changeset 4d8b7783a692 in /z/repo/gem5
details: http://repo.gem5.org/gem5?cmd=changeset;node=4d8b7783a692
description:
mem: Tidy up the snoop state-transition logic
Remove broken and unused option to pass dirty data on non-exclusive
snoops. Also beef up the comments a bit.
diffstat:
src/mem/cache/cache.cc | 21 +++++++++------------
1 files changed, 9 insertions(+), 12 deletions(-)
diffs (40 lines):
diff -r 31ab5ca6836d -r 4d8b7783a692 src/mem/cache/cache.cc
--- a/src/mem/cache/cache.cc Fri Sep 04 13:13:55 2015 -0400
+++ b/src/mem/cache/cache.cc Fri Sep 04 13:13:58 2015 -0400
@@ -1828,17 +1828,13 @@
}
if (!pkt->req->isUncacheable() && pkt->isRead() && !invalidate) {
+ // reading non-exclusive shared data, note that we retain
+ // the block in owned state if it is dirty, with the response
+ // taken care of below, and otherwhise simply downgrade to
+ // shared
assert(!needs_exclusive);
pkt->assertShared();
- int bits_to_clear = BlkWritable;
- const bool haveOwnershipState = true; // for now
- if (!haveOwnershipState) {
- // if we don't support pure ownership (dirty && !writable),
- // have to clear dirty bit here, assume memory snarfs data
- // on cache-to-cache xfer
- bits_to_clear |= BlkDirty;
- }
- blk->status &= ~bits_to_clear;
+ blk->status &= ~BlkWritable;
}
if (respond) {
@@ -1850,9 +1846,10 @@
// will write it back at a later point
pkt->assertMemInhibit();
if (have_exclusive) {
- // 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
+ // in the case of an uncacheable request there is no point
+ // in setting the exclusive flag, but since the recipient
+ // does not care there is no harm in doing so, in any case
+ // it is just a hint
pkt->setSupplyExclusive();
}
if (is_timing) {
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