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Commit 1c99315b authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Rusty Russell
Browse files

kthread: move sched-realeted initialization from kthreadd context 



kthreadd is the single thread which implements ths "create" request, move
sched_setscheduler/etc from create_kthread() to kthread_create() to
improve the scalability.

We should be careful with sched_setscheduler(), use _nochek helper.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Vitaliy Gusev <vgusev@openvz.org
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 3217ab97

kernel/kthread.c

+11 −11
Original line number Diff line number Diff line
@@ -97,19 +97,10 @@ static void create_kthread(struct kthread_create_info *create) 


	/* We want our own signal handler (we take no signals by default). */

	pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD);

	if (pid < 0) {

	if (pid < 0)

		create->result = ERR_PTR(pid);

	} else {

		struct sched_param param = { .sched_priority = 0 };

	else

		wait_for_completion(&create->started);

		/*

		 * 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_ptr(create->result, cpu_all_mask);

	}

	complete(&create->done);

}
@@ -152,11 +143,20 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), 
	wait_for_completion(&create.done);



	if (!IS_ERR(create.result)) {

		struct sched_param param = { .sched_priority = 0 };

		va_list args;



		va_start(args, namefmt);

		vsnprintf(create.result->comm, sizeof(create.result->comm),

			  namefmt, args);

		va_end(args);

		/*

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

		 * 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;

}