. > > Now, I'm not sure if we should just add a raw_smp_processor_id(). The > idea is just to make sure that the CPU we are running on is online, > because it is possible to call theses trace points when the CPU is > going offline. If that happens, then there's a race with RCU. > > Since a task can not be migrated to an offline CPU, we don't need to > worry about the cpu_online(smp_processor_id()) returning a false > positive. A false negative would just skip a tracepoint, but I'm not > sure that is possible either. > > In any case, comments should also be added to why the condition is > there. > I'll send a patch adding the comments. Thanks, Shreyas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
