layout: Report memory usage for fragment and box trees. (#36553)

Add memory reporter integration for the fragment and box trees that are
persisted in the layout thread.

Testing: Looked at the numbers for https://servo.org and
https://html.spec.whatwg.org/. The former was very small, but the latter
was 700mb.

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

33 files changed, 230 insertions, 69 deletions

diff --git a/Cargo.lock b/Cargo.lock
index c29bfe22631..71d909d01d3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1134,11 +1134,13 @@ dependencies = [
  "image",
  "ipc-channel",
  "log",
+ "malloc_size_of_derive",
  "pixels",
  "profile_traits",
  "raw-window-handle",
  "serde",
  "servo_geometry",
+ "servo_malloc_size_of",
  "strum_macros",
  "stylo",
  "stylo_traits",
@@ -4162,6 +4164,7 @@ dependencies = [
  "ipc-channel",
  "itertools 0.13.0",
  "log",
+ "malloc_size_of_derive",
  "net_traits",
  "num-traits",
  "parking_lot",
@@ -4174,6 +4177,7 @@ dependencies = [
  "servo_arc",
  "servo_config",
  "servo_geometry",
+ "servo_malloc_size_of",
  "servo_url",
  "stylo",
  "stylo_traits",
@@ -6822,6 +6826,7 @@ version = "0.0.1"
 dependencies = [
  "accountable-refcell",
  "app_units",
+ "atomic_refcell",
  "content-security-policy",
  "crossbeam-channel",
  "euclid",
@@ -6837,8 +6842,11 @@ dependencies = [
  "stylo",
  "stylo_dom",
  "stylo_malloc_size_of",
+ "taffy",
  "thin-vec",
  "tokio",
+ "unicode-bidi",
+ "unicode-script",
  "url",
  "uuid",
  "webrender_api",
diff --git a/components/fonts/glyph.rs b/components/fonts/glyph.rs
index e0e85ed7f74..db97ee0ebee 100644
--- a/components/fonts/glyph.rs
+++ b/components/fonts/glyph.rs
@@ -741,9 +741,10 @@ impl fmt::Debug for GlyphStore {
 }
 
 /// A single series of glyphs within a text run.
-#[derive(Clone, Debug, Deserialize, Serialize)]
+#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
 pub struct GlyphRun {
     /// The glyphs.
+    #[conditional_malloc_size_of]
     pub glyph_store: Arc<GlyphStore>,
     /// The byte range of characters in the containing run.
     pub range: Range<ByteIndex>,
diff --git a/components/layout_2020/Cargo.toml b/components/layout_2020/Cargo.toml
index 8739f66f4e9..1501c52c7e2 100644
--- a/components/layout_2020/Cargo.toml
+++ b/components/layout_2020/Cargo.toml
@@ -36,6 +36,8 @@ icu_segmenter = { workspace = true }
 ipc-channel = { workspace = true }
 itertools = { workspace = true }
 log = { workspace = true }
+malloc_size_of = { workspace = true }
+malloc_size_of_derive = { workspace = true }
 net_traits = { workspace = true }
 parking_lot = { workspace = true }
 pixels = { path = "../pixels" }
diff --git a/components/layout_2020/cell.rs b/components/layout_2020/cell.rs
index d725362b0fa..8b35fdf7943 100644
--- a/components/layout_2020/cell.rs
+++ b/components/layout_2020/cell.rs
@@ -6,9 +6,12 @@ use std::fmt;
 use std::ops::Deref;
 
 use atomic_refcell::AtomicRefCell;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc;
 
+#[derive(MallocSizeOf)]
 pub struct ArcRefCell<T> {
+    #[conditional_malloc_size_of]
     value: Arc<AtomicRefCell<T>>,
 }
 
diff --git a/components/layout_2020/flexbox/geom.rs b/components/layout_2020/flexbox/geom.rs
index 6a302e27486..90145dceafe 100644
--- a/components/layout_2020/flexbox/geom.rs
+++ b/components/layout_2020/flexbox/geom.rs
@@ -4,6 +4,7 @@
 
 //! <https://drafts.csswg.org/css-flexbox/#box-model>
 
+use malloc_size_of_derive::MallocSizeOf;
 use style::properties::longhands::flex_direction::computed_value::T as FlexDirection;
 
 use crate::geom::{LogicalRect, LogicalSides, LogicalVec2};
@@ -67,7 +68,7 @@ impl<T> FlexRelativeSides<T> {
 
 /// One of the two bits set by the `flex-direction` property
 /// (The other is "forward" v.s. reverse.)
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub(super) enum FlexAxis {
     /// The main axis is the inline axis of the container (not necessarily of flex items!),
     /// cross is block.
@@ -78,7 +79,7 @@ pub(super) enum FlexAxis {
 
 /// Which flow-relative sides map to the main-start and cross-start sides, respectively.
 /// See <https://drafts.csswg.org/css-flexbox/#box-model>
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, MallocSizeOf)]
 pub(super) enum MainStartCrossStart {
     InlineStartBlockStart,
     InlineStartBlockEnd,
diff --git a/components/layout_2020/flexbox/mod.rs b/components/layout_2020/flexbox/mod.rs
index f51caca65e8..e1f8213f1e9 100644
--- a/components/layout_2020/flexbox/mod.rs
+++ b/components/layout_2020/flexbox/mod.rs
@@ -3,6 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use geom::{FlexAxis, MainStartCrossStart};
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc as ServoArc;
 use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
@@ -27,7 +28,7 @@ mod layout;
 
 /// A structure to hold the configuration of a flex container for use during layout
 /// and preferred width calculation.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) struct FlexContainerConfig {
     container_is_single_line: bool,
     writing_mode: WritingMode,
@@ -85,10 +86,11 @@ impl FlexContainerConfig {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct FlexContainer {
     children: Vec<ArcRefCell<FlexLevelBox>>,
 
+    #[conditional_malloc_size_of]
     style: ServoArc<ComputedValues>,
 
     /// The configuration of this [`FlexContainer`].
@@ -137,7 +139,7 @@ impl FlexContainer {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum FlexLevelBox {
     FlexItem(FlexItemBox),
     OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
@@ -171,6 +173,7 @@ impl FlexLevelBox {
     }
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct FlexItemBox {
     independent_formatting_context: IndependentFormattingContext,
 }
diff --git a/components/layout_2020/flow/float.rs b/components/layout_2020/flow/float.rs
index f07c6a91594..0570ce0d0f4 100644
--- a/components/layout_2020/flow/float.rs
+++ b/components/layout_2020/flow/float.rs
@@ -13,6 +13,7 @@ use std::ops::Range;
 
 use app_units::{Au, MAX_AU, MIN_AU};
 use euclid::num::Zero;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc;
 use style::computed_values::float::T as FloatProperty;
 use style::computed_values::position::T as Position;
@@ -31,7 +32,7 @@ use crate::style_ext::{DisplayInside, PaddingBorderMargin};
 use crate::{ContainingBlock, PropagatedBoxTreeData};
 
