[Xen-devel] Re: state dumps on large machines corrupting time

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

Perhaps provide such alternative tasklet-based implementations on different
keys? Or shift the current unsafe ones to different keys to use as fallback?

There is no alternative as the problem is dumping in IRQ context in
log_everything context. Either we have to dump outside hardirq context or
not log everything. I assume the former is preferable, especially if the old
method is also kept as a fallback when the machine is really hosed.

 -- Keir

On 17/02/2010 13:04, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

> Keir,
> 
> since state dumps (namely 'd' and '0') may take rather long on large
> machines, time handling can get broken (we observed this in reality
> on a system with 96 CPUs). Do you see any alternative to converting
> the respective dumping routines to use continuation tasklets (e.g.
> for 'd' dump the local CPU's state right away, but process all other
> CPUs step by step from a tasklet action)? For non-IRQ-callback
> keys this would generally seem reasonable (as their handlers get
> invoked from a tasklet anyway), but for IRQ-callback ones this
> bears the uncertainty that not all information might make it out of
> the system.
> 
> Jan
> 



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