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From: Kalesh Singh <kaleshsingh@google.com>
Date: Thu, 30 Jun 2022 19:12:29 +0000
Subject: [1/2] pm/sleep: Add PM_USERSPACE_AUTOSLEEP Kconfig
Origin: https://git.kernel.org/linus/261e224d6a5c43e2bb8a07b7662f9b4ec425cfec
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: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Link: https://lore.kernel.org/r/20220630191230.235306-1-kaleshsingh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
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