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Message-ID: <9810cff90802221643g7d993af4k33f29fb4a4663407@mail.gmail.com>
Date: Fri, 22 Feb 2008 16:43:40 -0800
From: "Bill Huey (hui)" <bill.huey@gmail.com>
To: gregory.haskins@gmail.com
Subject: Re: [PATCH [RT] 11/14] optimize the !printk fastpath through the lock acquisition
Cc: "Pavel Machek" <pavel@ucw.cz>, "Gregory Haskins" <ghaskins@novell.com>,
       mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de,
       rostedt@goodmis.org, linux-rt-users@vger.kernel.org,
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       dsingleton@mvista.com, dwalker@mvista.com, npiggin@suse.de,
       dsaxena@plexity.net, ak@suse.de, gregkh@suse.de, sdietrich@novell.com,
       pmorreale@novell.com, mkohari@novell.com
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On Fri, Feb 22, 2008 at 2:20 PM, Gregory Haskins
<gregory.haskins.ml@gmail.com> wrote:
>  Agreed, but it's still correct afaict.  I added an extra might_sleep()
>  to a path that really might sleep.  I should have mentioned that in the
>  header.
>
>  In any case, its moot.  Andi indicated this patch is probably a no-op so
>  I was considering dropping it on the v2 pass.

The might_sleep is annotation and well as a conditional preemption
point for the regular kernel. You might want to do a schedule check
there, but it's the wrong function if memory serves me correctly. It's
reserved for things that actually are design to sleep. The rt_spin*()
function are really a method of preserving BKL semantics across real
schedule() calls. You'd have to use something else instead for that
purpose like cond_reschedule() instead.

bill
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