Re: [PATCH v1 3/8] migration: Introduce dirty-limit capability

[Markus Armbruster]

huangy81@chinatelecom.cn writes:

> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>
> Introduce migration dirty-limit capability, which can
> be turned on before live migration and limit dirty
> page rate durty live migration.
>
> Introduce migrate_dirty_limit function to help check
> if dirty-limit capability enabled during live migration.
>
> Meanwhile, refactor vcpu_dirty_rate_stat_collect
> so that period can be configured instead of hardcoded.
>
> dirty-limit capability is kind of like auto-converge
> but using dirty limit instead of traditional cpu-throttle
> to throttle guest down. To enable this feature, turn on
> the dirty-limit capability before live migration using
> migratioin-set-capabilities, and set the parameters

migrate-set-capabilities

> "x-vcpu-dirty-limit-period", "vcpu-dirty-limit" suitably

"x-vcpu-dirty-limit"

> to speed up convergence.
>
> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>

Hmm.  You make dirty-limiting as a whole a stable interface (evidence:
capability "dirty-limit" is stable), but keep its two parameters
unstable.  Rationale behind that?