Copy qemu-devel. On Wed, Feb 07, 2024 at 04:07:40PM +0800, Peter Xu wrote: > Hi, > > I'm sending this email just to leave a generic comment to the recent > migration efforts to enable these new Intel technologies. > > The relevant patchsets (latest version so far) we're discussing are: > > [PATCH v3 0/4] Live Migration Acceleration with IAA Compression > https://lore.kernel.org/r/20240103112851.908082-1-yuan1....@intel.com > > [PATCH v3 00/20] Use Intel DSA accelerator to offload zero page checking in > multifd live migration. > https://lore.kernel.org/r/20240104004452.324068-1-hao.xi...@bytedance.com > > [PATCH 0/5] *** Implement using Intel QAT to offload ZLIB > https://lore.kernel.org/r/20231231205804.2366509-1-bryan.zh...@bytedance.com > > I want to comment in a generic way since this should apply to all these > series: > > - A heads-up that multifd code is rapidly changing recently, I apologize > that you'll need a rebase. It's just that it's probably much better to > do this before anything lands there. > > IIUC the good thing is we found that send_prepare() doesn't need to be > changed that much, however there's still some change; please refer to > the new code (I'll prepare a pull tomorrow to include most of the > changes, and we should have a major thread race fixed too with Fabiano > & Avihai's help). I hope this will also provide some kind of isolation > to e.g. other works that may touch other areas. E.g., I hope fixed-ram > won't need to conflict much with any of the above series now. > > - When posting the new patchset (if there is a plan..), please make sure > we have: > > - Proper unit tests for the new code (probably mostly software > fallbacks to be tested on the new libraries being introduced; just to > make sure the new library code paths can get some torture please). > > - Proper documentation for the new code. Please feel free to start > creating your own .rst file under docs/devel/migration/, we can try > to merge them later. It should help avoid conflictions. Please also > link the new file into index.rst there. > > IMHO the document can contain many things, the important ones could > start from: who should enable such feature; what one can get from > having it enabled; what is the HW requirement to enable it; how > should one tune the new parameters, and so on... some links to the > technology behinds it would be nice too to be referenced. > > - Try to add new code (especially HW/library based) into new file. > I see that QPL & QAT already proposed its own files (multifd-pql.c, > multifd-qatzip.c) which is great. > > Xiang, please also consider doing so for the DSA based zero page > detection. It can be called multifd-zero-page.c, for example, and > you can create it when working on the > offload-zero-page-detect-to-multifd patchset already. > > - Please provide someone who can potentially maintain this code if ever > possible. Pushing these code upstream is great, but maintaining will > also take effort. It might be impractical this keeps growing for > migration maintainers (currently Fabiano and myself), so we may like > to have people covering these areas, especially when the new codes > are not directly relevant to migration framework. > > I'd suggest for each of the project we can add an entry in > MAINTAINERS below "Migration" section, adding relevant files (and > these files should exist in both the new section and "Migration"). I > am not sure whether Bytedance would be able to cover this, or we > should try to find someone from Intel? If you're willing to add > yourself to maintain such codes, please attach the maintainers file > change together with the series. It will be very much appreciated. > > Thanks, > > -- > Peter Xu
-- Peter Xu
