Skip to content
Commit 63706172 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

kthreads: rework kthread_stop()



Based on Eric's patch which in turn was based on my patch.

kthread_stop() has the nasty problems:

- it runs unpredictably long with the global semaphore held.

- it deadlocks if kthread itself does kthread_stop() before it obeys
  the kthread_should_stop() request.

- it is not useable if kthread exits on its own, see for example the
  ugly "wait_to_die:" hack in migration_thread()

- it is not possible to just tell kthread it should stop, we must always
  wait for its exit.

With this patch kthread() allocates all neccesary data (struct kthread) on
its own stack, globals kthread_stop_xxx are deleted.  ->vfork_done is used
as a pointer into "struct kthread", this means kthread_stop() can easily
wait for kthread's exit.

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: Rusty Russell <rusty@rustcorp.com.au>
Cc: Vitaliy Gusev <vgusev@openvz.org
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cdd140bd
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment