From: Patrick Donnelly <pdonnell@redhat.com>
Date: Wed, 24 Apr 2024 19:35:14 +0000 (-0400)
Subject: mds: use regular dispatch for processing metrics
X-Git-Tag: v20.0.0~1886^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=ed1fe9909338bc1bc0a29df22666e9ba11fa52fe;p=ceph.git

mds: use regular dispatch for processing metrics

There have been cases where the MDS does an undesirable failover because it
misses heartbeat resets after a long recovery in up:replay.  It was observed
that the MDS was processing a flood of metrics messages from all reconnecting
clients. This likely caused undersiable MetricAggregator::lock contention in
the messenger threads while fast dispatching client metrics.

Instead, use the normal dispatch where acquiring locks is okay to do.

See-also: linux.git/f7c2f4f6ce16fb58f7d024f3e1b40023c4b43ff9
Fixes: https://tracker.ceph.com/issues/65658
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
---

diff --git a/src/mds/MetricAggregator.cc b/src/mds/MetricAggregator.cc
index f2e520792b5a..547579169d1f 100644
--- a/src/mds/MetricAggregator.cc
+++ b/src/mds/MetricAggregator.cc
@@ -126,15 +126,6 @@ void MetricAggregator::shutdown() {
   }
 }
 
-bool MetricAggregator::ms_can_fast_dispatch2(const cref_t<Message> &m) const {
-  return m->get_type() == MSG_MDS_METRICS;
-}
-
-void MetricAggregator::ms_fast_dispatch2(const ref_t<Message> &m) {
-  bool handled = ms_dispatch2(m);
-  ceph_assert(handled);
-}
-
 bool MetricAggregator::ms_dispatch2(const ref_t<Message> &m) {
   if (m->get_type() == MSG_MDS_METRICS &&
       m->get_connection()->get_peer_type() == CEPH_ENTITY_TYPE_MDS) {
diff --git a/src/mds/MetricAggregator.h b/src/mds/MetricAggregator.h
index 6d48756f76dc..72c37217e624 100644
--- a/src/mds/MetricAggregator.h
+++ b/src/mds/MetricAggregator.h
@@ -34,11 +34,6 @@ public:
 
   void notify_mdsmap(const MDSMap &mdsmap);
 
-  bool ms_can_fast_dispatch_any() const override {
-    return true;
-  }
-  bool ms_can_fast_dispatch2(const cref_t<Message> &m) const override;
-  void ms_fast_dispatch2(const ref_t<Message> &m) override;
   bool ms_dispatch2(const ref_t<Message> &m) override;
 
   void ms_handle_connect(Connection *c) override {