From 8129a0b4e3bfe81d287906c872ef5391f0df7f6d Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Mon, 3 Mar 2025 00:57:00 +0300
Subject: [PATCH] Loop once after registering eventfd to prevent skipping
 previous events

---
 src/util/ringloop.cpp | 9 +++++++++
 src/util/ringloop.h   | 1 +
 2 files changed, 10 insertions(+)

diff --git a/src/util/ringloop.cpp b/src/util/ringloop.cpp
index 3c4ad52b..c447b289 100644
--- a/src/util/ringloop.cpp
+++ b/src/util/ringloop.cpp
@@ -29,6 +29,7 @@ ring_loop_t::ring_loop_t(int qd, bool multithreaded)
     {
         free_ring_data[i] = i;
     }
+    in_loop = false;
 }
 
 ring_loop_t::~ring_loop_t()
@@ -86,6 +87,11 @@ io_uring_sqe* ring_loop_t::get_sqe()
 
 void ring_loop_t::loop()
 {
+    if (in_loop)
+    {
+        return;
+    }
+    in_loop = true;
     if (ring_eventfd >= 0)
     {
         // Reset eventfd counter
@@ -140,6 +146,7 @@ void ring_loop_t::loop()
             }
         }
     } while (loop_again);
+    in_loop = false;
 }
 
 unsigned ring_loop_t::save()
@@ -189,5 +196,7 @@ int ring_loop_t::register_eventfd()
         ring_eventfd = -1;
         return r;
     }
+    // Loop once to prevent skipping events happened before eventfd was registered
+    loop();
     return ring_eventfd;
 }
diff --git a/src/util/ringloop.h b/src/util/ringloop.h
index e1945526..b9fa9100 100644
--- a/src/util/ringloop.h
+++ b/src/util/ringloop.h
@@ -129,6 +129,7 @@ class ring_loop_t
     bool mt;
     int *free_ring_data;
     unsigned free_ring_data_ptr;
+    bool in_loop;
     bool loop_again;
     struct io_uring ring;
     int ring_eventfd = -1;