On Wed, Jul 11, 2018 at 05:47:58PM +0200, Michal Privoznik wrote:
> On 07/11/2018 05:25 PM, Pavel Hrdina wrote:
> > On Wed, Jul 11, 2018 at 05:05:07PM +0200, Michal Privoznik wrote:
> >> On 07/11/2018 10:22 AM, Pavel Hrdina wrote:
> >>> We can safely validate the hugepage nodeset attribute at a define time.
> >>> This validation is not done for already existing domains when the daemon
> >>> is restarted.
> >>>
> >>> All the changes to the tests are necessary because we move the error
> >>> from domain start into XML parse.
> >>>
> >>> Signed-off-by: Pavel Hrdina <phrdina@xxxxxxxxxx>
> >>> ---
> >>> src/conf/domain_conf.c | 32 +++++++++++++++++
> >>> src/qemu/qemu_command.c | 34 -------------------
> >>> .../seclabel-dynamic-none-relabel.xml | 2 +-
> >>> tests/qemuxml2argvtest.c | 16 +++++----
> >>> .../qemuxml2xmloutdata/hugepages-pages10.xml | 30 ----------------
> >>> tests/qemuxml2xmloutdata/hugepages-pages4.xml | 1 -
> >>> tests/qemuxml2xmloutdata/hugepages-pages9.xml | 31 -----------------
> >>> .../seclabel-dynamic-none-relabel.xml | 2 +-
> >>> tests/qemuxml2xmltest.c | 3 --
> >>> 9 files changed, 43 insertions(+), 108 deletions(-)
> >>> delete mode 100644 tests/qemuxml2xmloutdata/hugepages-pages10.xml
> >>> delete mode 120000 tests/qemuxml2xmloutdata/hugepages-pages4.xml
> >>> delete mode 100644 tests/qemuxml2xmloutdata/hugepages-pages9.xml
> >>>
> >>> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> >>> index 7396616eda..20d67e7854 100644
> >>> --- a/src/conf/domain_conf.c
> >>> +++ b/src/conf/domain_conf.c
> >>> @@ -6104,6 +6104,35 @@ virDomainDefLifecycleActionValidate(const virDomainDef *def)
> >>> }
> >>>
> >>>
> >>> +static int
> >>> +virDomainDefMemtuneValidate(const virDomainDef *def)
> >>> +{
> >>> + const virDomainMemtune *mem = &(def->mem);
> >>> + size_t i;
> >>> + ssize_t pos = virDomainNumaGetNodeCount(def->numa) - 1;
> >>> +
> >>> + for (i = 0; i < mem->nhugepages; i++) {
> >>> + ssize_t nextBit;
> >>> +
> >>> + if (!mem->hugepages[i].nodemask) {
> >>> + /* This is the master hugepage to use. Skip it as it has no
> >>> + * nodemask anyway. */
> >>> + continue;
> >>> + }
> >>> +
> >>> + nextBit = virBitmapNextSetBit(mem->hugepages[i].nodemask, pos);
> >>> + if (nextBit >= 0) {
> >>
> >> I think its fair to enable hugepages for node #0 which is always there
> >> (even if not configured in domain XML). Just try to run 'numactl -H'
> >> from a domain that has no <numa/> in its XML.
> >
> > Well yes, linux always assumes that there is at least one NUMA node
> > but other systems might not consider it the same.
>
> I don't think the assumption is limited to Linux only. Even Windows
> behave the same. For instance the following example shows that on
> non-NUMA machine there is NUMA node #0.
>
> https://docs.microsoft.com/en-us/windows/desktop/Memory/allocating-memory-from-a-numa-node
Well if we can change the assumption into a fact I'm definitely for
that change to consider all guest to have at least one NUMA node.
I was trying to lookup some documentation/specification but failed
to do so.
>
> >
> >>
> >>> + virReportError(VIR_ERR_XML_DETAIL,
> >>> + _("hugepages: node %zd not found"),
> >>> + nextBit);
> >>> + return -1;
> >>> + }
> >>> + }
> >>
> >> Also, I see that you're removing hugepages-pages9 test from xml2xml
> >> test. But that is needed only because you disallowed nodeset='0' for
> >> nonnuma domain. The real problem there is that the default page size has
> >
> > That is already disallowed but only once you try to start such domain,
> > I'm just moving this check from start time to parse time.
>
> Yes because we have a bug in the code. So when you introduced the test
> it was doomed to fail.
This test case should fail every time because it is invalid
configuration. You have non-NUMA guest with two different pages
and also specific node configured for one page.
> >
> > If you look into qemuxml2argvtest.c you will see that hugepages-pages9
> > is expected to fail.
> >
> >> no numa node to apply to, not nodeset='0'. I guess we need to check for
> >> that too (or do we want to?)
> >
> > That is yet different issue that can be addressed but it should not
> > block this patch.
>
> Well, maybe. I'm not saying your patches are wrong. Apart from allowing
> nodeset='0' (which I think we should do, but I don't have that much of a
> strong opinion there).
To make it clear I'll summarize all the possible combinations and how it
should work so we are on the same page.
Pavel
Attachment:
signature.asc
Description: PGP signature
-- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
