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[Xen-devel] event priority

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>
Subject: [Xen-devel] event priority
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Mon, 10 Apr 2006 22:31:26 +0800
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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Thread-topic: event priority
Hi, Keir,
        Seems current event priority is simple by 
earlier-alloc-higher-priority style, because event ports are allocated
incrementally from 1 and event dispatcher uses bit search instruction
to walk pending events sequentially. Is there any plan (or benefit) to
add more flexible priority policy, since by current way the priority is 
decided completely by compilation sequence of different drivers?

        2nd question is, why is there check/fix upon nested events only
for critical regions at end of hypervisor_callback? Though it's possible
to see nested events occurring at that small slice, seems the
possibility to overflow stack at that place is similar to the normal
nested cases where if some irq handler enables interrupt itself. If we
really want to prevent stack overflow, is it possible to add similar
in CONFIG_DEBUG_STACKOVERFLOW to entry point of callback, 
and thus make this check common for all nested cases? Seems
current logic being there for a long time, and so sorry if I missed
important hints here. :-)


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