From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753501AbdFVRaW convert rfc822-to-8bit (ORCPT ); Thu, 22 Jun 2017 13:30:22 -0400 Received: from mout.gmx.net ([212.227.15.18]:56634 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753213AbdFVRaU (ORCPT ); Thu, 22 Jun 2017 13:30:20 -0400 Message-ID: <1498152607.5559.19.camel@gmx.de> Subject: Re: [ANNOUNCE] v4.11.5-rt1 From: Mike Galbraith To: Sebastian Andrzej Siewior Cc: Steven Rostedt , Thomas Gleixner , LKML , linux-rt-users Date: Thu, 22 Jun 2017 19:30:07 +0200 In-Reply-To: <20170622163453.iymm3ctqv2a76k6k@linutronix.de> References: <20170616105610.rbc6itylcrsla56l@linutronix.de> <1497687277.6908.31.camel@gmx.de> <20170619085206.n2n22lpdfsoqbp5m@linutronix.de> <1497867291.19618.52.camel@gmx.de> <20170619100838.343faaee@gandalf.local.home> <20170619141341.m243ivutmwlzyhc4@linutronix.de> <20170619104131.05fdc76f@gandalf.local.home> <1497889784.15817.17.camel@gmx.de> <1497944706.5454.7.camel@gmx.de> <20170622163453.iymm3ctqv2a76k6k@linutronix.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Content-Transfer-Encoding: 8BIT X-Provags-ID: V03:K0:0ElqaCUDeXmfrLmemELda94pREPycdJcYOYIUc7nh5faeRf7Sgb deOPsdw/nxrmzQQfui+3xe3sr4CS4CrkUiiAaITH/Ik4adrelDP6dkSaV6C1r/0TQbmJuG3 lJeAPPOqCGse9nK/dSKdEyJh4ZAWxehHC+dgduNrYWQJXb1lez/ZzRTQ/W1sYERGUCT6m40 zAF3m6zyDJx7jTSnLuh4g== X-UI-Out-Filterresults: notjunk:1;V01:K0:f2HhIA4j0Po=:3w36E70FDQJ/Do1z9U9ae1 PXLIzpjGCxNTv8ub4x5eshPCOXqk4AOfnR72dTusvWKEoNLzJES6rokUP9IvDCMT7pH9SfCxd HvxDhcoiiJmTR1vy9HDaoRa3cxcU/HD8bWDJ/txSDMDbg5L4qF53N6hzhHgSSGbTlxrv4S6M0 xMs5NIesJhxK8genmcvjYRvRoHz0mu14zy1PvW4Ga6EfNrttngNtBQ2Tf0IFLJfghY7nB3sHc JbWQhY6kLekH7ZO3N0j+pSxs9KIBHI+dNmP4rBMV94l4oUhpN9xY53RxPbjZczREgErye0vSw 2UaXBKlaWhlR0hM8BAMTpCr0XjEExAeVvQ+KaXN6b7h5jESZfcbtHRobo0RSCydso+8Hum1lw hEN8Uyl+BbRKI35nlQ4Kmvjxt16pwOqCLKfnI0f0CfmxC/nevVVEd6GtYztgo+13+nFZgJ5aL HKn4DlcR1BKAe0mE9vBpLSgRPc33wZWqY8HxrAaxYM1AYRrK7eUh1DHOHmc0R19N4+ZctdwYT ItyMtDBBoqbFFtoJln0KmuIg9xK019InXTvRccV77xlHeTx6Nmy1L6UFyK26n1QEOvj+LXy3m OxJsBSrldQVQGNINDMHtky3zJo1zCKz9gyxfFzyZsCMMGnUa6zV3K7TjTGlYCht/O19iBemij AAuK0qcSSg/wh95FVAu6h9mAxlXm7vH5C0kUP1z9iAPIEee0oMZfINC/fMeCWAx+NeZEY/dBC nBeVjQG1JXUnx/vbIPKgQOnmDx1gcRovoP/lVKv1x0lu1xm27si1YuALseM6D6F+I6ojkX1wu ZaE9XEG Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2017-06-22 at 18:34 +0200, Sebastian Andrzej Siewior wrote: > On 2017-06-20 09:45:06 [+0200], Mike Galbraith wrote: > > See ! and ? > > See see. > What about this: I'll give it a go, likely during the weekend. I moved 4.11-rt today (also repros nicely) due to ftrace annoying me.  