[RFC,1/4] acpi: Use CPUIDLE_FLAG_TIMER_STOP

Message ID 20200915103806.280265587@infradead.org
State New
Headers show
Series
  • [RFC,1/4] acpi: Use CPUIDLE_FLAG_TIMER_STOP
Related show

Commit Message

Peter Zijlstra Sept. 15, 2020, 10:31 a.m.
Make acpi_processor_idle use the common broadcast code, there's no
reason not to. This also removes some RCU usage after
rcu_idle_enter().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 drivers/acpi/processor_idle.c |   49 +++++++++++++-----------------------------
 1 file changed, 16 insertions(+), 33 deletions(-)

Comments

Rafael J. Wysocki Sept. 15, 2020, 4:26 p.m. | #1
On Tue, Sep 15, 2020 at 12:44 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> Make acpi_processor_idle use the common broadcast code, there's no
> reason not to. This also removes some RCU usage after
> rcu_idle_enter().
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

The whole series looks good to me, so please feel free to add

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

to all of the four patches.

Alternatively, please let me know if you want me to take the patches.

> ---
>  drivers/acpi/processor_idle.c |   49 +++++++++++++-----------------------------
>  1 file changed, 16 insertions(+), 33 deletions(-)
>
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -161,18 +161,10 @@ static void lapic_timer_propagate_broadc
>  }
>
>  /* Power(C) State timer broadcast control */
> -static void lapic_timer_state_broadcast(struct acpi_processor *pr,
> -                                      struct acpi_processor_cx *cx,
> -                                      int broadcast)
> -{
> -       int state = cx - pr->power.states;
> -
> -       if (state >= pr->power.timer_broadcast_on_state) {
> -               if (broadcast)
> -                       tick_broadcast_enter();
> -               else
> -                       tick_broadcast_exit();
> -       }
> +static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
> +                                       struct acpi_processor_cx *cx)
> +{
> +       return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
>  }
>
>  #else
> @@ -180,9 +172,9 @@ static void lapic_timer_state_broadcast(
>  static void lapic_timer_check_state(int state, struct acpi_processor *pr,
>                                    struct acpi_processor_cx *cstate) { }
>  static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
> -static void lapic_timer_state_broadcast(struct acpi_processor *pr,
> -                                      struct acpi_processor_cx *cx,
> -                                      int broadcast)
> +
> +static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
> +                                       struct acpi_processor_cx *cx)
>  {
>  }
>
> @@ -568,21 +560,13 @@ static DEFINE_RAW_SPINLOCK(c3_lock);
>   * acpi_idle_enter_bm - enters C3 with proper BM handling
>   * @pr: Target processor
>   * @cx: Target state context
> - * @timer_bc: Whether or not to change timer mode to broadcast
>   */
>  static void acpi_idle_enter_bm(struct acpi_processor *pr,
> -                              struct acpi_processor_cx *cx, bool timer_bc)
> +                              struct acpi_processor_cx *cx)
>  {
>         acpi_unlazy_tlb(smp_processor_id());
>
>         /*
> -        * Must be done before busmaster disable as we might need to
> -        * access HPET !
> -        */
> -       if (timer_bc)
> -               lapic_timer_state_broadcast(pr, cx, 1);
> -
> -       /*
>          * disable bus master
>          * bm_check implies we need ARB_DIS
>          * bm_control implies whether we can do ARB_DIS
> @@ -609,9 +593,6 @@ static void acpi_idle_enter_bm(struct ac
>                 c3_cpu_count--;
>                 raw_spin_unlock(&c3_lock);
>         }
> -
> -       if (timer_bc)
> -               lapic_timer_state_broadcast(pr, cx, 0);
>  }
>
>  static int acpi_idle_enter(struct cpuidle_device *dev,
> @@ -630,7 +611,7 @@ static int acpi_idle_enter(struct cpuidl
>                         cx = per_cpu(acpi_cstate[index], dev->cpu);
>                 } else if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check) {
>                         if (cx->bm_sts_skip || !acpi_idle_bm_check()) {
> -                               acpi_idle_enter_bm(pr, cx, true);
> +                               acpi_idle_enter_bm(pr, cx);
>                                 return index;
>                         } else if (drv->safe_state_index >= 0) {
>                                 index = drv->safe_state_index;
> @@ -642,15 +623,11 @@ static int acpi_idle_enter(struct cpuidl
>                 }
>         }
>
> -       lapic_timer_state_broadcast(pr, cx, 1);
> -
>         if (cx->type == ACPI_STATE_C3)
>                 ACPI_FLUSH_CPU_CACHE();
>
>         acpi_idle_do_entry(cx);
>
> -       lapic_timer_state_broadcast(pr, cx, 0);
> -
>         return index;
>  }
>
> @@ -666,7 +643,7 @@ static int acpi_idle_enter_s2idle(struct
>                         return 0;
>
>                 if (pr->flags.bm_check) {
> -                       acpi_idle_enter_bm(pr, cx, false);
> +                       acpi_idle_enter_bm(pr, cx);
>                         return 0;
>                 } else {
>                         ACPI_FLUSH_CPU_CACHE();
> @@ -682,6 +659,7 @@ static int acpi_processor_setup_cpuidle_
>  {
>         int i, count = ACPI_IDLE_STATE_START;
>         struct acpi_processor_cx *cx;
> +       struct cpuidle_state *state;
>
>         if (max_cstate == 0)
>                 max_cstate = 1;
> @@ -694,6 +672,11 @@ static int acpi_processor_setup_cpuidle_
>
>                 per_cpu(acpi_cstate[count], dev->cpu) = cx;
>
> +               if (lapic_timer_needs_broadcast(pr, cx)) {
> +                       state = &acpi_idle_driver.states[count];
> +                       state->flags |= CPUIDLE_FLAG_TIMER_STOP;
> +               }
> +
>                 count++;
>                 if (count == CPUIDLE_STATE_MAX)
>                         break;
>
>
Borislav Petkov Sept. 16, 2020, 4:01 p.m. | #2
On Wed, Sep 16, 2020 at 05:42:12PM +0200, peterz@infradead.org wrote:
> On Tue, Sep 15, 2020 at 06:26:52PM +0200, Rafael J. Wysocki wrote:
> > On Tue, Sep 15, 2020 at 12:44 PM Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > > Make acpi_processor_idle use the common broadcast code, there's no
> > > reason not to. This also removes some RCU usage after
> > > rcu_idle_enter().
> > >
> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > 
> > The whole series looks good to me, so please feel free to add
> > 
> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > 
> > to all of the four patches.
> > 
> > Alternatively, please let me know if you want me to take the patches.
> 
> Feel free to take them. All the prerequisite borkage is in linus' tree
> already.

