1726865 - Make new toplevel sites prefer a new content process, new iframes prefer an existing content process

Status: RESOLVED FIXED

(Core :: DOM: Content Processes, enhancement)

Description

[Chris Peterson [:cpeterson]]

For new iframes, try to use an existing content process. For new toplevel sites, try to allocate a new content process, unless we have reach the dom.ipc.processCount.webIsolated limit.

Replace GetNewOrUsedLaunchingBrowserProcess(/* aPreferUsed = */ false) with GetNewOrUsedLaunchingBrowserProcess(/* aPreferUsed = */ !IsTop()) here:

https://searchfox.org/mozilla-central/rev/9dceacf3d761eb91237108ec438d64099a56f442/docshell/base/CanonicalBrowsingContext.cpp#1853

Comment 1

[Emilio Cobos Álvarez (:emilio)]

What's the reasoning for this out of curiosity?

Comment 2

[Chris Peterson [:cpeterson]]

What's the reasoning for this out of curiosity?

Based on the promising early results from our Nightly experiment comparing dom.ipc.processCount.webIsolated limit 1 versus 4 processes per site, we'd like to increase dom.ipc.processCount.webIsolated to something greater than 1. That is bug 1727158.

This bug's proposed change will try to balance the responsiveness benefits versus increased memory usage by preferring to reuse existing content processes for new iframes (assuming they will be lightweight) and use new content processes (until we hit the limit) for toplevel sites in tabs (for improved responsiveness and crash isolation).

Assigning to Nika because, IIRC, she offered last week to write this patch.

Comment 3

[Chris Peterson [:cpeterson]]

Deferring this bug from Fission Milestone M8 to MVP. This bug doesn't need to block our Release channel experiment (M8) and we wouldn't uplift a fix to Beta 92 this late in the beta cycle.

Comment 4

[Nika Layzell [:nika] (ni? for response)]

Attachment: Bug 1726865 - Prefer using existing content processes for subframes during process selection, r=farre

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7fffdb095dd9
Prefer using existing content processes for subframes during process selection, r=farre

Comment 6

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/7fffdb095dd9