On Thu, Jul 01, 2010 at 08:13:40PM +0800, Xiao Guangrong wrote: > > > Avi Kivity wrote: > > On 07/01/2010 04:11 AM, Xiao Guangrong wrote: > >> > >> Marcelo Tosatti wrote: > >> > >> > >>>> + > >>>> + addr = gfn_to_hva_many(vcpu->kvm, gfn,&entry); > >>>> + if (kvm_is_error_hva(addr)) > >>>> + return -1; > >>>> + > >>>> + entry = min(entry, (int)(end - start)); > >>>> + ret = __get_user_pages_fast(addr, entry, 1, pages); > >>>> + if (ret<= 0) > >>>> + return -1; > >>>> > >>> Why can't you use gfn_to_pfn_atomic() here, one page at a time? Is > >>> the overhead significant that this is worthwhile? > >>> > >>> You're bypassing the centralized interface. > >>> > >> I think it's worthwhile to do since we can reduce gup overhead, no reason > >> to traverse process's page table again and again for the consecutive > >> pages. > >> > > > > Then we should make the centralized interface work in terms of multiple > > pages, and write the single-page interfaces in terms of the multipage > > interfaces. > > > > Umm, i'll import a new function named gfn_to_pfn_many_atomic(... int *enough), > using 'enough' to indicate whether have got the all consecutive pages in the slot, > Marcelo, how about it? :-) Fine. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
