On Tue, Sep 3, 2024 at 10:49 AM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > On Mon, Sep 2, 2024 at 1:58 AM Piotr Oniszczuk > <piotr.oniszczuk@xxxxxxxxx> wrote: > > > > > > > > > Wiadomość napisana przez Yosry Ahmed <yosryahmed@xxxxxxxxxx> w dniu 31.08.2024, o godz. 19:23: > > > > > > On Sat, Aug 31, 2024 at 2:41 AM Piotr Oniszczuk > > > <piotr.oniszczuk@xxxxxxxxx> wrote: > > >> > > >> > > >> > > >>> Wiadomość napisana przez Yosry Ahmed <yosryahmed@xxxxxxxxxx> w dniu 29.08.2024, o godz. 23:54: > > >>> > > >>> I also noticed that you are using z3fold as the zpool. Is the problem > > >>> reproducible with zsmalloc? I wouldn't be surprised if there's a > > >>> z3fold bug somewhere. > > >>> > > >> > > >> Hmm - yesterday i recompiled 6.9.12 with zsmalloc and …. after 16h of continuous tests I can’t reproduce issue. > > >> With zsmalloc 6.9.12 looks to me like stable. > > > > > > Interesting, and a little bit what I hoped for tbh. > > > > :-) > > > > I tested mainline 6.10.7 with 26h test and also it is stable with zsmalloc > > > > > > > >> > > >> With this - what will be your advice to move forward? > > > > > > Well, it's possible that some zswap change was not fully compatible > > > with z3fold, or surfaced a dormant bug in z3fold. Either way, my > > > recommendation is to use zsmalloc. > > > I have been trying to deprecate > > > > IMHO - isn’t bug in this report + difficulties to reproduce->fix enough to depreciate z3fold? > > I would say this bug report is yet another reason why we should deprecate it. +100000. This is precisely why I was asking which allocator was being used here. We have also accidentally selected z3fold internally a couple times in the past, which had bitten us as well. > > > > > > z3fold, and honestly you are the only person I have seen use z3fold in > > > a while -- which is probably why no one else reported such a problem. > > > > Well - in fact this is ArchLinux - not me. > > I’m using Arch and kernel in builder machine with ArchLinux config + packaging > > According to [1], zsmalloc should be the default allocator for zswap > on ArchLinux. Anyway, I initially thought that no one was using z3fold > and it was bitrot, but apparently some people are using it and it's > actively harming them. > > [1]https://wiki.archlinux.org/title/Zswap > > > > > > > > > > I see benefits already: on very memory demanding qtwebkit compile: > > z3fold: swap frequently gets 6..8G from 16G available > > zsmalloc: can’t see more than 1..2G Exactly :) zsmalloc is better than z3fold in a lot of workloads that I have observed. > > > > > doubt that you (or anyone) wants to spend time debugging a z3fold > > > problem :) > > > > lets depreciate it! > > I tried deprecating it before [2] and performed some analysis [3], but > there was some.. resistance. Maybe I will try again and use this bug > report as yet another argument for deprecating z3fold :) > > [2] https://lore.kernel.org/linux-mm/20240112193103.3798287-1-yosryahmed@xxxxxxxxxx/ > [3] https://lore.kernel.org/lkml/CAJD7tkbRF6od-2x_L8-A1QL3=2Ww13sCj4S3i4bNndqF+3+_Vg@xxxxxxxxxxxxxx/ I don't wanna sound like a broken record. But this has been the nth time we need to spend extra engineering time and effort unnecessarily because we have not deprecated z3fold. If you need more datapoint - here's our last conversation where z3fold was a problem: https://lore.kernel.org/lkml/CAKEwX=Mo+EaaxBYcLMTHYADB4WhqC3QmWV3WQ0h2KM491FRuQA@xxxxxxxxxxxxxx/
