Zack's Kernel News

Zack's Kernel News

Article from Issue 184/2016
Author(s):

Chronicler Zack Brown reports on the latest news, views, dilemmas, and developments within the Linux kernel community.

Fixing Memory Usage by Not Fixing It

Al Viro recently posted some "flagday" patches – changes that were so invasive, they couldn't be done piecemeal. His idea was to convert the kernel memory handling APIs so that functions like free_page() and a bunch of others would return a pointer instead of just a plain number. His thinking was that everyone doing anything with RAM wanted to get a usable memory pointer, instead of having to do a typecast every time they called the memory handling functions.

Linus Torvalds, however, put the kibosh on the whole idea. Changing an API that had been in place for almost the entire lifespan of the Linux kernel project would cause a lot of confusion among developers. It would also, he said, make backporting new features to earlier versions of the kernel an even bigger headache than it already was, because the backport would have to make sure it undid all of Al's flagday changes, just to get a patch that would successfully apply to the earlier kernel version.

The proper way to do what Al had proposed, said Linus, would be to create a new set of functions that had different names and to allow both versions of each function to exist side by side. That way, people could migrate their portions of the kernel to the new functions in a piecemeal way over time.

[...]

Use Express-Checkout link below to read the full article (PDF).

Buy this article as PDF

Express-Checkout as PDF
Price $2.95
(incl. VAT)

Buy Linux Magazine

SINGLE ISSUES
 
SUBSCRIPTIONS
 
TABLET & SMARTPHONE APPS
Get it on Google Play

US / Canada

Get it on Google Play

UK / Australia

Related content

  • Optimizing Linux Performance

    When you're tuning up Linux performance, you need to keep an eye on a number of components and parameters. This article describes some techniques for optimizing performance by tuning TCP/IP, reducing latency, and configuring NUMA-aware systems. You'll also learn about CPU scheduling and memory management tuning.

  • Kernel News

    In kernel news: Heap Hardening Against Hostile Spraying; and Core Contention Improvements … or Not.

  • Packet Telemetry with Host-INT

    Inband Network Telemetry and Host-INT can provide valuable insights on network performance – including information on latency and packet drops.

  • Kernel News

    Chronicler Zack Brown reports on the latest news, views, dilemmas, and developments within the Linux kernel community.

  • NEWS

    In the news: Patreon Project Looks to Bring Linux to Apple Silicon; A New Chrome OS-Like Ubuntu Remix Is Now Available; System76 Refreshes the Galago Pro Laptop; Linux Kernel 5.10 Is Almost Ready for Release; Canonical Launches Curated Container Images; NS AWS Container Image Library in the Works.

comments powered by Disqus
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters

Support Our Work

Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

Learn More

News