From: Uladzislau Rezki <urezki@gmail.com>
To: Joel Fernandes <joel@joelfernandes.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Uladzislau Rezki (Sony)" <urezki@gmail.com>,
LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"Paul E . McKenney" <paulmck@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Theodore Y . Ts'o" <tytso@mit.edu>,
Matthew Wilcox <willy@infradead.org>,
Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: Re: [PATCH 1/1] rcu/tree: Drop the lock before entering to page allocator
Date: Thu, 16 Jul 2020 11:19:13 +0200 [thread overview]
Message-ID: <20200716091913.GA28595@pc636> (raw)
In-Reply-To: <CAEXW_YRoTvQfqqcM9fi+MkMxCPEaoJh4zHRM3qNYkv=-nAVuBQ@mail.gmail.com>
On Wed, Jul 15, 2020 at 07:13:33PM -0400, Joel Fernandes wrote:
> On Wed, Jul 15, 2020 at 2:56 PM Sebastian Andrzej Siewior
> <bigeasy@linutronix.de> wrote:
> >
> > On 2020-07-15 20:35:37 [+0200], Uladzislau Rezki (Sony) wrote:
> > > @@ -3306,6 +3307,9 @@ kvfree_call_rcu_add_ptr_to_bulk(struct kfree_rcu_cpu *krcp, void *ptr)
> > > if (IS_ENABLED(CONFIG_PREEMPT_RT))
> > > return false;
> > >
> > > + preempt_disable();
> > > + krc_this_cpu_unlock(*krcp, *flags);
> >
> > Now you enter memory allocator with disabled preemption. This isn't any
> > better but we don't have a warning for this yet.
> > What happened to the part where I asked for a spinlock_t?
>
> Ulad,
> Wouldn't the replacing of preempt_disable() with migrate_disable()
> above resolve Sebastian's issue?
>
This for regular kernel only. That means that migrate_disable() is
equal to preempt_disable(). So, no difference.
>
> Or which scenario breaks?
>
Proposed patch fixes Sebastian's finding about CONFIG_PROVE_RAW_LOCK_NESTING
kernel option, that checks nesting rules and forbids raw_spinlock versus
spinlock mixing.
Sebastian, could you please confirm that if that patch that is in
question fixes it?
It would be appreciated!
--
Vlad Rezki
next prev parent reply other threads:[~2020-07-16 9:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 18:35 [PATCH 1/1] rcu/tree: Drop the lock before entering to page allocator Uladzislau Rezki (Sony)
2020-07-15 18:56 ` Sebastian Andrzej Siewior
2020-07-15 19:02 ` Uladzislau Rezki
2020-07-15 19:32 ` Sebastian Andrzej Siewior
2020-07-15 19:36 ` Uladzislau Rezki
2020-07-15 22:14 ` Paul E. McKenney
2020-07-16 14:14 ` Sebastian Andrzej Siewior
2020-07-16 15:20 ` Paul E. McKenney
2020-07-16 15:36 ` Sebastian Andrzej Siewior
2020-07-16 16:36 ` Paul E. McKenney
2020-07-15 23:13 ` Joel Fernandes
2020-07-16 9:19 ` Uladzislau Rezki [this message]
2020-07-16 13:36 ` Joel Fernandes
2020-07-16 14:37 ` Uladzislau Rezki
2020-07-16 18:27 ` Joel Fernandes
2020-07-16 19:03 ` Uladzislau Rezki
2020-07-16 14:25 ` Sebastian Andrzej Siewior
2020-07-16 14:47 ` Uladzislau Rezki
2020-07-16 15:04 ` Sebastian Andrzej Siewior
2020-07-16 15:34 ` Uladzislau Rezki
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