On Tue, 10 Jun 2025 15:31:22 GMT, Kevin Rushforth <k...@openjdk.org> wrote:
>> PR to replace the use of sun.misc.Unsafe memory access methods in the Marlin >> rasterizer with FFM. >> >> I broke this up into the following commits. The bulk of the work is in the >> first two: >> >> 1. Encapsulate all off-heap access in OffHeapArray -- All of the memory >> allocation and management was already done in the OffHeapArray class, but >> the users of OffHeapArray, primarily Renderer and RendererNoAA, called >> Unsafe methods directly. I encapsulated all of the calls to Unsafe in >> OffHeapArray. The main impact on calling code is that the base address is no >> longer accessible or needed. Instead, the `(put|get)(Byte|Int)` methods take >> only an offset. This commit was straight refactoring with no behavioral >> changes. >> 2. Initial FFM implementation -- I changed the memory management and access >> methods to use FFM. Each OffHeap array uses a shared Arena to manage the >> single memory segment allocated at construction time. The resize method >> creates a new Arena and memory segment, copying the data from the old and >> then closing it >> 3. Set `used` to 0 in `dispose()` -- While testing and instrumenting the >> code, I discovered that the Renderer dispose methods resize the edges array >> back to the default size without clearing the "used" field. The used field >> will be cleared before the next time it is accessed, but clearing it in >> dispose allows optimizing resize to not copy any data. >> 4. Remove '--sun-misc-unsafe-memory-access=allow' from test and app >> execution, since it is no longer needed. This also enables `-Werror` for the >> `javafx.graphics` module. >> 5. ~~Temporary debug prints that will be removed before making this "rfr"~~ >> >> Additional commits address review comments. > > Kevin Rushforth has updated the pull request incrementally with one > additional commit since the last revision: > > Initialize alpha maps in constructor to ensure they are created on the > right thread (QuantumRenderer) modules/javafx.graphics/src/main/java/com/sun/marlin/MaskMarlinAlphaConsumer.java line 111: > 109: byte[] _ALPHA_MAP = buildAlphaMap(MarlinConst.MAX_AA_ALPHA); > 110: ALPHA_MAP = _ALPHA_MAP; // Keep alive the OffHeapArray > 111: ALPHA_MAP_OFF_HEAP = new OffHeapArray(ALPHA_MAP, > ALPHA_MAP.length); // 1K L110: is `ALPHA_MAP` needed to keep the `parent` reference? if so, why not use a single `Object` instead of an array? ------------- PR Review Comment: https://git.openjdk.org/jfx/pull/1814#discussion_r2140345005
