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Message-ID: <05623846-03c7-89f1-e1dd-0ee23723c7e9@redhat.com>
Date:   Fri, 10 Jun 2022 12:23:50 +0200
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Subject: Re: [PATCH] resource: re-factor page_is_ram()
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To:     Vaibhav Jain <vaibhav@linux.ibm.com>, linux-kernel@vger.kernel.org
Cc:     "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Muchun Song <songmuchun@bytedance.com>
References: <20220601163243.3806231-1-vaibhav@linux.ibm.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20220601163243.3806231-1-vaibhav@linux.ibm.com>
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On 01.06.22 18:32, Vaibhav Jain wrote:
> Presently page_is_ram() relies on walk_system_ram_range() that performs a walk
> on kernel iomem resources hierarchy with a dummy callback __is_ram(). Before
> calling find_next_iomem_res(), walk_system_ram_range() does some book-keeping
> which can be avoided for page_is_ram() use-case.
> 
> Hence this patch proposes to update page_is_ram() to directly call
> find_next_iomem_res() with minimal book-keeping needed.

I consider the code harder to get compared to just reusing the
more-generic and expressive walk_system_ram_range().

It somehow feels like we're duplicating the code here just to optimize
out a handful of instructions.

If it doesn't make the code easier to read (at least for me), why do we
care?

-- 
Thanks,

David / dhildenb