sdm: Reduce the fb_id cache limit for UI layers

Reduce the fb_id cache limit for UI layers to 3 and for Rotator
use cases to 2. This is required to reduce orphaned allocations
in pre-rotation use cases.

CRs-Fixed: 2253973
Change-Id: I3989c0179d5a97b596605dd5405b89abbba5c509

2 files changed, 30 insertions, 15 deletions

diff --git a/sdm/libs/core/drm/hw_device_drm.cpp b/sdm/libs/core/drm/hw_device_drm.cpp
index aa318be3..aee7cae3 100644
--- a/sdm/libs/core/drm/hw_device_drm.cpp
+++ b/sdm/libs/core/drm/hw_device_drm.cpp
@@ -258,9 +258,11 @@ void HWDeviceDRM::Registry::Register(HWLayers *hw_layers) {
     LayerBuffer *input_buffer = &layer.input_buffer;
     HWRotatorSession *hw_rotator_session = &hw_layers->config[i].hw_rotator_session;
     HWRotateInfo *hw_rotate_info = &hw_rotator_session->hw_rotate_info[0];
+    fbid_cache_limit_ = input_buffer->flags.video ? VIDEO_FBID_LIMIT : UI_FBID_LIMIT;
 
     if (hw_rotator_session->mode == kRotatorOffline && hw_rotate_info->valid) {
       input_buffer = &hw_rotator_session->output_buffer;
+      fbid_cache_limit_ = ROTATOR_FBID_LIMIT;
     }
 
     MapBufferToFbId(&layer, input_buffer);
@@ -300,16 +302,20 @@ void HWDeviceDRM::Registry::MapBufferToFbId(Layer* layer, LayerBuffer* buffer) {
   }
 
   uint64_t handle_id = buffer->handle_id;
-  bool legacy_path = !handle_id || disable_fbid_cache_;
-
-  if (legacy_path || (layer->buffer_map->buffer_map.size() > fbid_cache_limit_)) {
-    // Clear fb_id map in each frame in legacy path or if the map size exceeds limit.
+  if (!handle_id || disable_fbid_cache_) {
+    // In legacy path, clear fb_id map in each frame.
     layer->buffer_map->buffer_map.clear();
-  }
+  } else {
 
-  if (layer->buffer_map->buffer_map.find(handle_id) != layer->buffer_map->buffer_map.end()) {
-    // Found fb_id for given handle_id key
-    return;
+    if (layer->buffer_map->buffer_map.find(handle_id) != layer->buffer_map->buffer_map.end()) {
+      // Found fb_id for given handle_id key
+      return;
+    }
+
+    if (layer->buffer_map->buffer_map.size() >= fbid_cache_limit_) {
+      // Clear fb_id map, if the size reaches cache limit.
+      layer->buffer_map->buffer_map.clear();
+    }
   }
 
   uint32_t fb_id = 0;
@@ -325,14 +331,19 @@ void HWDeviceDRM::Registry::MapOutputBufferToFbId(LayerBuffer *output_buffer) {
   }
 
   uint64_t handle_id = output_buffer->handle_id;
-
-  if (!handle_id || disable_fbid_cache_ || (output_buffer_map_.size() > fbid_cache_limit_)) {
-    // Clear output buffer map in each frame in legacy path or if the map size exceeds limit.
+  if (!handle_id || disable_fbid_cache_) {
+    // In legacy path, clear output buffer map in each frame.
     output_buffer_map_.clear();
-  }
+  } else {
 
-  if (output_buffer_map_.find(handle_id) != output_buffer_map_.end()) {
-    return;
+    if (output_buffer_map_.find(handle_id) != output_buffer_map_.end()) {
+      return;
+    }
+
+    if (output_buffer_map_.size() >= UI_FBID_LIMIT) {
+      // Clear output buffer map, if the size reaches cache limit.
+      output_buffer_map_.clear();
+    }
   }
 
   uint32_t fb_id = 0;
diff --git a/sdm/libs/core/drm/hw_device_drm.h b/sdm/libs/core/drm/hw_device_drm.h
index 728b47c5..9caa0955 100644
--- a/sdm/libs/core/drm/hw_device_drm.h
+++ b/sdm/libs/core/drm/hw_device_drm.h
@@ -44,6 +44,10 @@
 #define IOCTL_LOGE(ioctl, type) \
   DLOGE("ioctl %s, device = %d errno = %d, desc = %s", #ioctl, type, errno, strerror(errno))
 
+#define UI_FBID_LIMIT 3
+#define VIDEO_FBID_LIMIT 16
+#define ROTATOR_FBID_LIMIT 2
+
 namespace sdm {
 class HWInfoInterface;
 
@@ -157,7 +161,7 @@ class HWDeviceDRM : public HWInterface {
     bool disable_fbid_cache_ = false;
     std::unordered_map<uint64_t, std::shared_ptr<LayerBufferObject>> output_buffer_map_ {};
     BufferAllocator *buffer_allocator_ = {};
-    const uint8_t fbid_cache_limit_ = 16;
+    uint8_t fbid_cache_limit_ = UI_FBID_LIMIT;
   };
 
  protected: