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Subject: Re: BKL removal
From: Robert Love <rml@mvista.com>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>,
       Rick Lindsley <ricklind@us.ibm.com>, Greg KH <greg@kroah.com>,
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On Tue, 2002-07-09 at 07:19, Dave Hansen wrote:

> Robert Love wrote:
>
> > The problem is, it is needed in a _lot_ of places.  Mostly instances
> > where the lock is held across something that may implicitly sleep.
> 
> And _that_ is why I wrote the BKL debugging patch, to help find these 
> places at runtime.  It may not be pretty, but it works.  I'll post it 
> again if you're interested.

I saw the patch... the problem is we cannot say "oh I ran this code path
with the patch and did not see anything, it is safe".  Can sleep != will
sleep, and thus we have code that 99% will not sleep but it may.

I suspect on my 1GB machine I rarely page fault on copy_*_user but that
does not mean it could not sleep.

If you find all the culprits and think you can safely remove the
release/reacquire routines from schedule, all the power to you.

	Robert Love

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