Commit 261e224d authored by Kalesh Singh's avatar Kalesh Singh Committed by Greg Kroah-Hartman
Browse files

pm/sleep: Add PM_USERSPACE_AUTOSLEEP Kconfig 

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-hch@lst.de/



Suggested-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Acked-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarKalesh Singh <kaleshsingh@google.com>
Link: https://lore.kernel.org/r/20220630191230.235306-1-kaleshsingh@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 80fc671b

drivers/char/random.c

+2 −2
Original line number Diff line number Diff line
@@ -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");

	}

drivers/net/wireguard/device.c

+2 −1
Original line number Diff line number Diff line
@@ -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)

kernel/power/Kconfig

+20 −0
Original line number Diff line number Diff line
@@ -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