diff --git a/NEWS b/NEWS
index 57bbefc880..1efe2729a6 100644
--- 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
index b509e092a8..13c8203c91 100644
--- a/src/MusicBuffer.hxx
+++ b/src/MusicBuffer.hxx
@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 // Copyright The Music Player Daemon Project
 
-#ifndef MPD_MUSIC_BUFFER_HXX
-#define MPD_MUSIC_BUFFER_HXX
+#pragma once
 
 #include "MusicChunk.hxx"
 #include "MusicChunkPtr.hxx"
@@ -29,9 +28,10 @@ public:
 
 #ifndef NDEBUG
 	/**
-	 * Check whether the buffer is empty.  This call is not
-	 * protected with the mutex, and may only be used while this
-	 * object is inaccessible to other threads.
+	 * Check whether the buffer is empty.
+	 *
+	 * This call is not protected with the #mutex, and may only be
+	 * used while this object is inaccessible to other threads.
 	 */
 	bool IsEmptyUnsafe() const {
 		return buffer.empty();
@@ -45,14 +45,27 @@ public:
 
 	/**
 	 * Returns the total number of reserved chunks in this buffer.  This
-	 * is the same value which was passed to the constructor
-	 * music_buffer_new().
+	 * is the same value which was passed to the constructor.
 	 */
 	[[gnu::pure]]
 	unsigned GetSize() const noexcept {
 		return buffer.GetCapacity();
 	}
 
+	void PopulateMemory() noexcept {
+		buffer.PopulateMemory();
+	}
+
+	/**
+	 * Give all memory allocations back to the kernel.
+	 *
+	 * This call is not protected with the #mutex, and may only be
+	 * used while this object is inaccessible to other threads.
+	 */
+	void DiscardMemory() noexcept {
+		buffer.DiscardMemory();
+	}
+
 	/**
 	 * Allocates a chunk from the buffer.  When it is not used anymore,
 	 * call Return().
@@ -68,5 +81,3 @@ public:
 	 */
 	void Return(MusicChunk *chunk) noexcept;
 };
-
-#endif
diff --git a/src/event/Backend.hxx b/src/event/Backend.hxx
index e2194bbfdc..7aa54ed476 100644
--- a/src/event/Backend.hxx
+++ b/src/event/Backend.hxx
@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 // Copyright The Music Player Daemon Project
 
-#ifndef EVENT_BACKEND_HXX
-#define EVENT_BACKEND_HXX
+#pragma once
 
-#include "event/Features.h"
+#include "event/config.h"
 
 #ifdef _WIN32
 
@@ -22,5 +21,3 @@ using EventPollBackend = EpollBackend;
 using EventPollBackend = PollBackend;
 
 #endif
-
-#endif
diff --git a/src/event/BackendEvents.hxx b/src/event/BackendEvents.hxx
index ed183f5e37..87975d5f42 100644
--- a/src/event/BackendEvents.hxx
+++ b/src/event/BackendEvents.hxx
@@ -2,7 +2,7 @@
 
 #pragma once
 
-#include "event/Features.h"
+#include "event/config.h" // for USE_EPOLL
 
 #ifdef _WIN32
 
diff --git a/src/event/FineTimerEvent.hxx b/src/event/FineTimerEvent.hxx
index 536540511a..0977e24ca7 100644
--- a/src/event/FineTimerEvent.hxx
+++ b/src/event/FineTimerEvent.hxx
@@ -5,7 +5,6 @@
 #pragma once
 
 #include "Chrono.hxx"
-#include "event/Features.h"
 #include "util/BindMethod.hxx"
 #include "util/IntrusiveTreeSet.hxx"
 
diff --git a/src/event/Loop.hxx b/src/event/Loop.hxx
index 6301899d74..ebe05c3e69 100644
--- a/src/event/Loop.hxx
+++ b/src/event/Loop.hxx
@@ -7,9 +7,9 @@
 #include "Chrono.hxx"
 #include "TimerWheel.hxx"
 #include "Backend.hxx"
-#include "event/Features.h"
 #include "time/ClockCache.hxx"
 #include "util/IntrusiveList.hxx"
+#include "event/config.h"
 
 #ifndef NO_FINE_TIMER_EVENT
 #include "TimerList.hxx"
diff --git a/src/event/MultiSocketMonitor.hxx b/src/event/MultiSocketMonitor.hxx
index 6b9c1ffad1..5e776401b0 100644
--- a/src/event/MultiSocketMonitor.hxx
+++ b/src/event/MultiSocketMonitor.hxx
@@ -1,13 +1,12 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 // Copyright The Music Player Daemon Project
 
