commit 61cbe54d9479ad98283b2dda686deae4c34b2d59
author Mike Galbraith <efault@gmx.de> Wed Sep 09 15:41:37 2009 +0200
committer Ingo Molnar <mingo@elte.hu> Wed Sep 09 17:30:06 2009 +0200
tree e7d4766daaf2895aab96b035a973b67439baecf2
parent 172e082a9111ea504ee34cbba26284a5ebdc53a7

sched: Keep kthreads at default priority

Removes kthread/workqueue priority boost, they increase worst-case
desktop latencies.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1252486344.28645.18.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/kthread.c

diff --git a/kernel/kthread.c b/kernel/kthread.c
index eb8751a..5fe7099 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -16,8 +16,6 @@
 #include <linux/mutex.h>
 #include <trace/events/sched.h>
 
-#define KTHREAD_NICE_LEVEL (-5)
-
 static DEFINE_SPINLOCK(kthread_create_lock);
 static LIST_HEAD(kthread_create_list);
 struct task_struct *kthreadd_task;
@@ -145,7 +143,6 @@
 		 * The kernel thread should not inherit these properties.
 		 */
 		sched_setscheduler_nocheck(create.result, SCHED_NORMAL, &param);
-		set_user_nice(create.result, KTHREAD_NICE_LEVEL);
 		set_cpus_allowed_ptr(create.result, cpu_all_mask);
 	}
 	return create.result;
@@ -221,7 +218,6 @@
 	/* Setup a clean context for our children to inherit. */
 	set_task_comm(tsk, "kthreadd");
 	ignore_signals(tsk);
-	set_user_nice(tsk, KTHREAD_NICE_LEVEL);
 	set_cpus_allowed_ptr(tsk, cpu_all_mask);
 	set_mems_allowed(node_possible_map);
 

kernel/workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0668795..ea1b4e7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -317,8 +317,6 @@
 	if (cwq->wq->freezeable)
 		set_freezable();
 
-	set_user_nice(current, -5);
-
 	for (;;) {
 		prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
 		if (!freezing(current) &&