* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Fri, Jul 12, 2013 at 10:44:06AM +0200, Ingo Molnar wrote: > > It makes tons of sense. > > > > Just like we have a task's cmd-name it makes a lot of sense to name > > objects in a human readable fashion, to help debugging, instrumentation, > > performance analysis, etc. > > > > Yes, in theory user-space could do all that. That's not the point: the > > point is to make it fast, easy enough and to have a central version (the > > kernel). > > > > Doing it via temporary files has various disadvantages: > > We need those files anyway.. The current proposal is that the entire VMA > has a single userspace pointer in it. Or rather a 64bit value. Yes but accessible via /proc/<PID>/mem or so? > > I guess the real question is not whether it's useful, I think it > > clearly is. The question should be: are there real downsides? Does the > > addition to the anon mmap field blow up the size of vma_struct by a > > pointer, or is there still space? > > I don't see how the single u64 is useful at all for perf; you can have > at most one u64 per page; that's not nearly enough to put symbol > information in. Therefore we still require external files. I was thinking about it in the context of its original purpose: naming heap areas, which are pretty anonymous right now - /proc/*/maps is full of mystery ranges today. It's indeed not good enough for finer grained structure. Thanks, Ingo -- 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>