diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index 0848fac..c770db9 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -415,14 +415,12 @@
                                                     stat.frameEventStats.dequeueReadyTime);
                 }
                 auto currFrameNumber = stat.frameEventStats.frameNumber;
-                std::vector<ReleaseCallbackId> staleReleases;
-                for (const auto& [key, value]: mSubmitted) {
-                    if (currFrameNumber > key.framenumber) {
-                        staleReleases.push_back(key);
+                // Release stale buffers.
+                for (const auto& [key, _] : mSubmitted) {
+                    if (currFrameNumber <= key.framenumber) {
+                        continue; // not stale.
                     }
-                }
-                for (const auto& staleRelease : staleReleases) {
-                    releaseBufferCallbackLocked(staleRelease,
+                    releaseBufferCallbackLocked(key,
                                                 stat.previousReleaseFence
                                                         ? stat.previousReleaseFence
                                                         : Fence::NO_FENCE,
@@ -618,7 +616,7 @@
     mNumAcquired++;
     mLastAcquiredFrameNumber = bufferItem.mFrameNumber;
     ReleaseCallbackId releaseCallbackId(buffer->getId(), mLastAcquiredFrameNumber);
-    mSubmitted[releaseCallbackId] = bufferItem;
+    mSubmitted.emplace_or_replace(releaseCallbackId, bufferItem);
 
     bool needsDisconnect = false;
     mBufferItemConsumer->getConnectionEvents(bufferItem.mFrameNumber, &needsDisconnect);
@@ -851,7 +849,7 @@
 
 void BLASTBufferQueue::onFrameDequeued(const uint64_t bufferId) {
     std::lock_guard _lock{mTimestampMutex};
-    mDequeueTimestamps[bufferId] = systemTime();
+    mDequeueTimestamps.emplace_or_replace(bufferId, systemTime());
 };
 
 void BLASTBufferQueue::onFrameCancelled(const uint64_t bufferId) {
diff --git a/libs/gui/include/gui/BLASTBufferQueue.h b/libs/gui/include/gui/BLASTBufferQueue.h
index b97a496..cdc2150 100644
--- a/libs/gui/include/gui/BLASTBufferQueue.h
+++ b/libs/gui/include/gui/BLASTBufferQueue.h
@@ -20,6 +20,7 @@
 #include <optional>
 #include <queue>
 
+#include <ftl/small_map.h>
 #include <gui/BufferItem.h>
 #include <gui/BufferItemConsumer.h>
 #include <gui/IGraphicBufferConsumer.h>
@@ -36,6 +37,10 @@
 
 namespace android {
 
+// Sizes determined empirically to avoid allocations during common activity.
+constexpr size_t kSubmittedBuffersMapSizeHint = 8;
+constexpr size_t kDequeueTimestampsMapSizeHint = 32;
+
 class BLASTBufferQueue;
 class BufferItemConsumer;
 
@@ -206,7 +211,7 @@
 
     // Keep a reference to the submitted buffers so we can release when surfaceflinger drops the
     // buffer or the buffer has been presented and a new buffer is ready to be presented.
-    std::unordered_map<ReleaseCallbackId, BufferItem, ReleaseBufferCallbackIdHash> mSubmitted
+    ftl::SmallMap<ReleaseCallbackId, BufferItem, kSubmittedBuffersMapSizeHint> mSubmitted
             GUARDED_BY(mMutex);
 
     // Keep a queue of the released buffers instead of immediately releasing
@@ -291,8 +296,8 @@
     std::mutex mTimestampMutex;
     // Tracks buffer dequeue times by the client. This info is sent to SurfaceFlinger which uses
     // it for debugging purposes.
-    std::unordered_map<uint64_t /* bufferId */, nsecs_t> mDequeueTimestamps
-            GUARDED_BY(mTimestampMutex);
+    ftl::SmallMap<uint64_t /* bufferId */, nsecs_t, kDequeueTimestampsMapSizeHint>
+            mDequeueTimestamps GUARDED_BY(mTimestampMutex);
 
     // Keep track of SurfaceControls that have submitted a transaction and BBQ is waiting on a
     // callback for them.