 /// A floating box.
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct FloatBox {
     /// The formatting context that makes up the content of this box.
     pub contents: IndependentFormattingContext,
diff --git a/components/layout_2020/flow/inline/inline_box.rs b/components/layout_2020/flow/inline/inline_box.rs
index 2eceae944f2..97398d6e708 100644
--- a/components/layout_2020/flow/inline/inline_box.rs
+++ b/components/layout_2020/flow/inline/inline_box.rs
@@ -6,6 +6,7 @@ use std::vec::IntoIter;
 
 use app_units::Au;
 use fonts::FontMetrics;
+use malloc_size_of_derive::MallocSizeOf;
 
 use super::{InlineContainerState, InlineContainerStateFlags, inline_container_needs_strut};
 use crate::ContainingBlock;
@@ -17,7 +18,7 @@ use crate::fragment_tree::BaseFragmentInfo;
 use crate::layout_box_base::LayoutBoxBase;
 use crate::style_ext::{LayoutStyle, PaddingBorderMargin};
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct InlineBox {
     pub base: LayoutBoxBase,
     /// The identifier of this inline box in the containing [`super::InlineFormattingContext`].
@@ -56,7 +57,7 @@ impl InlineBox {
     }
 }
 
-#[derive(Debug, Default)]
+#[derive(Debug, Default, MallocSizeOf)]
 pub(crate) struct InlineBoxes {
     /// A collection of all inline boxes in a particular [`super::InlineFormattingContext`].
     inline_boxes: Vec<ArcRefCell<InlineBox>>,
@@ -162,7 +163,7 @@ impl InlineBoxes {
     }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub(super) enum InlineBoxTreePathToken {
     Start(InlineBoxIdentifier),
     End(InlineBoxIdentifier),
@@ -183,7 +184,7 @@ impl InlineBoxTreePathToken {
 /// [`u32`] is used for the index, in order to save space. The value refers to the token
 /// in the start tree data structure which can be fetched to find the actual index of
 /// of the [`InlineBox`] in [`InlineBoxes::inline_boxes`].
-#[derive(Clone, Copy, Debug, Default, Eq, Hash, PartialEq)]
+#[derive(Clone, Copy, Debug, Default, Eq, Hash, MallocSizeOf, PartialEq)]
 pub(crate) struct InlineBoxIdentifier {
     pub index_of_start_in_tree: u32,
     pub index_in_inline_boxes: u32,
diff --git a/components/layout_2020/flow/inline/mod.rs b/components/layout_2020/flow/inline/mod.rs
index 7564b5004c6..490917d95a3 100644
--- a/components/layout_2020/flow/inline/mod.rs
+++ b/components/layout_2020/flow/inline/mod.rs
@@ -88,6 +88,7 @@ use line::{
     TextRunLineItem,
 };
 use line_breaker::LineBreaker;
+use malloc_size_of_derive::MallocSizeOf;
 use range::Range;
 use servo_arc::Arc;
 use style::Zero;
@@ -136,7 +137,7 @@ use crate::{ConstraintSpace, ContainingBlock, PropagatedBoxTreeData};
 static FONT_SUBSCRIPT_OFFSET_RATIO: f32 = 0.20;
 static FONT_SUPERSCRIPT_OFFSET_RATIO: f32 = 0.34;
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct InlineFormattingContext {
     /// All [`InlineItem`]s in this [`InlineFormattingContext`] stored in a flat array.
     /// [`InlineItem::StartInlineBox`] and [`InlineItem::EndInlineBox`] allow representing
@@ -173,14 +174,14 @@ pub(crate) struct InlineFormattingContext {
 }
 
 /// A collection of data used to cache [`FontMetrics`] in the [`InlineFormattingContext`]
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct FontKeyAndMetrics {
     pub key: FontInstanceKey,
     pub pt_size: Au,
     pub metrics: FontMetrics,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum InlineItem {
     StartInlineBox(ArcRefCell<InlineBox>),
     EndInlineBox,
@@ -189,9 +190,9 @@ pub(crate) enum InlineItem {
         ArcRefCell<AbsolutelyPositionedBox>,
         usize, /* offset_in_text */
     ),
-    OutOfFlowFloatBox(Arc<FloatBox>),
+    OutOfFlowFloatBox(#[conditional_malloc_size_of] Arc<FloatBox>),
     Atomic(
-        Arc<IndependentFormattingContext>,
+        #[conditional_malloc_size_of] Arc<IndependentFormattingContext>,
         usize, /* offset_in_text */
         Level, /* bidi_level */
     ),
diff --git a/components/layout_2020/flow/inline/text_run.rs b/components/layout_2020/flow/inline/text_run.rs
index b0687900000..0d0c6398017 100644
--- a/components/layout_2020/flow/inline/text_run.rs
+++ b/components/layout_2020/flow/inline/text_run.rs
@@ -12,6 +12,7 @@ use fonts::{
 };
 use fonts_traits::ByteIndex;
 use log::warn;
+use malloc_size_of_derive::MallocSizeOf;
 use range::Range as ServoRange;
 use servo_arc::Arc;
 use style::computed_values::text_rendering::T as TextRendering;
@@ -37,9 +38,10 @@ pub(crate) const XI_LINE_BREAKING_CLASS_WJ: u8 = 30;
 pub(crate) const XI_LINE_BREAKING_CLASS_ZWJ: u8 = 42;
 
 /// <https://www.w3.org/TR/css-display-3/#css-text-run>
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct TextRun {
     pub base_fragment_info: BaseFragmentInfo,
+    #[conditional_malloc_size_of]
     pub parent_style: Arc<ComputedValues>,
     pub text_range: Range<usize>,
 
@@ -47,6 +49,7 @@ pub(crate) struct TextRun {
     /// segments, and shaped.
     pub shaped_text: Vec<TextRunSegment>,
     pub selection_range: Option<ServoRange<ByteIndex>>,
+    #[conditional_malloc_size_of]
     pub selected_style: Arc<ComputedValues>,
 }
 
