Re: [libvirt] [PATCH] blkio: change the minimum weight from 100 to 10

On 08/18/2013 11:59 PM, Gao feng wrote: > kernel had changed the minimum weight of device blkio from > 100 to 10 in commit df457f845e5449be2e7d96668791f789b3770ac7. > > commit df457f845e5449be2e7d96668791f789b3770ac7 > Author: Justin TerAvest <teravest(a)google.com&gt; > Date: Tue Mar 8 19:45:00 2011 +0100 > > blk-cgroup: Lower minimum weight from 100 to 10. > > We've found that we still get good, useful isolation at weights this > low. I'd like to adjust the minimum so that any other changes can take > these values into account. > > Signed-off-by: Justin TerAvest <teravest(a)google.com&gt; > Acked-by: Vivek Goyal <vgoyal(a)redhat.com&gt; > Signed-off-by: Jens Axboe <jaxboe(a)fusionio.com&gt; > > libvirt should comport with kernel. > > Signed-off-by: Gao feng <gaofeng(a)cn.fujitsu.com&gt; > --- > docs/formatdomain.html.in | 4 ++-- > src/util/vircgroup.c | 10 +++++----- > 2 files changed, 7 insertions(+), 7 deletions(-) What happens when running a newer libvirt with an older kernel? Or in other words, what error message do you get if you pass a limit lower than the current kernel can support? I want to make sure the message looks sane to an end-user before accepting this patch. > > - if (weight && (weight > 1000 || weight < 100)) { > + if (weight && (weight > 1000 || weight < 10)) { > virReportError(VIR_ERR_INVALID_ARG, > - _("weight '%u' must be in range (100, 1000)"), > + _("weight '%u' must be in range (10, 1000)"), > weight); > return -1; In other words, I suspect this code needs to be beefed up to actually probe whether the kernel accepted the change, rather than blindly doing the filter ourselves and hoping that it was correct.