From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752619AbdHKIP1 (ORCPT ); Fri, 11 Aug 2017 04:15:27 -0400 Received: from mout.gmx.net ([212.227.15.15]:61630 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751618AbdHKIPY (ORCPT ); Fri, 11 Aug 2017 04:15:24 -0400 Message-ID: <1502439312.16425.19.camel@gmx.de> Subject: Re: [patch-rt] hotplug, hrtimer: Migrate expired/deferred timers during cpu offline From: Mike Galbraith To: Sebastian Andrzej Siewior Cc: Thomas Gleixner , LKML , linux-rt-users , Steven Rostedt Date: Fri, 11 Aug 2017 10:15:12 +0200 In-Reply-To: <1502438116.16425.18.camel@gmx.de> References: <20170804173823.lzuhnejlnxczr2lj@linutronix.de> <1501913583.7917.42.camel@gmx.de> <1501945043.5473.31.camel@gmx.de> <20170807073350.nwytftryfp34mrwi@linutronix.de> <1502094121.5568.22.camel@gmx.de> <1502186459.8042.31.camel@gmx.de> <1502438116.16425.18.camel@gmx.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:ewWWKZwNp9+Tc8chkJ9+0sXJtF6FfHvwbbK5gnSKHK5uEABZNuj 0Pmxy4scuCmzctD+7kGYcbfzeC3uTWZiChjZ+g4gkYAIkT7E8Je8S3L2mz7qkgJoFOfLjWq 34/TnhrwGvX31et6zxPUiy8xTXppOC2Ab6IWSQPywBR8HfqVEjajStdIorwJKNZn90QItFw a3dpywau5ayJE4vACGH+w== X-UI-Out-Filterresults: notjunk:1;V01:K0:MM97+pBUZeA=:T5/foV2Jdwn4MkrYDd2WrK iWEjQJlts8EwSegMjRCQ5m2YU07s3E6v9NEUdsy8fer0+gnPIwhjFlTOjV1mJMFyFYQNGO45k 6l9UGVoPImHfPavHt1FFWk0UVm6ADTsc7kO1PgPpygOjnWdgOLjIv1AMhrwGLSb4TpYq3NBuh XPh/fFdu10cheU3721cs4380JsvYgFGgvHWTcoy4c9LsLJ7wHNpCYVS28cYCmUzKxd4ZBzLCD Rl4/bV7mXZheeFVlfLLOFg/3I9Za//HRKrW29LteDM8CBOGFEtc8LRs3bdssF+KpiuUPoruyp 0UVSnOChZDahUYmvlMN5AEb5ZvJSL5uENIEB8LkcPw4AKcF9heavj9CbwXZG0fFfq8NtflqGa tQohU1nOxYcgCI0DPWeD0OCflKbIdIZMnDO2TO8t3OW3U8TE5/qZ1l8KLeUez0WFhgGCzjkrs Odf8ohNXEuHH74qYJqYqUay+FUmP/I/iOKn4Q7j5Wajdqd0O+m4gfIUDvdoJ5bQqvy2cct6vy g4xvKjjP/H8mhNFL1BGdrPUlBJSdsbvC5dDT4mLJJjkRW86Y50yeipUSzo/xDm4tRubEMsueB 9Vi/sDFN8oWU4b2GiSihDtI3UAdAKKclQRldTIDCeU18X+b8Rl3XoJwm5EqXeXMSIbXCqnEM5 09j8t7WM/myzF3GE6DwGMmrUzQZMZqRffRj7GGqOqwB6xusHiWo3oWUjaMmbdrbWG5uhxAbMQ Kz8gwh5aTzedJLHWWHwiyJ0Z4jn5WyiCQbsJi25By28ePIn9WH8DxkN+482jCGqKFgWL2Hd4q 1K7+6ZqtcVnNks7Owh298XX+lOjnFzMsSCrVxy8LYwKl/vDF7o= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2017-08-11 at 09:55 +0200, Mike Galbraith wrote: > The below fixes the list debug explosion up. > > If we do not migrate expired/deferred timers during cpu offline, ->cb_entry > will be corrupted by online initialization of base->expired, leading to a > loud list debug complaint should someone call __remove_hrtimer() thereafter. > > Signed-off-by: Mike Galvraith ahem.....................b > --- > kernel/time/hrtimer.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > --- a/kernel/time/hrtimer.c > +++ b/kernel/time/hrtimer.c > @@ -1802,6 +1802,19 @@ static void migrate_hrtimer_list(struct > */ > enqueue_hrtimer(timer, new_base); > } > + > + /* > + * Finally, migrate any expired timers deferred by RT. > + */ > + while (!list_empty(&old_base->expired)) { > + struct list_head *entry = old_base->expired.next; > + > + timer = container_of(entry, struct hrtimer, cb_entry); > + /* XXX: hm, perhaps defer again instead of enqueueing. */ > + __remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0); > + timer->base = new_base; > + enqueue_hrtimer(timer, new_base); > + } > } > > int hrtimers_dead_cpu(unsigned int scpu)