@@ -64,7 +67,7 @@ enum SegmentStartSoftWrapPolicy {
     FollowLinebreaker,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct TextRunSegment {
     /// The index of this font in the parent [`super::InlineFormattingContext`]'s collection of font
     /// information.
diff --git a/components/layout_2020/flow/mod.rs b/components/layout_2020/flow/mod.rs
index a45c0bcb9c1..f92650ef340 100644
--- a/components/layout_2020/flow/mod.rs
+++ b/components/layout_2020/flow/mod.rs
@@ -7,6 +7,7 @@
 
 use app_units::{Au, MAX_AU};
 use inline::InlineFormattingContext;
+use malloc_size_of_derive::MallocSizeOf;
 use rayon::iter::{IndexedParallelIterator, IntoParallelRefIterator, ParallelIterator};
 use servo_arc::Arc;
 use style::Zero;
@@ -53,13 +54,13 @@ mod root;
 pub(crate) use construct::BlockContainerBuilder;
 pub use root::{BoxTree, CanvasBackground};
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct BlockFormattingContext {
     pub contents: BlockContainer,
     pub contains_floats: bool,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum BlockContainer {
     BlockLevelBoxes(Vec<ArcRefCell<BlockLevelBox>>),
     InlineFormattingContext(InlineFormattingContext),
@@ -76,7 +77,7 @@ impl BlockContainer {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum BlockLevelBox {
     Independent(IndependentFormattingContext),
     OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
@@ -246,8 +247,9 @@ pub(crate) struct CollapsibleWithParentStartMargin(bool);
 
 /// The contentes of a BlockContainer created to render a list marker
 /// for a list that has `list-style-position: outside`.
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct OutsideMarker {
+    #[conditional_malloc_size_of]
     pub list_item_style: Arc<ComputedValues>,
     pub base: LayoutBoxBase,
     pub block_container: BlockContainer,
diff --git a/components/layout_2020/flow/root.rs b/components/layout_2020/flow/root.rs
index f02703f58d2..390b4664e60 100644
--- a/components/layout_2020/flow/root.rs
+++ b/components/layout_2020/flow/root.rs
@@ -5,6 +5,7 @@
 use app_units::Au;
 use atomic_refcell::AtomicRef;
 use compositing_traits::display_list::AxesScrollSensitivity;
+use malloc_size_of_derive::MallocSizeOf;
 use script_layout_interface::wrapper_traits::{
     LayoutNode, ThreadSafeLayoutElement, ThreadSafeLayoutNode,
 };
@@ -32,6 +33,7 @@ use crate::style_ext::{ComputedValuesExt, Display, DisplayGeneratingBox, Display
 use crate::taffy::{TaffyItemBox, TaffyItemBoxInner};
 use crate::{DefiniteContainingBlock, PropagatedBoxTreeData};
 
+#[derive(MallocSizeOf)]
 pub struct BoxTree {
     /// Contains typically exactly one block-level box, which was generated by the root element.
     /// There may be zero if that element has `display: none`.
@@ -437,7 +439,7 @@ impl BoxTree {
 }
 
 /// <https://drafts.csswg.org/css-backgrounds/#root-background>
-#[derive(Clone)]
+#[derive(Clone, MallocSizeOf)]
 pub struct CanvasBackground {
     /// DOM node for the root element
     pub root_element: OpaqueNode,
@@ -448,6 +450,7 @@ pub struct CanvasBackground {
     pub from_element: OpaqueNode,
 
     /// The computed styles to take background properties from.
+    #[conditional_malloc_size_of]
     pub style: Option<Arc<ComputedValues>>,
 }
 
diff --git a/components/layout_2020/formatting_contexts.rs b/components/layout_2020/formatting_contexts.rs
index 9877dcb287d..4661c44592c 100644
--- a/components/layout_2020/formatting_contexts.rs
+++ b/components/layout_2020/formatting_contexts.rs
@@ -3,6 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc;
 use style::properties::ComputedValues;
 use style::selector_parser::PseudoElement;
@@ -27,13 +28,13 @@ use crate::{
 };
 
 /// <https://drafts.csswg.org/css-display/#independent-formatting-context>
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct IndependentFormattingContext {
     pub base: LayoutBoxBase,
     pub contents: IndependentFormattingContextContents,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum IndependentFormattingContextContents {
     NonReplaced(IndependentNonReplacedContents),
     Replaced(ReplacedContents),
@@ -41,7 +42,7 @@ pub(crate) enum IndependentFormattingContextContents {
 
 // Private so that code outside of this module cannot match variants.
 // It should got through methods instead.
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum IndependentNonReplacedContents {
     Flow(BlockFormattingContext),
     Flex(FlexContainer),
@@ -52,7 +53,7 @@ pub(crate) enum IndependentNonReplacedContents {
 
 /// The baselines of a layout or a [`crate::fragment_tree::BoxFragment`]. Some layout
 /// uses the first and some layout uses the last.
-#[derive(Clone, Copy, Debug, Default)]
+#[derive(Clone, Copy, Debug, Default, MallocSizeOf)]
 pub(crate) struct Baselines {
     pub first: Option<Au>,
     pub last: Option<Au>,
diff --git a/components/layout_2020/fragment_tree/base_fragment.rs b/components/layout_2020/fragment_tree/base_fragment.rs
index d26ae71264f..48d672a8547 100644
--- a/components/layout_2020/fragment_tree/base_fragment.rs
+++ b/components/layout_2020/fragment_tree/base_fragment.rs
@@ -3,6 +3,8 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use bitflags::bitflags;
+use malloc_size_of::malloc_size_of_is_0;
+use malloc_size_of_derive::MallocSizeOf;
 use script_layout_interface::combine_id_with_fragment_type;
 use style::dom::OpaqueNode;
 use style::selector_parser::PseudoElement;
@@ -10,7 +12,7 @@ use style::selector_parser::PseudoElement;
 /// This data structure stores fields that are common to all non-base
 /// Fragment types and should generally be the first member of all
 /// concrete fragments.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) struct BaseFragment {
     /// A tag which identifies the DOM node and pseudo element of this
     /// Fragment's content. If this fragment is for an anonymous box,
@@ -38,7 +40,7 @@ impl BaseFragment {
 }
 
 /// Information necessary to construct a new BaseFragment.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, MallocSizeOf)]
 pub(crate) struct BaseFragmentInfo {
     /// The tag to use for the new BaseFragment, if it is not an anonymous Fragment.
     pub tag: Option<Tag>,
@@ -107,9 +109,11 @@ bitflags! {
     }
 }
 
+malloc_size_of_is_0!(FragmentFlags);
+
 /// A data structure used to hold DOM and pseudo-element information about
 /// a particular layout object.
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq)]
 pub(crate) struct Tag {
     pub(crate) node: OpaqueNode,
     pub(crate) pseudo: Option<PseudoElement>,
diff --git a/components/layout_2020/fragment_tree/box_fragment.rs b/components/layout_2020/fragment_tree/box_fragment.rs
index d0c96b3ea03..30be154caf1 100644
--- a/components/layout_2020/fragment_tree/box_fragment.rs
+++ b/components/layout_2020/fragment_tree/box_fragment.rs
@@ -5,6 +5,7 @@
 use app_units::Au;
 use atomic_refcell::AtomicRefCell;
 use base::print_tree::PrintTree;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc as ServoArc;
 use style::Zero;
 use style::computed_values::border_collapse::T as BorderCollapse;
@@ -24,6 +25,7 @@ use crate::table::SpecificTableGridInfo;
 use crate::taffy::SpecificTaffyGridInfo;
 
