From 5e4908a02d8a42cbdbb9a7876fd35621f811eb08 Mon Sep 17 00:00:00 2001
From: Ronen Friedman <rfriedma@redhat.com>
Date: Wed, 29 Apr 2026 04:14:23 +0000
Subject: [PATCH] crimson/osd: collect total snap-trim queueus length

Periodically collect the total snap-trim
queue length across all PGs. Expose it through
OSDService::get_snap_trim_queue_total().

Signed-off-by: Ronen Friedman <rfriedma@redhat.com>
---
 src/crimson/osd/osd.cc              | 10 ++++++++++
 src/crimson/osd/osd.h               |  4 ++++
 src/crimson/osd/pg_shard_manager.cc | 12 ++++++++++++
 src/crimson/osd/pg_shard_manager.h  |  2 ++
 4 files changed, 28 insertions(+)

diff --git a/src/crimson/osd/osd.cc b/src/crimson/osd/osd.cc
index 1ba7669fef6..77b8f85fb9c 100644
--- a/src/crimson/osd/osd.cc
+++ b/src/crimson/osd/osd.cc
@@ -69,6 +69,7 @@ SET_SUBSYS(osd);
 
 namespace {
   static constexpr int TICK_INTERVAL = 1;
+  static constexpr int TRIM_QLENGTHS_UPDATE_PERIOD = 5;
 }
 
 using std::make_unique;
@@ -122,6 +123,15 @@ OSD::OSD(int id, uint32_t nonce,
       ).then([this] {
 	update_stats();
         mgrc->update_daemon_health(get_health_metrics());
+	if (++trim_queue_length_countdown >= TRIM_QLENGTHS_UPDATE_PERIOD) {
+	  trim_queue_length_countdown = 0;
+	  std::ignore = pg_shard_manager.calc_snap_trim_queue_total(
+	  ).then([this](uint64_t total) {
+	    LOG_PREFIX(OSD::tick);
+	    snap_trim_queue_total = total;
+	    DEBUG("snap_trim_queue_total: {}", total);
+	  });
+	}
 	tick_timer.arm(
 	  std::chrono::seconds(TICK_INTERVAL));
       });
diff --git a/src/crimson/osd/osd.h b/src/crimson/osd/osd.h
index 730336e6bff..703ccd3ae5e 100644
--- a/src/crimson/osd/osd.h
+++ b/src/crimson/osd/osd.h
@@ -127,6 +127,10 @@ class OSD final : public crimson::net::Dispatcher,
 
   std::unique_ptr<Heartbeat> heartbeat;
   seastar::timer<seastar::lowres_clock> tick_timer;
+  uint_fast16_t trim_queue_length_countdown = 0;
+  /// caching the total snap trim queue length across all PGs,
+  /// updated periodically by the tick_timer
+  uint64_t snap_trim_queue_total = 0;
 
   seastar::timer<seastar::lowres_clock> stats_timer;
   std::vector<ShardServices::shard_stats_t> shard_stats;
diff --git a/src/crimson/osd/pg_shard_manager.cc b/src/crimson/osd/pg_shard_manager.cc
index e9563e63b68..6467f221a08 100644
--- a/src/crimson/osd/pg_shard_manager.cc
+++ b/src/crimson/osd/pg_shard_manager.cc
@@ -117,4 +117,16 @@ seastar::future<> PGShardManager::set_superblock(OSDSuperblock superblock) {
   });
 }
 
+seastar::future<uint64_t>
+PGShardManager::calc_snap_trim_queue_total() const
+{
+  uint64_t total = 0;
+  co_await for_each_pg([&total](const auto&, const auto &pg) {
+    if (pg->is_primary()) {
+      total += pg->get_snap_trimq_size();
+    }
+  });
+  co_return total;
+}
+
 }
diff --git a/src/crimson/osd/pg_shard_manager.h b/src/crimson/osd/pg_shard_manager.h
index 04ab77ee5d0..fcc16ef1ec5 100644
--- a/src/crimson/osd/pg_shard_manager.h
+++ b/src/crimson/osd/pg_shard_manager.h
@@ -337,6 +337,8 @@ public:
       });
   }
 
+  seastar::future<uint64_t> calc_snap_trim_queue_total() const;
+
   /**
    * for_each_pgid
    *
-- 
2.47.3