Global GPU memory manager for android webview

android_webview/browser/browser_view_renderer.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "android_webview/browser/browser_view_renderer.h"
 
 #include "android_webview/browser/browser_view_renderer_client.h"
 #include "android_webview/browser/shared_renderer_state.h"
 #include "android_webview/public/browser/draw_gl.h"
 #include "base/android/jni_android.h"
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/browser/android/synchronous_compositor.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
 #include "ui/gfx/vector2d_conversions.h"
 
 using base::android::AttachCurrentThread;
 using base::android::JavaRef;
 using base::android::ScopedJavaLocalRef;
+using content::BrowserThread;
+using content::SynchronousCompositorMemoryPolicy;
 
 namespace android_webview {
 
 namespace {
 
 const int64 kFallbackTickTimeoutInMilliseconds = 20;
 
+// Used to calculate memory allocation. Determined experimentally.
+const size_t kMemoryMultiplier = 10;
+const size_t kBytesPerPixel = 4;
+const size_t kMemoryAllocationStep = 5 * 1024 * 1024;
+
+// Used to calculate tile allocatino. Determined experimentally.
+const size_t kTileMultiplier = 12;
+const size_t kTileAllocationStep = 20;
+const size_t kTileArea = 372 * 372;

[boliu, 2014/05/02 17:54:34]

I lied, it's kDefaultTileSize in HR, which is 384.

Can you not duplicate this the constant?

+
 class AutoResetWithLock {
  public:
   AutoResetWithLock(gfx::Vector2dF* scoped_variable,
                     gfx::Vector2dF new_value,
                     base::Lock& lock)
       : scoped_variable_(scoped_variable),
         original_value_(*scoped_variable),
         lock_(lock) {
     base::AutoLock auto_lock(lock_);
     *scoped_variable_ = new_value;
@@ skipping 40 matching lines @@
       height_(0) {
   CHECK(web_contents_);
   content::SynchronousCompositor::SetClientForWebContents(web_contents_, this);
 
   // Currently the logic in this class relies on |has_compositor_| remaining
   // false until the DidInitializeCompositor() call, hence it is not set here.
 }
 
 BrowserViewRenderer::~BrowserViewRenderer() {
   content::SynchronousCompositor::SetClientForWebContents(web_contents_, NULL);
+  // OnDetachedFromWindow should be called before the destructor, so the memory
+  // policy should have already been updated.
+}
+
+// This function updates the cached memory policy in shared renderer state, as
+// well as the tile resource allocation in GlobalTileManager.
+void BrowserViewRenderer::TrimMemory(const int level, const bool visible) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  // Constants from Android ComponentCallbacks2.
+  enum {
+    TRIM_MEMORY_RUNNING_LOW = 10,
+    TRIM_MEMORY_UI_HIDDEN = 20,
+    TRIM_MEMORY_BACKGROUND = 40,
+  };
+
+  // Not urgent enough. TRIM_MEMORY_UI_HIDDEN is treated specially because
+  // it does not indicate memory pressure, but merely that the app is
+  // backgrounded.
+  if (level < TRIM_MEMORY_RUNNING_LOW || level == TRIM_MEMORY_UI_HIDDEN)
+    return;
+
+  // Do not release resources on view we expect to get DrawGL soon.
+  if (level < TRIM_MEMORY_BACKGROUND && visible)
+    return;
+
+  // Just set the memory limit to 0 and drop all tiles. This will be reset to
+  // normal levels in the next DrawGL call.
+  SynchronousCompositorMemoryPolicy zero_policy;
+  if (shared_renderer_state_->GetMemoryPolicy() == zero_policy)
+    return;
+
+  TRACE_EVENT0("android_webview", "BrowserViewRenderer::TrimMemory");
+
+  RequestMemoryPolicy(zero_policy, true);
+}
+
+SynchronousCompositorMemoryPolicy
+BrowserViewRenderer::CalculateDesiredMemoryPolicy() {
+  SynchronousCompositorMemoryPolicy policy;
+  size_t width = draw_gl_input_.global_visible_rect.width();
+  size_t height = draw_gl_input_.global_visible_rect.height();
+  policy.bytes_limit = kMemoryMultiplier * kBytesPerPixel * width * height;
+  // Round up to a multiple of kMemoryAllocationStep.
+  policy.bytes_limit =
+      (policy.bytes_limit / kMemoryAllocationStep + 1) * kMemoryAllocationStep;
+  policy.num_resources_limit = CalculateTileRequest(width, height);
+  return policy;
+}
+
+// This function updates the cached memory policy in shared renderer state, as
+// well as the tile resource allocation in GlobalTileManager.
+void BrowserViewRenderer::RequestMemoryPolicy(
+    SynchronousCompositorMemoryPolicy& new_policy,
+    bool effective_immediately) {
+  // This will be used in SetNumTiles.
+  num_bytes_ = new_policy.bytes_limit;
+
+  GlobalTileManager* manager = GlobalTileManager::GetInstance();
+
+  // The following line will call BrowserViewRenderer::SetTilesNum().
+  manager->RequestTiles(
+      new_policy.num_resources_limit, effective_immediately, tile_manager_key_);
+}
+
+size_t BrowserViewRenderer::CalculateTileRequest(
+    size_t global_visible_width,
+    size_t global_visible_height) const {
+  double area =
+      static_cast<double>(global_visible_width * global_visible_height);
+  size_t tiles = std::max(area / kTileArea * kTileMultiplier, 1.0);
+  // Round up to a multiple of kTileAllocationStep. The minimum number of tiles
+  // is also kTileAllocationStep.
+  tiles = (tiles + kTileAllocationStep - 1) / kTileAllocationStep *
+          kTileAllocationStep;
+  return tiles;
+}
+
+void BrowserViewRenderer::SetNumTiles(size_t num_tiles,
+                                      bool effective_immediately) {
+  num_tiles_ = num_tiles;
+
+  SynchronousCompositorMemoryPolicy new_policy;
+  new_policy.num_resources_limit = num_tiles_;
+  new_policy.bytes_limit = num_bytes_;
+  shared_renderer_state_->SetMemoryPolicy(new_policy);
+
+  if (effective_immediately) {
+    shared_renderer_state_->GetCompositor()->SetMemoryPolicy(new_policy);
+    ForceFakeCompositeSW();
+  }
+}
+
+size_t BrowserViewRenderer::GetNumTiles() const {
+  return shared_renderer_state_->GetMemoryPolicy().num_resources_limit;
 }
 