 /// Describes how a [`BoxFragment`] paints its background.
+#[derive(MallocSizeOf)]
 pub(crate) enum BackgroundMode {
     /// Draw the normal [`BoxFragment`] background as well as the extra backgrounds
     /// based on the style and positioning rectangles in this data structure.
@@ -36,12 +38,14 @@ pub(crate) enum BackgroundMode {
     Normal,
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct ExtraBackground {
+    #[conditional_malloc_size_of]
     pub style: ServoArc<ComputedValues>,
     pub rect: PhysicalRect<Au>,
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) enum SpecificLayoutInfo {
     Grid(Box<SpecificTaffyGridInfo>),
     TableCellWithCollapsedBorders,
@@ -49,9 +53,11 @@ pub(crate) enum SpecificLayoutInfo {
     TableWrapper,
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct BoxFragment {
     pub base: BaseFragment,
 
+    #[conditional_malloc_size_of]
     pub style: ServoArc<ComputedValues>,
     pub children: Vec<Fragment>,
 
diff --git a/components/layout_2020/fragment_tree/fragment.rs b/components/layout_2020/fragment_tree/fragment.rs
index f8ba80369ed..d0d1b9b1104 100644
--- a/components/layout_2020/fragment_tree/fragment.rs
+++ b/components/layout_2020/fragment_tree/fragment.rs
@@ -8,6 +8,7 @@ use app_units::Au;
 use base::id::PipelineId;
 use base::print_tree::PrintTree;
 use fonts::{ByteIndex, FontMetrics, GlyphStore};
+use malloc_size_of_derive::MallocSizeOf;
 use range::Range as ServoRange;
 use servo_arc::Arc as ServoArc;
 use style::Zero;
@@ -23,7 +24,7 @@ use crate::cell::ArcRefCell;
 use crate::geom::{LogicalSides, PhysicalRect};
 use crate::style_ext::ComputedValuesExt;
 
-#[derive(Clone)]
+#[derive(Clone, MallocSizeOf)]
 pub(crate) enum Fragment {
     Box(ArcRefCell<BoxFragment>),
     /// Floating content. A floated fragment is very similar to a normal
@@ -46,25 +47,28 @@ pub(crate) enum Fragment {
     IFrame(ArcRefCell<IFrameFragment>),
 }
 
-#[derive(Clone)]
+#[derive(Clone, MallocSizeOf)]
 pub(crate) struct CollapsedBlockMargins {
     pub collapsed_through: bool,
     pub start: CollapsedMargin,
     pub end: CollapsedMargin,
 }
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, MallocSizeOf)]
 pub(crate) struct CollapsedMargin {
     max_positive: Au,
     min_negative: Au,
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct TextFragment {
     pub base: BaseFragment,
+    #[conditional_malloc_size_of]
     pub parent_style: ServoArc<ComputedValues>,
     pub rect: PhysicalRect<Au>,
     pub font_metrics: FontMetrics,
     pub font_key: FontInstanceKey,
+    #[conditional_malloc_size_of]
     pub glyphs: Vec<Arc<GlyphStore>>,
 
     /// A flag that represents the _used_ value of the text-decoration property.
@@ -73,21 +77,26 @@ pub(crate) struct TextFragment {
     /// Extra space to add for each justification opportunity.
     pub justification_adjustment: Au,
     pub selection_range: Option<ServoRange<ByteIndex>>,
+    #[conditional_malloc_size_of]
     pub selected_style: ServoArc<ComputedValues>,
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct ImageFragment {
     pub base: BaseFragment,
+    #[conditional_malloc_size_of]
     pub style: ServoArc<ComputedValues>,
     pub rect: PhysicalRect<Au>,
     pub clip: PhysicalRect<Au>,
     pub image_key: Option<ImageKey>,
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct IFrameFragment {
     pub base: BaseFragment,
     pub pipeline_id: PipelineId,
     pub rect: PhysicalRect<Au>,
+    #[conditional_malloc_size_of]
     pub style: ServoArc<ComputedValues>,
 }
 
diff --git a/components/layout_2020/fragment_tree/fragment_tree.rs b/components/layout_2020/fragment_tree/fragment_tree.rs
index 32542ccd155..bb3c659466c 100644
--- a/components/layout_2020/fragment_tree/fragment_tree.rs
+++ b/components/layout_2020/fragment_tree/fragment_tree.rs
@@ -7,6 +7,7 @@ use base::print_tree::PrintTree;
 use compositing_traits::display_list::AxesScrollSensitivity;
 use euclid::default::{Point2D, Rect, Size2D};
 use fxhash::FxHashSet;
+use malloc_size_of_derive::MallocSizeOf;
 use style::animation::AnimationSetKey;
 use style::dom::OpaqueNode;
 use webrender_api::units;
@@ -16,6 +17,7 @@ use crate::display_list::StackingContext;
 use crate::flow::CanvasBackground;
 use crate::geom::{PhysicalPoint, PhysicalRect};
 
+#[derive(MallocSizeOf)]
 pub struct FragmentTree {
     /// Fragments at the top-level of the tree.
     ///
diff --git a/components/layout_2020/fragment_tree/hoisted_shared_fragment.rs b/components/layout_2020/fragment_tree/hoisted_shared_fragment.rs
index 4d3eb1f7265..fa3862058da 100644
--- a/components/layout_2020/fragment_tree/hoisted_shared_fragment.rs
+++ b/components/layout_2020/fragment_tree/hoisted_shared_fragment.rs
@@ -3,6 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
+use malloc_size_of_derive::MallocSizeOf;
 use style::logical_geometry::WritingMode;
 use style::values::specified::align::AlignFlags;
 
@@ -12,6 +13,7 @@ use crate::geom::{LogicalVec2, PhysicalRect, PhysicalVec};
 /// A reference to a Fragment which is shared between `HoistedAbsolutelyPositionedBox`
 /// and its placeholder `AbsoluteOrFixedPositionedFragment` in the original tree position.
 /// This will be used later in order to paint this hoisted box in tree order.
+#[derive(MallocSizeOf)]
 pub(crate) struct HoistedSharedFragment {
     pub fragment: Option<Fragment>,
     /// The "static-position rect" of this absolutely positioned box. This is defined by the
diff --git a/components/layout_2020/fragment_tree/positioning_fragment.rs b/components/layout_2020/fragment_tree/positioning_fragment.rs
index b2e6c0ebfd3..853caed6709 100644
--- a/components/layout_2020/fragment_tree/positioning_fragment.rs
+++ b/components/layout_2020/fragment_tree/positioning_fragment.rs
@@ -4,6 +4,7 @@
 
 use app_units::Au;
 use base::print_tree::PrintTree;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc as ServoArc;
 use style::properties::ComputedValues;
 
