Messages in this thread | | | Date | Tue, 3 Sep 2013 16:45:45 +0200 | Subject | Re: [gcv v3 06/35] scheduler: Replace __get_cpu_var uses | From | Frederic Weisbecker <> |
| |
2013/9/3 Christoph Lameter <cl@linux.com>: > On Thu, 29 Aug 2013, Steven Rostedt wrote: > >> How many places use the this_cpu_*() without preemption disabled? I >> wouldn't think there's many. I never complained about another variant, >> so you need to ask those that have. The tough question for me is what >> that variant name should be ;-) > > Tried to add preemption checks but the basic issue is that many of the > checks themselves use this_cpu_ops. percpu.h is very basic to the > operation of fundamental primitives for preempt etc. Use of a BUG_ON needs > a seris of includes in percpu.h that cause more trouble. > > If I switch __this_cpu ops to check for preemption then the logic for > preemption etc must use the raw_this_cpu ops.
IIUC the issue is that preempt debug checks themselves use per cpu operations that can result in preempt debug checks? Hence a recursion. Do you have an example of that?
Also in this case this must be fixed anyway given the checks that already exist in smp_processor_id(), __get_cpu_var(), ...
| |