[tip:core/futexes] futex: use current->time_slack_ns for rt tasks too

Darren Hart
2009-03-12T10:26:44Z

Commit-ID: 16f4993f4e9860715918efd4eeac928f8de1218b
Gitweb: http://git.kernel.org/tip/16f4993f4e9860715918efd4eeac928f8de1218b
Author: "Darren Hart" <dvhltc@us.ibm.com>
AuthorDate: Thu, 12 Mar 2009 00:55:59 -0700
Commit: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 12 Mar 2009 11:20:57 +0100

futex: use current->time_slack_ns for rt tasks too

RT tasks should set their timer slack to 0 on their own. This
patch removes the 'if (rt_task()) slack = 0;' block in
futex_wait.

Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.

Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20090312075559.9856.28822.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
kernel/futex.c | 7 ++-----
1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index e149545..6579912 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1253,16 +1253,13 @@ retry:
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,
clockrt ? CLOCK_REALTIME :
CLOCK_MONOTONIC,
HRTIMER_MODE_ABS);
hrtimer_init_sleeper(&t, current);
- hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
+ hrtimer_set_expires_range_ns(&t.timer, *abs_time,
+ current->timer_slack_ns);

hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
if (!hrtimer_active(&t.timer))