From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Wang Subject: Re: [Qemu-devel] [RFC] Buffers/caches in VirtIO Balloon driver stats Date: Tue, 29 Aug 2017 20:01:53 +0800 Message-ID: <59A557B1.7080704@intel.com> References: <20170827233033.7afa49b9@fiorina> <20170829095726.GL25960@stefanha-x1.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, "Michael S. Tsirkin" To: Stefan Hajnoczi , =?UTF-8?B?VG9tw6HFoSBHb2xlbWJpbw==?= =?UTF-8?B?dnNrw70=?= Return-path: Received: from mga07.intel.com ([134.134.136.100]:25164 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752504AbdH2L64 (ORCPT ); Tue, 29 Aug 2017 07:58:56 -0400 In-Reply-To: <20170829095726.GL25960@stefanha-x1.localdomain> Sender: kvm-owner@vger.kernel.org List-ID: On 08/29/2017 05:57 PM, Stefan Hajnoczi wrote: > On Sun, Aug 27, 2017 at 11:30:33PM +0200, Tomáš Golembiovský wrote: >> Hi, > I have CCed the relevant mailing lists and people most recently involved > in virtio-balloon discussions. Hopefully this will help get the right > people to see your questions. > >> We'd like to include information about reclaimable memory into the >> statistics in VirtiO Balloon driver. Namely, we'd like to include >> counters for bufferes and caches of Linux kernel. The patch itself is >> pretty trivial -- no problem there. But before we do that I'd like to >> get some input from the QEMU community. >> >> 1) Is there any reason not to have the stats there? Could you please share the usages of reclaimable memory via the stats? >> >> 2) Considering the balloon device is multiplatform (Linux, BSD, >> Windows), is there a problem with including buffers/caches? These seem >> to be specific to the Linux virtual memory subsystem. Of course, other >> OSes could just report zeros. Are there some internal stats on those >> OSes that could be filled in? I don't now if such or similar statistic >> are available on BSD. On Windows only SystemCache stat looks like >> something relevant. Anyone familiar with those OSes has any suggestions? >> >> One of the solutions that I'm thinking about is to make virtio platform-ware. That is, the device by default supports VIRTIO_F_LINUX, VIRTIO_F_WINDOWS, VIRTIO_F_BSD. For the Linux driver, only VIRTIO_F_LINUX is supported, then we can have Linux specific driver implementations under that feature. Best, Wei