@@ -14,6 +15,7 @@ use crate::geom::PhysicalRect;
 /// Can contain child fragments with relative coordinates, but does not contribute to painting
 /// itself. [`PositioningFragment`]s may be completely anonymous, or just non-painting Fragments
 /// generated by boxes.
+#[derive(MallocSizeOf)]
 pub(crate) struct PositioningFragment {
     pub base: BaseFragment,
     pub rect: PhysicalRect<Au>,
@@ -22,6 +24,7 @@ pub(crate) struct PositioningFragment {
     pub scrollable_overflow: PhysicalRect<Au>,
 
     /// If this fragment was created with a style, the style of the fragment.
+    #[conditional_malloc_size_of]
     pub style: Option<ServoArc<ComputedValues>>,
 }
 
diff --git a/components/layout_2020/geom.rs b/components/layout_2020/geom.rs
index 638dfae04ea..49f031cbd18 100644
--- a/components/layout_2020/geom.rs
+++ b/components/layout_2020/geom.rs
@@ -8,6 +8,7 @@ use std::fmt;
 use std::ops::{Add, AddAssign, Neg, Sub, SubAssign};
 
 use app_units::{Au, MAX_AU};
+use malloc_size_of_derive::MallocSizeOf;
 use style::Zero;
 use style::logical_geometry::{BlockFlowDirection, Direction, InlineBaseDirection, WritingMode};
 use style::values::computed::{
@@ -28,7 +29,7 @@ pub type PhysicalSides<U> = euclid::SideOffsets2D<U, CSSPixel>;
 pub type AuOrAuto = AutoOr<Au>;
 pub type LengthPercentageOrAuto<'a> = AutoOr<&'a LengthPercentage>;
 
-#[derive(Clone, Copy, PartialEq)]
+#[derive(Clone, Copy, MallocSizeOf, PartialEq)]
 pub struct LogicalVec2<T> {
     pub inline: T,
     pub block: T,
@@ -950,7 +951,7 @@ impl Size<Au> {
 
 /// Represents the sizing constraint that the preferred, min and max sizing properties
 /// impose on one axis.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
 pub(crate) enum SizeConstraint {
     /// Represents a definite preferred size, clamped by minimum and maximum sizes (if any).
     Definite(Au),
diff --git a/components/layout_2020/layout_box_base.rs b/components/layout_2020/layout_box_base.rs
index 54f7575391c..71fbfdeced1 100644
--- a/components/layout_2020/layout_box_base.rs
+++ b/components/layout_2020/layout_box_base.rs
@@ -6,6 +6,7 @@ use std::fmt::{Debug, Formatter};
 
 use app_units::Au;
 use atomic_refcell::AtomicRefCell;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc;
 use style::properties::ComputedValues;
 
@@ -23,8 +24,10 @@ use crate::{ConstraintSpace, ContainingBlockSize};
 /// passes.
 ///
 /// In the future, this will hold layout results to support incremental layout.
+#[derive(MallocSizeOf)]
 pub(crate) struct LayoutBoxBase {
     pub base_fragment_info: BaseFragmentInfo,
+    #[conditional_malloc_size_of]
     pub style: Arc<ComputedValues>,
     pub cached_inline_content_size:
         AtomicRefCell<Option<Box<(SizeConstraint, InlineContentSizesResult)>>>,
@@ -95,7 +98,7 @@ impl Debug for LayoutBoxBase {
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, MallocSizeOf)]
 pub(crate) struct CacheableLayoutResult {
     pub fragments: Vec<Fragment>,
 
@@ -124,6 +127,7 @@ pub(crate) struct CacheableLayoutResult {
 }
 
 /// A collection of layout inputs and a cached layout result for a [`LayoutBoxBase`].
+#[derive(MallocSizeOf)]
 pub(crate) struct CacheableLayoutResultAndInputs {
     /// The [`CacheableLayoutResult`] for this layout.
     pub result: CacheableLayoutResult,
diff --git a/components/layout_2020/lib.rs b/components/layout_2020/lib.rs
index 9e5926e7381..e649c8090b2 100644
--- a/components/layout_2020/lib.rs
+++ b/components/layout_2020/lib.rs
@@ -32,6 +32,7 @@ use app_units::Au;
 pub use cell::ArcRefCell;
 pub use flow::BoxTree;
 pub use fragment_tree::FragmentTree;
+use malloc_size_of_derive::MallocSizeOf;
 use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
 use style::values::computed::TextDecorationLine;
@@ -113,7 +114,7 @@ impl<'a> From<&'_ DefiniteContainingBlock<'a>> for IndefiniteContainingBlock {
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) struct ContainingBlockSize {
     inline: Au,
     block: SizeConstraint,
diff --git a/components/layout_2020/positioned.rs b/components/layout_2020/positioned.rs
index f345947416d..5f08e4e86c5 100644
--- a/components/layout_2020/positioned.rs
+++ b/components/layout_2020/positioned.rs
@@ -5,6 +5,7 @@
 use std::mem;
 
 use app_units::Au;
+use malloc_size_of_derive::MallocSizeOf;
 use rayon::iter::IntoParallelRefMutIterator;
 use rayon::prelude::{IndexedParallelIterator, ParallelIterator};
 use style::Zero;
@@ -35,12 +36,12 @@ use crate::{
     PropagatedBoxTreeData, SizeConstraint,
 };
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct AbsolutelyPositionedBox {
     pub context: IndependentFormattingContext,
 }
 
-#[derive(Clone)]
+#[derive(Clone, MallocSizeOf)]
 pub(crate) struct PositioningContext {
     for_nearest_positioned_ancestor: Option<Vec<HoistedAbsolutelyPositionedBox>>,
 
@@ -50,7 +51,7 @@ pub(crate) struct PositioningContext {
     for_nearest_containing_block_for_all_descendants: Vec<HoistedAbsolutelyPositionedBox>,
 }
 
