On Sat, Nov 3, 2012 at 6:09 PM, Frederic Weisbecker <fweis...@gmail.com> wrote: > Create a new subsystem that probes on kernel boundaries > to keep track of the transitions between level contexts > with two basic initial contexts: user or kernel. > > This is an abstraction of some RCU code that use such tracking > to implement its userspace extended quiescent state. > > We need to pull this up from RCU into this new level of indirection > because this tracking is also going to be used to implement an "on > demand" generic virtual cputime accounting. A necessary step to > shutdown the tick while still accounting the cputime. > ... > > diff --git a/arch/Kconfig b/arch/Kconfig > index 366ec06..3855e06 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -300,15 +300,15 @@ config SECCOMP_FILTER > > See Documentation/prctl/seccomp_filter.txt for details. > > -config HAVE_RCU_USER_QS > +config HAVE_CONTEXT_TRACKING > bool > help > - Provide kernel entry/exit hooks necessary for userspace > + Provide kernel/user boundaries probes necessary for userspace > RCU extended quiescent state. Syscalls need to be wrapped inside
A minor nit pick: if whole point of the patch is to turn an RCU specific mechanism to a generic one that RCU happens to use, then the text needs to reflect that. How about: "Provide kernel/user boundaries probes necessary for subsystems that need it, such as userspace RCU extended quiescent state. " > - rcu_user_exit()-rcu_user_enter() through the slow path using > - TIF_NOHZ flag. Exceptions handlers must be wrapped as well. Irqs > - are already protected inside rcu_irq_enter/rcu_irq_exit() but > - preemption or signal handling on irq exit still need to be > protected. > + user_exit()-user_enter() through the slow path using TIF_NOHZ flag. > + Exceptions handlers must be wrapped as well. Irqs are already > + protected inside rcu_irq_enter/rcu_irq_exit() but preemption or > + signal handling on irq exit still need to be protected. > Thanks, Gilad -- Gilad Ben-Yossef Chief Coffee Drinker gi...@benyossef.com Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com "If you take a class in large-scale robotics, can you end up in a situation where the homework eats your dog?" -- Jean-Baptiste Queru -- 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/
