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Re: Thread state during interruption
- From: Jonathan Larmour <jifl at eCosCentric dot com>
- To: Michele Portolan <michele dot Portolan at imag dot fr>
- Cc: ecos-discuss at sources dot redhat dot com
- Date: Fri, 13 Jun 2003 05:33:55 +0100
- Subject: Re: [ECOS] Thread state during interruption
- References: <00ef01c33014$6d44a400$9881ab93@imag.fr>
Michele Portolan wrote:
I'm programming an interrupt handler,but there's a thing I cannot
understand:
if I do not change the interrupted thread state inside the ISR do I risk for
it to be scheduled before the DSR has terminated?
Yes an ISR can run again before the DSR is terminated unless you mask that
interrupt. Allowing interrupts to remain enabled is one of the points of
the ISR being separate from a DSR. An ISR can run before the DSR is even
started!
But there are not states like "blocked on interrution".
ISRs are run "outside" the kernel - kernel interaction is for DSRs
(althoug that doesn't by itself change thread state either,
intentionally). The thread state is not altered just because an ISR is
running.
Jifl
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