logd: track SerializedFlushToState instances within SerializedLogChunk
Previously, NotifyReadersOfPrune() would iterate through the list of
reader_threads_ to find SerializedFlushToState instances, but that
misses some instances, which leads to violating important CHECK()'s.
This change 'attaches' a SerializedFlushToState instance to a
SerializedLogChunk instance when it begins reading from it and
'detaches' it when it has finished with it. This allows a new
SerializedLogChunk::NotifyReadersOfPrune() function to notify exactly
those SerializedFlushToState instances that are currently 'attached'
to it.
Bug: 169736426
Bug: 172279637
Test: logging unit tests
Change-Id: I0ab4979c8fe2b84a0e23fc5ea5fb6dd54fadc691
diff --git a/logd/SerializedFlushToState.cpp b/logd/SerializedFlushToState.cpp
index 30276ff..a514772 100644
--- a/logd/SerializedFlushToState.cpp
+++ b/logd/SerializedFlushToState.cpp
@@ -34,7 +34,7 @@
SerializedFlushToState::~SerializedFlushToState() {
log_id_for_each(i) {
if (log_positions_[i]) {
- log_positions_[i]->buffer_it->DecReaderRefCount();
+ log_positions_[i]->buffer_it->DetachReader(this);
}
}
}
@@ -49,7 +49,7 @@
if (it == logs_[log_id].end()) {
--it;
}
- it->IncReaderRefCount();
+ it->AttachReader(this);
log_position.buffer_it = it;
// Find the offset of the first log with sequence number >= start().
@@ -80,9 +80,9 @@
logs_needed_from_next_position_[log_id] = true;
} else {
// Otherwise, if there is another buffer piece, move to that and do the same check.
- buffer_it->DecReaderRefCount();
+ buffer_it->DetachReader(this);
++buffer_it;
- buffer_it->IncReaderRefCount();
+ buffer_it->AttachReader(this);
log_positions_[log_id]->read_offset = 0;
if (buffer_it->write_offset() == 0) {
logs_needed_from_next_position_[log_id] = true;
@@ -145,15 +145,11 @@
return {log_id, entry};
}
-void SerializedFlushToState::Prune(log_id_t log_id,
- const std::list<SerializedLogChunk>::iterator& buffer_it) {
- // If we don't have a position for this log or if we're not referencing buffer_it, ignore.
- if (!log_positions_[log_id].has_value() || log_positions_[log_id]->buffer_it != buffer_it) {
- return;
- }
+void SerializedFlushToState::Prune(log_id_t log_id) {
+ CHECK(log_positions_[log_id].has_value());
// Decrease the ref count since we're deleting our reference.
- buffer_it->DecReaderRefCount();
+ log_positions_[log_id]->buffer_it->DetachReader(this);
// Delete in the reference.
log_positions_[log_id].reset();