Re: [ECOS] newbie query! spinlocks mlqueue

[Nick Garnett <nickg at ecoscentric dot com>]

jeane <jeane.genet@gmail.com> writes:

> bonjour!
> I was browsing through the code looking for implemantation pour the
> spinlock in uni-processor modes. All it does is is add one to the
> flag! What happens if there are two threads (with mlqueue based
> scheduling preemption enabled) and thread A acquire spinlocks and gets
> scheduled out and thread B tries to acquire the spinlock ? It look it
> will acquire the spinlock :-S I miss something? how does spinlock
> (cyg_spinlock_spin)disables scheduling?
> Excuse my poor englais, any help will be grateful.
> Thank you,
> Jeane.

Take a look at the spinlock documentation, it explains there the
situations in which spinlocks are appropriate and the potential
pitfalls of using then inappropriately:

http://ecos.sourceware.org/docs-latest/ref/kernel-spinlocks.html


-- 
Nick Garnett                                     eCos Kernel Architect
http://www.ecoscentric.com                The eCos and RedBoot experts


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