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Commit 4f05b98d authored by Michal Schmidt's avatar Michal Schmidt Committed by Ingo Molnar
Browse files

sched: fix, always create kernel threads with normal priority 



Ensure that the kernel threads are created with the usual nice level
and affinity even if kthreadd's properties were changed from the
default by root.

Signed-off-by: default avatarMichal Schmidt <mschmidt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1ad82fd5

kernel/kthread.c

+11 −1
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ 
#include <linux/mutex.h>

#include <asm/semaphore.h>



#define KTHREAD_NICE_LEVEL (-5)



static DEFINE_SPINLOCK(kthread_create_lock);

static LIST_HEAD(kthread_create_list);

struct task_struct *kthreadd_task;
@@ -94,10 +96,18 @@ static void create_kthread(struct kthread_create_info *create) 
	if (pid < 0) {

		create->result = ERR_PTR(pid);

	} else {

		struct sched_param param = { .sched_priority = 0 };

		wait_for_completion(&create->started);

		read_lock(&tasklist_lock);

		create->result = find_task_by_pid(pid);

		read_unlock(&tasklist_lock);

		/*

		 * root may have changed our (kthreadd's) priority or CPU mask.

		 * The kernel thread should not inherit these properties.

		 */

		sched_setscheduler(create->result, SCHED_NORMAL, &param);

		set_user_nice(create->result, KTHREAD_NICE_LEVEL);

		set_cpus_allowed(create->result, CPU_MASK_ALL);

	}

	complete(&create->done);

}
@@ -221,7 +231,7 @@ int kthreadd(void *unused) 
	/* Setup a clean context for our children to inherit. */

	set_task_comm(tsk, "kthreadd");

	ignore_signals(tsk);

	set_user_nice(tsk, -5);

	set_user_nice(tsk, KTHREAD_NICE_LEVEL);

	set_cpus_allowed(tsk, CPU_MASK_ALL);



	current->flags |= PF_NOFREEZE;