diff mbox

[1/3] cpuidle: powerpc: cpuidle set polling before enabling irqs

Message ID 20170614130241.19865-2-npiggin@gmail.com (mailing list archive)
State Accepted
Commit 3fc5ee927ff4ffed6aa2fcd44d2fbf07ac893cdc
Headers show

Commit Message

Nicholas Piggin June 14, 2017, 1:02 p.m. UTC 
local_irq_enable can cause interrupts to be taken which could
take significant amount of processing time. The idle process
should set its polling flag before this, so another process that
wakes it during this time will not have to send an IPI.

Expand the TIF_POLLING_NRFLAG coverage to as large as possible.

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 drivers/cpuidle/cpuidle-powernv.c | 4 +++-
 drivers/cpuidle/cpuidle-pseries.c | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

Comments

Michael Ellerman June 29, 2017, 12:21 p.m. UTC | #1 
On Wed, 2017-06-14 at 13:02:39 UTC, Nicholas Piggin wrote:
> local_irq_enable can cause interrupts to be taken which could
> take significant amount of processing time. The idle process
> should set its polling flag before this, so another process that
> wakes it during this time will not have to send an IPI.
> 
> Expand the TIF_POLLING_NRFLAG coverage to as large as possible.
> 
> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/3fc5ee927ff4ffed6aa2fcd44d2fbf

cheers
Rafael J. Wysocki June 29, 2017, 8:38 p.m. UTC | #2 
On Thu, Jun 29, 2017 at 2:21 PM, Michael Ellerman
<patch-notifications@ellerman.id.au> wrote:
> On Wed, 2017-06-14 at 13:02:39 UTC, Nicholas Piggin wrote:
>> local_irq_enable can cause interrupts to be taken which could
>> take significant amount of processing time. The idle process
>> should set its polling flag before this, so another process that
>> wakes it during this time will not have to send an IPI.
>>
>> Expand the TIF_POLLING_NRFLAG coverage to as large as possible.
>>
>> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>
> Series applied to powerpc next, thanks.
>
> https://git.kernel.org/powerpc/c/3fc5ee927ff4ffed6aa2fcd44d2fbf

OK

I've applied it too, so I guess I should drop it?

Thanks,
Rafael
Michael Ellerman June 30, 2017, 3:45 a.m. UTC | #3 
"Rafael J. Wysocki" <rafael@kernel.org> writes:

> On Thu, Jun 29, 2017 at 2:21 PM, Michael Ellerman
> <patch-notifications@ellerman.id.au> wrote:
>> On Wed, 2017-06-14 at 13:02:39 UTC, Nicholas Piggin wrote:
>>> local_irq_enable can cause interrupts to be taken which could
>>> take significant amount of processing time. The idle process
>>> should set its polling flag before this, so another process that
>>> wakes it during this time will not have to send an IPI.
>>>
>>> Expand the TIF_POLLING_NRFLAG coverage to as large as possible.
>>>
>>> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
>>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>>
>> Series applied to powerpc next, thanks.
>>
>> https://git.kernel.org/powerpc/c/3fc5ee927ff4ffed6aa2fcd44d2fbf
>
> OK
>
> I've applied it too, so I guess I should drop it?

Erk sorry. I hadn't heard anything so I picked it up.

If you can drop it that would be good, but if not git will probably work
it out mostly :)

cheers
Rafael J. Wysocki June 30, 2017, 12:51 p.m. UTC | #4 
On Fri, Jun 30, 2017 at 5:45 AM, Michael Ellerman <mpe@ellerman.id.au> wrote:
> "Rafael J. Wysocki" <rafael@kernel.org> writes:
>
>> On Thu, Jun 29, 2017 at 2:21 PM, Michael Ellerman
>> <patch-notifications@ellerman.id.au> wrote:
>>> On Wed, 2017-06-14 at 13:02:39 UTC, Nicholas Piggin wrote:
>>>> local_irq_enable can cause interrupts to be taken which could
>>>> take significant amount of processing time. The idle process
>>>> should set its polling flag before this, so another process that
>>>> wakes it during this time will not have to send an IPI.
>>>>
>>>> Expand the TIF_POLLING_NRFLAG coverage to as large as possible.
>>>>
>>>> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
>>>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>>>
>>> Series applied to powerpc next, thanks.
>>>
>>> https://git.kernel.org/powerpc/c/3fc5ee927ff4ffed6aa2fcd44d2fbf
>>
>> OK
>>
>> I've applied it too, so I guess I should drop it?
>
> Erk sorry. I hadn't heard anything so I picked it up.
>
> If you can drop it that would be good, but if not git will probably work
> it out mostly :)

I've dropped it, no problem.

Thanks,
Rafael
Michael Ellerman July 4, 2017, 2:59 a.m. UTC | #5 
"Rafael J. Wysocki" <rafael@kernel.org> writes:

> On Fri, Jun 30, 2017 at 5:45 AM, Michael Ellerman <mpe@ellerman.id.au> wrote:
>> "Rafael J. Wysocki" <rafael@kernel.org> writes:
>>
>>> On Thu, Jun 29, 2017 at 2:21 PM, Michael Ellerman
>>> <patch-notifications@ellerman.id.au> wrote:
>>>> On Wed, 2017-06-14 at 13:02:39 UTC, Nicholas Piggin wrote:
>>>>> local_irq_enable can cause interrupts to be taken which could
>>>>> take significant amount of processing time. The idle process
>>>>> should set its polling flag before this, so another process that
>>>>> wakes it during this time will not have to send an IPI.
>>>>>
>>>>> Expand the TIF_POLLING_NRFLAG coverage to as large as possible.
>>>>>
>>>>> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
>>>>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>>>>
>>>> Series applied to powerpc next, thanks.
>>>>
>>>> https://git.kernel.org/powerpc/c/3fc5ee927ff4ffed6aa2fcd44d2fbf
>>>
>>> OK
>>>
>>> I've applied it too, so I guess I should drop it?
>>
>> Erk sorry. I hadn't heard anything so I picked it up.
>>
>> If you can drop it that would be good, but if not git will probably work
>> it out mostly :)
>
> I've dropped it, no problem.

Thanks.

cheers
diff mbox

Patch

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 45eaf06462ae..77bc50ad9f57 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -51,9 +51,10 @@  static int snooze_loop(struct cpuidle_device *dev,
 {
 	u64 snooze_exit_time;
 
-	local_irq_enable();
 	set_thread_flag(TIF_POLLING_NRFLAG);
 
+	local_irq_enable();
+
 	snooze_exit_time = get_tb() + snooze_timeout;
 	ppc64_runlatch_off();
 	HMT_very_low();
@@ -66,6 +67,7 @@  static int snooze_loop(struct cpuidle_device *dev,
 	ppc64_runlatch_on();
 	clear_thread_flag(TIF_POLLING_NRFLAG);
 	smp_mb();
+
 	return index;
 }
 
diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c
index 166ccd711ec9..7b12bb2ea70f 100644
--- a/drivers/cpuidle/cpuidle-pseries.c
+++ b/drivers/cpuidle/cpuidle-pseries.c
@@ -62,9 +62,10 @@  static int snooze_loop(struct cpuidle_device *dev,
 	unsigned long in_purr;
 	u64 snooze_exit_time;
 
+	set_thread_flag(TIF_POLLING_NRFLAG);
+
 	idle_loop_prolog(&in_purr);
 	local_irq_enable();
-	set_thread_flag(TIF_POLLING_NRFLAG);
 	snooze_exit_time = get_tb() + snooze_timeout;
 
 	while (!need_resched()) {