Date:   Thu, 9 Mar 2023 15:53:43 -0800
From:   David Matlack <dmatlack@google.com>
To:     Vipin Sharma <vipinsh@google.com>
Cc:     seanjc@google.com, pbonzini@redhat.com, bgardon@google.com,
        jmattson@google.com, mizhang@google.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [Patch v4 03/18] KVM: x86/mmu: Track count of pages in KVM MMU
 page caches globally
Message-ID: <ZApxh/GYfqev7sHA@google.com>
References: <20230306224127.1689967-1-vipinsh@google.com>
 <20230306224127.1689967-4-vipinsh@google.com>
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On Mon, Mar 06, 2023 at 02:41:12PM -0800, Vipin Sharma wrote:
> Create a global counter for total number of pages available
> in MMU page caches across all VMs. Add mmu_shadow_page_cache
> pages to this counter.

I think I prefer counting the objects on-demand in mmu_shrink_count(),
instead of keeping track of the count. Keeping track of the count adds
complexity to the topup/alloc paths for the sole benefit of the
shrinker. I'd rather contain that complexity to the shrinker code unless
there is a compelling reason to optimize mmu_shrink_count().

IIRC we discussed this at one point. Was there a reason to take this
approach that I'm just forgetting?