1414505 - consider to evict bfcache in background tabs sooner than in foreground

Status: NEW

(Core :: DOM: Navigation, enhancement, P2)

Description

[Olli Pettay [:smaug][[e-mail]]]

In order to possibly reduce memory usage, but also to make foreground tab behave
better (more pages there in bfcache), perhaps we should evict bfcache in background tabs sooner.

Comment 1

[Ben Kelly [:bkelly, not reviewing]]

Do we have any measurements about how much memory bfcache pages take?

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Well, whatever web pages happen to take. I assume it varies a lot.
But no, we don't have anything. I don't think we have any measurements on web pages either, if you're talking about telemetry probes or so.

Comment 3

[Eric Rahm [:erahm]]

(In reply to Ben Kelly [:bkelly] from comment #1)
> Do we have any measurements about how much memory bfcache pages take?

We saw a 219MiB regression in our tabs opened measurement in AWSY when we turned this back on. It's pretty bad. See bug 1415125 and bug 1411393.

Comment 4

[Eric Rahm [:erahm]]

This would be nice to tweak, but we think some telemetry would help us decide what to do. At this point we're not even sure how deep the cache is and how often it's used.