diff options
| author | Jonas Meurer | 2020-01-16 12:53:54 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki | 2020-01-16 21:47:03 +0100 |
| commit | c052bf82c6b00ca27aab0859addc4b3159dfd3a4 (patch) | |
| tree | 5d705708933306bc2c9600133255c8110869bd3a /kernel/power/Kconfig | |
| parent | 5c0e9de06577ba7599b75f97a8bb8cc63f6cb2ad (diff) | |
PM: suspend: Add sysfs attribute to control the "sync on suspend" behavior
The sysfs attribute `/sys/power/sync_on_suspend` controls, whether or not
filesystems are synced by the kernel before system suspend.
Congruously, the behaviour of build-time switch CONFIG_SUSPEND_SKIP_SYNC
is slightly changed: It now defines the run-tim default for the new sysfs
attribute `/sys/power/sync_on_suspend`.
The run-time attribute is added because the existing corresponding
build-time Kconfig flag for (`CONFIG_SUSPEND_SKIP_SYNC`) is not flexible
enough. E.g. Linux distributions that provide pre-compiled kernels
usually want to stick with the default (sync filesystems before suspend)
but under special conditions this needs to be changed.
One example for such a special condition is user-space handling of
suspending block devices (e.g. using `cryptsetup luksSuspend` or `dmsetup
suspend`) before system suspend. The Kernel trying to sync filesystems
after the underlying block device already got suspended obviously leads
to dead-locks. Be aware that you have to take care of the filesystem sync
yourself before suspending the system in those scenarios.
Signed-off-by: Jonas Meurer <jonas@freesources.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/power/Kconfig')
| -rw-r--r-- | kernel/power/Kconfig | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index d3667b4075c1..7cbfbeacd68a 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -27,7 +27,10 @@ config SUSPEND_SKIP_SYNC Skip the kernel sys_sync() before freezing user processes. Some systems prefer not to pay this cost on every invocation of suspend, or they are content with invoking sync() from - user-space before invoking suspend. Say Y if that's your case. + user-space before invoking suspend. There's a run-time switch + at '/sys/power/sync_on_suspend' to configure this behaviour. + This setting changes the default for the run-tim switch. Say Y + to change the default to disable the kernel sys_sync(). config HIBERNATE_CALLBACKS bool |