diff --git a/gfx/gl/GLUploadHelpers.cpp b/gfx/gl/GLUploadHelpers.cpp
index 6080eb00d3ae..3532ff1a0846 100644
--- a/gfx/gl/GLUploadHelpers.cpp
+++ b/gfx/gl/GLUploadHelpers.cpp
@@ -126,13 +126,20 @@ static void TexSubImage2DWithUnpackSubimageGLES(
   // row. We only upload the first height-1 rows using GL_UNPACK_ROW_LENGTH,
   // and then we upload the final row separately. See bug 697990.
   int rowLength = stride / pixelsize;
-  gl->fPixelStorei(LOCAL_GL_UNPACK_ROW_LENGTH, rowLength);
-  gl->fTexSubImage2D(target, level, xoffset, yoffset, width, height - 1, format,
-                     type, pixels);
-  gl->fPixelStorei(LOCAL_GL_UNPACK_ROW_LENGTH, 0);
-  gl->fTexSubImage2D(target, level, xoffset, yoffset + height - 1, width, 1,
-                     format, type,
-                     (const unsigned char*)pixels + (height - 1) * stride);
+  if (gl->HasPBOState()) {
+    gl->fPixelStorei(LOCAL_GL_UNPACK_ROW_LENGTH, rowLength);
+    gl->fTexSubImage2D(target, level, xoffset, yoffset, width, height, format,
+                       type, pixels);
+    gl->fPixelStorei(LOCAL_GL_UNPACK_ROW_LENGTH, 0);
+  } else {
+    gl->fPixelStorei(LOCAL_GL_UNPACK_ROW_LENGTH, rowLength);
+    gl->fTexSubImage2D(target, level, xoffset, yoffset, width, height - 1,
+                       format, type, pixels);
+    gl->fPixelStorei(LOCAL_GL_UNPACK_ROW_LENGTH, 0);
+    gl->fTexSubImage2D(target, level, xoffset, yoffset + height - 1, width, 1,
+                       format, type,
+                       (const unsigned char*)pixels + (height - 1) * stride);
+  }
   gl->fPixelStorei(LOCAL_GL_UNPACK_ALIGNMENT, 4);
 }
 
@@ -211,7 +218,8 @@ static void TexSubImage2DHelper(GLContext* gl, GLenum target, GLint level,
       gl->fTexSubImage2D(target, level, xoffset, yoffset, width, height, format,
                          type, pixels);
       gl->fPixelStorei(LOCAL_GL_UNPACK_ALIGNMENT, 4);
-    } else if (gl->IsExtensionSupported(GLContext::EXT_unpack_subimage)) {
+    } else if (gl->IsExtensionSupported(GLContext::EXT_unpack_subimage) ||
+               gl->HasPBOState()) {
       TexSubImage2DWithUnpackSubimageGLES(gl, target, level, xoffset, yoffset,
                                           width, height, stride, pixelsize,
                                           format, type, pixels);
diff --git a/gfx/layers/opengl/TextureHostOGL.h b/gfx/layers/opengl/TextureHostOGL.h
index 70fbfe56a4d6..35683dcea0c3 100644
--- a/gfx/layers/opengl/TextureHostOGL.h
+++ b/gfx/layers/opengl/TextureHostOGL.h
@@ -195,6 +195,8 @@ class TextureImageTextureSourceOGL final : public DataTextureSource,
 
   bool NextTile() override { return mTexImage->NextTile(); }
 
+  gl::GLContext* gl() const { return mGL; }
+
  protected:
   ~TextureImageTextureSourceOGL();
 
diff --git a/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp b/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp
index e83d87b32d5c..d88c61c05662 100644
--- a/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp
+++ b/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp
@@ -249,16 +249,10 @@ LayoutDeviceIntSize RenderCompositorOGLSWGL::GetBufferSize() {
 
 UniquePtr<RenderCompositorLayersSWGL::Tile>
 RenderCompositorOGLSWGL::DoCreateTile(Surface* aSurface) {
-  const auto tileSize = aSurface->TileSize();
-
-  RefPtr<DataTextureSource> source = new TextureImageTextureSourceOGL(
+  auto source = MakeRefPtr<TextureImageTextureSourceOGL>(
       mCompositor->AsCompositorOGL(), layers::TextureFlags::NO_FLAGS);
 
