On Mon, Sep 14, 2020 at 10:00 AM Nicholas Piggin <npiggin@xxxxxxxxx> wrote: > > Excerpts from Nicholas Piggin's message of September 14, 2020 2:52 pm: > > [...] > > > The basic fix for sparc64 is to remove its mm_cpumask clearing code. The > > optimisation could be effectively restored by sending IPIs to mm_cpumask > > members and having them remove themselves from mm_cpumask. This is more > > tricky so I leave it as an exercise for someone with a sparc64 SMP. > > powerpc has a (currently similarly broken) example. > > So this compiles and boots on qemu, but qemu does not support any > sparc64 machines with SMP. Attempting some simple hacks doesn't get > me far because openbios isn't populating an SMP device tree, which > blows up everywhere. > > The patch is _relatively_ simple, hopefully it shouldn't explode, so > it's probably ready for testing on real SMP hardware, if someone has > a few cycles. Nick, applied this patch to over 'v5.9-rc5' tag , used my test VM (ldom) with 32 vcpus. Machine boot, stress-ng test ( run as "stress-ng --cpu 8 --io 8 --vm 8 --vm-bytes 2G --fork 8 --timeout 15m" ) finishes without errors.
