On 25.07.2011, at 21:25, Scott Wood wrote: > On Sun, 24 Jul 2011 11:16:32 +0200 > Alexander Graf <agraf@xxxxxxx> wrote: > >> On 19.07.2011, at 13:20, Johannes Weiner wrote: >> >>> You don't have to work around the mm subsystem trying to reclaim your >>> memory, > > The pages are pinned by get_free_pages_fast(). > >>> maintain disk coherency that is guaranteed by the filebacked >>> memory semantics etc. >>> >>> If your driver provides the memory, there are much less assumptions >>> from userspace that you have to consider and memory management will >>> not interfere either. >> >> Ah, thanks a lot. Scott, mind to switch this to the normal scheme then? Sounds like we don't need to dirty set by then either. > > That's a fair bit of churn and added complexity, both here and in qemu. Is > it really worth redesigning this API again, to avoid setting a few dirty > bits on an already-slow heavyweight exit? Well, alternatively we could simply bail out if the memory is not anonymous, right? Then the pinning on get_user_pages_fast should be enough. Johannes, would there be any downside to this approach? Alex -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
