Messages in this thread | | | Date | Fri, 24 Mar 2023 10:27:14 +0100 | Subject | Re: [RFC 00/12] module: avoid userspace pressure on unwanted allocations | From | David Hildenbrand <> |
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On 21.03.23 20:32, David Hildenbrand wrote: > On 20.03.23 22:27, Luis Chamberlain wrote: >> On Mon, Mar 20, 2023 at 02:23:36PM -0700, Luis Chamberlain wrote: >>> On Mon, Mar 20, 2023 at 10:15:23PM +0100, David Hildenbrand wrote: >>>> Not able to reproduce with 20230319-module-alloc-opts so far (2 tries). >>> >>> Oh wow, so to clarify, it boots OK? >>> >> >> Now that we know that tree works, I'm curious also now if you can >> confirm just re-ordering the patches still works (it should) >> >> https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git/log/?h=20230319-module-alloc-opts-adjust >> > > So far no vmap errors booting the debug/kasan kernel (2 tries). > >> And although it's *probably* just noise, but I'm very curious how much, >> if any difference there is if you just revert "module: use >> list_add_tail_rcu() when adding module". > > Dito, no vmap errors booting the debug/kasan kernel (2 tries). > >> >> The data on that commit log is pretty small as I have a low end system, >> and I'm not yet done beating the hell out of a system with stress-ng, >> but getting some data froma pretty large system would be great. >> Specially if this series seems to prove fixing boot on them. > > 2x booting RHEL9.1 on a !debug kernel. Something went wrong with kdump in 2 runs (think I > had to delete the kdump initrd to make space for another kernel), but we can just mostly > ignore that. I wanted to rerun with kdump disabled completely, but I'm out of time for today. > > > 1) v6.3-rc1: > > #1 > > Startup finished in 25.354s (kernel) + 7.662s (initrd) + 1min 8.805s (userspace) = 1min 41.822s > multi-user.target reached after 29.186s in userspace > > 47.178s kdump.service > 14.898s tuned.service > 11.394s chrony-wait.service > 7.486s systemd-udev-settle.service > 7.334s NetworkManager-wait-online.service > 2.908s initrd-switch-root.service > 2.451s smartd.service > 2.316s dracut-initqueue.service > 2.057s polkit.service > 1.290s NetworkManager.service > 1.046s cups.service > ... > > #2 > > Startup finished in 25.375s (kernel) + 7.497s (initrd) + 29.428s (userspace) = 1min 2.301s > multi-user.target reached after 29.392s in userspace > > 14.552s tuned.service > 9.410s chrony-wait.service > 8.126s systemd-udev-settle.service > 7.502s NetworkManager-wait-online.service > 2.871s initrd-switch-root.service > 2.401s kdump.service > 2.297s polkit.service > 2.116s dracut-initqueue.service > 2.027s smartd.service > 1.262s NetworkManager.service > 1.102s cups.service > 1.011s sshd.service > ... > > > 2) 20230319-module-alloc-opts-adjust + revert of list_add_tail_rcu(): > > #1 > > Startup finished in 25.441s (kernel) + 7.285s (initrd) + 1min 7.644s (userspace) = 1min 40.371s > multi-user.target reached after 27.213s in userspace > > 47.232s kdump.service > 14.235s tuned.service > 8.220s chrony-wait.service > 7.444s NetworkManager-wait-online.service > 5.986s systemd-udev-settle.service > 2.881s initrd-switch-root.service > 2.236s smartd.service > 1.899s dracut-initqueue.service > 1.812s polkit.service > 1.554s NetworkManager.service > 1.140s ModemManager.service > ... > > #2 > > Startup finished in 25.377s (kernel) + 7.271s (initrd) + 28.247s (userspace) = 1min 897ms > multi-user.target reached after 28.210s in userspace > > 15.435s tuned.service > 11.365s chrony-wait.service > 7.512s NetworkManager-wait-online.service > 5.962s systemd-udev-settle.service > 2.889s initrd-switch-root.service > 2.846s smartd.service > 2.819s kdump.service > 2.228s polkit.service > 1.872s dracut-initqueue.service > 1.312s NetworkManager.service > 1.152s ModemManager.service > 1.011s sshd.service > ... > > 3) 20230319-module-alloc-opts-adjust: > > > #1 > > Startup finished in 25.320s (kernel) + 7.192s (initrd) + 1min 6.511s (userspace) = 1min 39.024s > multi-user.target reached after 28.205s in userspace > > 46.307s kdump.service > 14.199s tuned.service > 13.358s chrony-wait.service > 7.468s NetworkManager-wait-online.service > 6.329s systemd-udev-settle.service > 2.910s initrd-switch-root.service > 2.752s smartd.service > 2.142s polkit.service > 1.909s dracut-initqueue.service > 1.210s NetworkManager.service > 1.041s ModemManager.service > 925ms sshd.service > ... > > #2 > > Startup finished in 25.368s (kernel) + 7.303s (initrd) + 1min 6.897s (userspace) = 1min 39.569s > multi-user.target reached after 27.326s in userspace > > 45.626s kdump.service > 14.707s tuned.service > 13.246s chrony-wait.service > 7.428s NetworkManager-wait-online.service > 6.507s systemd-udev-settle.service > 3.038s initrd-switch-root.service > 3.001s smartd.service > 2.057s polkit.service > 1.746s dracut-initqueue.service > 1.221s NetworkManager.service > ... > > > I think we primarily only care about systemd-udev-settle.service. > > That is fastest without the rcu patch (~6s), compared to with the rcu > patch (~6.5s) and with stock (~7.5s -- 8s). > > Looks like dracut-initqueue also might be a bit faster with your changes, but > maybe it's mostly noise (would have to do more runs). > > So maybe drop that rcu patch? But of course, there could be other scenarios where it's > helpful ...
Are there any other things you would like me to measure/test? I'll have to hand back that test machine soonish.
-- Thanks,
David / dhildenb
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