| Message ID | 20220919101520.534233547@infradead.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | cpuidle,rcu: Clean up the mess | expand |
On Mon, Sep 19, 2022 at 11:59:42AM +0200, Peter Zijlstra wrote: > cpuidle_state::enter() methods should be IRQ invariant Got a bit confused with the invariant thing since the first chunck I see in this patch is a conversion to an non-traceable local_irq_enable(). Maybe just add a short mention about that and why? Thanks. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/cpuidle/poll_state.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > --- a/drivers/cpuidle/poll_state.c > +++ b/drivers/cpuidle/poll_state.c > @@ -17,7 +17,7 @@ static int __cpuidle poll_idle(struct cp > > dev->poll_time_limit = false; > > - local_irq_enable(); > + raw_local_irq_enable(); > if (!current_set_polling_and_test()) { > unsigned int loop_count = 0; > u64 limit; > @@ -36,6 +36,8 @@ static int __cpuidle poll_idle(struct cp > } > } > } > + raw_local_irq_disable(); > + > current_clr_polling(); > > return index; > >
On Mon, Sep 19, 2022 at 03:19:27PM +0200, Frederic Weisbecker wrote: > On Mon, Sep 19, 2022 at 11:59:42AM +0200, Peter Zijlstra wrote: > > cpuidle_state::enter() methods should be IRQ invariant > > Got a bit confused with the invariant thing since the first chunck I > see in this patch is a conversion to an non-traceable local_irq_enable(). > > Maybe just add a short mention about that and why? Changelog now reads: --- Subject: cpuidle/poll: Ensure IRQ state is invariant From: Peter Zijlstra <peterz@infradead.org> Date: Tue May 31 15:43:32 CEST 2022 cpuidle_state::enter() methods should be IRQ invariant. Additionally make sure to use raw_local_irq_*() methods since this cpuidle callback will be called with RCU already disabled. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> ---
On Tue, Sep 20, 2022 at 10:57:00AM +0200, Peter Zijlstra wrote: > On Mon, Sep 19, 2022 at 03:19:27PM +0200, Frederic Weisbecker wrote: > > On Mon, Sep 19, 2022 at 11:59:42AM +0200, Peter Zijlstra wrote: > > > cpuidle_state::enter() methods should be IRQ invariant > > > > Got a bit confused with the invariant thing since the first chunck I > > see in this patch is a conversion to an non-traceable local_irq_enable(). > > > > Maybe just add a short mention about that and why? > > Changelog now reads: > > --- > Subject: cpuidle/poll: Ensure IRQ state is invariant > From: Peter Zijlstra <peterz@infradead.org> > Date: Tue May 31 15:43:32 CEST 2022 > > cpuidle_state::enter() methods should be IRQ invariant. > > Additionally make sure to use raw_local_irq_*() methods since this > cpuidle callback will be called with RCU already disabled. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Thanks!
--- a/drivers/cpuidle/poll_state.c +++ b/drivers/cpuidle/poll_state.c @@ -17,7 +17,7 @@ static int __cpuidle poll_idle(struct cp dev->poll_time_limit = false; - local_irq_enable(); + raw_local_irq_enable(); if (!current_set_polling_and_test()) { unsigned int loop_count = 0; u64 limit; @@ -36,6 +36,8 @@ static int __cpuidle poll_idle(struct cp } } } + raw_local_irq_disable(); + current_clr_polling(); return index;