-#ifndef MPD_MULTI_SOCKET_MONITOR_HXX
-#define MPD_MULTI_SOCKET_MONITOR_HXX
+#pragma once
 
 #include "IdleEvent.hxx"
 #include "FineTimerEvent.hxx"
 #include "SocketEvent.hxx"
-#include "event/Features.h"
+#include "event/config.h"
 
 #include <cassert>
 #include <forward_list>
@@ -244,5 +243,3 @@ private:
 
 	void OnIdle() noexcept;
 };
-
-#endif
diff --git a/src/event/SignalMonitor.cxx b/src/event/SignalMonitor.cxx
index 7182050c0e..134ea932a3 100644
--- a/src/event/SignalMonitor.cxx
+++ b/src/event/SignalMonitor.cxx
@@ -2,7 +2,7 @@
 // Copyright The Music Player Daemon Project
 
 #include "SignalMonitor.hxx"
-#include "event/Features.h"
+#include "event/config.h"
 
 #ifndef _WIN32
 
diff --git a/src/event/SocketEvent.cxx b/src/event/SocketEvent.cxx
index 8b4eac7bb3..b2b333e7b0 100644
--- a/src/event/SocketEvent.cxx
+++ b/src/event/SocketEvent.cxx
@@ -3,7 +3,6 @@
 
 #include "SocketEvent.hxx"
 #include "Loop.hxx"
-#include "event/Features.h"
 
 #include <cassert>
 #include <utility>
diff --git a/src/event/SocketEvent.hxx b/src/event/SocketEvent.hxx
index 63de91a42a..bc7e49c4aa 100644
--- a/src/event/SocketEvent.hxx
+++ b/src/event/SocketEvent.hxx
@@ -4,7 +4,7 @@
 #pragma once
 
 #include "BackendEvents.hxx"
-#include "event/Features.h" // for USE_EPOLL
+#include "event/config.h" // for USE_EPOLL
 #include "net/SocketDescriptor.hxx"
 #include "util/BindMethod.hxx"
 #include "util/IntrusiveList.hxx"
diff --git a/src/event/TimerList.cxx b/src/event/TimerList.cxx
index 21cb9a4039..03cd433cd0 100644
--- a/src/event/TimerList.cxx
+++ b/src/event/TimerList.cxx
@@ -11,7 +11,7 @@ TimerList::GetDue::operator()(const FineTimerEvent &timer) const noexcept
 	return timer.GetDue();
 }
 
-TimerList::TimerList() = default;
+TimerList::TimerList() noexcept = default;
 
 TimerList::~TimerList() noexcept
 {
diff --git a/src/event/TimerList.hxx b/src/event/TimerList.hxx
index 90f048fc60..a4179438dc 100644
--- a/src/event/TimerList.hxx
+++ b/src/event/TimerList.hxx
@@ -5,7 +5,6 @@
 #pragma once
 
 #include "Chrono.hxx"
-#include "event/Features.h"
 #include "util/IntrusiveTreeSet.hxx"
 
 class FineTimerEvent;
@@ -22,7 +21,7 @@ class TimerList final {
 			 IntrusiveTreeSetOperators<FineTimerEvent, GetDue>> timers;
 
 public:
-	TimerList();
+	TimerList() noexcept;
 	~TimerList() noexcept;
 
 	TimerList(const TimerList &other) = delete;
diff --git a/src/event/WakeFD.hxx b/src/event/WakeFD.hxx
index 1f91eb27a3..3099ecd98f 100644
--- a/src/event/WakeFD.hxx
+++ b/src/event/WakeFD.hxx
@@ -1,11 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 // Copyright The Music Player Daemon Project
 
-#ifndef MPD_WAKE_FD_HXX
-#define MPD_WAKE_FD_HXX
+#pragma once
 
 #include "net/SocketDescriptor.hxx"
-#include "event/Features.h"
+#include "event/config.h"
 
