On Wed, 13 Mar 2019, Barret Rhoden wrote: > > It is very expensive. VMSP exchanges 4K segments via RDMA between servers > > to build a large address space and run a kernel in the large address > > space. Using smaller segments can cause a lot of > > "cacheline" bouncing (meaning transfers of 4K segments back and forth > > between servers). > > > > Given that these are large machines, would it be OK to statically reserve 64K > on them for modules' percpu data?
Likely. > The bug that led me to here was from someone running on a non-VSMP machine but > had that config set. Perhaps we make it more clear in the Kconfig option to > not set it on other machines. That might make it less likely anyone on a > non-VSMP machine pays the 64K overhead. Right. > Are there any other alternatives? Not using static SRCU in any code that > could be built as a module seems a little harsh. Sorry this ended up in my spam folder somehow. Just fished it out.
