Re: [v3, 1/5] rfi-flush: Move the logic to avoid a redo into the debugfs code

[Michael Ellerman]

On Wed, 2018-03-14 at 22:40:38 UTC, Mauricio Faria de Oliveira wrote:
> From: Michael Ellerman 
> 
> rfi_flush_enable() includes a check to see if we're already
> enabled (or disabled), and in that case does nothing.
> 
> But that means calling setup_rfi_flush() a 2nd time doesn't actually
> work, which is a bit confusing.
> 
> Move that check into the debugfs code, where it really belongs.
> 
> Signed-off-by: Michael Ellerman 
> Signed-off-by: Mauricio Faria de Oliveira 

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/1e2a9fc7496955faacbbed49461d61

cheers

Re: [PATCH v3 1/5] rfi-flush: Move the logic to avoid a redo into the debugfs code

[Mauricio Faria de Oliveira]

Hi Murilo and Michal,

On 03/16/2018 05:52 AM, Michal Suchánek wrote:

Do we need to take into account if no_rfi_flush == true?



I think it makes sense you are able to override that using debugfs.

It's interface used for diagnostics and testing.

If this was in sysfs it would be a different story.


Yes, I agree. The debugfs is way to override the cmdline option.

Thanks for looking carefully at this :)

cheers,
Mauricio

Re: [PATCH v3 1/5] rfi-flush: Move the logic to avoid a redo into the debugfs code

[Michal Suchánek]

On Thu, 15 Mar 2018 17:36:00 -0300
Murilo Opsfelder Araujo  wrote:

> On 03/14/2018 07:40 PM, Mauricio Faria de Oliveira wrote:
> > From: Michael Ellerman 
> > 
> > rfi_flush_enable() includes a check to see if we're already
> > enabled (or disabled), and in that case does nothing.
> > 
> > But that means calling setup_rfi_flush() a 2nd time doesn't actually
> > work, which is a bit confusing.
> > 
> > Move that check into the debugfs code, where it really belongs.
> > 
> > Signed-off-by: Michael Ellerman 
> > Signed-off-by: Mauricio Faria de Oliveira
> >  ---
> >  arch/powerpc/kernel/setup_64.c | 13 -
> >  1 file changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/powerpc/kernel/setup_64.c
> > b/arch/powerpc/kernel/setup_64.c index c388cc3..3efc01a 100644
> > --- a/arch/powerpc/kernel/setup_64.c
> > +++ b/arch/powerpc/kernel/setup_64.c
> > @@ -846,9 +846,6 @@ static void do_nothing(void *unused)
> > 
> >  void rfi_flush_enable(bool enable)
> >  {
> > -   if (rfi_flush == enable)
> > -   return;
> > -
> > if (enable) {
> > do_rfi_flush_fixups(enabled_flush_types);
> > on_each_cpu(do_nothing, NULL, 1);
> > @@ -902,13 +899,19 @@ void __init setup_rfi_flush(enum
> > l1d_flush_type types, bool enable) #ifdef CONFIG_DEBUG_FS
> >  static int rfi_flush_set(void *data, u64 val)
> >  {
> > +   bool enable;
> > +
> > if (val == 1)
> > -   rfi_flush_enable(true);
> > +   enable = true;
> > else if (val == 0)
> > -   rfi_flush_enable(false);
> > +   enable = false;
> > else
> > return -EINVAL;
> > 
> > +   /* Only do anything if we're changing state */
> > +   if (enable != rfi_flush)  
> 
> Hi, Mauricio.
> 
> Do we need to take into account if no_rfi_flush == true?

I think it makes sense you are able to override that using debugfs.

It's interface used for diagnostics and testing.

If this was in sysfs it would be a different story.

Thanks

Michal

Re: [PATCH v3 1/5] rfi-flush: Move the logic to avoid a redo into the debugfs code

[Murilo Opsfelder Araujo]

On 03/14/2018 07:40 PM, Mauricio Faria de Oliveira wrote:
> From: Michael Ellerman 
> 
> rfi_flush_enable() includes a check to see if we're already
> enabled (or disabled), and in that case does nothing.
> 
> But that means calling setup_rfi_flush() a 2nd time doesn't actually
> work, which is a bit confusing.
> 
> Move that check into the debugfs code, where it really belongs.
> 
> Signed-off-by: Michael Ellerman 
> Signed-off-by: Mauricio Faria de Oliveira 
> ---
>  arch/powerpc/kernel/setup_64.c | 13 -
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index c388cc3..3efc01a 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -846,9 +846,6 @@ static void do_nothing(void *unused)
> 
>  void rfi_flush_enable(bool enable)
>  {
> - if (rfi_flush == enable)
> - return;
> -
>   if (enable) {
>   do_rfi_flush_fixups(enabled_flush_types);
>   on_each_cpu(do_nothing, NULL, 1);
> @@ -902,13 +899,19 @@ void __init setup_rfi_flush(enum l1d_flush_type types, 
> bool enable)
>  #ifdef CONFIG_DEBUG_FS
>  static int rfi_flush_set(void *data, u64 val)
>  {
> + bool enable;
> +
>   if (val == 1)
> - rfi_flush_enable(true);
> + enable = true;
>   else if (val == 0)
> - rfi_flush_enable(false);
> + enable = false;
>   else
>   return -EINVAL;
> 
> + /* Only do anything if we're changing state */
> + if (enable != rfi_flush)

Hi, Mauricio.

Do we need to take into account if no_rfi_flush == true?

if ((enable != rfi_flush) && !no_rfi_flush)

> + rfi_flush_enable(enable);
> +
>   return 0;
>  }
> 

Cheers
Murilo

[PATCH v3 1/5] rfi-flush: Move the logic to avoid a redo into the debugfs code

[Mauricio Faria de Oliveira]

From: Michael Ellerman 

rfi_flush_enable() includes a check to see if we're already
enabled (or disabled), and in that case does nothing.

But that means calling setup_rfi_flush() a 2nd time doesn't actually
work, which is a bit confusing.

Move that check into the debugfs code, where it really belongs.

Signed-off-by: Michael Ellerman 
Signed-off-by: Mauricio Faria de Oliveira 
---
 arch/powerpc/kernel/setup_64.c | 13 -
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index c388cc3..3efc01a 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -846,9 +846,6 @@ static void do_nothing(void *unused)
 
 void rfi_flush_enable(bool enable)
 {
-   if (rfi_flush == enable)
-   return;
-
if (enable) {
do_rfi_flush_fixups(enabled_flush_types);
on_each_cpu(do_nothing, NULL, 1);
@@ -902,13 +899,19 @@ void __init setup_rfi_flush(enum l1d_flush_type types, 
bool enable)
 #ifdef CONFIG_DEBUG_FS
 static int rfi_flush_set(void *data, u64 val)
 {
+   bool enable;
+
if (val == 1)
-   rfi_flush_enable(true);
+   enable = true;
else if (val == 0)
-   rfi_flush_enable(false);
+   enable = false;
else
return -EINVAL;
 
+   /* Only do anything if we're changing state */
+   if (enable != rfi_flush)
+   rfi_flush_enable(enable);
+
return 0;
 }
 
-- 
2.7.4