On Fri, Apr 30, 2021 at 12:38 AM Konstantin Kharlamov <hi-angel@xxxxxxxxx> wrote: > > Btw, I noticed a fun thing, an improvement. I don't know yet if it can be > attributed to 5.12 (which I didn't try alone yet) or to the LRU patchset, but > I'd assume the latter, because 5.12 seems didn't to have had anything > interesting regarding memory performance¹. I appreciate the testing and the report. They mean a lot to us. This improvement is to be expected, and it works both ways. There are cases that swapping is not a good idea, for example, when building large repos. Without this patchset, some of my browser memory usually gets swapped out while tons of memory is used to cache files I don't really care about. I completely agree with you on the memory cgroup part: theoretically it could work around the problem but nobody knows how much memory to reserve for Skype or Firefox :) I will keep you posted on the following developments. Thanks! > I usually have Skype running in background for work purposes, which is only used > 2-3 times in a week. So one would expect it to be one the first victims to > memory reclaim. Unfortunately, I never seen this to actually happen (till now, > that is): all skypeforlinux processes routinely have 0 bytes in SWAP, and the > only circumstances under which its processes can get into SWAP is after > experiencing many SWAP-storms. It was so hard for the kernel to move these > unused processes to SWAP that at some point I even tried to research if there > are any odd flags a userspace may have set on a process to keep it in RAM, just > in case that's what happens to Skype (A: no, that wasn't the case, running Skype > in a memory limited cgroup makes it swap. It's just that kernel decision were > lacking for some reason). > > So, anyway, I am delighted to see now that while testing this patchset, and > without encountering even a single SWAP-storm yet, skypeforlinux are one of the > processes residing in SWAP!! > > λ smem -kc "name user pid pss swap" | grep skype > skypeforlinux constantine 1151 60.0K 7.5M > skypeforlinux constantine 1215 195.0K 8.1M > skypeforlinux constantine 1149 706.0K 7.5M > skypeforlinux constantine 1148 743.0K 7.3M > skypeforlinux constantine 1307 1.4M 8.0M > skypeforlinux constantine 1213 2.1M 46.1M > skypeforlinux constantine 1206 14.0M 10.8M > skypeforlinux constantine 818 38.5M 34.3M > skypeforlinux constantine 1242 103.2M 46.8M > > !!! > > 1: https://kernelnewbies.org/Linux_5.12#Memory_management > > On Fri, 2021-04-30 at 02:46 +0300, Konstantin Kharlamov wrote: > > In case you need it yet, this series is: > > > > Tested-by: Konstantin Kharlamov <Hi-Angel@xxxxxxxxx> > > > > My success story: I have Archlinux with 8G RAM + zswap + swap. While developing, > > I have lots of apps opened such as multiple LSP-servers for different langs, > > chats, two browsers, etc… Usually, my system gets quickly to a point of SWAP- > > storms, where I have to kill LSP-servers, restart browsers to free memory, etc, > > otherwise the system lags heavily and is barely usable. > > > > 1.5 day ago I migrated from 5.11.15 kernel to 5.12 + the LRU patchset, and I > > started up by opening lots of apps to create memory pressure, and worked for a > > day like this. Till now I had *not a single SWAP-storm*, and mind you I got 3.4G > > in SWAP. I was never getting to the point of 3G in SWAP before without a single > > SWAP-storm. > > > > Right now my gf on Fedora 33 also suffers from SWAP-storms on her old Macbook > > 2013 with 4G RAM + zswap + swap, I think the next week I'll build for her 5.12 + > > LRU patchset as well. Will see how it goes, I expect it will improve her > > experience by a lot too. > > > > P.S.: upon replying please keep me CCed, I'm not subscribed to the list >
