On 9/1/23 03:17, Chao Peng wrote: > On Thu, Aug 31, 2023 at 11:29:22AM -0700, Sean Christopherson wrote: >> On Tue, Aug 29, 2023, Chao Peng wrote: >> > On Fri, Aug 25, 2023 at 10:47:12AM -0700, Sean Christopherson wrote: >> > > >> > > >> > > Filemap vs. xarray >> > > ------------------ >> > > This is the main item that needs attention. I don't want to merge guest_memfd() >> > > without doing this comparison, as not using filemap means we don't need AS_UNMOVABLE. >> > > Arguably we could merge a filemap implementation without AS_UNMOVABLE and just eat >> > > the suboptimal behavior, but not waiting a little while longer to do everything we >> > > can to get this right the first time seems ridiculous after we've been working on >> > > this for literally years. >> > > >> > > Paolo was going to work on an axarray implementation, but AFAIK he hasn't done >> > > anything yet. We (Google) don't have anyone available to work on an xarray >> > > implementation for several weeks (at best), so if anyone has the bandwidth and >> > > desire to take stab at an xarray implementation, please speak up. >> > >> > I can do some experiments in the following weeks on the xarray >> > direction. I'm not quite confident I understood all what Paolo >> > originally wanted to do, so questions may have. >> >> FYI, I jumped the gun, sounds like Paolo got far enough along to form a strong >> opinion[*]. > > Yeah, I see that, that is a good news actually, then we can go ahead with > the current filemap one. I personally think these mm touchpoints are not > a big deal when compared to previous versions, most part we are just using > the APIs. I also agree with the outcome, I think staying will filemap will be more future proof e.g. if migration and swapout becomes possible in the future. I don't think having to touch some mm/ code is that much of a problem. Hopefully the AS_UNMOVABLE issue will be sufficiently addressed by this: https://lore.kernel.org/all/20230901082025.20548-2-vbabka@xxxxxxx/ >> >> Thanks for volunteering though, much appreciated! > > NP, any collaboration is to make this lasting years series merge earlier. > > Chao >> >> [*] https://lore.kernel.org/all/CABgObfay4FKV=foWLZzAWaC2kVHRnF1ib+6NC058QVZVFhGeyA@xxxxxxxxxxxxxx