-  RefPtr<gfx::DataSourceSurface> surf = gfx::Factory::CreateDataSourceSurface(
-      gfx::IntSize(tileSize.width, tileSize.height),
-      gfx::SurfaceFormat::B8G8R8A8);
-
-  return MakeUnique<TileOGL>(source, surf);
+  return MakeUnique<TileOGL>(std::move(source), aSurface->TileSize());
 }
 
 bool RenderCompositorOGLSWGL::MaybeReadback(
@@ -283,27 +277,133 @@ bool RenderCompositorOGLSWGL::MaybeReadback(
   return true;
 }
 
-RenderCompositorOGLSWGL::TileOGL::TileOGL(layers::DataTextureSource* aTexture,
-                                          gfx::DataSourceSurface* aSurface)
-    : Tile(), mTexture(aTexture), mSurface(aSurface) {}
+// This is a DataSourceSurface that represents a 0-based PBO for GLTextureImage.
+class PBOUnpackSurface : public gfx::DataSourceSurface {
+ public:
+  MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(PBOUnpackSurface, override)
+
+  explicit PBOUnpackSurface(const gfx::IntSize& aSize) : mSize(aSize) {}
+
+  uint8_t* GetData() override { return nullptr; }
+  int32_t Stride() override { return mSize.width * sizeof(uint32_t); }
+  gfx::SurfaceType GetType() const override {
+    return gfx::SurfaceType::DATA_ALIGNED;
+  }
+  gfx::IntSize GetSize() const override { return mSize; }
+  gfx::SurfaceFormat GetFormat() const override {
+    return gfx::SurfaceFormat::B8G8R8A8;
+  }
+
+  // PBO offsets need to start from a 0 address, but DataSourceSurface::Map
+  // checks for failure by comparing the address against nullptr. Override Map
+  // to work around this. Due to DataSourceSurface::Map checking for failure via
+  bool Map(MapType, MappedSurface* aMappedSurface) override {
+    aMappedSurface->mData = GetData();
+    aMappedSurface->mStride = Stride();
+    return true;
+  }
+
+  void Unmap() override {}
+
+ private:
+  gfx::IntSize mSize;
+};
+
+RenderCompositorOGLSWGL::TileOGL::TileOGL(
+    RefPtr<layers::TextureImageTextureSourceOGL>&& aTexture,
+    const gfx::IntSize& aSize)
+    : mTexture(aTexture) {
+  auto* gl = mTexture->gl();
+  if (gl && gl->HasPBOState() && gl->MakeCurrent()) {
+    mSurface = new PBOUnpackSurface(aSize);
+    // Create a PBO large enough to encompass any valid rects within the tile.
+    gl->fGenBuffers(1, &mPBO);
+    gl->fBindBuffer(LOCAL_GL_PIXEL_UNPACK_BUFFER, mPBO);
+    gl->fBufferData(LOCAL_GL_PIXEL_UNPACK_BUFFER,
+                    mSurface->Stride() * aSize.height, nullptr,
+                    LOCAL_GL_DYNAMIC_DRAW);
+    gl->fBindBuffer(LOCAL_GL_PIXEL_UNPACK_BUFFER, 0);
+  } else {
+    // Couldn't allocate a PBO, so just use a memory surface instead.
+    mSurface = gfx::Factory::CreateDataSourceSurface(
+        aSize, gfx::SurfaceFormat::B8G8R8A8);
+  }
+}
+
+RenderCompositorOGLSWGL::TileOGL::~TileOGL() {
+  if (mPBO) {
+    auto* gl = mTexture->gl();
+    if (gl && gl->MakeCurrent()) {
+      gl->fDeleteBuffers(1, &mPBO);
+      mPBO = 0;
+    }
+  }
+}
+
+layers::DataTextureSource*
+RenderCompositorOGLSWGL::TileOGL::GetTextureSource() {
+  return mTexture.get();
+}
 
