Re: [PATCH v2 0/3] Clean the policy manipulation path in domain creation

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, May 17, 2024 at 05:08:33PM +0100, Alejandro Vallejo wrote:
> v2:
>   * Removed xc_cpu_policy from xenguest.h
>   * Added accessors for xc_cpu_policy so the serialised form can be extracted.
>   * Modified xen-cpuid to use accessors.
> 
> ==== Original cover letter ====
> 
> In the context of creating a domain, we currently issue a lot of hypercalls
> redundantly while populating its CPU policy; likely a side effect of
> organic growth more than anything else.
> 
> However, the worst part is not the overhead (this is a glacially cold
> path), but the insane amounts of boilerplate that make it really hard to
> pick apart what's going on. One major contributor to this situation is the
> fact that what's effectively "setup" and "teardown" phases in policy
> manipulation are not factored out from the functions that perform said
> manipulations, leading to the same getters and setter being invoked many
> times, when once each would do.
> 
> Another big contributor is the code being unaware of when a policy is
> serialised and when it's not.
> 
> This patch attempts to alleviate this situation, yielding over 200 LoC
> reduction.
> 
> Patch 1: Mechanical change. Makes xc_cpu_policy_t public so it's usable
>          from clients of libxc/libxg.
> Patch 2: Changes the (de)serialization wrappers in xenguest so they always
>          serialise to/from the internal buffers of xc_cpu_policy_t. The
>          struct is suitably expanded to hold extra information required.
> Patch 3: Performs the refactor of the policy manipulation code so that it
>          follows a strict: PULL_POLICIES, MUTATE_POLICY (n times), 
> PUSH_POLICY.

I think patch 3 is no longer part of the set?  I don't see anything
in the review of v1 that suggests patch 3 was not going to be part of
the next submission?

Thanks, Roger.