-#[derive(Clone)]
+#[derive(Clone, MallocSizeOf)]
 pub(crate) struct HoistedAbsolutelyPositionedBox {
     absolutely_positioned_box: ArcRefCell<AbsolutelyPositionedBox>,
 
diff --git a/components/layout_2020/replaced.rs b/components/layout_2020/replaced.rs
index 58d09700e6e..6a6b1979ff9 100644
--- a/components/layout_2020/replaced.rs
+++ b/components/layout_2020/replaced.rs
@@ -11,6 +11,7 @@ use base::id::{BrowsingContextId, PipelineId};
 use data_url::DataUrl;
 use embedder_traits::ViewportDetails;
 use euclid::{Scale, Size2D};
+use malloc_size_of_derive::MallocSizeOf;
 use net_traits::image_cache::{ImageOrMetadataAvailable, UsePlaceholder};
 use pixels::Image;
 use script_layout_interface::IFrameSize;
@@ -37,7 +38,7 @@ use crate::sizing::{ComputeInlineContentSizes, ContentSizes, InlineContentSizesR
 use crate::style_ext::{AspectRatio, Clamp, ComputedValuesExt, ContentBoxSizesAndPBM, LayoutStyle};
 use crate::{ConstraintSpace, ContainingBlock, SizeConstraint};
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct ReplacedContents {
     pub kind: ReplacedContentKind,
     natural_size: NaturalSizes,
@@ -61,7 +62,7 @@ pub(crate) struct ReplacedContents {
 ///
 /// * IFrames do not have natural width and height or natural ratio according
 ///   to <https://drafts.csswg.org/css-images/#intrinsic-dimensions>.
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct NaturalSizes {
     pub width: Option<Au>,
     pub height: Option<Au>,
@@ -95,6 +96,7 @@ impl NaturalSizes {
     }
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) enum CanvasSource {
     WebGL(ImageKey),
     Image(ImageKey),
@@ -118,25 +120,25 @@ impl fmt::Debug for CanvasSource {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct CanvasInfo {
     pub source: CanvasSource,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct IFrameInfo {
     pub pipeline_id: PipelineId,
     pub browsing_context_id: BrowsingContextId,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct VideoInfo {
     pub image_key: webrender_api::ImageKey,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum ReplacedContentKind {
-    Image(Option<Arc<Image>>),
+    Image(#[conditional_malloc_size_of] Option<Arc<Image>>),
     IFrame(IFrameInfo),
     Canvas(CanvasInfo),
     Video(Option<VideoInfo>),
diff --git a/components/layout_2020/sizing.rs b/components/layout_2020/sizing.rs
index cde1a2b246a..c6e4b7f9498 100644
--- a/components/layout_2020/sizing.rs
+++ b/components/layout_2020/sizing.rs
@@ -8,6 +8,7 @@ use std::cell::LazyCell;
 use std::ops::{Add, AddAssign};
 
 use app_units::Au;
+use malloc_size_of_derive::MallocSizeOf;
 use style::Zero;
 use style::values::computed::LengthPercentage;
 
@@ -32,7 +33,7 @@ pub(crate) enum IntrinsicSizingMode {
     Size,
 }
 
-#[derive(Clone, Copy, Debug, Default)]
+#[derive(Clone, Copy, Debug, Default, MallocSizeOf)]
 pub(crate) struct ContentSizes {
     pub min_content: Au,
     pub max_content: Au,
@@ -267,7 +268,7 @@ pub(crate) fn outer_inline(
     }
 }
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, MallocSizeOf)]
 pub(crate) struct InlineContentSizesResult {
     pub sizes: ContentSizes,
     pub depends_on_block_constraints: bool,
diff --git a/components/layout_2020/style_ext.rs b/components/layout_2020/style_ext.rs
index d734b7532d5..c28511766b2 100644
--- a/components/layout_2020/style_ext.rs
+++ b/components/layout_2020/style_ext.rs
@@ -3,6 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
+use malloc_size_of_derive::MallocSizeOf;
 use style::Zero;
 use style::color::AbsoluteColor;
 use style::computed_values::direction::T as Direction;
@@ -238,7 +239,7 @@ pub(crate) struct ContentBoxSizesAndPBM {
     pub preferred_size_computes_to_auto: LogicalVec2<bool>,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
 pub(crate) struct BorderStyleColor {
     pub style: BorderStyle,
     pub color: AbsoluteColor,
diff --git a/components/layout_2020/table/mod.rs b/components/layout_2020/table/mod.rs
index 42978416a23..120270fc7cf 100644
--- a/components/layout_2020/table/mod.rs
+++ b/components/layout_2020/table/mod.rs
@@ -75,6 +75,7 @@ use atomic_refcell::AtomicRef;
 pub(crate) use construct::AnonymousTableContent;
 pub use construct::TableBuilder;
 use euclid::{Point2D, Size2D, UnknownUnit, Vector2D};
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc;
 use style::properties::ComputedValues;
 use style::properties::style_structs::Font;
@@ -92,15 +93,17 @@ use crate::table::layout::TableLayout;
 
 pub type TableSize = Size2D<usize, UnknownUnit>;
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub struct Table {
     /// The style of this table. These are the properties that apply to the "wrapper" ie the element
     /// that contains both the grid and the captions. Not all properties are actually used on the
     /// wrapper though, such as background and borders, which apply to the grid.
+    #[conditional_malloc_size_of]
     style: Arc<ComputedValues>,
 
     /// The style of this table's grid. This is an anonymous style based on the table's style, but
     /// eliminating all the properties handled by the "wrapper."
+    #[conditional_malloc_size_of]
     grid_style: Arc<ComputedValues>,
 
     /// The [`BaseFragmentInfo`] for this table's grid. This is necessary so that when the
@@ -194,7 +197,7 @@ impl Table {
 type TableSlotCoordinates = Point2D<usize, UnknownUnit>;
 pub type TableSlotOffset = Vector2D<usize, UnknownUnit>;
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub struct TableSlotCell {
     /// The [`LayoutBoxBase`] of this table cell.
     base: LayoutBoxBase,
@@ -236,6 +239,7 @@ impl TableSlotCell {
 /// to a previous cell that is spanned here
 ///
 /// In case of table model errors, it may be multiple references
+#[derive(MallocSizeOf)]
 pub enum TableSlot {
     /// A table cell, with a colspan and a rowspan.
     Cell(ArcRefCell<TableSlotCell>),
@@ -272,7 +276,7 @@ impl TableSlot {
 }
 
 /// A row or column of a table.
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub struct TableTrack {
     /// The [`LayoutBoxBase`] of this [`TableTrack`].
     base: LayoutBoxBase,
@@ -286,7 +290,7 @@ pub struct TableTrack {
     is_anonymous: bool,
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, MallocSizeOf, PartialEq)]
 pub enum TableTrackGroupType {
     HeaderGroup,
     FooterGroup,
@@ -294,7 +298,7 @@ pub enum TableTrackGroupType {
     ColumnGroup,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub struct TableTrackGroup {
     /// The [`LayoutBoxBase`] of this [`TableTrackGroup`].
     base: LayoutBoxBase,
@@ -312,14 +316,14 @@ impl TableTrackGroup {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub struct TableCaption {
     /// The contents of this cell, with its own layout.
     context: IndependentFormattingContext,
 }
 
