sched/deadline: Make GRUB a task's flag

This patch introduces the SCHED_FLAG_RECLAIM flag to specify
that a DL task is allowed to reclaim unused CPU time (using
the GRUB algorithm).

Tested-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Claudio Scordino <claudio@evidence.eu.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Link: http://lkml.kernel.org/r/1495138417-6203-7-git-send-email-luca.abeni@santannapisa.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
index 5f0fe01..e2a6c7b 100644 (file)
--- a/include/uapi/linux/sched.h
+++ b/include/uapi/linux/sched.h
@@ -47,5 +47,6 @@
  * For the sched_{set,get}attr() calls
  */
 #define SCHED_FLAG_RESET_ON_FORK       0x01
+#define SCHED_FLAG_RECLAIM             0x02
 
 #endif /* _UAPI_LINUX_SCHED_H */

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7abd064..8d1a5a6 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4195,7 +4195,8 @@ recheck:
                        return -EINVAL;
        }
 
-       if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK))
+       if (attr->sched_flags &
+               ~(SCHED_FLAG_RESET_ON_FORK | SCHED_FLAG_RECLAIM))
                return -EINVAL;
 
        /*

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 6a0614b..61ea303 100644 (file)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -985,7 +985,8 @@ static void update_curr_dl(struct rq *rq)
 
        sched_rt_avg_update(rq, delta_exec);
 
-       delta_exec = grub_reclaim(delta_exec, rq);
+       if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM))
+               delta_exec = grub_reclaim(delta_exec, rq);
        dl_se->runtime -= delta_exec;
 
 throttle: