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From: Steven Rostedt <rostedt@goodmis.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
	Daniel Wagner <wagi@monom.org>, Tom Zanussi <zanussi@kernel.org>,
	"Srivatsa S. Bhat" <srivatsa@csail.mit.edu>,
	Clark Williams <williams@redhat.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Subject: Re: [PATCH RT 09/10] drm/i915/gt: Queue and wait for the irq_work item.
Date: Tue, 23 Nov 2021 10:37:55 -0500	[thread overview]
Message-ID: <20211123103755.12d4b776@gandalf.local.home> (raw)
In-Reply-To: <20211123082500.hprw3gmjzrd3i4ib@linutronix.de>

On Tue, 23 Nov 2021 09:25:00 +0100
Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> On 2021-11-22 15:38:56 [-0500], Steven Rostedt wrote:
> > 5.10.78-rt56-rc2 stable review patch.
> > If anyone has any objections, please let me know.  
> 
> I don't mind releasing this as it is but could you please add the
> following irq-work patches:
> 
> * 09089db79859c irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT

Is there something else missing here, as this gives the following rejects in
irq_work.c:

--- kernel/irq_work.c
+++ kernel/irq_work.c
@@ -217,7 +217,8 @@ void irq_work_single(void *arg)
         */
        (void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY);
 
-       if (!arch_irq_work_has_interrupt())
+       if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
+           !arch_irq_work_has_interrupt())
                rcuwait_wake_up(&work->irqwait);
 }
 
@@ -277,7 +278,8 @@ void irq_work_sync(struct irq_work *work)
        lockdep_assert_irqs_enabled();
        might_sleep();
 
-       if (!arch_irq_work_has_interrupt()) {
+       if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
+           !arch_irq_work_has_interrupt()) {
                rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work),
                                   TASK_UNINTERRUPTIBLE);
                return;

And there's no test here, and no irq_work_is_hard() in 5.10-rt.

This is why I didn't add them.

-- Steve



> * b4c6f86ec2f64 irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
> * 810979682ccc9 irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
> 
> in a follow-up release?
> 
> Sebastian


  reply	other threads:[~2021-11-23 15:38 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-22 20:38 [PATCH RT 00/10] Linux 5.10.78-rt56-rc2 Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 01/10] mm, zsmalloc: Convert zsmalloc_handle.lock to spinlock_t Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 02/10] sched: Fix get_push_task() vs migrate_disable() Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 03/10] sched: Switch wait_task_inactive to HRTIMER_MODE_REL_HARD Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 04/10] preempt: Move preempt_enable_no_resched() to the RT block Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 05/10] mm: Disable NUMA_BALANCING_DEFAULT_ENABLED and TRANSPARENT_HUGEPAGE on PREEMPT_RT Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 06/10] fscache: Use only one fscache_object_cong_wait Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 07/10] fscache: Use only one fscache_object_cong_wait (2) Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 08/10] locking: Drop might_resched() from might_sleep_no_state_check() Steven Rostedt
2021-11-22 20:38 ` [PATCH RT 09/10] drm/i915/gt: Queue and wait for the irq_work item Steven Rostedt
2021-11-23  8:25   ` Sebastian Andrzej Siewior
2021-11-23 15:37     ` Steven Rostedt [this message]
2021-11-24 16:12       ` Sebastian Andrzej Siewior
2021-11-24 16:12         ` [PATCH RT 1/3] irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support Sebastian Andrzej Siewior
2021-11-24 16:12         ` [PATCH RT 2/3] irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT Sebastian Andrzej Siewior
2021-11-24 16:12         ` [PATCH RT 3/3] irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ " Sebastian Andrzej Siewior
2021-11-22 20:38 ` [PATCH RT 10/10] Linux 5.10.78-rt56-rc2 Steven Rostedt

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