[PATCH] sched: make task_noninteractive use sleep_type

Alterations to the pipe code in the kernel made it possible for relative
starvation to occur with tasks that slept waiting on a pipe getting unfair
priority bonuses even if they were otherwise fully cpu bound so the
TASK_NONINTERACTIVE flag was introduced which prevented any change to
sleep_avg while sleeping waiting on a pipe.  This change also leads to the
converse though, preventing any priority boost from occurring in truly
interactive tasks that wait on pipes.

Convert the TASK_NONINTERACTIVE flag to set sleep_type to SLEEP_NONINTERACTIVE
which will allow a linear bonus to priority based on sleep time thus allowing
interactive tasks to get high priority if they sleep enough.

Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 8 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index f55ce5adac55..589e55a42214 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1273,18 +1273,18 @@ out_activate:
                  * sleep_avg beyond just interactive state.
                  */
                 p->sleep_type = SLEEP_NONINTERACTIVE;
-        }
+        } else
 
         /*
          * Tasks that have marked their sleep as noninteractive get
-         * woken up without updating their sleep average. (i.e. their
-         * sleep is handled in a priority-neutral manner, no priority
-         * boost and no penalty.)
+         * woken up with their sleep average not weighted in an
+         * interactive way.
          */
-        if (old_state & TASK_NONINTERACTIVE)
-                __activate_task(p, rq);
-        else
-                activate_task(p, rq, cpu == this_cpu);
+                if (old_state & TASK_NONINTERACTIVE)
+                        p->sleep_type = SLEEP_NONINTERACTIVE;
+
+
+        activate_task(p, rq, cpu == this_cpu);
         /*
          * Sync wakeups (i.e. those types of wakeups where the waker
          * has indicated that it will leave the CPU in short order)