Updated information about limits

Author: mortent

keps/sig-scheduling/5234-dra-resourceslice-mixins/README.md

@@ -74,6 +74,7 @@ SIG Architecture for cross-cutting KEPs).
 - [Design Details](#design-details)
   - [API](#api)
   - [Implementation](#implementation)
+  - [Limits](#limits)
   - [Test Plan](#test-plan)
       - [Prerequisite testing updates](#prerequisite-testing-updates)
       - [Unit tests](#unit-tests)
@@ -485,7 +486,33 @@ might pick a different device than expected or fails to allocate any device at a
 think this failure mode is preferable than allowing the scheduler to make allocation decisions
 based on incomplete data.
 
-###
+### Limits
+
+For DRA, we have gradually moved away from individual per-slice and per-map limits towards
+aggregating at the higher level. The reason for this is to give users maximum flexibility between
+defining a small number of complex devices or a large number of simple devices in a single
+ResourceSlice without exceeding the limit on the size of Kubernetes objects.
+
+For this KEP, we propose taking this to what is essentially the logical conclusion, where
+we enforce most of the limits across all devices, mixins and counter sets in a ResourceSlice,
+rather than setting separate limits for each of them.
+
+The ResourceSlice-wide limits will be:
+* Total number of devices is 128.
+* Total combined number of attributes and capacity in a ResourceSlice is 4096 (so with the maximum number of devices, there can be 32 per device).
+* Total number of counters is 256.
+* Total number of consumed counters is 2048 (so with the maximum number of devices, there can be 16 per device).
+
+We will still enforce some per-slice limits:
+* The number of mixins that can be referenced from each device, counter set or device counter consumption is 8.
+* The number of taints per device is 4.
+
+The limits on the number of counters across counter sets, mixins and device counter consumption in 1.33 for the
+Partitionable Devices KEP will be removed, as those are still in alpha.
+The limit of 32 on the number of attributes and capacities per device will be removed over the next 2 releases (1.34 and 1.35) to
+preserve safe rollbacks.
+
+With these limits, the worst-case size for a ResourceSlice increases from 1,107,864 bytes to 1,288,825 bytes.
 
 ### Test Plan
 
@@ -808,15 +835,6 @@ size of the ResourceSlice object. However, it also provides features that
 allows drivers to represent devices and counter sets in a more compact way,
 thereby potentially reducing the size of the ResourceSlice object.
 
-To manage the worst-case size of the `ResourceSlice` object, the following limits
-are introduced in addition to the ones already described in the
-[Partitionable Devices KEP](https://github.com/kubernetes/enhancements/tree/master/keps/sig-scheduling/4815-dra-partitionable-devices#will-enabling--using-this-feature-result-in-increasing-size-or-count-of-the-existing-api-objects):
-* The total number of attributes, capacities and counters defined in mixins in a
-  `ResourceSlice` is limited to 256.
-* The total number of mixins allowed in `Device`, `CounterSet` and
-  `DeviceCounterConsumption` is limited to 8.
-
-
 ###### Will enabling / using this feature result in increasing time taken by any operations covered by existing SLIs/SLOs?
 
 Flattening the devices and counter sets will require slightly more work, but