Re: [PATCH 10/13] x86: Move cond resched for copy_{from,to}_userinto low level code 64bit

From: Borislav Petkov
Date: Sat Aug 10 2013 - 14:23:17 EST

On Sat, Aug 10, 2013 at 09:27:33AM -0700, Linus Torvalds wrote:
> Now, the *debug* logic is entirely different, of course. Maybe the
> problem is that we have mixed up the two so badly, and we have
> "might_sleep()" that implies more of a debug issue than a preemption
> issue, and then people add those because they want the debug coverage
> (and then you *absolutely* want it even for a single-byte user
> mode access). And then because the concept is tied together with
> preemption, we end up doing preemption even for that single-byte
> access despite the fact that it makes no sense what-so-ever.

Sounds like the debug aspect and the preemption point addition need
to be sorf-of split into two different functions/macros and each used

Something like keep the current might_sleep and have debug_sleep or
similar which does only __might_sleep without the resched...


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