On Fri, 14 Jun 2024 19:51:11 -0700 Chris Li <chrisl@xxxxxxxxxx> wrote: > > I'm having trouble understanding the overall impact of this on users. > > We fail the mTHP swap allocation and fall back, but things continue to > > operate OK? > > Continue to operate OK in the sense that the mTHP will have to split > into 4K pages before the swap out, aka the fall back. The swap out and > swap in can continue to work as 4K pages, not as the mTHP. Due to the > fallback, the mTHP based zsmalloc compression with 64K buffer will not > happen. That is the effect of the fallback. But mTHP swap out and swap > in is relatively new, it is not really a regression. Sure, but it's pretty bad to merge a new feature only to have it ineffective after a few hours use. > > > > > There is some test number in the V1 thread of this series: > > > https://lore.kernel.org/r/20240524-swap-allocator-v1-0-47861b423b26@xxxxxxxxxx > > > > Well, please let's get the latest numbers into the latest patchset. > > Along with a higher-level (and quantitative) description of the user impact. > > I will need Barray's help to collect the number. I don't have the > setup to reproduce his test result. > Maybe a follow up commit message amendment for the test number when I get it? Yep, I alter changelogs all the time. > > > > I'll add this into mm-unstable now for some exposure, but at this point > > I'm not able to determine whether it should go in as a hotfix for > > 6.10-rcX. > > Maybe not need to be a hotfix. Not all Barry's mTHP swap out and swap > in patch got merged yet. OK, well please let's give appropriate consideration to what we should add to 6.10-rcX in order to have this feature working well.
