On Mon, Apr 12, 2021 at 11:18:43PM +0200, Ben Hutchings wrote: > On Sun, 2021-04-11 at 18:44 -0700, Josh Triplett wrote: > > On Sun, Apr 11, 2021 at 10:45:27PM +0200, Ben Hutchings wrote: > > That wouldn't actually solve the issue as reported. I was hoping > > specifically for the in-kernel support. > > > > I'd like to use this on a cloud instance that uses ext4 on NVMe, and > > thus doesn't currently need an initramfs. > > I think I missed or forgot about that change when it happened. I'm not > super happy about it, to be honest. It's been half-assed in that the > cloud flavours still have a dependency on an initramfs builder, that > should be a Recommends if we really want to support non-initramfs > booting. There's no documentation that explains when that should work.
I didn't realize this would be an issue, and I *definitely* didn't intend for this change to be a surprise. In this context, I was much more concerned about boot speed than disk usage, and I was willing to take what I could get. I would be willing (after the release) to do more work to make this a supported configuration, if you'd be willing to consider that. I'd love to see initramfs-tools in Recommends, and I'd be happy to write documentation for the Description that explains when it's required. Something like this: """ This kernel package Recommends initramfs-tools. On cloud systems meeting all of the following requirements, you can skip installing initramfs-tools and boot without an initramfs: - The root filesystem lives on an NVMe drive (no RAID, LVM, dm-crypt, or similar). - The root filesystem uses ext4. - The root filesystem is identified by PARTUUID or by device name. - Required system components such as /usr are part of the root filesystem. """ Does that sound potentially reasonable? > Have you tried using tiny-initramfs? Does that still significantly > slow down boot relative to not using an initramfs image? This is the first time I've heard of tiny-initramfs. I'm currently counting the milliseconds, and loading any initramfs at all does substantially add to boot time, compared to not requiring an initramfs; the kernel has to extract it into memory and mount it, and the bootloader has to load it from disk. - Josh Triplett
