From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 5/5] KVM: PPC: Book3S HV: Provide a method for userspace to read and write the HPT Date: Wed, 17 Oct 2012 12:27:47 +0200 Message-ID: <507E8823.3090006@redhat.com> References: <20121016035836.GL1218@drongo> <20121016040152.GQ1218@drongo> <507D31C2.1060800@redhat.com> <20121016115847.GA8331@bloggs.ozlabs.ibm.com> <507D5BD9.3050700@redhat.com> <87txtuyykr.fsf@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Paul Mackerras , Alexander Graf , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, David Gibson , Juan Quintela , Orit Wasserman To: Anthony Liguori Return-path: In-Reply-To: <87txtuyykr.fsf@codemonkey.ws> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 10/16/2012 10:03 PM, Anthony Liguori wrote: >> >> This forces userspace to dedicate a thread for the HPT. > > If no changes are available, does read return a size > 0? I don't think > it's necessary to support polling. The kernel should always be able to > respond to userspace here. The only catch is whether to return !0 read > sizes when there are no changes. > > At any case, I can't see why a dedicated thread is needed. QEMU is > going to poll HPT based on how fast we can send data over the wire. That means spinning if we can send the data faster than we dirty it. But we do that anyway for memory. -- error compiling committee.c: too many arguments to function