Re: [PATCH] mutex: have non-spinning mutexes on s390 by default

[Folkert van Heusden]

> The adaptive spinning mutexes will not always do what one would expect on
> virtualized architectures like s390. Especially the cpu_relax() loop in
> mutex_spin_on_owner might hurt if the mutex holding cpu has been scheduled
> away by the hypervisor.
> We would end up in a cpu_relax() loop when there is no chance that the
> state of the mutex changes until the target cpu has been scheduled again by
> the hypervisor.
> For that reason we should change the default behaviour to no-spin on s390.

Hmmm. Wouldn't this be a change that applies to ibm system p as wel?
E.g. with linux in an lpar.


Folkert van Heusden

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