From: ysay <ysaydong@xxxxxxxxx>
When guest_halt_poll_allow_shrink=N,setting guest_halt_poll_ns
from a large value to 0 does not reset the CPU polling time,
despite guest_halt_poll_ns being intended as a mandatory maximum
time limit.
The problem was situated in the adjust_poll_limit() within
drivers/cpuidle/governors/haltpoll.c:79.
Specifically, when guest_halt_poll_allow_shrink was set to N,
resetting guest_halt_poll_ns to zero did not lead to executing any
section of code that adjusts dev->poll_limit_ns.
The issue has been resolved by relocating the check and assignment for
dev->poll_limit_ns outside of the conditional block.
This ensures that every modification to guest_halt_poll_ns
properly influences the CPU polling time.
Signed-off-by: ysay <ysaydong@xxxxxxxxx>
Fixes: 2cffe9f6b96f ("cpuidle: add haltpoll governor")
---
drivers/cpuidle/governors/haltpoll.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
index 663b7f164..99c6260d7 100644
--- a/drivers/cpuidle/governors/haltpoll.c
+++ b/drivers/cpuidle/governors/haltpoll.c
@@ -78,26 +78,22 @@ static int haltpoll_select(struct cpuidle_driver *drv,
static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
{
- unsigned int val;
+ unsigned int val = dev->poll_limit_ns;
/* Grow cpu_halt_poll_us if
* cpu_halt_poll_us < block_ns < guest_halt_poll_us
*/
if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {
- val = dev->poll_limit_ns * guest_halt_poll_grow;
+ val *= guest_halt_poll_grow;
if (val < guest_halt_poll_grow_start)
val = guest_halt_poll_grow_start;
- if (val > guest_halt_poll_ns)
- val = guest_halt_poll_ns;
trace_guest_halt_poll_ns_grow(val, dev->poll_limit_ns);
- dev->poll_limit_ns = val;
} else if (block_ns > guest_halt_poll_ns &&
guest_halt_poll_allow_shrink) {
unsigned int shrink = guest_halt_poll_shrink;
- val = dev->poll_limit_ns;
if (shrink == 0) {
val = 0;
} else {
@@ -108,8 +104,12 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
}
trace_guest_halt_poll_ns_shrink(val, dev->poll_limit_ns);
- dev->poll_limit_ns = val;
}
+
+ if (val > guest_halt_poll_ns)
+ val = guest_halt_poll_ns;
+
+ dev->poll_limit_ns = val;
}
/**
--
2.43.5
