From: Max Kellermann <max.kellermann@ionos.com>
Date: Mon, 7 Oct 2024 20:12:41 +0000 (+0200)
Subject: common/Finisher: do not wake up the thread if already running
X-Git-Tag: v20.0.0~789^2~10
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=e30551eb86cfde834e3b759e3cb99b783bc57371;p=ceph.git

common/Finisher: do not wake up the thread if already running

If `finisher_running` is set, then the `Finisher` thread will
automatically pick up new items queued by other threads.  It is
therefore not needed to wake it up and we can eliminate one system
call.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---

diff --git a/src/common/Finisher.h b/src/common/Finisher.h
index 81211c82269..215930116d3 100644
--- a/src/common/Finisher.h
+++ b/src/common/Finisher.h
@@ -67,9 +67,9 @@ class Finisher {
   void queue(Context *c, int r = 0) {
     {
       const std::lock_guard l{finisher_lock};
-      const bool was_empty = finisher_queue.empty();
+      const bool should_notify = finisher_queue.empty() && !finisher_running;
       finisher_queue.push_back(std::make_pair(c, r));
-      if (was_empty) {
+      if (should_notify) {
 	finisher_cond.notify_one();
       }
     }
@@ -83,7 +83,7 @@ class Finisher {
   auto queue(T &ls) -> decltype(std::distance(ls.begin(), ls.end()), void()) {
     {
       const std::lock_guard l{finisher_lock};
-      if (finisher_queue.empty()) {
+      if (finisher_queue.empty() && !finisher_running) {
 	finisher_cond.notify_all();
       }
       for (Context *i : ls) {