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authorLen Brown2015-07-31 18:46:17 +0200
committerRafael J. Wysocki2015-07-31 23:46:05 +0200
commit2fd77fff4b440c29b48c31db0ce2aec7d319959f (patch)
treefe1c131b86a1cefe66e2ed2b7641b8c8db78c757 /kernel/power/suspend.c
parentPM / sleep: Allow devices without runtime PM to do direct-complete (diff)
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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 <len.brown@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/power/suspend.c')
-rw-r--r--kernel/power/suspend.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 53266b729fd9..7e4cda4a8dd9 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -484,11 +484,13 @@ static int enter_state(suspend_state_t state)
if (state == PM_SUSPEND_FREEZE)
freeze_begin();
+#ifndef CONFIG_SUSPEND_SKIP_SYNC
trace_suspend_resume(TPS("sync_filesystems"), 0, true);
printk(KERN_INFO "PM: Syncing filesystems ... ");
sys_sync();
printk("done.\n");
trace_suspend_resume(TPS("sync_filesystems"), 0, false);
+#endif
pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]);
error = suspend_prepare(state);