On Wed, Jun 22, 2016 at 12:56:56PM -0700, Dave Hansen wrote: > >> > +1. Also it might be (not sure though, just guessing) suitable to do such > >> > thing via memory cgroup controller, instead of carrying this limit per > >> > each process (or task structure/vma or mm). > > I think we'll want this per mm. After all, a high-VA-limit-aware bash > > should be able run high-VA-unaware programs without fiddling with > > cgroups. > > Yeah, cgroups don't make a lot of sense. cgroups make sense in terms of shriking data: we only need to setup the limit once and every process lives in the cgroup get the limit, no need to carry it per every mm. So I guessed it might be usefull. > On x86, the 48-bit virtual address is even hard-coded in the ABI[1]. So > we can't change *any* program's layout without either breaking the ABI > or having it opt in. > > But, we're also lucky to only have one VA layout since day one. > > 1. www.x86-64.org/documentation/abi.pdf - “... Therefore, conforming > processes may only use addresses from 0x00000000 00000000 to 0x00007fff > ffffffff .” Cyrill -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>