Hey guys, was looking over the generic GUP while working on a sparc64 issue and I noticed that you guys do speculative page gets, and after talking with Johannes Weiner (CC:'d) about this we don't see how it could be necessary. If interrupts are disabled during the page table scan (which they are), no IPI tlb flushes can arrive. Therefore any removal from the page tables is guarded by interrupts being re-enabled. And as a result, page counts of pages we see in the page tables must always have a count > 0. x86 does direct atomic_add() on &page->_count because of this invariant and I would rather see the generic version do this too. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
