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From: Thomas Gleixner <tglx@linutronix.de>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Greg KH <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Mel Gorman <mgorman@techsingularity.net>,
	Jan Kara <jack@suse.cz>
Subject: Re: [PATCH] rtmutex: Add acquire semantics for rtmutex lock acquisition slow path
Date: Fri, 21 Apr 2023 18:33:30 +0200	[thread overview]
Message-ID: <87edod2o11.ffs@tglx> (raw)
In-Reply-To: <20230421160947.Sh0eyEWC@linutronix.de>

On Fri, Apr 21 2023 at 18:09, Sebastian Andrzej Siewior wrote:
> On 2023-04-21 17:30:24 [+0200], Thomas Gleixner wrote:
>> >> > The out-of-tree RT patches make extensive use of the code. Since it is
>> >> > upstream code, I assumed it should go via the official stable trees.
>> >> > Without RT, the code is limited the rt_mutex_lock() used by I2C and the
>> >> > RCU booster-mutex.
>> >> 
>> >> Which is a reason to route it through the upstream stable trees, no?
>> >
>> > I do not understand.  Why would we take a patch in the stable tree
>> > because an out-of-tree change requires it?
>> 
>> The change is to the rtmutex core which _IS_ used in tree by futex, RCU
>> and some drivers.
>
> not back stab but to clarify: futex does not use the annotation (it does
> not use the fastpath) but RCU-boosting _and_ I2C-bus code does use it.

Futex requires it too, really. The patch is about the slowpath, no?



  reply	other threads:[~2023-04-21 16:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-18 15:43 [PATCH] rtmutex: Add acquire semantics for rtmutex lock acquisition slow path Sebastian Andrzej Siewior
2023-04-18 16:25 ` Greg KH
2023-04-19  7:25   ` Sebastian Andrzej Siewior
2023-04-21  7:29     ` Thomas Gleixner
2023-04-21 12:45       ` Greg KH
2023-04-21 15:30         ` Thomas Gleixner
2023-04-21 16:09           ` Sebastian Andrzej Siewior
2023-04-21 16:33             ` Thomas Gleixner [this message]
2023-04-22 15:07               ` Greg KH
  -- strict thread matches above, loose matches on Subject: below --
2023-01-30 11:36 Sebastian Andrzej Siewior

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