The 4.9 kernel has been released

[Posted December 11, 2016 by corbet]

Linus has released the 4.9 kernel, as expected. Some of the headline features in 4.9 include improved security with virtually mapped kernel stacks, the memory-protection keys system calls, the BBR congestion-control algorithm, support for the Greybus bus architecture, shared extents in the XFS filesystem (which will be used to support lightweight copy operations among other things), and much more. The code name has also been changed to "Roaring Lionus". In the end, 16,216 non-merge changesets were pulled for the 4.9 release, making this development cycle the busiest ever by far.

The 4.9 kernel has been released

Posted Dec 12, 2016 7:47 UTC (Mon) by kragil (guest, #34373) [Link] (3 responses)

XFS is getting a lot of love lately (even from Oracle). Is that a sign that BTRFS is not all it was supposed to be (RAID5+ won't work etc) and the community is moving more in the direction of XFS?

The 4.9 kernel has been released

Posted Dec 12, 2016 8:07 UTC (Mon) by tim_small (guest, #35401) [Link] (2 responses)

It'd certainly be nice to have two Linux file-systems with dedup, native snapshots (without licensing and architectural complications). I look forward to testing these feature in XFS once they're complete and upstream.

Over the weekend I hit two bugs on btrfs systems, and cursed my choice of file-system.

One was a CPU hang during btrfs send - but after a quick web search, this turned out to be a performance bug due to a heavily fragmented file (>10,000 fragments), and was pretty easily fixed.

The other looked like filesystem corruption (bad checksums), but whilst backing up the filesystem prior to repair it turned out that the RAM was bad in this box - other filesystems would have gone on silently corrupting, whereas btrfs caught this early.

So what looks like btrfs losing badly twice, was actually one win to btrfs, and I'll call the other one a narrow defeat. In my experience now that Facebook are deploying it in production btrfs is stabilising fairly quickly.

The 4.9 kernel has been released

Posted Dec 12, 2016 21:10 UTC (Mon) by niner (subscriber, #26151) [Link] (1 responses)

When trying out btrfs send/receive for the first time I stumbled over some corruption in my file system. Turned out it was just a lost extent that wasn't referenced by any file and could be fixed easily by btrfsck. It made me question our decision to deploy btrfs on our servers and use send/receive for backups. But then I tried it on my desktop, too and had to shrink my ext4 partition. Which made me discover several corruptions of the ext4 file system. And that's on my desktop which never suffers a power loss while my laptop has endured much over the years in which I've had all my stuff on btrfs.

The result was that send/receive is awesome, file systems are fallible and the important bit is having backups and backups of the backups.

The 4.9 kernel has been released

Posted Dec 13, 2016 11:29 UTC (Tue) by bluss (guest, #47454) [Link]

When minor corruptions like that are a normal occurence, file systems should be designed to handle them in their regular use, without having to run full restore from backup. (If fsck handles it, it's fine).

The 4.9 kernel has been released

Posted Dec 12, 2016 7:51 UTC (Mon) by tpo (subscriber, #25713) [Link] (1 responses)

Greybus from the article links to another article on LWN from 2015 (https://lwn.net/Articles/648400/) about "Project Ara". As far as I'm informed that project got dropped by Google.

So I'm surprised Greybus got merged. Are there any products that actually do use Greybus/UniPro?

The 4.9 kernel has been released

Posted Dec 12, 2016 8:04 UTC (Mon) by micka (subscriber, #38720) [Link]

It was (briefly) mentioned in the 4.9 merge window article.
https://lwn.net/Articles/703110/

You'll find a link to an explaination https://lwn.net/Articles/703353/

The 4.9 kernel has been released

Posted Dec 12, 2016 9:00 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link] (5 responses)

What happened with KernelNewbies ( https://kernelnewbies.org/LinuxVersions )?

The wiki page hasn't been updated for the 4.8 and 4.9 kernels :(

The 4.9 kernel has been released

Posted Dec 12, 2016 10:11 UTC (Mon) by pabs (subscriber, #43278) [Link] (3 responses)

The 4.8 version of the page exists but isn't completed, so I guess they didn't update the page to include it yet.

https://kernelnewbies.org/Linux_4.8

The 4.9 kernel has been released

Posted Dec 12, 2016 15:51 UTC (Mon) by rknight (subscriber, #26792) [Link] (2 responses)

4.9 page also seems to exist at https://kernelnewbies.org/Linux_4.9.

The 4.9 kernel has been released

Posted Dec 12, 2016 16:05 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link] (1 responses)

It doesn't look like there's any activity, though.

I liked KernelNewbies in the past for their same-day kernel release coverage. Do they accept donations? I can't find it in their wiki.

The 4.9 kernel has been released

Posted Dec 13, 2016 4:50 UTC (Tue) by voltagex (guest, #86296) [Link]

Who runs KernelNewbies? They need to nuke or lock down their forum, which has become overrun with spam.

The 4.9 kernel has been released

Posted Dec 13, 2016 8:42 UTC (Tue) by jem (subscriber, #24231) [Link]

If you read German, I recommend reading Kernel-Log at heise.de.

https://www.heise.de/ct/entdecken/?hauptrubrik=Trends+%26...

The 4.9 kernel has been released

Posted Dec 12, 2016 16:31 UTC (Mon) by yokem_55 (subscriber, #10498) [Link]

Greg K-H previously had indicated that this release might become a longterm supported kernel if people didn't go too crazy and abuse the forewarning. Has a final determination been made yet?