From 2fd77fff4b440c29b48c31db0ce2aec7d319959f Mon Sep 17 00:00:00 2001 From: Len Brown Date: Fri, 31 Jul 2015 12:46:17 -0400 Subject: PM / suspend: make sync() on suspend-to-RAM build-time optional The Linux kernel suspend path has traditionally invoked sys_sync() before freezing user threads. But sys_sync() can be expensive, and some user-space OS's do not want the kernel to pay the cost of sys_sync() on every suspend -- preferring invoke sync() from user-space if/when they want it. So make sys_sync on suspend build-time optional. The default is unchanged. Signed-off-by: Len Brown Signed-off-by: Rafael J. Wysocki --- kernel/power/Kconfig | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel/power/Kconfig') diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index 9e302315e33d..02e8dfaa1ce2 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -18,6 +18,16 @@ config SUSPEND_FREEZER Turning OFF this setting is NOT recommended! If in doubt, say Y. +config SUSPEND_SKIP_SYNC + bool "Skip kernel's sys_sync() on suspend to RAM/standby" + depends on SUSPEND + depends on EXPERT + help + 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. + config HIBERNATE_CALLBACKS bool -- cgit v1.2.3