Before this fix, hint permutations such as:
permutation: [{11 true} {0101 true}]
Could result in merged hints of:
mergedHint: {01 true}
This was possible because both hints in the permutation container a "preferred"
allocation (i.e. the full set of NUMA nodes set in the affinity bitmask are
*required* to satisfy the allocation). With this in place, the simplified logic
we had simply kept the merged hint as preferred as well.
However, what we really want is to ensure that the merged hint is only
preferred if *true* alignment of all resources is possible (i.e. if all hints
in the permutation are preferred AND their affinities are exactly equal).
The only exception to this is if *no* topology information is provided by a
given hint provider. In this case, we assume alignment doesn't matter and only
consider the resources that actually have hints provided for them.
This changes the semantics of permutations of the form:
permutation: [{111 true} {011 true}]
To now result in the merged hint of:
mergedHint: {011 false}
Instead of:
mergedHint: {011 true}
This is arguably how it should always have been though (because a hint should
not be preferred if true alignment isn't possible), and two tests have had to
change to accomodate these new semantics.
This commit changes the merge function to implement the updated logic, adds a
test to verify it is functioning correctly, and updates the two tests mentioned
above to adjust to the new semantics.
Signed-off-by: Kevin Klues <kklues@nvidia.com>
Introduce a new `admission` subpackage to factor out the responsability
to create `PodAdmitResult` objects. This enables resource manager
to report specific errors in Allocate() and to bubble up them
in the relevant fields of the `PodAdmitResult`.
To demonstrate the approach we refactor TopologyAffinityError as a
proper error.
Co-authored-by: Kevin Klues <kklues@nvidia.com>
Co-authored-by: Swati Sehgal <swsehgal@redhat.com>
Signed-off-by: Francesco Romani <fromani@redhat.com>
* Add topologyScopeName parameter to NewManager().
* Add scope interface and structure that implement common logic
* Add pod scope & container scopes
* Add pod lifecycle functions
Co-authored-by: sw.han <sw.han@samsung.com>
Signed-off-by: Krzysztof Wiatrzyk <k.wiatrzyk@samsung.com>
This patch removes GetNUMANodeInfo, cadvisor.MachineInfo will be used
instead of it. GetNUMANodeInfo was introduced due to difference of meaning of
MachineInfo.Topology. On the arm it was NUMA nodes, but on the x86 it
represents sockets (since reading from /proc/cpuinfo). Now it unified
and MachineInfo.Topology represents NUMA node.
Signed-off-by: Alexey Perevalov <alexey.perevalov@huawei.com>
Having this interface allows us to perform a tight loop of:
for each container {
containerHints = {}
for each provider {
containerHints[provider] = provider.GatherHints(container)
}
containerHints.MergeAndPublish()
for each provider {
provider.Allocate(container)
}
}
With this in place we can now be sure that the hints gathered in one
iteration of the loop always consider the allocations made in the
previous.
Previously, the verious Merge() policies of the TopologyManager all
eturned their own lifecycle.PodAdmitResult result. However, for
consistency in any failed admits, this is better handled in the
top-level Topology manager, with each policy only returning a boolean
about whether or not they would like to admit the pod or not. This
commit changes the semantics to match this logic.
Previously, we unconditionally removed *all* topology hints from a pod
whenever just one container was being removed. This commit makes it so
we only remove the hints for the single container being removed, and
then conditionally remove the pod from the podTopologyHints[podUID] when
no containers left in it.
- Move remaining logic from mergeProvidersHints to generic top level
mergeFilteredHints function.
- Add numaNodes as parameter in order to make generic.
- Move single NUMA node specific check to single-numa-node Merge
function.
- Move initial 'filtering' functionality to generic function
filterProvidersHints level policy.go.
- Call new function from top level Merge function.
- Rename some variables/parameters to reflect changes.
The logic has been updated to match the logic of the best-effort policy
except in two places:
1) The hint filtering frunction has been updated to allow "don't care"
hints encoded with a `nil` affinity mask, to pass through the filter in
addition to hints that have just a single NUMA bit set.
2) After calculating the `bestHint` we transform "don't care" affinities
encoded as having all NUMA bits set in their affinity masks into "don't
care" affinities encoded as `nil`.