 /// A calculated collapsed border.
-#[derive(Clone, Debug, Default, PartialEq)]
+#[derive(Clone, Debug, Default, MallocSizeOf, PartialEq)]
 pub(crate) struct CollapsedBorder {
     pub style_color: BorderStyleColor,
     pub width: Au,
@@ -328,7 +332,7 @@ pub(crate) struct CollapsedBorder {
 /// Represents a piecewise sequence of collapsed borders along a line.
 pub(crate) type CollapsedBorderLine = Vec<CollapsedBorder>;
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) struct SpecificTableGridInfo {
     pub collapsed_borders: PhysicalVec<Vec<CollapsedBorderLine>>,
     pub track_sizes: PhysicalVec<Vec<Au>>,
diff --git a/components/layout_2020/taffy/mod.rs b/components/layout_2020/taffy/mod.rs
index 7aca7286bcd..55a678cd89a 100644
--- a/components/layout_2020/taffy/mod.rs
+++ b/components/layout_2020/taffy/mod.rs
@@ -6,6 +6,7 @@ mod stylo_taffy;
 use std::fmt;
 
 use app_units::Au;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc;
 use style::properties::ComputedValues;
 use stylo_taffy::TaffyStyloStyle;
@@ -20,9 +21,10 @@ use crate::formatting_contexts::IndependentFormattingContext;
 use crate::fragment_tree::Fragment;
 use crate::positioned::{AbsolutelyPositionedBox, PositioningContext};
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) struct TaffyContainer {
     children: Vec<ArcRefCell<TaffyItemBox>>,
+    #[conditional_malloc_size_of]
     style: Arc<ComputedValues>,
 }
 
@@ -69,15 +71,17 @@ impl TaffyContainer {
     }
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct TaffyItemBox {
     pub(crate) taffy_layout: taffy::Layout,
     pub(crate) child_fragments: Vec<Fragment>,
     pub(crate) positioning_context: PositioningContext,
+    #[conditional_malloc_size_of]
     pub(crate) style: Arc<ComputedValues>,
     pub(crate) taffy_level_box: TaffyItemBoxInner,
 }
 
-#[derive(Debug)]
+#[derive(Debug, MallocSizeOf)]
 pub(crate) enum TaffyItemBoxInner {
     InFlowBox(IndependentFormattingContext),
     OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
@@ -145,7 +149,7 @@ impl TaffyItemBox {
 }
 
 /// Details from Taffy grid layout that will be stored
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) struct SpecificTaffyGridInfo {
     pub rows: SpecificTaffyGridTrackInfo,
     pub columns: SpecificTaffyGridTrackInfo,
@@ -174,7 +178,7 @@ impl SpecificTaffyGridInfo {
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) struct SpecificTaffyGridTrackInfo {
     pub sizes: Box<[Au]>,
 }
diff --git a/components/layout_thread_2020/lib.rs b/components/layout_thread_2020/lib.rs
index 6a9922701e4..89a12341bbf 100644
--- a/components/layout_thread_2020/lib.rs
+++ b/components/layout_thread_2020/lib.rs
@@ -8,8 +8,9 @@
 //! Layout. Performs layout on the DOM, builds display lists and sends them to be
 //! painted.
 
-use std::cell::{Cell, RefCell};
-use std::collections::HashMap;
+use std::cell::{Cell, LazyCell, RefCell};
+use std::collections::{HashMap, HashSet};
+use std::ffi::c_void;
 use std::fmt::Debug;
 use std::process;
 use std::sync::{Arc, LazyLock};
@@ -38,7 +39,7 @@ use layout::query::{
 use layout::traversal::RecalcStyle;
 use layout::{BoxTree, FragmentTree};
 use log::{debug, error};
-use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
+use malloc_size_of::{MallocConditionalSizeOf, MallocSizeOf, MallocSizeOfOps};
 use net_traits::image_cache::{ImageCache, UsePlaceholder};
 use parking_lot::{Mutex, RwLock};
 use profile_traits::mem::{Report, ReportKind};
@@ -417,7 +418,28 @@ impl Layout for LayoutThread {
         reports.push(Report {
             path: path![formatted_url, "layout-thread", "font-context"],
             kind: ReportKind::ExplicitJemallocHeapSize,
-            size: self.font_context.size_of(ops),
+            size: self.font_context.conditional_size_of(ops),
+        });
+
+        reports.push(Report {
+            path: path![formatted_url, "layout-thread", "box-tree"],
+            kind: ReportKind::ExplicitJemallocHeapSize,
+            size: self
+                .box_tree
+                .borrow()
+                .as_ref()
+                .map_or(0, |tree| tree.conditional_size_of(ops)),
+        });
+
+        reports.push(Report {
+            path: path![formatted_url, "layout-thread", "fragment-tree"],
+            kind: ReportKind::ExplicitJemallocHeapSize,
+            size: self
+                .fragment_tree
+                .borrow()
+                .as_ref()
+                .map(|tree| tree.conditional_size_of(ops))
+                .unwrap_or_default(),
         });
     }
 
@@ -1210,3 +1232,7 @@ impl Debug for LayoutFontMetricsProvider {
         f.debug_tuple("LayoutFontMetricsProvider").finish()
     }
 }
+
+thread_local!(static SEEN_POINTERS: LazyCell<RefCell<HashSet<*const c_void>>> = const {
+    LazyCell::new(|| RefCell::new(HashSet::new()))
+});
diff --git a/components/malloc_size_of/Cargo.toml b/components/malloc_size_of/Cargo.toml
index 88c86239d50..f6f25075ed6 100644
--- a/components/malloc_size_of/Cargo.toml
+++ b/components/malloc_size_of/Cargo.toml
@@ -13,6 +13,7 @@ path = "lib.rs"
 [dependencies]
 accountable-refcell = { workspace = true }
 app_units = { workspace = true }
+atomic_refcell = { workspace = true }
 content-security-policy = { workspace = true }
 crossbeam-channel = { workspace = true }
 euclid = { workspace = true }
@@ -28,8 +29,11 @@ string_cache = { workspace = true }
 stylo = { workspace = true }
 stylo_dom = { workspace = true }
 stylo_malloc_size_of = { workspace = true }
+taffy = { workspace = true }
 thin-vec = { workspace = true }
 tokio = { workspace = true, features = ["sync"] }
+unicode-bidi = { workspace = true }
+unicode-script = { workspace = true }
 url = { workspace = true }
 uuid = { workspace = true }
 webrender_api = { workspace = true }
diff --git a/components/malloc_size_of/lib.rs b/components/malloc_size_of/lib.rs
index dbecc0da2c3..b7f677f8044 100644
--- a/components/malloc_size_of/lib.rs
+++ b/components/malloc_size_of/lib.rs
@@ -52,6 +52,7 @@ use std::hash::{BuildHasher, Hash};
 use std::ops::Range;
 use std::sync::Arc;
 
+use style::values::generics::length::GenericLengthPercentageOrAuto;
 pub use stylo_malloc_size_of::MallocSizeOfOps;
 use uuid::Uuid;
 