You can add:

Reported-by: Borislav Petkov <bp@suse.de>

for this one and for this whole series:

Tested-by: Borislav Petkov <bp@suse.de>

Thx.
Rafael J. Wysocki Sept. 16, 2020, 5:38 p.m. | #3
On Wed, Sep 16, 2020 at 5:42 PM <peterz@infradead.org> wrote:
>
> On Tue, Sep 15, 2020 at 06:26:52PM +0200, Rafael J. Wysocki wrote:
> > On Tue, Sep 15, 2020 at 12:44 PM Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > > Make acpi_processor_idle use the common broadcast code, there's no
> > > reason not to. This also removes some RCU usage after
> > > rcu_idle_enter().
> > >
> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> >
> > The whole series looks good to me, so please feel free to add
> >
> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > to all of the four patches.
> >
> > Alternatively, please let me know if you want me to take the patches.
>
> Feel free to take them. All the prerequisite borkage is in linus' tree
> already.

OK

All applied (with some minor edits in the subjects) for 5.9-rc6.

Thanks!
Guenter Roeck Sept. 22, 2020, 3:26 a.m. | #4
On Tue, Sep 15, 2020 at 12:31:58PM +0200, Peter Zijlstra wrote:
> Make acpi_processor_idle use the common broadcast code, there's no

> reason not to. This also removes some RCU usage after

> rcu_idle_enter().

