On Thu, May 01, 2014 at 10:57:39AM +0100, Peter Zijlstra wrote: > On Thu, May 01, 2014 at 10:52:47AM +0100, Catalin Marinas wrote: > > Does gup_fast walking increment the mm_users? Or is it a requirement of > > the calling code? I can't seem to find where this happens. > > No, its not required at all. One should only walk current->mm with > gup_fast, any other usage is broken. OK, I get it now. > And by delaying TLB shootdown, either through disabling IRQs and > stalling IPIs or by using RCU freeing, you're guaranteed your own page > tables won't disappear underneath your feet. And for RCU to work, we still need to use the full tlb_remove_table() logic (Steve's patches just use tlb_remove_page() for table freeing). Thanks. -- Catalin -- 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>