From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx198.postini.com [74.125.245.198]) by kanga.kvack.org (Postfix) with SMTP id 7043F6B0037 for ; Wed, 10 Jul 2013 06:52:08 -0400 (EDT) Subject: Re: [PATCH 3/4] PF: Provide additional direct page notification Mime-Version: 1.0 (Apple Message framework v1278) Content-Type: text/plain; charset=us-ascii From: Alexander Graf In-Reply-To: <20130710104843.GS24941@redhat.com> Date: Wed, 10 Jul 2013 12:52:06 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <1373378207-10451-1-git-send-email-dingel@linux.vnet.ibm.com> <1373378207-10451-4-git-send-email-dingel@linux.vnet.ibm.com> <51DC33E7.1030404@de.ibm.com> <282EB214-206B-4A04-9830-D97679C9F4EC@suse.de> <20130710104253.GQ24941@redhat.com> <13B3500B-18A9-4B97-8C85-597BEAFC9250@suse.de> <20130710104843.GS24941@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Gleb Natapov Cc: Christian Borntraeger , Dominik Dingel , Paolo Bonzini , Heiko Carstens , Martin Schwidefsky , Cornelia Huck , Xiantao Zhang , Christoffer Dall , Marc Zyngier , Ralf Baechle , kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 10.07.2013, at 12:48, Gleb Natapov wrote: > On Wed, Jul 10, 2013 at 12:45:59PM +0200, Alexander Graf wrote: >>=20 >> On 10.07.2013, at 12:42, Gleb Natapov wrote: >>=20 >>> On Wed, Jul 10, 2013 at 12:39:01PM +0200, Alexander Graf wrote: >>>>=20 >>>> On 09.07.2013, at 18:01, Christian Borntraeger wrote: >>>>=20 >>>>> On 09/07/13 15:56, Dominik Dingel wrote: >>>>>> By setting a Kconfig option, the architecture can control when >>>>>> guest notifications will be presented by the apf backend. >>>>>> So there is the default batch mechanism, working as before, where = the vcpu thread >>>>>> should pull in this information. On the other hand there is now = the direct >>>>>> mechanism, this will directly push the information to the guest. >>>>>>=20 >>>>>> Still the vcpu thread should call check_completion to cleanup = leftovers, >>>>>> that leaves most of the common code untouched. >>>>>>=20 >>>>>> Signed-off-by: Dominik Dingel >>>>>=20 >>>>> Acked-by: Christian Borntraeger =20 >>>>> for the "why". We want to use the existing architectured = interface. >>>>=20 >>>> Shouldn't this be a runtime option? >>>>=20 >>> Why? What is the advantage of using sync delivery when HW can do it >>> async? >>=20 >> What's the advantage of having an option at all then? Who selects it? >>=20 > x86 is stupid and cannot deliver the even asynchronously. Platform = that > can do it select the option. We're in generic code. S390x enables it. X86 does not. That was the = missing link! Thanks a lot and sorry for the fuss :). Alex -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org