Hi Yosry, > -----Original Message----- > From: Yosry Ahmed <yosryahmed@xxxxxxxxxx> > Sent: Friday, August 23, 2024 8:10 PM > To: Nhat Pham <nphamcs@xxxxxxxxx> > Cc: Sridhar, Kanchana P <kanchana.p.sridhar@xxxxxxxxx>; linux- > kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; hannes@xxxxxxxxxxx; > ryan.roberts@xxxxxxx; Huang, Ying <ying.huang@xxxxxxxxx>; > 21cnbao@xxxxxxxxx; akpm@xxxxxxxxxxxxxxxxxxxx; Zou, Nanhai > <nanhai.zou@xxxxxxxxx>; Feghali, Wajdi K <wajdi.k.feghali@xxxxxxxxx>; > Gopal, Vinodh <vinodh.gopal@xxxxxxxxx> > Subject: Re: [PATCH v4 0/4] mm: ZSWAP swap-out of mTHP folios > > [..] > > > > I'm not trying to delay this patch - I fully believe in supporting > > zswap for larger pages (both mTHP and THP - whatever the memory > > reclaim subsystem throws at us). > > > > But we need to get to the bottom of this :) These are very suspicious > > and concerning data. If this is something urgent, I can live with a > > gate to enable/disable this, but I'd much prefer we understand what's > > going on here. > > Agreed. I don't think merging this support is urgent, so I think we > should better understand what is happening here. If there is a problem > with how we charge compressed memory today (temporary double charges), > we need to sort this out before the the mTHP support, as it will only > make things worse. > > I have to admit I didn't take a deep look at the discussion and data, > so there may be other problems that I didn't notice. It seems to me > like Kanchana is doing more debugging to understand what is happening, > so that's great! This sounds good. I just shared the data and my learnings from some debugging experiments. I would appreciate it if you can review this and suggest next steps. > > As for the patches, we should sort out the impact on a higher level > before discussing implementation details. From a quick look though it > seems like the first patch can be dropped after Usama's patches that > remove the same-filled handling from zswap land, and the last two > patches can be squashed. Sure, this sounds good. Thanks, Kanchana
