mem: Promote deferred targets only when the block is valid
authorNikos Nikoleris <nikos.nikoleris@arm.com>
Thu, 8 Sep 2016 11:02:47 +0000 (12:02 +0100)
committerNikos Nikoleris <nikos.nikoleris@arm.com>
Tue, 5 Dec 2017 11:47:01 +0000 (11:47 +0000)
commit2141c2904af0f72dba4f6ec19983392d53c718bd
tree78b31286cf25c2cad316b7c1c913684b0e0fa27d
parente67c97ee4cd61dda4378f27e0baa329b020a2fee
mem: Promote deferred targets only when the block is valid

When a response indicates that there are no other sharers of the
block, the cache can promote its copy of the block to writable and
potential service deferred targets even if the request didn't ask for
a writable copy.

Previously, a response would guarantee the presence of the block in
the cache. A response could either be filling, upgrading or a response
to an invalidation due to a pending whole line write. Responses to
cache maintenance invalidations break this assumption. This change
adds an extra check to make sure that the block was already valid or
that the response is filling before promoting the block.

Change-Id: I6839f683a05d4dad4205c23f365a925b7b05e366
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Anouk Van Laer <anouk.vanlaer@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5048
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
src/mem/cache/cache.cc