Jens Axboe On Kernel Development

BlockHead writes "Kerneltrap.org is running an interview with Jens Axboe, 15 year Linux veteran and the maintainer of the linux kernel block layer, 'the piece of software that sits between the block device drivers (managing your hard drives, cdroms, etc) and the file systems.' The interview examines what's involved in maintaining this complex portion of the Linux kernel, and offers an accessible explanation of how IO schedulers work. Jens details his own CFQ, or Complete Fair Queue scheduler which is the default Linux IO scheduler. Finally, the article examines the current state of Linux kernel development, how it's changed over the years, and what's in store for the future."

Comments

Disagree with Mr. Axboe...

[isaac]

JA: In your opinion, with the increased rate of development happening on the 2.6 kernel, has it remained stable and reliable?

Jens Axboe: I think so. With the new development model, we have essentially pushed a good part of the serious stabilization work to the distros.

I respectfully disagree that the new development model works well from an end-user's perspective (an "end user" of many thousands of linux hosts, not a toy desktop environment). Minor point releases now contain major changes in e.g. schedulers. This makes for a lot of work for real Linux users, backporting the useful bugfixes while retaining older algorithsm for which workloads are optimized. Result: a severely splintered kernel and a lot more work for us.

If core changes of such magnitude are no longer sufficient to merit a dev branch or even a major point release, why bother with the "2.6" designation at all? Just pull a Solaris and call the next release "Linux 20" or "Linux XX."

-Isaac

Re:Disagree with Mr. Axboe...

[Kjella]

Well, on the other side distros were backporting *huge* amounts of patches from 2.5 to 2.4, so while plain vanilla 2.4 was stable, almost noone was running it. The 2.6 releases means the distros are shipping "stabilized unstables" instead of "destabilized stables", I guess that works out better for some and worse for some. Are RHEL, SLES, Debian stable kernels not good enough kernels to start out with, if stability is what you need? I feel there's quite a few things I see come which I find great that arrive in a timely fashion, not at the release of 2.8 in a few years. I think most that use a distro's kernel feel that way.

If you're the kind of kernel hacker who liked to get yours directly from kernel.org, yes then it sucks. But IMO the kernel has grown too big for just the core devs, think of it as an "extended" kernel team including the distros, where kernel.org releases are "internal betas". I think if you cut it back and expect just kernel.org to deliver stable kernels with the resources they have (which admittingly, they used to) then kernel development will slow way down.