[PATCH v2 2/4] cpuidle-haltpoll: set haltpoll as preferred governor

From: Joao Martins
Date: Tue Sep 03 2019 - 09:25:13 EST


Right now, guest current governors have the following ratings:

* ladder -> 10
* teo -> 19
* menu -> 20
* haltpoll -> 21
* ladder + nohz=off -> 25

haltpoll governor got introduced and it is now the default governor given
its highest rating -- with ladder+nohz being the exception -- regardless of
idle driver in the guest. An example of an undesirable case is x86 KVM
guests with MWAIT which have intel_idle registered first, and consequently
will have haltpoll be used as governor which would get limited to a poll
state and state 1 and the other states wouldn't get used.

To keep the previous defaults we decrease rating of governor to 9 (below
current lowest rating) and thus rely on @governor switch on
cpuidle_register_driver() to tie in haltpoll idle driver and governor
together.

Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
drivers/cpuidle/cpuidle-haltpoll.c | 1 +
drivers/cpuidle/governors/haltpoll.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index 56d8ab814466..519e90d125cf 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -34,6 +34,7 @@ static int default_enter_idle(struct cpuidle_device *dev,

static struct cpuidle_driver haltpoll_driver = {
.name = "haltpoll",
+ .governor = "haltpoll",
.owner = THIS_MODULE,
.states = {
{ /* entry 0 is for polling */ },
diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
index 797477bda486..7a703d2e0064 100644
--- a/drivers/cpuidle/governors/haltpoll.c
+++ b/drivers/cpuidle/governors/haltpoll.c
@@ -133,7 +133,7 @@ static int haltpoll_enable_device(struct cpuidle_driver *drv,

static struct cpuidle_governor haltpoll_governor = {
.name = "haltpoll",
- .rating = 21,
+ .rating = 9,
.enable = haltpoll_enable_device,
.select = haltpoll_select,
.reflect = haltpoll_reflect,
--
2.17.1