Re: [Xen-devel] [PATCH v3 1/4] xen: sched/credit1: make vcpu_migration_delay per-cpupool

[George Dunlap <george.dunlap@xxxxxxxxxx>]

On 03/15/2018 05:51 PM, Dario Faggioli wrote:
> Right now, vCPU migration delay is controlled by
> the vcpu_migration_delay boot parameter. This means
> the same value will always be used for every instance
> of Credit1, in any cpupool that will be created.
> 
> Also, in order to get and set such value, a special
> purpose libxc interface is defined, and used by the
> xenpm tool. And this is problematic if Xen is built
> without Credit1 support.
> 
> This commit adds a vcpu_migr_delay field inside
> struct csched_private, so that we can get/set the
> migration delay indepently for each Credit1 instance,
> in different cpupools.
> 
> Getting and setting now happens via XEN_SYSCTL_SCHEDOP_*,
> which is much better suited for this parameter.
> 
> The value of the boot time parameter is used for
> initializing the vcpu_migr_delay field of the private
> structure of all the scheduler instances, when they're
> created.
> 
> While there, save reading NOW() and doing any s_time_t
> operation, when the migration delay of a scheduler is
> zero (as it is, by default), in
> __csched_vcpu_is_cache_hot().
> 
> Finally, note that, from this commit on, using `xenpm
> {set,get}-vcpu-migration-delay' will have no effect
> any longer. A subsequent commit will re-enable it, for
> the sake of backwards-compatibility.
> 
> Signed-off-by: Dario Faggioli <dfaggioli@xxxxxxxx>

Looks good, thanks!

Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>

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