An apparatus for cache management includes an interface and a processor. The interface is for communicating with a cache memory configured to store data items. The cache controller is configured to obtain a classification of the data items into a plurality of groups, to obtain respective target capacities for at least some of the groups, each target capacity defining a respective required size of a portion of the cache memory that is permitted to be occupied by the data items belonging to the group, and to cache new data items in the cache memory, or evict cached data items from the cache memory, in accordance with a policy that complies with the target capacities specified for the groups.