On Wed, Aug 24, 2022 at 6:41 AM Juhyung Park <qkrwngud825@xxxxxxxxx> wrote:
>
> Commit 2fd77fff4b44 ("PM / suspend: make sync() on suspend-to-RAM build-time
> optional") added an option to skip sync() on suspend entry to avoid heavy
> overhead on platforms with frequent suspends.
>
> Years later, commit 261e224d6a5c ("pm/sleep: Add PM_USERSPACE_AUTOSLEEP
> Kconfig") added a dedicated config for indicating that the kernel is subject to
> frequent suspends.
>
> While SUSPEND_SKIP_SYNC is also available as a knob that the userspace can
> configure, it makes sense to enable this by default if PM_USERSPACE_AUTOSLEEP
> is selected already.
>
> Signed-off-by: Juhyung Park <qkrwngud825@xxxxxxxxx>
> ---
> kernel/power/Kconfig | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
> index 60a1d3051cc7..5725df6c573b 100644
> --- a/kernel/power/Kconfig
> +++ b/kernel/power/Kconfig
> @@ -23,6 +23,7 @@ config SUSPEND_SKIP_SYNC
> bool "Skip kernel's sys_sync() on suspend to RAM/standby"
> depends on SUSPEND
> depends on EXPERT
> + default PM_USERSPACE_AUTOSLEEP
Why is this better than selecting SUSPEND_SKIP_SYNC from PM_USERSPACE_AUTOSLEEP?
> help
> Skip the kernel sys_sync() before freezing user processes.
> Some systems prefer not to pay this cost on every invocation
> --
