On Thu, Feb 02, 2023 at 12:15:36PM +0100, Linux kernel regression tracking (Thorsten Leemhuis) wrote: > [adding Konstantin and Greg to the list of recipients] > > On 01.02.23 12:52, Thorsten Leemhuis wrote: > > Add a text explaining how to quickly build a kernel, as that's something > > users will often have to do when they want to report an issue or test > > proposed fixes. This is a huge and frightening task for quite a few > > users these days, as many rely on pre-compiled kernels and have never > > built their own. They find help on quite a few websites explaining the > > process in various ways, but those howtos often omit important details > > or make things too hard for the 'quickly build just for testing' case > > that 'localmodconfig' is really useful for. Hence give users something > > at hand to guide them, as that makes it easier for them to help with > > testing, debugging, and fixing the kernel. > > Side note: after feedback on social media I'll likely switch to a title > like "how to quickly configure & build a trimmed-down Linux kernel", as > some people from the current title assumed this would be about things > like ccache. I'll also likely will switch to using a localversion file > in the buildroot instead of modifying the EXTRAVERSION in the top-level > makefile (but I haven't actually tried it yet). > > > [...] > > > > The text currently describes two approaches to retrieve Linux' sources > > using git: the regular clone with linux-stable as a remote and a shallow > > clone with just one branch from linux-stable. The shallow clone approach > > is a little bit more tricky to describe and handle, but downloads way > > less data – and thus is a lot quicker, unless you have a really really > > quick link to the internet (which in some parts of the world is hard to > > come by). That's why I wonder if the text should switch to making the > > shallow clone with selected stable branches the default. What do you > > think, dear reader? > > So, I looked into what Greg suggested (e.g. > https://kernel.org/best-way-to-do-linux-clones-for-your-ci.html and > https://www.kernel.org/cloning-linux-from-a-bundle.html > ). Assuming users have a up2date git (afaics 2.38+) I could use commands > like this in my text: > > curl -L > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/clone.bundle > -o ~/linux/linux-stable.git.bundle > git clone --bundle-uri=linux-stable.git.bundle > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git > ~/linux/sources > rm ~/linux/linix-stable.git.bundle > > This took roundabout 16 minutes with my 100 Mbit cable internet > connection (~9 min for the download, 7 for the clone [the machine used > is somewhat old]) and downloads & stores ~4,5 GByte data (without checkout). > > [side note: using > "--bundle-uri=https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/clone.bundle"; > does not work (due to the redirect? whatever) -- but that might be > unwise anyway in case the download is interrupted] > > > Then I tried creating a shallow clone like this: > > git clone > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > --depth 1 -b v6.1 > git remote set-branches --add origin master > git fetch --all --shallow-exclude=v6.1 > git remote add -t linux-6.1.y linux-stable > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git > git fetch --all --shallow-exclude=v6.1 > > This took only roundabout 2 minutes and downloads & stores ~512 MByte > data (without checkout). > > > Not totally sure, but the shallow clone somehow feels more appropriate > for the use case (reminder, there is a "quickly" in the document title), > even if such a clone is less flexible (e.g. users have to manually add > stable branches they are interested it; and they need to be careful when > using git fetch). > > That's why I now strongly consider using the shallow clone method by > default in v2 of this text. Or does that also create a lot of load on > the servers? Or are there other strong reason why using a shallow clone > might be a bad idea for this use case? I think Konstantin answered your question already on a social network based on the server load question. For the "will this work for testing", sure, a shallow clone should work just fine, if no one has to use 'git bisect' to go back further than the version you originally clone. Hopefully that's not a normal thing. thanks, greg k-h
