Re: [RFC/PATCH, 2/4] readX_check() performance evaluation

From: Andi Kleen
Date: Wed Jan 28 2004 - 16:11:53 EST


On Wed, 28 Jan 2004 12:28:56 -0800 (PST)
Linus Torvalds <torvalds@xxxxxxxx> wrote:

>
> Alternatively, if you get a lot of information at MCE time (CPU that did
> the access + some device data), just queue up the information in a per-CPU
> queue. You don't have to worry about overflow - you can just drop if if

That assumes that the access happened with preempt off ?

That's fine if it's guaranteed that the MCE still happened inside
readl/writel. But if it's delayed longer for some reason there is no guarantee
that you can find back to the CPU that caused the fault.

Putting it into the pci_dev and using RCU would be probably better.

-Andi
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