TIF_NOHZ can escape nonhz mask? (Was: [PATCH v3 6/8] x86: Split syscall_trace_enter into two phases)
From: Frederic Weisbecker <hidden>
Date: 2014-07-31 18:50:35
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linux-arch, linux-mips, lkml
2014-07-31 20:47 GMT+02:00 Frederic Weisbecker [off-list ref]:
On Thu, Jul 31, 2014 at 08:12:30PM +0200, Oleg Nesterov wrote:quoted
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 :)