summaryrefslogtreecommitdiff
path: root/src/mem
diff options
context:
space:
mode:
Diffstat (limited to 'src/mem')
-rw-r--r--src/mem/cache/cache.cc12
-rw-r--r--src/mem/cache/mshr.cc37
2 files changed, 22 insertions, 27 deletions
diff --git a/src/mem/cache/cache.cc b/src/mem/cache/cache.cc
index 29919ccdf..67e889453 100644
--- a/src/mem/cache/cache.cc
+++ b/src/mem/cache/cache.cc
@@ -2005,15 +2005,9 @@ Cache::handleSnoop(PacketPtr pkt, CacheBlk *blk, bool is_timing,
}
if (!respond && is_timing && is_deferred) {
- // if it's a deferred timing snoop then we've made a copy of
- // both the request and the packet, and so if we're not using
- // those copies to respond and delete them here
- DPRINTF(Cache, "Deleting pkt %p and request %p for cmd %s addr: %p\n",
- pkt, pkt->req, pkt->cmdString(), pkt->getAddr());
-
- // the packets needs a response (just not from us), so we also
- // need to delete the request and not rely on the packet
- // destructor
+ // if it's a deferred timing snoop to which we are not
+ // responding, then we've made a copy of both the request and
+ // the packet, delete them here
assert(pkt->needsResponse());
delete pkt->req;
delete pkt;
diff --git a/src/mem/cache/mshr.cc b/src/mem/cache/mshr.cc
index b58c256cd..1a97d5594 100644
--- a/src/mem/cache/mshr.cc
+++ b/src/mem/cache/mshr.cc
@@ -364,36 +364,37 @@ MSHR::handleSnoop(PacketPtr pkt, Counter _order)
if (isPendingDirty() || pkt->isInvalidate()) {
// We need to save and replay the packet in two cases:
// 1. We're awaiting an exclusive copy, so ownership is pending,
- // and we need to respond after we receive data.
+ // and we need to deal with the snoop after we receive data.
// 2. It's an invalidation (e.g., UpgradeReq), and we need
// to forward the snoop up the hierarchy after the current
// transaction completes.
-
- // Actual target device (typ. a memory) will delete the
- // packet on reception, so we need to save a copy here.
- // Clear flags and also allocate new data as the original
- // packet data storage may have been deleted by the time we
- // get to send this packet.
- PacketPtr cp_pkt = nullptr;
+ // Start by determining if we will eventually respond or not,
+ // matching the conditions checked in Cache::handleSnoop
+ bool will_respond = isPendingDirty() && pkt->needsResponse() &&
+ pkt->cmd != MemCmd::InvalidateReq;
+
+ // The packet we are snooping may be deleted by the time we
+ // actually process the target, and we consequently need to
+ // save a copy here. Clear flags and also allocate new data as
+ // the original packet data storage may have been deleted by
+ // the time we get to process this packet. In the cases where
+ // we are not responding after handling the snoop we also need
+ // to create a copy of the request to be on the safe side. In
+ // the latter case the cache is responsible for deleting both
+ // the packet and the request as part of handling the deferred
+ // snoop.
+ PacketPtr cp_pkt = will_respond ? new Packet(pkt, true, true) :
+ new Packet(new Request(*pkt->req), pkt->cmd);
if (isPendingDirty()) {
- // Case 1: The new packet will need to get the response from the
+ // The new packet will need to get the response from the
// MSHR already queued up here
- cp_pkt = new Packet(pkt, true, true);
pkt->assertMemInhibit();
// in the case of an uncacheable request there is no need
// to set the exclusive flag, but since the recipient does
// not care there is no harm in doing so
pkt->setSupplyExclusive();
- } else {
- // Case 2: We only need to buffer the packet for information
- // purposes; the original request can proceed without waiting
- // => Create a copy of the request, as that may get deallocated as
- // well
- cp_pkt = new Packet(new Request(*pkt->req), pkt->cmd);
- DPRINTF(Cache, "Copying packet %p -> %p and request %p -> %p\n",
- pkt, cp_pkt, pkt->req, cp_pkt->req);
}
targets.add(cp_pkt, curTick(), _order, Target::FromSnoop,
downstreamPending && targets.needsExclusive);