Performance-Boosting MGLRU Patches Updated Against Current Linux 5.19 State

While there are many exciting new features coming with Linux 5.19, one of the features that wasn't submitted this cycle unfortunately was the Multi-Gen "MGLRU" code led by Google. As covered in several prior Phoronix articles, the MGLRU support has exciting performance implications for making the Linux kernel's page reclaim code far more efficient.

MGLRU patches have been revised over the past year for making the Linux kernel's page reclaim code far more efficient than its current implementation. MGLRU has shown very exciting performance improvements across a variety of real-world workloads. MGLRU was started when Google engineers found the current page reclaim code to be too expensive on CPU resources and making poor decisions around page eviction.

Google is already using MGLRU with Android and Chrome OS. These MGLRU patches have turned up as well in various downstream kernel flavors like XanMod, Liquorix, and the Arch Linux Zen kernel. There was some hope that MGLRU could land for the Linux 5.19 kernel but no pull request was submitted during the recent 5.19 merge window.

The simple synopsis of Multi-Gen LRU (MGLRU).

Out today though is the "v12" patch revision to the Multi-Gen LRU code. MGLRU v12 fixes a bug in the code as well as re-bases the code against the Linux 5.19-rc2 Git state and has been re-tested to verify it's still working nicely on the state of Linux 5.19 upstream code. There are no other v12 changes with MGLRU development appearing to be fairly settled at this stage.

Those interested can see the v12 patches. Here's to hoping MGLRU will get mainlined later this summer for the Linux 5.20 cycle!