It's Looking Like Folios / Pagesets Might Miss Making It Into Linux 5.15

We are now down to the last day of the Linux 5.15 merge window and one of the patch series we have been waiting to see if it would land during this two week period was the "folios" code -- or that also was recently renamed to "pagesets" to address some concerns over the name.

Folios is the months-long effort working to improve Linux memory management and for some workloads can translate into performance advantages given the current overhead when managing memory in 4KiB pages.

Folios has gone through many rounds of review and interest by some kernel developers in seeing the initial code merged for Linux 5.15. Ahead of the merge window, the folios pull request was sent out for Linux 5.15. As there were some concerns over the "folios" name and it not being too clear, there is also a pull request introducing it under the name of "pageset".

Linus Torvalds hasn't yet commented on his intentions around this pull request for Linux 5.15. However, as the merge window is ending today and given his silence on the matter, it's looking increasingly like the folios/pagesets code won't make it for this cycle unless he decides to pull it in at the last minute.

While Linus has been silent on the matter during the merge window, there was some discussion in the recent days. However, that became somewhat heated with Folios lead developer Matthew Wilcox ending the discussion with:

Ugh. I'm not dealing with this shit. I'm supposed to be on holiday. I've been checking in to see what needs to happen for folios to be merged. But now I'm just fucking done. I shan't be checking my email until September 19th.

Merge the folio branch, merge the pageset branch, or don't merge anything. I don't fucking care any more.

So we'll see if folios/pagesets lands today or is punted off for another kernel cycle in striving to improve Linux memory management.