TIF_NOHZ can escape nonhz mask? (Was: [PATCH v3 6/8] x86: Split syscall_trace_enter into two phases)

[Frederic Weisbecker]

2014-07-31 20:47 GMT+02:00 Frederic Weisbecker <fweisbec at gmail.com>:
> On Thu, Jul 31, 2014 at 08:12:30PM +0200, Oleg Nesterov wrote:
>> On 07/31, Frederic Weisbecker wrote:
> No, because preempt_schedule_irq() does the ctx_state save and restore with
> exception_enter/exception_exit.

Similar thing happens with schedule_user().

preempt_schedule_irq() handles kernel preemption and schedule_user()
the user preemption. On both cases we save and restore the context
tracking state.

This might be the missing piece you were missing :)