Merge #5990: refactor: minimize locking in ChainLocks Cleanup

04ba164 refactor: immediately update lastCleanupTime (pasta)
d0d2641 refactor: minimize locking of cs_main in chainlocks.cpp (pasta)

Pull request description:

  ## Issue being fixed or feature implemented
  Simple changes, just look at the two commits: first we minimize scope of cs_main to what actually needs it. Then we change where we update the `lastCleanupTime` to right after we check it to minimize any chance of two threads entering at the same time.

  ## What was done?

  ## How Has This Been Tested?
  Built, ran for a bit

  ## Breaking Changes
  None

  ## Checklist:
    _Go over all the following points, and put an `x` in all the boxes that apply._
  - [ ] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

Top commit has no ACKs.

Tree-SHA512: 63432ccc16a67e6478e578c96fe809cf33d08e5068285c21e65ccc175c0c9e82c23519d57f0c4ebac162a094bfc20eb44df30cbe85b26815d02eaac06ceb66ad

src/llmq/chainlocks.cpp

@@ -622,19 +622,22 @@ void CChainLocksHandler::Cleanup()
  if (GetTimeMillis() - lastCleanupTime < CLEANUP_INTERVAL) {
  return;
  }
+ lastCleanupTime = GetTimeMillis();
 
+ {
+ LOCK(cs);
+ for (auto it = seenChainLocks.begin(); it != seenChainLocks.end(); ) {
+ if (GetTimeMillis() - it->second >= CLEANUP_SEEN_TIMEOUT) {
+ it = seenChainLocks.erase(it);
+ } else {
+ ++it;
+ }
+ }
+ }
  // need mempool.cs due to GetTransaction calls
  LOCK2(cs_main, mempool.cs);
  LOCK(cs);
 
- for (auto it = seenChainLocks.begin(); it != seenChainLocks.end(); ) {
- if (GetTimeMillis() - it->second >= CLEANUP_SEEN_TIMEOUT) {
- it = seenChainLocks.erase(it);
- } else {
- ++it;
- }
- }
-
  for (auto it = blockTxs.begin(); it != blockTxs.end(); ) {
  const auto* pindex = m_chainstate.m_blockman.LookupBlockIndex(it->first);
  if (InternalHasChainLock(pindex->nHeight, pindex->GetBlockHash())) {
@@ -666,8 +669,6 @@ void CChainLocksHandler::Cleanup()
  ++it;
  }
  }
-
- lastCleanupTime = GetTimeMillis();
 }
 
 bool AreChainLocksEnabled(const CSporkManager& sporkman)