From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 8 Sep 2008 16:03:57 +0000 (-0700)
Subject: hrtimer: make the futex() system call use the per process slack value
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ae4b748e81b7e366f04f55229d5e372e372c33af;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git

hrtimer: make the futex() system call use the per process slack value

This patch makes the futex() system call use the per process
slack value; with this users are able to externally control existing
applications to reduce the wakeup rate.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---

diff --git a/kernel/futex.c b/kernel/futex.c
index 4cd5b4319b04..8af10027514b 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1296,10 +1296,14 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
 		if (!abs_time)
 			schedule();
 		else {
+			unsigned long slack;
+			slack = current->timer_slack_ns;
+			if (rt_task(current))
+				slack = 0;
 			hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC,
 						HRTIMER_MODE_ABS);
 			hrtimer_init_sleeper(&t, current);
-			hrtimer_set_expires(&t.timer, *abs_time);
+			hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
 
 			hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
 			if (!hrtimer_active(&t.timer))