From 5ed5864460216650125d3c6ccf4abac2c1f5d316 Mon Sep 17 00:00:00 2001
From: Kefu Chai <kchai@redhat.com>
Date: Thu, 28 Jan 2021 13:27:40 +0800
Subject: [PATCH] crimson/osd: keep a local copy of pg_stat

so we don't need to prepare it every time when sending pg stats to
mgr.

Signed-off-by: Kefu Chai <kchai@redhat.com>
---
 src/crimson/osd/pg.cc | 23 +++++++++++++----------
 src/crimson/osd/pg.h  |  8 +++++---
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/src/crimson/osd/pg.cc b/src/crimson/osd/pg.cc
index bb638f9a5524..17452c511bb6 100644
--- a/src/crimson/osd/pg.cc
+++ b/src/crimson/osd/pg.cc
@@ -145,21 +145,24 @@ void PG::publish_stats_to_osd()
 {
   if (!is_primary())
     return;
+  const bool is_stats_valid = pg_stats.has_value();
+  if (auto new_pg_stats = peering_state.prepare_stats_for_publish(
+        is_stats_valid,
+        pg_stats.value_or(pg_stat_t{}),
+        object_stat_collection_t());
+      new_pg_stats.has_value()) {
+    pg_stats = std::move(new_pg_stats);
+  }
+}
 
-  (void) peering_state.prepare_stats_for_publish(
-    false,
-    pg_stat_t(),
-    object_stat_collection_t());
+void PG::clear_publish_stats()
+{
+  pg_stats.reset();
 }
 
 pg_stat_t PG::get_stats()
 {
-  auto stats = peering_state.prepare_stats_for_publish(
-    false,
-    pg_stat_t(),
-    object_stat_collection_t());
-  ceph_assert(stats);
-  return *stats;
+  return pg_stats.value_or(pg_stat_t{});
 }
 
 void PG::queue_check_readable(epoch_t last_peering_reset, ceph::timespan delay)
diff --git a/src/crimson/osd/pg.h b/src/crimson/osd/pg.h
index 61d3f407891c..1a5c3c5c36a1 100644
--- a/src/crimson/osd/pg.h
+++ b/src/crimson/osd/pg.h
@@ -561,13 +561,15 @@ private:
 
   PeeringState peering_state;
   eversion_t projected_last_update;
+
 public:
   // PeeringListener
   void publish_stats_to_osd() final;
-  void clear_publish_stats() final {
-    // Not needed yet
-  }
+  void clear_publish_stats() final;
   pg_stat_t get_stats();
+private:
+  std::optional<pg_stat_t> pg_stats;
+
 public:
   RecoveryBackend* get_recovery_backend() final {
     return recovery_backend.get();
-- 
2.47.3