linux-kernel - Re: [PATCH 07/13] selftests: KVM: Add NX huge pages test

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Date:   Thu, 10 Mar 2022 11:07:00 -0600
From:   Ben Gardon <bgardon@...gle.com>
To:     David Dunn <daviddunn@...gle.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Jing Zhang <jingzhangos@...gle.com>,
        Junaid Shahid <junaids@...gle.com>
Subject: Re: [PATCH 07/13] selftests: KVM: Add NX huge pages test

On Thu, Mar 10, 2022 at 10:59 AM David Dunn <daviddunn@...gle.com> wrote:
>
> Ben,
>
> Thanks for adding this test.  Nit below.
>
> Reviewed-by: David Dunn <daviddunn@...gle.com>
>
> On Thu, Mar 10, 2022 at 8:46 AM Ben Gardon <bgardon@...gle.com> wrote:
>>
>>
>> +       /* Give recovery thread time to run */
>> +       sleep(3);
>>
> Is there any way to make this sleep be based on constants which control the recovery thread?  Looking at the parameters below, this seems excessive.  The recovery period is 2ms with a 1/1=100% recovery ratio.  So this is padded out 1000x.  Maybe it doesn't matter because normally this test runs in parallel with other tests, but it does seem like a pretty large hardcoded sleep.

Woops, I meant to make the recovery period 2 seconds, which would also
be preposterously large. We absolutely can and should tighten that up.
100ms recovery period and 150ms sleep would probably work perfectly.
I'll make that change if/when I send out a v2.

>
> Dave