Systems that initiate frequent suspend/resume from userspace can make the kernel aware by enabling PM_USERSPACE_AUTOSLEEP config.
This allows for certain sleep-sensitive code (wireguard/rng) to decide on what preparatory work should be performed (or not) in their pm_notification callbacks. This patch was prompted by the discussion at [1] which attempts to remove CONFIG_ANDROID that currently guards these code paths. [1] https://lore.kernel.org/r/20220629150102.1582425-1-...@lst.de/ Suggested-by: Jason A. Donenfeld <ja...@zx2c4.com> Signed-off-by: Kalesh Singh <kaleshsi...@google.com> --- drivers/char/random.c | 4 ++-- drivers/net/wireguard/device.c | 3 ++- kernel/power/Kconfig | 20 ++++++++++++++++++++ 3 files changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index e3dd1dd3dd22..8c90f535d149 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -755,8 +755,8 @@ static int random_pm_notification(struct notifier_block *nb, unsigned long actio spin_unlock_irqrestore(&input_pool.lock, flags); if (crng_ready() && (action == PM_RESTORE_PREPARE || - (action == PM_POST_SUSPEND && - !IS_ENABLED(CONFIG_PM_AUTOSLEEP) && !IS_ENABLED(CONFIG_ANDROID)))) { + (action == PM_POST_SUSPEND && !IS_ENABLED(CONFIG_PM_AUTOSLEEP) && + !IS_ENABLED(CONFIG_PM_USERSPACE_AUTOSLEEP)))) { crng_reseed(); pr_notice("crng reseeded on system resumption\n"); } diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c index aa9a7a5970fd..d58e9f818d3b 100644 --- a/drivers/net/wireguard/device.c +++ b/drivers/net/wireguard/device.c @@ -69,7 +69,8 @@ static int wg_pm_notification(struct notifier_block *nb, unsigned long action, v * its normal operation rather than as a somewhat rare event, then we * don't actually want to clear keys. */ - if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || IS_ENABLED(CONFIG_ANDROID)) + if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || + IS_ENABLED(CONFIG_PM_USERSPACE_AUTOSLEEP)) return 0; if (action != PM_HIBERNATION_PREPARE && action != PM_SUSPEND_PREPARE) diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index a12779650f15..60a1d3051cc7 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -143,6 +143,26 @@ config PM_AUTOSLEEP Allow the kernel to trigger a system transition into a global sleep state automatically whenever there are no active wakeup sources. +config PM_USERSPACE_AUTOSLEEP + bool "Userspace opportunistic sleep" + depends on PM_SLEEP + help + Notify kernel of aggressive userspace autosleep power management policy. + + This option changes the behavior of various sleep-sensitive code to deal + with frequent userspace-initiated transitions into a global sleep state. + + Saying Y here, disables code paths that most users really should keep + enabled. In particular, only enable this if it is very common to be + asleep/awake for very short periods of time (<= 2 seconds). + + Only platforms, such as Android, that implement opportunistic sleep from + a userspace power manager service should enable this option; and not + other machines. Therefore, you should say N here, unless you are + extremely certain that this is what you want. The option otherwise has + bad, undesirable effects, and should not be enabled just for fun. + + config PM_WAKELOCKS bool "User space wakeup sources interface" depends on PM_SLEEP base-commit: 03c765b0e3b4cb5063276b086c76f7a612856a9a -- 2.37.0.rc0.161.g10f37bed90-goog
