From: Peter Zijlstra <peterz@infradead.org>
To: Byungchul Park <max.byungchul.park@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>,
Tejun Heo <tj@kernel.org>,
johannes.berg@intel.com, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
oleg@redhat.com, david@fromorbit.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
kernel-team@lge.com
Subject: Re: [PATCH] lockdep: Remove unnecessary acquisitions wrt workqueue flush
Date: Thu, 7 Sep 2017 17:21:07 +0200 [thread overview]
Message-ID: <20170907152107.v4wbvzi2zxlaelms@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CANrsvROa_ppmezwL9Se+jUVy_Yie+TMjP-s85Y==a9Ku4mqDYA@mail.gmail.com>
On Thu, Sep 07, 2017 at 08:37:08PM +0900, Byungchul Park wrote:
> On Thu, Sep 7, 2017 at 6:41 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Thu, Sep 07, 2017 at 09:33:16AM +0900, Byungchul Park wrote:
> >> Workqueue added manual acquisitions to catch deadlock cases. Now
> >> crossrelease was introduced, some of those are redundant because
> >> crossrelease-enabled wait_for_completeion() also does it. Removed it.
> >
> > This does not explain how it doesn't become the regular timing dependent
> > stuff cross-release normally is.
>
> Yes, I will add more explanation for it at the next spin.
>
> But, let me explain it a bit here to help you get it, since it's very
> simple. This has nothing to do with 'might' thing I introduced
> previously. For 'might' thing, I will start it after getting your response.
>
> Here, I just removed acquire() because wait_for_completion()
> already includes the acquire() by LOCKDEP_COMPLETIONS.
> That's all.
Ah I see, but it does so using some fairly nasty completion init stuff.
The old code was far easier to read.
next prev parent reply other threads:[~2017-09-07 15:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-07 0:33 [PATCH] lockdep: Remove unnecessary acquisitions wrt workqueue flush Byungchul Park
2017-09-07 9:41 ` Peter Zijlstra
2017-09-07 11:37 ` Byungchul Park
2017-09-07 15:21 ` Peter Zijlstra [this message]
2017-09-07 21:19 ` Byungchul Park
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