FireFox memory usage

[Jan Beich]

Jan Beich <jbeich at FreeBSD.org> writes:

> Andrea Venturoli <ml at netfence.it> writes:
>
>> Hello.
>>
>> I'm on 10.3/amd64 with firefox-esr 52.3.0.
>>
>> Since a few days my 4GiB desktop is crawling due to swap usage and
>> looking at top, I see FireFox using almost 7GiB of RAM (SIZE column),
>> 2.5 of which are "RES".
>
> Check about:memory and Devolper Tools -> Memory for clues. For more
> advanced debugging (DMD, Refcount tracing) you'd need a custom build.
>
> Firefox on FreeBSD is known to consume more memory than on other
> platforms because it uses system jemalloc rather than mozjemalloc.
> Mozilla doesn't test memory usage without mozjemalloc. However, porting
> mozjemalloc has stalled[1] unless someone helps.
>
> [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1153683

If one is on Firefox 55+ or FreeBSD 12+ while suboptimal compared to
mozjemalloc the old jemalloc4 optimizations can be restored by

  $ MALLOC_CONF="narenas:1,tcache:false" firefox ...

https://dxr.mozilla.org/mozilla-esr52/source/memory/build/jemalloc_config.cpp#35