After yet more staring at ever more huge traces (opposite of goal;), then taking a break to stare at source again, I decided that the dual wake_q business should die.. and the stall died with it. > diff --git a/include/linux/sched.h b/include/linux/sched.h > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1014,8 +1014,20 @@ struct wake_q_head { > #define WAKE_Q(name) \ > struct wake_q_head name = { WAKE_Q_TAIL, &name.first } > > -extern void wake_q_add(struct wake_q_head *head, > - struct task_struct *task); > +extern void __wake_q_add(struct wake_q_head *head, > + struct task_struct *task, bool sleeper); > +static inline void wake_q_add(struct wake_q_head *head, > + struct task_struct *task) > +{ > + __wake_q_add(head, task, false); > +} > + > +static inline void wake_q_add_sleeper(struct wake_q_head *head, > + struct task_struct *task) > +{ > + __wake_q_add(head, task, true); > +} > + > extern void __wake_up_q(struct wake_q_head *head, bool sleeper); > > static inline void wake_up_q(struct wake_q_head *head) > @@ -1745,6 +1757,7 @@ struct task_struct { > raw_spinlock_t pi_lock; > > struct wake_q_node wake_q; > + struct wake_q_node wake_q_sleeper; > > #ifdef CONFIG_RT_MUTEXES > /* PI waiters blocked on a rt_mutex held by this task */ > diff --git a/kernel/fork.c b/kernel/fork.c > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -558,6 +558,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) > tsk->splice_pipe = NULL; > tsk->task_frag.page = NULL; > tsk->wake_q.next = NULL; > + tsk->wake_q_sleeper.next = NULL; > > account_kernel_stack(tsk, 1); > > diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c > --- a/kernel/locking/rtmutex.c > +++ b/kernel/locking/rtmutex.c > @@ -1506,7 +1506,7 @@ static void mark_wakeup_next_waiter(struct wake_q_head *wake_q, > */ > preempt_disable(); > if (waiter->savestate) > - wake_q_add(wake_sleeper_q, waiter->task); > + wake_q_add_sleeper(wake_sleeper_q, waiter->task); > else > wake_q_add(wake_q, waiter->task); > raw_spin_unlock(¤t->pi_lock); > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -430,9 +430,15 @@ static bool set_nr_if_polling(struct task_struct *p) > #endif > #endif > > -void wake_q_add(struct wake_q_head *head, struct task_struct *task) > +void __wake_q_add(struct wake_q_head *head, struct task_struct *task, > + bool sleeper) > { > - struct wake_q_node *node = &task->wake_q; > + struct wake_q_node *node; > + > + if (sleeper) > + node = &task->wake_q_sleeper; > + else > + node = &task->wake_q; > > /* > * Atomically grab the task, if ->wake_q is !nil already it means > @@ -461,11 +467,17 @@ void __wake_up_q(struct wake_q_head *head, bool sleeper) > while (node != WAKE_Q_TAIL) { > struct task_struct *task; > > - task = container_of(node, struct task_struct, wake_q); > + if (sleeper) > + task = container_of(node, struct task_struct, wake_q_sleeper); > + else > + task = container_of(node, struct task_struct, wake_q); > BUG_ON(!task); > /* task can safely be re-inserted now */ > node = node->next; > - task->wake_q.next = NULL; > + if (sleeper) > + task->wake_q_sleeper.next = NULL; > + else > + task->wake_q.next = NULL; > > /* > * wake_up_process() implies a wmb() to pair with the queueing