1350292 - Memory allocated by WebGL in WebGLBuffer::BufferData is not tracked in about:memory (detected by DMD in heap-unclassified)

Status: NEW

(Core :: Graphics: CanvasWebGL, defect, P2)

Description

[Jukka Jylänki]

STR:

1. Do a DMD build of Firefox from https://developer.mozilla.org/en-US/docs/Mozilla/Performance/DMD
2. Visit http://mzl.la/webassemblydemo
3. Run a snapshot and analyze the content process

Observed:

There are 588 memory allocations that are untracked in about:memory, coming from

Unreported {
  588 blocks in heap block record 5 of 2,715
  4,747,008 bytes (4,379,230 requested / 367,778 slop)
  Individual block sizes: 1,048,576 x 2; 294,912; 196,608; 102,400; 65,536; 45,056 x 4; 32,768 x 4; 24,576 x 8; 20,480 x 8; 16,384 x 8; 12,288 x 4; 8,192 x 50; 4,096 x 101; 2,048 x 68; 1,024 x 129; 512 x 12; 480 x 8; 464 x 4; 448 x 4; 432 x 12; 384 x 8; 320 x 8; 272 x 4; 256 x 8; 240 x 12; 224 x 4; 192 x 25; 176 x 16; 144 x 4; 112 x 8; 96 x 6; 80 x 17; 64 x 4; 48 x 12; 32 x 13; 16 x 9
  0.81% of the heap (27.39% cumulative)
  2.76% of unreported (93.34% cumulative)
  Allocated at {
    #01: mozilla::WebGLBuffer::BufferData (e:\gecko-dev\dom\canvas\webglbuffer.cpp:126)
    #02: mozilla::WebGLContext::BufferDataImpl (e:\gecko-dev\dom\canvas\webglcontextbuffers.cpp:333)
  }
}

which is "newIndexCache" variable that is being malloc()ed at https://dxr.mozilla.org/mozilla-central/source/dom/canvas/WebGLBuffer.cpp#126.

This is the fourth highest call site of untracked memory on that page, so it would be good to track these in about:memory under a node "webgl->index-cache-memory" or something similar?

Comment 1

[Kelsey Gilbert [:jgilbert]]

This should be an easy fix.