On Tue, Jan 16, 2018 at 02:51:45PM -0800, Andy Lutomirski wrote: > On Tue, Jan 16, 2018 at 8:52 AM, Peter Zijlstra <pet...@infradead.org> wrote: > > On Tue, Jan 16, 2018 at 05:36:49PM +0100, Joerg Roedel wrote: > >> From: Joerg Roedel <jroe...@suse.de> > >> > >> Reserve 2MB/4MB of address space for mapping the LDT to > >> user-space. > > > > LDT is 64k, we need 2 per CPU, and NR_CPUS <= 64 on 32bit, that gives > > 64K*2*64=8M > 2M. > > If this works like it does on 64-bit, it only needs 128k regardless of > the number of CPUs. The LDT mapping is specific to the mm.
Ah, then I got my LDT things confused again... which is certainly possible, we had a few too many variants back then.