> 

> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> Reported-by: Borislav Petkov <bp@suse.de>

> Tested-by: Borislav Petkov <bp@suse.de>

> ---

>  drivers/acpi/processor_idle.c |   49 +++++++++++++-----------------------------

>  1 file changed, 16 insertions(+), 33 deletions(-)

> 

> --- a/drivers/acpi/processor_idle.c

> +++ b/drivers/acpi/processor_idle.c

> @@ -161,18 +161,10 @@ static void lapic_timer_propagate_broadc

>  }

>  

>  /* Power(C) State timer broadcast control */

> -static void lapic_timer_state_broadcast(struct acpi_processor *pr,

> -				       struct acpi_processor_cx *cx,

> -				       int broadcast)

> -{

> -	int state = cx - pr->power.states;

> -

> -	if (state >= pr->power.timer_broadcast_on_state) {

> -		if (broadcast)

> -			tick_broadcast_enter();

> -		else

> -			tick_broadcast_exit();

> -	}

> +static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,

> +					struct acpi_processor_cx *cx)

> +{

> +	return cx - pr->power.states >= pr->power.timer_broadcast_on_state;

>  }

>  

>  #else

> @@ -180,9 +172,9 @@ static void lapic_timer_state_broadcast(

>  static void lapic_timer_check_state(int state, struct acpi_processor *pr,

>  				   struct acpi_processor_cx *cstate) { }

>  static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }

> -static void lapic_timer_state_broadcast(struct acpi_processor *pr,

> -				       struct acpi_processor_cx *cx,

> -				       int broadcast)

> +

> +static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,

> +					struct acpi_processor_cx *cx)

>  {

>  }


drivers/acpi/processor_idle.c: In function 'lapic_timer_needs_broadcast':
drivers/acpi/processor_idle.c:179:1: warning: no return statement in function returning non-void [-Wreturn-type]

Should this return true or false ?

Guenter

>  

> @@ -568,21 +560,13 @@ static DEFINE_RAW_SPINLOCK(c3_lock);

>   * acpi_idle_enter_bm - enters C3 with proper BM handling

>   * @pr: Target processor

>   * @cx: Target state context

> - * @timer_bc: Whether or not to change timer mode to broadcast

>   */

>  static void acpi_idle_enter_bm(struct acpi_processor *pr,

> -			       struct acpi_processor_cx *cx, bool timer_bc)

> +			       struct acpi_processor_cx *cx)

>  {

>  	acpi_unlazy_tlb(smp_processor_id());

>  

>  	/*

> -	 * Must be done before busmaster disable as we might need to

> -	 * access HPET !

> -	 */

> -	if (timer_bc)

> -		lapic_timer_state_broadcast(pr, cx, 1);

> -

> -	/*

>  	 * disable bus master

>  	 * bm_check implies we need ARB_DIS

>  	 * bm_control implies whether we can do ARB_DIS

> @@ -609,9 +593,6 @@ static void acpi_idle_enter_bm(struct ac

>  		c3_cpu_count--;

>  		raw_spin_unlock(&c3_lock);

>  	}

> -

> -	if (timer_bc)

> -		lapic_timer_state_broadcast(pr, cx, 0);

>  }

>  

>  static int acpi_idle_enter(struct cpuidle_device *dev,

> @@ -630,7 +611,7 @@ static int acpi_idle_enter(struct cpuidl

>  			cx = per_cpu(acpi_cstate[index], dev->cpu);

>  		} else if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check) {

>  			if (cx->bm_sts_skip || !acpi_idle_bm_check()) {

> -				acpi_idle_enter_bm(pr, cx, true);

> +				acpi_idle_enter_bm(pr, cx);

>  				return index;

>  			} else if (drv->safe_state_index >= 0) {

>  				index = drv->safe_state_index;

> @@ -642,15 +623,11 @@ static int acpi_idle_enter(struct cpuidl

>  		}

>  	}

>  

> -	lapic_timer_state_broadcast(pr, cx, 1);

> -

>  	if (cx->type == ACPI_STATE_C3)

>  		ACPI_FLUSH_CPU_CACHE();

>  

>  	acpi_idle_do_entry(cx);

>  

> -	lapic_timer_state_broadcast(pr, cx, 0);

> -

>  	return index;

>  }

>  

> @@ -666,7 +643,7 @@ static int acpi_idle_enter_s2idle(struct

>  			return 0;

>  

>  		if (pr->flags.bm_check) {

> -			acpi_idle_enter_bm(pr, cx, false);

> +			acpi_idle_enter_bm(pr, cx);

>  			return 0;

>  		} else {

>  			ACPI_FLUSH_CPU_CACHE();

