linux-kernel - Re: [PATCH] resource: re-factor page_is

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <05623846-03c7-89f1-e1dd-0ee23723c7e9@redhat.com>
Date:   Fri, 10 Jun 2022 12:23:50 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Vaibhav Jain <vaibhav@...ux.ibm.com>, linux-kernel@...r.kernel.org
Cc:     "Aneesh Kumar K . V" <aneesh.kumar@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Muchun Song <songmuchun@...edance.com>
Subject: Re: [PATCH] resource: re-factor page_is_ram()

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