From: Yite Gu <yitegu0@gmail.com>
Date: Fri, 30 Aug 2024 11:31:36 +0000 (+0800)
Subject: blk/kerneldevice: notify_all only required when discard_drain wait for condition
X-Git-Tag: testing/wip-pdonnell-testing-20250429.182310-reef-debug~22^2~1
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=3a901add5236835f37480a205cc86e9ea24d161b;p=ceph-ci.git

blk/kerneldevice: notify_all only required when discard_drain wait for condition

This will cause discard threads to wake up each other
if bdev_async_discard_threads >= 2.

Fixes: https://tracker.ceph.com/issues/67835

Signed-off-by: Yite Gu <yitegu0@gmail.com>
(cherry picked from commit cec2e4550fe520fa60445678934c04ba605913be)
---

diff --git a/src/blk/kernel/KernelDevice.cc b/src/blk/kernel/KernelDevice.cc
index cb2b06a3de4..b6e637a6b21 100644
--- a/src/blk/kernel/KernelDevice.cc
+++ b/src/blk/kernel/KernelDevice.cc
@@ -591,6 +591,7 @@ void KernelDevice::discard_drain()
   dout(10) << __func__ << dendl;
   std::unique_lock l(discard_lock);
   while (!discard_queued.empty() || (discard_running > 0)) {
+    need_notify = true;
     discard_cond.wait(l);
   }
 }
@@ -756,7 +757,10 @@ void KernelDevice::_discard_thread(uint64_t tid)
       if (thr->stop)
 	break;
       dout(20) << __func__ << " sleep" << dendl;
-      discard_cond.notify_all(); // for the thread trying to drain...
+      if (need_notify) {
+        discard_cond.notify_all(); // for the thread trying to drain...
+        need_notify = false;
+      }
       discard_cond.wait(l);
       dout(20) << __func__ << " wake" << dendl;
     } else {
diff --git a/src/blk/kernel/KernelDevice.h b/src/blk/kernel/KernelDevice.h
index 99098d7fe40..c7d55d73edc 100644
--- a/src/blk/kernel/KernelDevice.h
+++ b/src/blk/kernel/KernelDevice.h
@@ -53,6 +53,7 @@ private:
   void *discard_callback_priv;
   bool aio_stop;
   bool discard_stop;
+  bool need_notify = false;
 
   ceph::mutex discard_lock = ceph::make_mutex("KernelDevice::discard_lock");
   ceph::condition_variable discard_cond;