 bool RenderCompositorOGLSWGL::TileOGL::Map(wr::DeviceIntRect aDirtyRect,
                                            wr::DeviceIntRect aValidRect,
                                            void** aData, int32_t* aStride) {
-  gfx::DataSourceSurface::MappedSurface map;
-  if (!mSurface->Map(gfx::DataSourceSurface::READ_WRITE, &map)) {
-    return false;
+  if (mPBO) {
+    auto* gl = mTexture->gl();
+    if (!gl) {
+      return false;
+    }
+    // Map the PBO, but only within the range of the buffer that spans from the
+    // linear start offset to the linear end offset. Since we don't care about
+    // the previous contents of the buffer, we can just tell OpenGL to
+    // invalidate the entire buffer, even though we're only mapping a sub-range.
+    gl->fBindBuffer(LOCAL_GL_PIXEL_UNPACK_BUFFER, mPBO);
+    size_t stride = mSurface->Stride();
+    size_t offset =
+        stride * aValidRect.origin.y + aValidRect.origin.x * sizeof(uint32_t);
+    size_t length = stride * (aValidRect.size.height - 1) +
+                    aValidRect.size.width * sizeof(uint32_t);
+    void* data = gl->fMapBufferRange(
+        LOCAL_GL_PIXEL_UNPACK_BUFFER, offset, length,
+        LOCAL_GL_MAP_WRITE_BIT | LOCAL_GL_MAP_INVALIDATE_BUFFER_BIT);
+    gl->fBindBuffer(LOCAL_GL_PIXEL_UNPACK_BUFFER, 0);
+    if (!data) {
+      return false;
+    }
+    *aData = data;
+    *aStride = stride;
+  } else {
+    // No PBO is available, so just directly write to the memory surface.
+    gfx::DataSourceSurface::MappedSurface map;
+    if (!mSurface->Map(gfx::DataSourceSurface::READ_WRITE, &map)) {
+      return false;
+    }
+    // Verify that we're not somehow using a PBOUnpackSurface.
+    MOZ_ASSERT(map.mData != nullptr);
+    *aData = map.mData + aValidRect.origin.y * map.mStride +
+             aValidRect.origin.x * sizeof(uint32_t);
+    *aStride = map.mStride;
   }
-  *aData =
-      map.mData + aValidRect.origin.y * map.mStride + aValidRect.origin.x * 4;
-  *aStride = map.mStride;
   return true;
 }
 
 void RenderCompositorOGLSWGL::TileOGL::Unmap(const gfx::IntRect& aDirtyRect) {
-  mSurface->Unmap();
   nsIntRegion dirty(aDirtyRect);
-  mTexture->Update(mSurface, &dirty);
+  if (mPBO) {
+    // If there is a PBO, it must be unmapped before it can be sourced from.
+    // Leave the PBO bound before the call to Update so that the texture uploads
+    // will source from it.
+    auto* gl = mTexture->gl();
+    if (!gl) {
+      return;
+    }
+    gl->fBindBuffer(LOCAL_GL_PIXEL_UNPACK_BUFFER, mPBO);
+    gl->fUnmapBuffer(LOCAL_GL_PIXEL_UNPACK_BUFFER);
+    mTexture->Update(mSurface, &dirty);
+    gl->fBindBuffer(LOCAL_GL_PIXEL_UNPACK_BUFFER, 0);
+  } else {
+    mTexture->Update(mSurface, &dirty);
+  }
 }
 
 }  // namespace wr
diff --git a/gfx/webrender_bindings/RenderCompositorOGLSWGL.h b/gfx/webrender_bindings/RenderCompositorOGLSWGL.h
index 55605b9be374..cd8e4f323f2b 100644
--- a/gfx/webrender_bindings/RenderCompositorOGLSWGL.h
+++ b/gfx/webrender_bindings/RenderCompositorOGLSWGL.h
@@ -12,6 +12,10 @@
 
 namespace mozilla {
 
+namespace layers {
+class TextureImageTextureSourceOGL;
+}
+
 namespace wr {
 
 class RenderCompositorOGLSWGL : public RenderCompositorLayersSWGL {
@@ -60,19 +64,20 @@ class RenderCompositorOGLSWGL : public RenderCompositorLayersSWGL {
 
   class TileOGL : public RenderCompositorLayersSWGL::Tile {
    public:
-    TileOGL(layers::DataTextureSource* aTexture,
-            gfx::DataSourceSurface* aSurface);
-    virtual ~TileOGL() = default;
+    TileOGL(RefPtr<layers::TextureImageTextureSourceOGL>&& aTexture,
+            const gfx::IntSize& aSize);
+    virtual ~TileOGL();
 
     bool Map(wr::DeviceIntRect aDirtyRect, wr::DeviceIntRect aValidRect,
              void** aData, int32_t* aStride) override;
     void Unmap(const gfx::IntRect& aDirtyRect) override;
-    layers::DataTextureSource* GetTextureSource() override { return mTexture; }
+    layers::DataTextureSource* GetTextureSource() override;
     bool IsValid() override { return true; }
 
    private:
-    RefPtr<layers::DataTextureSource> mTexture;
+    RefPtr<layers::TextureImageTextureSourceOGL> mTexture;
     RefPtr<gfx::DataSourceSurface> mSurface;
+    GLuint mPBO = 0;
   };
 };