 bool BrowserViewRenderer::OnDraw(jobject java_canvas,
                                  bool is_hardware_canvas,
                                  const gfx::Vector2d& scroll,
                                  const gfx::Rect& global_visible_rect,
                                  const gfx::Rect& clip) {
   draw_gl_input_.frame_id++;
   draw_gl_input_.scroll_offset = scroll;
   draw_gl_input_.global_visible_rect = global_visible_rect;
   draw_gl_input_.width = width_;
   draw_gl_input_.height = height_;
   if (clear_view_)
     return false;
   if (is_hardware_canvas && attached_to_window_) {
     shared_renderer_state_->SetDrawGLInput(draw_gl_input_);
+
+    SynchronousCompositorMemoryPolicy old_policy =
+        shared_renderer_state_->GetMemoryPolicy();
+    SynchronousCompositorMemoryPolicy new_policy =
+        CalculateDesiredMemoryPolicy();
+    RequestMemoryPolicy(new_policy, false);
     // We should be performing a hardware draw here. If we don't have the
     // compositor yet or if RequestDrawGL fails, it means we failed this draw
     // and thus return false here to clear to background color for this draw.
-    return has_compositor_ && client_->RequestDrawGL(java_canvas, false);
+    bool did_draw_gl =
+        has_compositor_ && client_->RequestDrawGL(java_canvas, false);
+    if (did_draw_gl)
+      GlobalTileManager::GetInstance()->DidUse(tile_manager_key_);
+    else
+      RequestMemoryPolicy(old_policy, false);
+
+    return did_draw_gl;
   }
   // Perform a software draw
   return DrawSWInternal(java_canvas, clip);
 }
 
 void BrowserViewRenderer::DidDrawGL(const DrawGLResult& result) {
   DidComposite(!result.clip_contains_visible_rect);
 }
 
 bool BrowserViewRenderer::DrawSWInternal(jobject java_canvas,
@@ skipping 100 matching lines @@
 void BrowserViewRenderer::OnAttachedToWindow(int width, int height) {
   TRACE_EVENT2("android_webview",
                "BrowserViewRenderer::OnAttachedToWindow",
                "width",
                width,
                "height",
                height);
   attached_to_window_ = true;
   width_ = width;
   height_ = height;
+  tile_manager_key_ = GlobalTileManager::GetInstance()->PushBack(this);
 }
 
 void BrowserViewRenderer::OnDetachedFromWindow() {
   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDetachedFromWindow");
   attached_to_window_ = false;
+  SynchronousCompositorMemoryPolicy zero_policy;
+  RequestMemoryPolicy(zero_policy, true);
+  GlobalTileManager::GetInstance()->Remove(tile_manager_key_);
+  // The hardware resources are released in the destructor of hardware renderer,
+  // so we don't need to do it here.
+  // See AwContents::ReleaseHardwareDrawOnRenderThread(JNIEnv*, jobject).
 }
 
 bool BrowserViewRenderer::IsAttachedToWindow() const {
   return attached_to_window_;
 }
 
 bool BrowserViewRenderer::IsVisible() const {
   // Ignore |window_visible_| if |attached_to_window_| is false.
   return view_visible_ && (!attached_to_window_ || window_visible_);
 }
@@ skipping 13 matching lines @@
   shared_renderer_state_->SetCompositorOnUiThread(compositor);
 }
 
 void BrowserViewRenderer::DidDestroyCompositor(
     content::SynchronousCompositor* compositor) {
   TRACE_EVENT0("android_webview", "BrowserViewRenderer::DidDestroyCompositor");
   DCHECK(has_compositor_);
   DCHECK(ui_task_runner_->BelongsToCurrentThread());
   has_compositor_ = false;
   shared_renderer_state_->SetCompositorOnUiThread(NULL);
+  SynchronousCompositorMemoryPolicy zero_policy;
+  DCHECK(shared_renderer_state_->GetMemoryPolicy() == zero_policy);
 }
 
 void BrowserViewRenderer::SetContinuousInvalidate(bool invalidate) {
   if (!ui_task_runner_->BelongsToCurrentThread()) {
     ui_task_runner_->PostTask(
         FROM_HERE,
         base::Bind(&BrowserViewRenderer::SetContinuousInvalidate,
                    ui_thread_weak_ptr_,
                    invalidate));
     return;
@@ skipping 317 matching lines @@
     base::StringAppendF(&str,
                         "surface width height: [%d %d] ",
                         draw_info->width,
                         draw_info->height);
     base::StringAppendF(&str, "is_layer: %d ", draw_info->is_layer);
   }
   return str;
 }
 
 }  // namespace android_webview