On Mon, Jul 25, 2022 at 02:23:20PM +0200, Borislav Petkov wrote: > On Fri, Jul 22, 2022 at 12:30:36PM -0700, Dave Hansen wrote: > > Sure does... *Something* has to manage the cache coherency so that old > > physical aliases of the converted memory don't write back and clobber > > new data. But, maybe the hardware is doing that now. > > Let's hope. > > > Yeah, that two-tier system is the way it's happening today from what > > I understand. This whole conversation is about how to handle the >4GB > > memory. > > Would it be possible to pre-accept a bunch of mem - think "pre-fault" - > from userspace? > > I.e., I'm thinking some huge process is going to start in the VM, VM > userspace goes and causes a chunk of memory to be pre-accepted and then > the process starts and runs more-or-less smoothly as the majority of its > memory has already been "prepared". An application in the VM can do mlock() or mmap(..., MAP_POPULATE, ...) and this will essentially force acceptance of that memory. But there's no sysctl or something for that. > Or does that not make any sense from mm perspective? > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette -- Sincerely yours, Mike.