> @@ -682,6 +659,7 @@ static int acpi_processor_setup_cpuidle_

>  {

>  	int i, count = ACPI_IDLE_STATE_START;

>  	struct acpi_processor_cx *cx;

> +	struct cpuidle_state *state;

>  

>  	if (max_cstate == 0)

>  		max_cstate = 1;

> @@ -694,6 +672,11 @@ static int acpi_processor_setup_cpuidle_

>  

>  		per_cpu(acpi_cstate[count], dev->cpu) = cx;

>  

> +		if (lapic_timer_needs_broadcast(pr, cx)) {

> +			state = &acpi_idle_driver.states[count];

> +			state->flags |= CPUIDLE_FLAG_TIMER_STOP;

> +		}

> +

>  		count++;

>  		if (count == CPUIDLE_STATE_MAX)

>  			break;
Rafael J. Wysocki Sept. 22, 2020, 7:03 p.m. | #5
On Tuesday, September 22, 2020 5:26:51 AM CEST Guenter Roeck wrote:
> On Tue, Sep 15, 2020 at 12:31:58PM +0200, Peter Zijlstra wrote:
> > Make acpi_processor_idle use the common broadcast code, there's no
> > reason not to. This also removes some RCU usage after
> > rcu_idle_enter().
> > 
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Reported-by: Borislav Petkov <bp@suse.de>
> > Tested-by: Borislav Petkov <bp@suse.de>
> > ---
> >  drivers/acpi/processor_idle.c |   49 +++++++++++++-----------------------------
> >  1 file changed, 16 insertions(+), 33 deletions(-)
> > 
> > --- a/drivers/acpi/processor_idle.c
> > +++ b/drivers/acpi/processor_idle.c
> > @@ -161,18 +161,10 @@ static void lapic_timer_propagate_broadc
> >  }
> >  
> >  /* Power(C) State timer broadcast control */
> > -static void lapic_timer_state_broadcast(struct acpi_processor *pr,
> > -				       struct acpi_processor_cx *cx,
> > -				       int broadcast)
> > -{
> > -	int state = cx - pr->power.states;
> > -
> > -	if (state >= pr->power.timer_broadcast_on_state) {
> > -		if (broadcast)
> > -			tick_broadcast_enter();
> > -		else
> > -			tick_broadcast_exit();
> > -	}
> > +static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
> > +					struct acpi_processor_cx *cx)
> > +{
> > +	return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
> >  }
> >  
> >  #else
> > @@ -180,9 +172,9 @@ static void lapic_timer_state_broadcast(
> >  static void lapic_timer_check_state(int state, struct acpi_processor *pr,
> >  				   struct acpi_processor_cx *cstate) { }
> >  static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
> > -static void lapic_timer_state_broadcast(struct acpi_processor *pr,
> > -				       struct acpi_processor_cx *cx,
> > -				       int broadcast)
> > +
> > +static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
> > +					struct acpi_processor_cx *cx)
> >  {
> >  }
> 
> drivers/acpi/processor_idle.c: In function 'lapic_timer_needs_broadcast':
> drivers/acpi/processor_idle.c:179:1: warning: no return statement in function returning non-void [-Wreturn-type]
> 
> Should this return true or false ?

false - if the lapic timer doesn't stop, it doesn't need broadcast.

FWIW, patch appended.

Cheers!

---
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Subject: [PATCH] ACPI: processor: Fix build for ARCH_APICTIMER_STOPS_ON_C3 unset

Fix the lapic_timer_needs_broadcast() stub for
ARCH_APICTIMER_STOPS_ON_C3 unset to actually return
a value.

Fixes: aa6b43d57f99 ("ACPI: processor: Use CPUIDLE_FLAG_TIMER_STOP")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/processor_idle.c |    1 +
 1 file changed, 1 insertion(+)

Index: linux-pm/drivers/acpi/processor_idle.c
===================================================================
--- linux-pm.orig/drivers/acpi/processor_idle.c
+++ linux-pm/drivers/acpi/processor_idle.c
@@ -176,6 +176,7 @@ static void lapic_timer_propagate_broadc
 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 					struct acpi_processor_cx *cx)
 {
+	return false;
 }
 
 #endif

Patch

--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -161,18 +161,10 @@  static void lapic_timer_propagate_broadc
 }
 
