Re: [Xen-devel] [PATCH] scrub pages on guest termination

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

The aim of the loop was to scrub enough pages in a batch that lock contention is kept tolerably low. Even if 16 pages is not sufficient for that, I’m surprised a ‘node’ (you mean a whole system, presumably?) would appear to lock up. Maybe pages would be scrubbed slower than we’d like, but still CPUs should be able to get the spinlock often enough to evaluate whether they have spent 1ms in the loop and hence get out of there.

What sort of system were you seeing the lockup on? Does it have very many physical CPUs?

 -- Keir

On 23/5/08 16:00, "Ben Guthro" <bguthro@xxxxxxxxxxxxxxx> wrote:

> This patch solves the following problem.  When a large VS terminates, the node locks
> up. The node locks up because the page_scrub_kick routine sends a softirq to
> all processors instructing them to run the page scrub code.  There they interfere
> with each other as they serialize behind the page_scrub_lock.




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