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cpuidle: powerpc: cpuidle set polling before enabling irqs 

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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2017-06-14 23:02:39 +10:00 committed by Michael Ellerman
parent 68fa6478e3
commit 3fc5ee927f
2 changed files with 5 additions and 2 deletions
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4
drivers/cpuidle/cpuidle-powernv.c
View File

@ -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;
}

3
drivers/cpuidle/cpuidle-pseries.c
View File

@ -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()) {