 #ifdef USE_EVENTFD
 #include "system/EventFD.hxx"
@@ -37,5 +36,3 @@ public:
 		fd.Write();
 	}
 };
-
-#endif
diff --git a/src/event/meson.build b/src/event/meson.build
index ff5818c9e2..5b5a4bcc36 100644
--- a/src/event/meson.build
+++ b/src/event/meson.build
@@ -3,7 +3,7 @@ event_features.set('USE_EVENTFD', is_linux and get_option('eventfd'))
 event_features.set('USE_SIGNALFD', is_linux and get_option('signalfd'))
 event_features.set('USE_EPOLL', is_linux and get_option('epoll'))
 event_features.set('HAVE_THREADED_EVENT_LOOP', true)
-configure_file(output: 'Features.h', configuration: event_features)
+configure_file(output: 'config.h', configuration: event_features)
 
 event_sources = []
 
diff --git a/src/memory/HugeAllocator.cxx b/src/memory/HugeAllocator.cxx
index eda938bd76..a1c797d013 100644
--- a/src/memory/HugeAllocator.cxx
+++ b/src/memory/HugeAllocator.cxx
@@ -43,6 +43,13 @@ HugeForkCow(std::span<std::byte> p, bool enable) noexcept
 	EnablePageFork(AlignToPageSize(p), enable);
 }
 
+void
+HugePopulate(std::span<std::byte> p) noexcept
+{
+	PagesPopulateWrite(p);
+	CollapseHugePages(p);
+}
+
 void
 HugeDiscard(std::span<std::byte> p) noexcept
 {
diff --git a/src/memory/HugeAllocator.hxx b/src/memory/HugeAllocator.hxx
index b9c22b0c12..2b796ffa75 100644
--- a/src/memory/HugeAllocator.hxx
+++ b/src/memory/HugeAllocator.hxx
@@ -43,6 +43,13 @@ HugeSetName(std::span<std::byte> p, const char *name) noexcept;
 void
 HugeForkCow(std::span<std::byte> p, bool enable) noexcept;
 
+/**
+ * Populate (prefault) page tables writable, faulting in all pages in
+ * the range just as if manually writing to each each page.
+ */
+void
+HugePopulate(std::span<std::byte> p) noexcept;
+
 /**
  * Discard any data stored in the allocation and give the memory back
  * to the kernel.  After returning, the allocation still exists and
@@ -75,6 +82,12 @@ HugeForkCow(std::span<std::byte>, bool) noexcept
 {
 }
 
+static inline void
+HugePopulate(std::span<std::byte> p) noexcept
+{
+	VirtualAlloc(p.data(), p.size(), MEM_COMMIT|MEM_RESERVE, PAGE_NOACCESS);
+}
+
 static inline void
 HugeDiscard(std::span<std::byte> p) noexcept
 {
@@ -109,6 +122,11 @@ HugeForkCow(std::span<std::byte>, bool) noexcept
 {
 }
 
+static inline void
+HugePopulate(std::span<std::byte>) noexcept
+{
+}
+
 static inline void
 HugeDiscard(std::span<std::byte>) noexcept
 {
diff --git a/src/memory/HugeArray.hxx b/src/memory/HugeArray.hxx
index ff59f7dd5d..16db9725e5 100644
--- a/src/memory/HugeArray.hxx
+++ b/src/memory/HugeArray.hxx
@@ -6,6 +6,10 @@
 #include "HugeAllocator.hxx"
 #include "util/SpanCast.hxx"
 
+#ifdef __linux__
+#include "system/PageAllocator.hxx"
+#endif
+
 #include <utility>
 
 /**
@@ -51,6 +55,10 @@ public:
 		HugeForkCow(std::as_writable_bytes(buffer), enable);
 	}
 
+	void Populate() noexcept {
+		HugePopulate(std::as_writable_bytes(buffer));
+	}
+
 	void Discard() noexcept {
 		HugeDiscard(std::as_writable_bytes(buffer));
 	}
diff --git a/src/memory/SliceBuffer.hxx b/src/memory/SliceBuffer.hxx
index f93089e96d..b530fe72c2 100644
--- a/src/memory/SliceBuffer.hxx
+++ b/src/memory/SliceBuffer.hxx
@@ -72,6 +72,10 @@ public:
 		buffer.SetName(name);
 	}
 
+	void PopulateMemory() noexcept {
+		buffer.Populate();
+	}
+
 	void DiscardMemory() noexcept {
 		assert(empty());
 
@@ -120,11 +124,5 @@ public:
 		slice->next = available;
 		available = slice;
 		--n_allocated;
-
-		/* give memory back to the kernel when the last slice
-		   was freed */
-		if (n_allocated == 0) {
-			DiscardMemory();
-		}
 	}
 };
diff --git a/src/player/Thread.cxx b/src/player/Thread.cxx
index 7c47763292..5a8ecc4d32 100644
--- 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
@@ -1306,6 +1312,7 @@ try {
 			CommandFinished();
 
 			assert(buffer.IsEmptyUnsafe());
+			buffer.DiscardMemory();
 
 			break;