From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id 18C9A6B000C for ; Fri, 15 Jun 2018 10:38:34 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id m4-v6so7642284qtn.19 for ; Fri, 15 Jun 2018 07:38:34 -0700 (PDT) Received: from mx1.redhat.com (mx3-rdu2.redhat.com. [66.187.233.73]) by mx.google.com with ESMTPS id c45-v6si913075qte.201.2018.06.15.07.38.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Jun 2018 07:38:33 -0700 (PDT) Date: Fri, 15 Jun 2018 17:38:31 +0300 From: "Michael S. Tsirkin" Subject: Re: [PATCH v33 0/4] Virtio-balloon: support free page reporting Message-ID: <20180615172933-mutt-send-email-mst@kernel.org> References: <1529037793-35521-1-git-send-email-wei.w.wang@intel.com> <20180615142610-mutt-send-email-mst@kernel.org> <286AC319A985734F985F78AFA26841F7396A3DC9@shsmsx102.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <286AC319A985734F985F78AFA26841F7396A3DC9@shsmsx102.ccr.corp.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Wang, Wei W" Cc: "virtio-dev@lists.oasis-open.org" , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "linux-mm@kvack.org" , "mhocko@kernel.org" , "akpm@linux-foundation.org" , "torvalds@linux-foundation.org" , "pbonzini@redhat.com" , "liliang.opensource@gmail.com" , "yang.zhang.wz@gmail.com" , "quan.xu0@gmail.com" , "nilal@redhat.com" , "riel@redhat.com" , "peterx@redhat.com" On Fri, Jun 15, 2018 at 02:28:49PM +0000, Wang, Wei W wrote: > On Friday, June 15, 2018 7:30 PM, Michael S. Tsirkin wrote: > > On Fri, Jun 15, 2018 at 12:43:09PM +0800, Wei Wang wrote: > > > - remove the cmd id related interface. Now host can just send a free > > > page hint command to the guest (via the host_cmd config register) > > > to start the reporting. > > > > Here we go again. And what if reporting was already started previously? > > I don't think it's a good idea to tweak the host/guest interface yet again. > > This interface is much simpler, and I'm not sure if that would be an > issue here now, because now the guest delivers the whole buffer of > hints to host once, instead of hint by hint as before. And the guest > notifies host after the buffer is delivered. In any case, the host > doorbell handler will be invoked, if host doesn't need the hints at > that time, it will just give back the buffer. There will be no stale > hints remained in the ring now. > > Best, > Wei I still think all the old arguments for cmd id apply. -- MST