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Date: Wed, 21 Feb 2024 16:41:38 +0100
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Maxime Ripard" <mripard@redhat.com>,
 "Krzysztof Kozlowski" <krzysztof.kozlowski@linaro.org>
Cc: "Javier Martinez Canillas" <javierm@redhat.com>,
 linux-kernel@vger.kernel.org,
 "Enric Balletbo i Serra" <eballetbo@redhat.com>,
 "Erico Nunes" <nunes.erico@gmail.com>, "Brian Masney" <bmasney@redhat.com>,
 "Bjorn Andersson" <quic_bjorande@quicinc.com>,
 "Catalin Marinas" <catalin.marinas@arm.com>,
 "Geert Uytterhoeven" <geert+renesas@glider.be>,
 "Konrad Dybcio" <konrad.dybcio@linaro.org>,
 "Marek Szyprowski" <m.szyprowski@samsung.com>,
 "Neil Armstrong" <neil.armstrong@linaro.org>,
 "Will Deacon" <will@kernel.org>, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] arm64: defconfig: Enable zram, xfs and loading compressed FW
 support
Content-Type: text/plain

On Wed, Feb 21, 2024, at 16:24, Maxime Ripard wrote:
> On Wed, Feb 21, 2024 at 04:10:12PM +0100, Krzysztof Kozlowski wrote:
>> On 21/02/2024 15:48, Maxime Ripard wrote:
>> > On Wed, Feb 21, 2024 at 03:22:38PM +0100, Krzysztof Kozlowski wrote:
>> >> On 21/02/2024 15:13, Javier Martinez Canillas wrote:
>> >>> These options are needed by some Linux distributions (e.g: Fedora), so
>> >>
>> >> How ZRAM is needed? Why Fedora cannot boot without it? Debian, which I
>> >> use on my arm64 boards, does not have any problem.
>> > 
>> > Is it relevant in any way?
>> 
>> Yes, because it is justification why we are doing it. Each commit is
>> supposed to explain "why" and the explanation here is not enough.
>
> There's a why though: it makes Fedora boot. It might not be enough for
> you, but that's a different story. So, if it's not enough, please state
> exactly what you expect from that patch description so Javier can
> provide it.

It's definitely enough for me. It makes a lot of sense to have
a defconfig that boots common and popular distros.

I don't use ZRAM either, but I can see that being useful to
avoid swapping to SD cards or eMMC when that is the only
available swap device.

>> >> I kind of repeat comments from similar patch earlier:
>> >> https://lore.kernel.org/all/fe1e74a2-e933-7cd9-f740-86d871076191@linaro.org/
>> >>
>> >> About XFS: I don't think it is needed to boot anything.
>> > 
>> > Just like 9P_FS, NFS or UBIFS.
>> 
>> NFS is often used on targets, e.g. my board farm, but also by other people.
>> 
>> UBIFS was added recently because one device was using it - you needed
>> it. 9P_FS looks unnecessary.
>
> So all we need is one person or use case to require it? Sounds like
> we've checked that mark here.

I think we want all of the above. We can probably drop ext2 since
we already need ext4, but that is a different question.

>> I was working in distro so trust me - they do stuff differently
>> and they not need XFS in our defconfig for anything.
>
> Sure, but you're not just arguing for XFS there.
>
> What I really don't get is this: this makes the life of people easier.
>
> Being able to test an upstream kernel quickly when you have a bug in a
> downstream distro is super valuable for any distro developper. And on
> the long run, if we don't make the switch from a kernel distro to a
> mainline kernel relatively easy, we're the ones that will lose out.
> Because people just won't bother, or be frustrated and thus super
> reluctant to do that work.

We had previously discussed adding config fragments for common
distros the way we have kvm_guest.config, but if the Javier's
patch is all that is actually needed for Fedora, that seems better
to me than the added complexity of fragments.

      Arnd