Messages in this thread | | | From | David Brownell <> | Subject | Re: [patch 2.6.24-rc2 1/3] generic gpio -- gpio_chip support | Date | Wed, 14 Nov 2007 22:28:10 -0800 |
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On Tuesday 13 November 2007, Nick Piggin wrote: > > All this does is prevent constant and needless checking for > > "do you want to preempt me now?" "now?" "now?" in "now?" the > > middle "now?" of "now?" i/o "now?" loops. > > Actually that's wrong.
Certainly it's right for the mainstream kernel. Dropping a lock (other than a raw spinlock) does that checking; when a loop needs to acquire then drop such a lock, that's exactly what's going on.
And in the RT kernel, it's got to do the same thing ... because dropping that lock may mean that a higher priority task should immediately run and grab the lock.
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