@@ -219,6 +220,26 @@ where
     }
 }
 
+impl<T: MallocConditionalSizeOf> MallocConditionalSizeOf for Option<T> {
+    fn conditional_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        if let Some(val) = self.as_ref() {
+            val.conditional_size_of(ops)
+        } else {
+            0
+        }
+    }
+}
+
+impl<T: MallocConditionalSizeOf> MallocConditionalSizeOf for Vec<T> {
+    fn conditional_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        let mut n = self.shallow_size_of(ops);
+        for elem in self.iter() {
+            n += elem.conditional_size_of(ops);
+        }
+        n
+    }
+}
+
 impl<T: MallocSizeOf> MallocSizeOf for Option<T> {
     fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
         if let Some(val) = self.as_ref() {
@@ -726,7 +747,11 @@ malloc_size_of_is_0!(std::time::Duration);
 malloc_size_of_is_0!(std::time::Instant);
 malloc_size_of_is_0!(std::time::SystemTime);
 malloc_size_of_is_0!(style::font_face::SourceList);
+malloc_size_of_is_0!(style::properties::ComputedValues);
 malloc_size_of_is_0!(style::queries::values::PrefersColorScheme);
+malloc_size_of_is_0!(taffy::Layout);
+malloc_size_of_is_0!(unicode_bidi::Level);
+malloc_size_of_is_0!(unicode_script::Script);
 
 macro_rules! malloc_size_of_is_webrender_malloc_size_of(
     ($($ty:ty),+) => (
@@ -790,6 +815,12 @@ where
     }
 }
 
+impl<T: MallocSizeOf> MallocSizeOf for atomic_refcell::AtomicRefCell<T> {
+    fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        self.borrow().size_of(ops)
+    }
+}
+
 malloc_size_of_is_stylo_malloc_size_of!(style::animation::DocumentAnimationSet);
 malloc_size_of_is_stylo_malloc_size_of!(style::attr::AttrIdentifier);
 malloc_size_of_is_stylo_malloc_size_of!(style::attr::AttrValue);
@@ -797,7 +828,15 @@ malloc_size_of_is_stylo_malloc_size_of!(style::color::AbsoluteColor);
 malloc_size_of_is_stylo_malloc_size_of!(style::computed_values::font_variant_caps::T);
 malloc_size_of_is_stylo_malloc_size_of!(style::dom::OpaqueNode);
 malloc_size_of_is_stylo_malloc_size_of!(style::invalidation::element::restyle_hints::RestyleHint);
+malloc_size_of_is_stylo_malloc_size_of!(style::logical_geometry::WritingMode);
 malloc_size_of_is_stylo_malloc_size_of!(style::media_queries::MediaList);
+malloc_size_of_is_stylo_malloc_size_of!(
+    style::properties::longhands::align_items::computed_value::T
+);
+malloc_size_of_is_stylo_malloc_size_of!(
+    style::properties::longhands::flex_direction::computed_value::T
+);
+malloc_size_of_is_stylo_malloc_size_of!(style::properties::longhands::flex_wrap::computed_value::T);
 malloc_size_of_is_stylo_malloc_size_of!(style::properties::style_structs::Font);
 malloc_size_of_is_stylo_malloc_size_of!(style::selector_parser::PseudoElement);
 malloc_size_of_is_stylo_malloc_size_of!(style::selector_parser::RestyleDamage);
@@ -805,8 +844,22 @@ malloc_size_of_is_stylo_malloc_size_of!(style::selector_parser::Snapshot);
 malloc_size_of_is_stylo_malloc_size_of!(style::shared_lock::SharedRwLock);
 malloc_size_of_is_stylo_malloc_size_of!(style::stylesheets::DocumentStyleSheet);
 malloc_size_of_is_stylo_malloc_size_of!(style::stylist::Stylist);
+malloc_size_of_is_stylo_malloc_size_of!(style::values::computed::AlignContent);
+malloc_size_of_is_stylo_malloc_size_of!(style::values::computed::BorderStyle);
 malloc_size_of_is_stylo_malloc_size_of!(style::values::computed::FontStretch);
 malloc_size_of_is_stylo_malloc_size_of!(style::values::computed::FontStyle);
 malloc_size_of_is_stylo_malloc_size_of!(style::values::computed::FontWeight);
 malloc_size_of_is_stylo_malloc_size_of!(style::values::computed::font::SingleFontFamily);
+malloc_size_of_is_stylo_malloc_size_of!(style::values::computed::JustifyContent);
+malloc_size_of_is_stylo_malloc_size_of!(style::values::specified::align::AlignFlags);
+malloc_size_of_is_stylo_malloc_size_of!(style::values::specified::TextDecorationLine);
 malloc_size_of_is_stylo_malloc_size_of!(stylo_dom::ElementState);
+
+impl<T> MallocSizeOf for GenericLengthPercentageOrAuto<T>
+where
+    T: stylo_malloc_size_of::MallocSizeOf,
+{
+    fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        <GenericLengthPercentageOrAuto<T> as stylo_malloc_size_of::MallocSizeOf>::size_of(self, ops)
+    }
+}
diff --git a/components/shared/compositing/Cargo.toml b/components/shared/compositing/Cargo.toml
index 2462d6b42e9..e3ff81615e6 100644
--- a/components/shared/compositing/Cargo.toml
+++ b/components/shared/compositing/Cargo.toml
@@ -26,6 +26,8 @@ glow = { workspace = true }
 image = { workspace = true }
 ipc-channel = { workspace = true }
 log = { workspace = true }
+malloc_size_of = { workspace = true }
+malloc_size_of_derive = { workspace = true }
 pixels = { path = '../../pixels' }
 profile_traits = { path = '../profile' }
 raw-window-handle = { version = "0.6" }
diff --git a/components/shared/compositing/display_list.rs b/components/shared/compositing/display_list.rs
index 2b7883c3ce1..6aa822cb145 100644
--- a/components/shared/compositing/display_list.rs
+++ b/components/shared/compositing/display_list.rs
@@ -6,6 +6,7 @@
 
 use base::id::ScrollTreeNodeId;
 use embedder_traits::Cursor;
+use malloc_size_of_derive::MallocSizeOf;
 use serde::{Deserialize, Serialize};
 use style::values::specified::Overflow;
 use webrender_api::units::{LayoutSize, LayoutVector2D};
@@ -13,7 +14,7 @@ use webrender_api::{Epoch, ExternalScrollId, PipelineId, ScrollLocation, Spatial
 
 /// The scroll sensitivity of a scroll node in a particular axis ie whether it can be scrolled due to
 /// input events and script events or only script events.
-#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
+#[derive(Clone, Copy, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
 pub enum ScrollSensitivity {
     /// This node can be scrolled by input and script events.
     ScriptAndInputEvents,
@@ -35,7 +36,7 @@ impl From<Overflow> for ScrollSensitivity {
 }
 
 /// The [ScrollSensitivity] of particular node in the vertical and horizontal axes.
-#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
+#[derive(Clone, Copy, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
 pub struct AxesScrollSensitivity {
     pub x: ScrollSensitivity,
     pub y: ScrollSensitivity,