From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756292AbcK2Rvb (ORCPT ); Tue, 29 Nov 2016 12:51:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44252 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755585AbcK2RvE (ORCPT ); Tue, 29 Nov 2016 12:51:04 -0500 Date: Tue, 29 Nov 2016 18:51:00 +0100 From: Oleg Nesterov To: Andrew Morton , Ingo Molnar Cc: Alex Deucher , Andy Lutomirski , Andy Lutomirski , Chunming Zhou , Peter Zijlstra , Petr Mladek , Roman Pen , Tejun Heo , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: [PATCH v2 2/5] Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function" Message-ID: <20161129175100.GA5333@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161129175037.GA5319@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 29 Nov 2016 17:51:03 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This reverts commit 23196f2e5f5d810578a772785807dcdc2b9fdce9. After the previous change struct kthread can't go away, no need to pin the stack. TODO: kill to_live_kthread(). Signed-off-by: Oleg Nesterov Acked-by: Thomas Gleixner --- kernel/kthread.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 9d64b65..7891a94 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -88,7 +88,7 @@ void free_kthread_struct(struct task_struct *k) static struct kthread *to_live_kthread(struct task_struct *k) { struct completion *vfork = ACCESS_ONCE(k->vfork_done); - if (likely(vfork) && try_get_task_stack(k)) + if (likely(vfork)) return __to_kthread(vfork); return NULL; } @@ -473,10 +473,8 @@ void kthread_unpark(struct task_struct *k) { struct kthread *kthread = to_live_kthread(k); - if (kthread) { + if (kthread) __kthread_unpark(k, kthread); - put_task_stack(k); - } } EXPORT_SYMBOL_GPL(kthread_unpark); @@ -505,7 +503,6 @@ int kthread_park(struct task_struct *k) wait_for_completion(&kthread->parked); } } - put_task_stack(k); ret = 0; } return ret; @@ -541,7 +538,6 @@ int kthread_stop(struct task_struct *k) __kthread_unpark(k, kthread); wake_up_process(k); wait_for_completion(&kthread->exited); - put_task_stack(k); } ret = k->exit_code; put_task_struct(k); -- 2.5.0