MusicBuffer: preallocate physical RAM for audio buffer when playback starts

MaxKellermann · MaxKellermann · commit d4e8fa5eded5 · 2026-02-09T22:16:30.000+01:00
To reduce page faults during playback.
diff --git a/NEWS b/NEWS
@@ -11,6 +11,7 @@ ver 0.25 (not yet released)
   - pipewire: add option "reconnect_stream"
 * player
   - support replay gain parameter in stream URI
+  - preallocate physical RAM for audio buffer when playback starts
 * switch to C++23
 * require Meson 1.2
 
diff --git a/src/MusicBuffer.hxx b/src/MusicBuffer.hxx
@@ -52,6 +52,10 @@ public:
 		return buffer.GetCapacity();
 	}
 
+	void PopulateMemory() noexcept {
+		buffer.PopulateMemory();
+	}
+
 	/**
 	 * Give all memory allocations back to the kernel.
 	 *
diff --git a/src/player/Thread.cxx b/src/player/Thread.cxx
@@ -1271,6 +1271,12 @@ try {
 
 			{
 				const ScopeUnlock unlock(mutex);
+
+				/* allocate physical RAM for the whole
+				   buffer to reduce page faults
+				   later */
+				buffer.PopulateMemory();
+
 				do_play(*this, dc, buffer);
 
 				/* give the main thread a chance to

Original file line number	Diff line number	Diff line change
`@@ -52,6 +52,10 @@ public:`
`52`	`52`	`return buffer.GetCapacity();`
`53`	`53`	`}`
`54`	`54`
	`55`	`+ void PopulateMemory() noexcept {`
	`56`	`+ buffer.PopulateMemory();`
	`57`	`+ }`
	`58`	`+`
`55`	`59`	`/**`
`56`	`60`	`* Give all memory allocations back to the kernel.`
`57`	`61`	`*`