Hi Russell,
On 20/10/2023 18:35, Russell King (Oracle) wrote:
On Fri, Oct 20, 2023 at 04:56:20PM +0000, Salil Mehta wrote:
From: Russell King linux@armlinux.org.uk Sent: Friday, October 20, 2023 5:48 PM To: Salil Mehta salil.mehta@huawei.com Cc: James Morse james.morse@arm.com; linaro-open-discussions@op- lists.linaro.org; Joyce Qi joyce.qi@linaro.org; Lorenzo Pieralisi lorenzo.pieralisi@linaro.org; Jonathan Cameron jonathan.cameron@huawei.com; Shameerali Kolothum Thodi shameerali.kolothum.thodi@huawei.com; karl.heubaum@oracle.com; darren@os.amperecomputing.com; ilkka@os.amperecomputing.com; miguel.luis@oracle.com; vishnu@os.amperecomputing.com; Linuxarm linuxarm@huawei.com; salil.mehta@opnsrc.net Subject: Re: [Request] Regarding non-RFC patch-set of Virtual CPU Hotplug kernel support
On Fri, Oct 20, 2023 at 04:40:59PM +0000, Salil Mehta wrote:
I'm afraid it isn't going to happen - going through the review comments there's some ambiguities there (at least to me) that I can't solve without input from the reviewers. I haven't even managed to get half way through the patches yet.
Possible to share the link of the specific review comments and the patches you are referring to here?
I'm preferring to the comments on the RFC v2 posting on the 13th September by James. I think you already provided a link.
https://lore.kernel.org/linux-arm-kernel/20230913163823.7880-1-james.morse@a...
IICRC, you mentioned that this patch-set was ready for submission?
I did, then I realised, as I explained, that I'd used James' old patch series from his other git tree, hadn't taken his latest patch set and fixed up the review comments. So it's anything but.
BTW, which comments in specific in above link are you referring to?
All of them from the RFC v2 posting. Since James has been completely silent, as far as I'm aware, no one has done any work to address the review comments.
So I'm having to go through all the comments and update James' patches, otherwise we're going to end up with reviewers deeming the series not worth the effort of reviewing because they've been ignored.
I have no idea what is going on with James - and I haven't been asked to take on this work, but in order to move this thing forward, someone has to step up to the plate and take action... otherwise I don't see vcpu hotplug ever making it into the kernel.
I have too much work going on with MPAM. This was posted as an RFC to try and get the Kubernetes and Kata-containers people to test it, and tell us that it works for them.
Without that, there is the risk we've solved the wrong problem.
I asked at kvm-forum, but evidently none of the container orchestration folk there were familiar with the problem.
One of the things that I'm trying to do as well with this patch set is to get pieces of it merged where it makes sense to do so, thereby making *some* progress towards reducing the excessive size of this series - and the size of the series is another detractor to getting review comments and eventually getting it merged.
Be aware that moving those ACPI architectures over to the generic cpu-register stuff is supposed to make this more palate-able, its not there to make this large. As noted in the cover letter, I did have a stab at moving all architectures over, but couldn't get my head round powerpc or s390...
At least we have one patch merged, and three more that are potential for merging. Admittedly I've added two patches... but it's still some forward progress rather than the series continuing to increase in size.
Also, I've had to add back some patches that James dropped between his trees - he dropped the IA64 changes, but that architecture is not going to be removed from the mainline kernel, so its necessary to update that as well. So that's added at least one extra patch to this 35 patch series.
Fair enough - it didn't even build from rc6 to rc1 of the last cycle, and Ard's series said there was prior agreement with the few (one?) person who still cared about that thing.
Given that I never got any response to my suggestion concerning the first patch (which moves the arch_.*register_cpu() prototypes to linux/cpu.h rather than the piecemeal changes through James' patch) which I would have expected James to at least reply to, I've come to the conclusion that James' efforts must be directed elsewhere now and he has no time at all for VCPU hotplug. So, I believe it's now down to those who want the feature in the kernel to take up the batton and progress these patches - and that's exactly what I'm now doing.
Please do. If you change more than 50% of a patch, feel free to change the author too.
Thanks,
James