Trying Out kGraft Live Kernel Patching On Ubuntu Linux

[phoronix]

Phoronix: Trying Out kGraft Live Kernel Patching On Ubuntu Linux

KGraft is the SUSE-developed approach to live-patching the Linux kernel as another reboot-less option similar to Ksplice...

http://www.phoronix.com/vr.php?view=MTcxMjc

[johnc]

This whole idea of patching the kernel seems kind of idiotic and really messy from a maintenance standpoint.

I thought this would be something more along the lines of doing a full kernel update without rebooting the system.

[liam]

This whole idea of patching the kernel seems kind of idiotic and really messy from a maintenance standpoint.

I thought this would be something more along the lines of doing a full kernel update without rebooting the system.

I'm going on the record as calling that impossible given the current architecture of the kernel.
This and kpatch work at the function level, but still need to be scrupulous with their cleanup of old references before inserting the new function.
Also, no abi changes, obviously
With a microkernel things are far easier, and cleaner.
I'm kind of bullish about the long-term prospects of ubiquitous ukernels, actually. As more items become networked, and in general far more things being appliance like, the stability and verifiability of ukernels, along with a safe user space, is going to become more important than ipc overhead or stack manipulation efficiency.
Also, c will go away.
Tomorrow my picks for the track.

[Guest]

With a microkernel things are far easier, and cleaner.
I'm kind of bullish about the long-term prospects of ubiquitous ukernels, actually. As more items become networked, and in general far more things being appliance like, the stability and verifiability of ukernels, along with a safe user space, is going to become more important than ipc overhead or stack manipulation efficiency.
Also, c will go away.
Tomorrow my picks for the track.

That's why Hurd and Minix are the most popular and the most advanced kernels. Oh, wait.. It seems you've got no idea what you're talking about.

[xeekei]

That's why Hurd and Minix are the most popular and the most advanced kernels. Oh, wait.. It seems you've got no idea what you're talking about.

The only one doing pretty good is Mac OS X's kernel. But I'd wager it has nothing to do with the fact that it's a microkernel, success on the desktop has very little to do with technical points of the OS. I don't know what's in Windows at all, if it's monolithic that'll explain why I need to reboot everytime I install a driver.

I still vote for monolithic kernels though, and so does Linus and the FreeBSD guys.

[Guest]

The only one doing pretty good is Mac OS X's kernel. But I'd wager it has nothing to do with the fact that it's a microkernel, success on the desktop has very little to do with technical points of the OS. I don't know what's in Windows at all, if it's monolithic that'll explain why I need to reboot everytime I install a driver.

I still vote for monolithic kernels though, and so does Linus and the FreeBSD guys.

OS X is using hybrid kernel and it's definitely not the reason of its somehow limited popularity.

[liam]

That's why Hurd and Minix are the most popular and the most advanced kernels. Oh, wait.. It seems you've got no idea what you're talking about.

I'm sorry if that's the extent of your knowledge about ukernels
Here's a hunt: ukernels are almost certainly the most used kernel design on existence.

[liam]

The only one doing pretty good is Mac OS X's kernel. But I'd wager it has nothing to do with the fact that it's a microkernel, success on the desktop has very little to do with technical points of the OS. I don't know what's in Windows at all, if it's monolithic that'll explain why I need to reboot everytime I install a driver.

I still vote for monolithic kernels though, and so does Linus and the FreeBSD guys.

As pawlerson says, osx is a weird hybrid kernel where freebsd sits alongside mach but certain functionality that BSD is usually responsible for is handled outside of it by mach(but keep in mind that BSD isn't running as a normal server like that hard real-time systems do with Linux but resides in kernel space). As I understand things it's those functions (like kernel/real-time threads, memory management, IRQ handling and a few other things) that give osx its fantastic latency and reliability. However, the whole thing seems a bit of a mess. It would've been much cleaner, though slower considering the incredibly old mach they're using, to apply the other model I mentioned. Ideally they would've dropped mach and used one of the L4 variants which can actually be really fast.
All of this is beside the point. If you're using a mobile phone you're running at least one ukernel. They're all over the place, but not necessarily user visible.