Resending. It did not reach virtio-dev the first time. On Tue, 12 Sep 2017 16:29:47 +0200 Tomáš Golembiovský <tgolembi@xxxxxxxxxx> wrote: > On Tue, 29 Aug 2017 20:01:53 +0800 > Wei Wang <wei.w.wang@xxxxxxxxx> wrote: > > > 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? > > I'll go ahead then and start sending patches. What would be the proper > course of action here? Send patch for the driver first, or send patch > for QEMU first or send both patches right away? > > > > >> > > >> 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. > > This is not necessary. IIUC the driver does not need to send all the > stats. We can simply treat those stats as specific to Linux driver and > other drivers will not send them. Then QEMU will treat them as if zero > was reported. > > > > > 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. > > > Since there were no suggestions for similar stats on other OSes I'd say > we treat the stats for buffers and caches as Linux specific. If there is > any need to send similar stats for other OSes we will add new stat fields > (specific for that particular OS). > > > Thanks, > > Tomas > > -- > Tomáš Golembiovský <tgolembi@xxxxxxxxxx> -- Tomáš Golembiovský <tgolembi@xxxxxxxxxx>
