Linux 5.9-rc6 Released With Soft Scrollback Removed, Performance Regression Fixed

Written by Michael Larabel in Linux Kernel on 20 September 2020 at 08:32 PM EDT. 20 Comments
The sixth weekly release candidate to Linux 5.9 is now available with at least two notable changes in particular.

Prominent in Linux 5.9-rc6 is the fix for the previously reported performance regression hitting 5.9. In case you missed it from the end of last week, see the article on controlling page lock unfairness as part of addressing the performance regression. That code is now in Linux 5.9-rc6 and the performance is back on track with Linux 5.8 while I will have out more benchmark numbers soon on the revised Linux 5.8 vs. 5.9 performance state.

Also significant with Linux 5.9-rc6 is the removal of soft scrollback support for the frame-buffer console / VGACON code. Linus noted there are people upset over software scrollback being removed but it remains to be seen if anyone will step up to maintain that code. In any case it's unlikely the soft scrollback code could be cleaned up and restored in time for Linux 5.9 but potentially could re-appear in a future kernel if indeed people are committed to its return.

As for the rest of the changes, Linus Torvalds noted in the 5.9-rc6 announcement, "things look fairly normal: the diffstat looks fairly flat (implying small changes) and we don't have any unusual amount of activity."

He does note that there still is a test regression in the kernel VM code that could potentially lead to Linux 5.9 being pushed back by an additional week depending upon how the patch work pans out.

See our Linux 5.9 feature overview to learn about the other changes coming with this kernel release due out in October.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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