Hi, On Wed, Apr 02 2025, Changyuan Lyu wrote:
> Hi Pratyush, Thanks for suggestions! > > On Thu, Mar 27, 2025 at 17:28:40 +0000, Pratyush Yadav <ptya...@amazon.de> > wrote: >> On Thu, Mar 27 2025, Jason Gunthorpe wrote: >> >> > On Thu, Mar 27, 2025 at 10:03:17AM +0000, Pratyush Yadav wrote: >> > >> >> Of course, with the current linked list structure, this cannot work. But >> >> I don't see why we need to have it. I think having a page-table like >> >> structure would be better -- only instead of having PTEs at the lowest >> >> levels, you have the bitmap. >> > >> > Yes, but there is a trade off here of what I could write in 30 mins >> > and what is maximally possible :) The xarray is providing a page table >> > implementation in a library form. >> > >> > I think this whole thing can be optimized, especially the >> > memblock_reserve side, but the idea here is to get started and once we >> > have some data on what the actual preservation workload is then >> > someone can optimize this. >> > >> > Otherwise we are going to be spending months just polishing this one >> > patch without any actual data on where the performance issues and hot >> > spots actually are. >> >> The memblock_reserve side we can optimize later, I agree. But the memory >> preservation format is ABI and I think that is worth spending a little >> more time on. And I don't think it should be that much more complex than >> the current format. >> >> I want to hack around with it, so I'll give it a try over the next few >> days and see what I can come up with. > > I agree with Jason that "nothing is ABI at this > point" and it will take some time for KHO to stabilize. > > On the other hand if you have already came up with something working and > simple, we can include it in the next version. I already have something that works with zero-order pages. I am currently implementing support for other orders. It is almost done, but I need to test it and do a performance comparison with the current patch. Will post something soon! -- Regards, Pratyush Yadav
