2007841 - Cached inline stylesheets do not release memory even after reloading the page and manually reducing memory

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Mayank Bansal]

Attachment: 1 stylesheet in total_no choie.htm

This is the testcase from bug 1962946

STR:

1. Open testcase
2. Enter 2000 in the input-box
3. Click on run. Wait for the page to get responsive which will take ~5s.
4. Now hard reload the page (CTRL+SHIFT +R)
5. Go to about:memory and click on "Manually reduce memory"

AR: in steps #4 and steps#5, the memory is not reduced
ER: It should?

The memory would go down before bug 1956486. So i am marking it as a regressor.

Comment 1

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 1956486

Comment 2

[Jonathan Kew [:jfkthame]]

This does seem somewhat leak-ish; by repeating the steps (after force-reloading the test page), the reported memory usage increases further (and generating the about:memory report gets a lot slower).

Navigating away from the test page does result in the memory being released, it seems. Still, it looks like as long as we're on the test page (even after force-reloading and running minimize-memory), stale cached stuff is being a bit persistent.

Comment 4

[Mayank Bansal]

Attachment: Stylesheet-memory-retention.html

This is a much simpler testcase that repros the issue.

STR:

1. Open testcase
2. Click Generate
3. Click Nativeclear
4. Force-reload the page
5. Go to about:memory and click on "Mnually free memory"

AR: Memory is not freed
ER: it should

Comment 5

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2007841 - GC the stylesheet cache. r=#style

I made it a global thing rather than something more subtle like
nsExpirationTracker, because nsExpirationTracker doesn't deal super-well
with the nested hashtable structure and different kinds of entries, and
this seems like it should be good enough (idle runnable + delay).

Much like the atom table GC:

https://searchfox.org/firefox-main/source/xpcom/ds/nsAtomTable.cpp#456

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/dfb3d67fae29
https://hg.mozilla.org/integration/autoland/rev/836395cb046f
GC the stylesheet cache. r=firefox-style-system-reviewers,dshin

Comment 7

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/836395cb046f

Comment 8

[Mayank Bansal]

This is fixed in nightly.
Profile: https://share.firefox.dev/4o4KWkw