Hi Roger and Jan, > -----Original Message----- > From: Roger Pau Monné <[email protected]> > Subject: For 4.17 (was: Re: [PATCH v3 0/2] Move calls to > memory_type_changed()) > > On Thu, Sep 29, 2022 at 12:14:10PM +0200, Jan Beulich wrote: > > On 28.09.2022 16:11, Roger Pau Monne wrote: > > > The current calls to memory_type_changed() are wider than strictly > > > necessary. Move them inside the iocap handlers and also limit to only > > > issue them when required. > > > > > > I would really like to get some feedback on the Arm change, since this > > > is now a prereq for the actual fix. > > > > > > Thanks, Roger. > > > > > > Roger Pau Monne (2): > > > arm/vgic: drop const attribute from gic_iomem_deny_access() > > > x86/ept: limit calls to memory_type_changed() > > > > Are there intentions for having these on 4.17? > > I wasn't sure. From XenServer PoV it's certainly a bug fix, > otherwise some workloads related to GPU passthrough are simply too > slow to be usable. > > I would certainly be fine with it making it's way into 4.17, let me > add Henry: > > Cons: > - Changes the number of issued memory_type_changed(), so there's a > risk I misplaced some of the conditions and we end up with wrong > cache types in the guest p2m due to missing memory_type_changed() > calls. That however won't affect Xen itself, just the guest. > > Pros: > - Removes unneeded memory_type_changed(), thus making some > operations > faster. It's effect it's greatly dependent on using a set of > hypercalls against a domain, which doesn't seem common in upstream. > It's possible other products based on Xen apart from XenServer will > also see an speedup as a result.
Thanks for the information and the detailed summary! I think my understanding is the same as what Jan has in "x86/NUMA: correct memnode_shift calculation for single node system", - we are still not in code freeze but in feature freeze, so properly-reviewed fixes are eligible for the release. For this specific series, (to me) it looks ok and I will not block the merging of this series if maintainers want to merge it :)) Kind regards, Henry > > Thanks, Roger.
