Feeds

Linux police offer deviant Android return from exile

Google, you have three options...

5 things you didn’t know about cloud backup

OSCON Linux kernel maintainers have offered Google three ways of returning Android into their good graces.

Google's options for re-admission to the kernel are: put the stubs of Android's wait locks into the main kernel, introduce Android's wait locks as PMQOS constraints, or adopt a patch written by a Linux kernel maintainer that would re-implement wait locks in a "socially acceptable way".

Android was booted from the Linux kernel when its drivers were deleted last year. It was claimed that nobody cared about the Android kernel code and that Google had made kernel integration difficult with a "sometimes bizarre" security model.

Linux kernel SCSI subsystem maintainer James Bottomley told The Reg that it's up to Google to decide which of the three ways back it prefers. "We need their feedback on the three options," Bottomley told us at the O'Reilly Open-Source Convention in Portland, Oregon.

Google said it has offered Android code for inclusion in the next version of the Linux kernel – version 2.6.34 – but these failed to materialize in the first release candidate.

Google open source programs manager Chris DiBona told The Reg that Google is now "hanging" and the fact its changes didn't make RC1 makes him doubt they'll be included in the final version of 2.6.34 at all.

DiBona said at OSCON: "We are still talking to them [kernel maintainers] – we'll see what happens. We want to be in there. It will open up a lot of devices to the kernel."

He's right to be doubtful. It seems Google's fix was shot down by kernel maintainers in the PMQOS sub system. They objected to hacking the kernel to facilitate changes designed for mobile devices.

The fix appears to have been the result of talks between Google and kernel maintainers at this year's Linux Collaboration Summit in San Francisco, California.

Google had proposed a set of suspend locks – actions that intervened in the race around the phone's system during shut down process in response to an incoming call. The suspend locks were designed to stop shut down so that the user doesn't miss their call.

"Although the sleep and suspend is very elegant, it introduced wait locks to get around the race problem and the kernel developers were not happy with the fact it's a hack around for a lot of races that got introduced into the infrastructure," Bottomley said.

Now, there are the three options on the table awaiting Google's approval.

Stubs would be a temporary measure that could do more harm than good. Developers could compile code to either the main kernel or the Android kernel, creating confusion. Stubs are used in programming to simulate functionality and are used when targeting different platforms.

In a further twist, stubs would be removed from Linux after a period of nine months if there's no permanent fix adding to the confusion.

"Stubs is a bit more dangerous because if nothing happens after a certain time the period stubs approach will get thrown out," Bottomley said.

Bottomley favored the PMQOS or full patch options. Modifications have already been written for the PMQOS subsystem that tackles locks so code's ready to go. The patch, meanwhile, would also perform locks but using what Bottomley called a more "socially acceptable way" – presumably keeping maintainers happy. Android would need to accept these changes, though.

"I'd like to see it sorted out fully... but we need Google to comment fully [on the proposals]," Bottomley said. ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
BBC: We're going to slip CODING into kids' TV
Pureed-carrot-in-ice cream C++ surprise
China: You, Microsoft. Office-Windows 'compatibility'. You have 20 days to explain
Told to cough up more details as antitrust probe goes deeper
Windows 7 settles as Windows XP use finally starts to slip … a bit
And at the back of the field, Windows 8.1 is sprinting away from Windows 8
Linux turns 23 and Linus Torvalds celebrates as only he can
No, not with swearing, but by controlling the release cycle
Scratched PC-dispatch patch patched, hatched in batch rematch
Windows security update fixed after triggering blue screens (and screams) of death
This is how I set about making a fortune with my own startup
Would you leave your well-paid job to chase your dream?
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Endpoint data privacy in the cloud is easier than you think
Innovations in encryption and storage resolve issues of data privacy and key requirements for companies to look for in a solution.
Why cloud backup?
Combining the latest advancements in disk-based backup with secure, integrated, cloud technologies offer organizations fast and assured recovery of their critical enterprise data.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?