From 3fc5ee927ff4ffed6aa2fcd44d2fbf07ac893cdc Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Wed, 14 Jun 2017 23:02:39 +1000
Subject: [PATCH] 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>
---
drivers/cpuidle/cpuidle-powernv.c | 4 +++-
drivers/cpuidle/cpuidle-pseries.c | 3 ++-
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 79152676f62b2..50b3c2e0306f9 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 166ccd711ec97..7b12bb2ea70f5 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()) {
--
GitLab