Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH 1/2] MN10300: Move asm-arm/cnt32_to_63.h to include/linux/ | Date | Mon, 06 Oct 2008 11:44:22 +0100 |
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Nicolas Pitre <nico@cam.org> wrote:
> If so then you're using this interface in an inappropriate way. > > The _absolute_ minimum frequency with which this should be fully > executed is once per half period of the base counter. I hope that in > practice it happens far more often than that.
I think you're misunderstanding my contention.
If preemption is enabled, cnt32_to_63() can be called with greater than minimum frequency and yet reversions can still happen.
The problem is that a process that's half way through executing cnt32_to_63() can be preempted for a period of time sufficient that when it is rescheduled and writes __m_cnt_hi, it corrupts it with an out of date value.
David
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