diff options
| author | Shrikanth Hegde <sshegde@linux.ibm.com> | 2026-03-11 11:47:09 +0530 |
|---|---|---|
| committer | Madhavan Srinivasan <maddy@linux.ibm.com> | 2026-04-01 09:21:06 +0530 |
| commit | 64ed1e3e728afb57ba9acb59e69de930ead847d9 (patch) | |
| tree | 99effcbfe278c5009aac4e752a6acb65ab1cff03 /drivers/cpuidle | |
| parent | 26d76caac47f44b3ee4cdf080614bbee07713007 (diff) | |
cpuidle: powerpc: avoid double clear when breaking snooze
snooze_loop is done often in any system which has fair bit of
idle time. So it qualifies for even micro-optimizations.
When breaking the snooze due to timeout, TIF_POLLING_NRFLAG is cleared
twice. Clearing the bit invokes atomics. Avoid double clear and thereby
avoid one atomic write.
dev->poll_time_limit indicates whether the loop was broken due to
timeout. Use that instead of defining a new variable.
Fixes: 7ded429152e8 ("cpuidle: powerpc: no memory barrier after break from idle")
Cc: stable@vger.kernel.org
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260311061709.1230440-1-sshegde@linux.ibm.com
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/cpuidle-powernv.c | 5 | ||||
| -rw-r--r-- | drivers/cpuidle/cpuidle-pseries.c | 5 |
2 files changed, 8 insertions, 2 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index 9ebedd972df0..b89e7111e7b8 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -95,7 +95,10 @@ static int snooze_loop(struct cpuidle_device *dev, HMT_medium(); ppc64_runlatch_on(); - clear_thread_flag(TIF_POLLING_NRFLAG); + + /* Avoid double clear when breaking */ + if (!dev->poll_time_limit) + clear_thread_flag(TIF_POLLING_NRFLAG); local_irq_disable(); diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c index f68c65f1d023..864dd5d6e627 100644 --- a/drivers/cpuidle/cpuidle-pseries.c +++ b/drivers/cpuidle/cpuidle-pseries.c @@ -64,7 +64,10 @@ int snooze_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, } HMT_medium(); - clear_thread_flag(TIF_POLLING_NRFLAG); + + /* Avoid double clear when breaking */ + if (!dev->poll_time_limit) + clear_thread_flag(TIF_POLLING_NRFLAG); raw_local_irq_disable(); |