1675837 - Lots of memory used by JS classes on Facebook

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect, P2)

Description

[flo]

User Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:4.7) Goanna/20170101 PaleMoon/28.15.0

Steps to reproduce:

facebook tab usage after a few minutes/hours
go up to 3GB memory

using firefox latest version
82.0.2 64bits

Actual results:

facebook tab usage after a few minutes/hours
go up to 3GB memory

may be related to bug https://bugzilla.mozilla.org/show_bug.cgi?id=1116992

Expected results:

tab usage should be under 1GB

Comment 1

[Andre Klapper]

Please enter the address
about:memory?verbose
in the address bar and attach (using the "Attach New File" link above) the output here.

Comment 2

[flo]

Attachment: memory-report.json.gz

about:memory?verbose result

Comment 3

[Raluca Popovici, Desktop QA]

This issue might be a duplicate of bug 1674295

Comment 4

[Andrew McCreight [:mccr8]]

I think it is better to leave reports separate until we can confirm that the underlying issues are the same. There's a lot of different things that could be going wrong.

Comment 5

[Andrew McCreight [:mccr8]]

There's almost a gig of JS classes, which is almost the entirety of the memory used for the page, which is odd. I see there's the Grammalecte addon, and another addon Grammarly has been responsible for memory issues in the past, so maybe try and see if disabling that helps? That leaves another 700MB in the process, which is a lot, but that is scattered among a lot of other categories, like strings, heap-unclassified and media/resources.

Comment 6

[Andrew McCreight [:mccr8]]

I'm making the summary more specific to the issue I am seeing in the memory report.

Comment 7

[flo]

Attachment: 2020-11-12 17_33_31-firefox-fb-usage.png

guess what tab is firefox usage
(mem usage after one day open)

Comment 8

[Jason Orendorff [:jorendorff]]

@flo, If you disable the Grammalecte and Grammarly addons, does that help?

Comment 9

[flo]

@jason yes, i tried
no difference

Comment 10

[flo]

Attachment: memory-report.json.gz

mem reported with Grammalecte disabled
no changes, still 3GB mem usage by facebook tab

Comment 11

[Nicolas B. Pierron [:nbp] {away}]

Hi flo,

Would you mind sharing the dominator view of the memory which is reported by the devtools, to help us isolate which part of the JS code is holding on memory. However, beware that the following memory profile would not be anonymized, as far as I can tell.

https://developer.mozilla.org/en-US/docs/Tools/Memory/Dominators_view

Comment 12

[flo]

problem still present in latest version v85
also, seems problem can occur with other sites
i have the same issue with youtube more than 2GB mem usage for 1 tab
(in this case for https://www.youtube.com/watch?v=K3JGxj2rvAs)

Comment 14

[andriyorehov]

I think we can close this bug. I tried to reproduce it on the latest Firefox and, even after hours of running, memory held steady at ~500 MB

task manager