 /* Power(C) State timer broadcast control */
-static void lapic_timer_state_broadcast(struct acpi_processor *pr,
-				       struct acpi_processor_cx *cx,
-				       int broadcast)
-{
-	int state = cx - pr->power.states;
-
-	if (state >= pr->power.timer_broadcast_on_state) {
-		if (broadcast)
-			tick_broadcast_enter();
-		else
-			tick_broadcast_exit();
-	}
+static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
+					struct acpi_processor_cx *cx)
+{
+	return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
 }
 
 #else
@@ -180,9 +172,9 @@  static void lapic_timer_state_broadcast(
 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 				   struct acpi_processor_cx *cstate) { }
 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
-static void lapic_timer_state_broadcast(struct acpi_processor *pr,
-				       struct acpi_processor_cx *cx,
-				       int broadcast)
+
+static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
+					struct acpi_processor_cx *cx)
 {
 }
 
@@ -568,21 +560,13 @@  static DEFINE_RAW_SPINLOCK(c3_lock);
  * acpi_idle_enter_bm - enters C3 with proper BM handling
  * @pr: Target processor
  * @cx: Target state context
- * @timer_bc: Whether or not to change timer mode to broadcast
  */
 static void acpi_idle_enter_bm(struct acpi_processor *pr,
-			       struct acpi_processor_cx *cx, bool timer_bc)
+			       struct acpi_processor_cx *cx)
 {
 	acpi_unlazy_tlb(smp_processor_id());
 
 	/*
-	 * Must be done before busmaster disable as we might need to
-	 * access HPET !
-	 */
-	if (timer_bc)
-		lapic_timer_state_broadcast(pr, cx, 1);
-
-	/*
 	 * disable bus master
 	 * bm_check implies we need ARB_DIS
 	 * bm_control implies whether we can do ARB_DIS
@@ -609,9 +593,6 @@  static void acpi_idle_enter_bm(struct ac
 		c3_cpu_count--;
 		raw_spin_unlock(&c3_lock);
 	}
-
-	if (timer_bc)
-		lapic_timer_state_broadcast(pr, cx, 0);
 }
 
 static int acpi_idle_enter(struct cpuidle_device *dev,
@@ -630,7 +611,7 @@  static int acpi_idle_enter(struct cpuidl
 			cx = per_cpu(acpi_cstate[index], dev->cpu);
 		} else if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check) {
 			if (cx->bm_sts_skip || !acpi_idle_bm_check()) {
-				acpi_idle_enter_bm(pr, cx, true);
+				acpi_idle_enter_bm(pr, cx);
 				return index;
 			} else if (drv->safe_state_index >= 0) {
 				index = drv->safe_state_index;
@@ -642,15 +623,11 @@  static int acpi_idle_enter(struct cpuidl
 		}
 	}
 
-	lapic_timer_state_broadcast(pr, cx, 1);
-
 	if (cx->type == ACPI_STATE_C3)
 		ACPI_FLUSH_CPU_CACHE();
 
 	acpi_idle_do_entry(cx);
 
-	lapic_timer_state_broadcast(pr, cx, 0);
-
 	return index;
 }
 
@@ -666,7 +643,7 @@  static int acpi_idle_enter_s2idle(struct
 			return 0;
 
 		if (pr->flags.bm_check) {
-			acpi_idle_enter_bm(pr, cx, false);
+			acpi_idle_enter_bm(pr, cx);
 			return 0;
 		} else {
 			ACPI_FLUSH_CPU_CACHE();
@@ -682,6 +659,7 @@  static int acpi_processor_setup_cpuidle_
 {
 	int i, count = ACPI_IDLE_STATE_START;
 	struct acpi_processor_cx *cx;
+	struct cpuidle_state *state;
 
 	if (max_cstate == 0)
 		max_cstate = 1;
@@ -694,6 +672,11 @@  static int acpi_processor_setup_cpuidle_
 
 		per_cpu(acpi_cstate[count], dev->cpu) = cx;
 
+		if (lapic_timer_needs_broadcast(pr, cx)) {
+			state = &acpi_idle_driver.states[count];
+			state->flags |= CPUIDLE_FLAG_TIMER_STOP;
+		}
+
 		count++;
 		if (count == CPUIDLE_STATE_MAX)
 			break;