On Mon, Jun 23, 2014 at 1:28 PM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > On 06/23/2014 01:06 PM, Andy Lutomirski wrote: >> Can the new vm_operation "name" be use for this? The magic "always >> written to core dumps" feature might need to be reconsidered. > > One thing I'd like to avoid is an MPX vma getting merged with a non-MPX > vma. I don't see any code to prevent two VMAs with different > vm_ops->names from getting merged. That seems like a bit of a design > oversight for ->name. Right? AFAIK there are no ->name users that don't also set ->close, for exactly that reason. I'd be okay with adding a check for ->name, too. Hmm. If MPX vmas had a real struct file attached, this would all come for free. Maybe vmas with non-default vm_ops and file != NULL should never be mergeable? > > Thinking out loud a bit... There are also some more complicated but more > performant cleanup mechanisms that I'd like to go after in the future. > Given a page, we might want to figure out if it is an MPX page or not. > I wonder if we'll ever collide with some other user of vm_ops->name. It > looks fairly narrowly used at the moment, but would this keep us from > putting these pages on, say, a tmpfs mount? Doesn't look that way at > the moment. You could always check the vm_ops pointer to see if it's MPX. One feature I've wanted: a way to have special per-process vmas that can be easily found. For example, I want to be able to efficiently find out where the vdso and vvar vmas are. I don't think this is currently supported. --Andy -- 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>