From 3809d96a5b53721b88602d662c4c1cd00dd727a0 Mon Sep 17 00:00:00 2001
From: Venky Shankar <vshankar@redhat.com>
Date: Tue, 3 Jul 2018 08:06:39 -0400
Subject: [PATCH] mds: allow request load average decay rate configurable via
 admin socket

Signed-off-by: Venky Shankar <vshankar@redhat.com>
---
 src/mds/MDSDaemon.cc  |  1 +
 src/mds/MDSRank.h     |  1 +
 src/mds/SessionMap.cc | 23 +++++++++++++++++++++++
 src/mds/SessionMap.h  |  2 ++
 4 files changed, 27 insertions(+)

diff --git a/src/mds/MDSDaemon.cc b/src/mds/MDSDaemon.cc
index 98c524556d7..30974291065 100644
--- a/src/mds/MDSDaemon.cc
+++ b/src/mds/MDSDaemon.cc
@@ -370,6 +370,7 @@ const char** MDSDaemon::get_tracked_conf_keys() const
     "mds_inject_migrator_session_race",
     "host",
     "fsid",
+    "mds_request_load_average_decay_rate",
     NULL
   };
   return KEYS;
diff --git a/src/mds/MDSRank.h b/src/mds/MDSRank.h
index f2ab258a4fe..2cd8951a8ca 100644
--- a/src/mds/MDSRank.h
+++ b/src/mds/MDSRank.h
@@ -224,6 +224,7 @@ class MDSRank {
     void handle_conf_change(const ConfigProxy& conf,
                             const std::set <std::string> &changed)
     {
+      sessionmap.handle_conf_change(conf, changed);
       mdcache->handle_conf_change(conf, changed, *mdsmap);
       purge_queue.handle_conf_change(conf, changed, *mdsmap);
     }
diff --git a/src/mds/SessionMap.cc b/src/mds/SessionMap.cc
index e64f45245bb..50976f0d42f 100644
--- a/src/mds/SessionMap.cc
+++ b/src/mds/SessionMap.cc
@@ -976,6 +976,29 @@ void SessionMap::hit_session(Session *session) {
   session->hit_session();
 }
 
+void SessionMap::handle_conf_change(const ConfigProxy &conf,
+                                    const std::set <std::string> &changed) {
+  if (changed.count("mds_request_load_average_decay_rate")) {
+    decay_rate = g_conf().get_val<double>("mds_request_load_average_decay_rate");
+    dout(20) << __func__ << " decay rate changed to " << decay_rate << dendl;
+
+    total_load_avg = DecayCounter(decay_rate);
+
+    auto p = by_state.find(Session::STATE_OPEN);
+    if (p != by_state.end()) {
+      for (const auto &session : *(p->second)) {
+        session->set_load_avg_decay_rate(decay_rate);
+      }
+    }
+    p = by_state.find(Session::STATE_STALE);
+    if (p != by_state.end()) {
+      for (const auto &session : *(p->second)) {
+        session->set_load_avg_decay_rate(decay_rate);
+      }
+    }
+  }
+}
+
 int SessionFilter::parse(
     const std::vector<std::string> &args,
     std::stringstream *ss)
diff --git a/src/mds/SessionMap.h b/src/mds/SessionMap.h
index 8a43e332f46..549e628298d 100644
--- a/src/mds/SessionMap.h
+++ b/src/mds/SessionMap.h
@@ -715,6 +715,8 @@ private:
 
 public:
   void hit_session(Session *session);
+  void handle_conf_change(const ConfigProxy &conf,
+                          const std::set <std::string> &changed);
 };
 
 std::ostream& operator<<(std::ostream &out, const Session &s);
-- 
2.39.5