On Mon, May 18, 2020 at 08:31:49AM -0700, Kees Cook wrote: > On Mon, May 18, 2020 at 02:32:31PM +0100, Mark Rutland wrote: > > On Mon, May 18, 2020 at 02:23:47PM +0100, Will Deacon wrote: > > > This is something I would like to revisit, but we need more > > > information from Sami about why Android rejected the larger allocation > > > size, since I don't think there's an awful lot of point merging this > > > series if Android doesn't pick it up. > > > > Indeed. I'd certainly prefer the robustness of a VMAP'd SCS if we can do > > that. > > For smaller devices, the memory overhead was too high. (i.e. 4x more > memory allocated to kernel stacks -- 4k vs 1k per thread.)
I just don't see an extra 3k per thread as being a real issue (the main stack is 16k already). Even just the CPU register state is around 1k. But I'd be very keen to see numbers/performance data that proves me wrong. Will
