about:memory doesn't report any information for the plugin-container process. We probably can't report much info for it, but some basics (eg. the amount of mapped and resident memory) would be nice. (If we can do more, that would be nice.) about:memory already handles the separate chrome and content processes for Fennec, so the infrastructure is already present for reporting for multiple processes. It just needs to be hooked up to the plugin-container process.
(We use the plugin-container process for all subprocess types. Yeah, sigh.) I think for this bug you're referring to the subprocesses in which plugin code runs. We can quite easily forward jemalloc, gfxASurface, and shmem stats from plugin processes.
(In reply to comment #1) > I think for this bug you're referring to the subprocesses in which plugin code > runs. Probably, I don't have the terminology down :) > We can quite easily forward jemalloc, gfxASurface, and shmem stats from plugin > processes. That'd be great!
You can get the basic numbers like resident from the OS pretty easily. This doesn't seem worth the effort.