Re: [Xen-devel] [Patch] don't spin with irq disabled

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>>> Juergen Gross <juergen.gross@xxxxxxxxxxxxxxxxxxx> 26.03.09 10:00 >>>
>Attached patch reduces interrupt latency in lock handling.
>spin_lock_irq and spin_lock_irqsave used to turn off IRQs and then tried to
>get the lock. If the lock was already held, waiting for the lock was done with
>IRQs still off.
>The patch reenables IRQs during the wait loop.

This is wrong - you must not enable interrupts if they weren't enabled upon
entry to these two functions.

Jan


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