A memory system is provided comprising a memory controller, a level 1 (L1)
cache including L1 tag memory and L1 data memory, a level 2 (L2) cache
coupled to the L1 cache, the L2 cache including L2 tag memory having a
plurality of L2 tag entries and a L2 data memory having a plurality of L2
data entries. The L2 tag entries are more than the L2 data entries. In
response to receiving a tag and an associated data, if L2 tag entries
having corresponding L2 data entries are unavailable and if a first tag
in a first L2 tag entry with an associated first data in a first L2 data
entry has a more recent or duplicate value of the first data in the L1
data memory, the memory controller moves the first tag to a second L2 tag
entry that does not have a corresponding L2 data entry, vacates the first
L2 tag entry and the first L2 data entry and stores the received tag in
the first L2 tag entry and the received data in the first L2 data entry.