1617434 - Avoid recreating reserved Clients when we process switch

Status: RESOLVED FIXED

(Core :: DOM: Workers, enhancement, P1)

Description

[Matt Woodrow (:mattwoodrow)]

The current flow for creating ClientSources for document loads with DocumentChannel is:

• The originating content process creates a reserved ClientSource for the initial URL of the load.
• If a redirect is encountered, then the parent process allocates a ClientInfo (for a 'future' ClientSource) using the new URL.
• If the load is to be delivered to the originating process:
  • If there were no redirects, then copy the reserved ClientSource across to the final channel.
  • If there were (so we have a ClientInfo), then we create a reserved ClientSource using that info (resolving the 'future' ClientSource). We also destroy the existing ClientSource created at the start.
• If we had to switch processes and the load is delivered to the new one:
  • The new process unconditionally allocates a new reserved ClientSource (and ClientInfo!), and then we have to notify the parent of the new id to make sure we update the controlled client.
  • The old process is torn down, destroying the existing ClientSource.

I think we can simplify this to:

• The parent process allocates a ClientInfo ('future' ClientSource) for both the initial URL, as well as any redirect URLs.
• When we deliver the load to a process (either originating or new), then we create a reserved ClientSource around the most recent ClientInfo.

Comment 1

[Matt Woodrow (:mattwoodrow)]

Attachment: Bug 1617434 - Split ClientChannelHelper into three separate classes instead of having a mode variable. r?perry,asuth

This should be a no-op, but should make the following changes easier to reason about.

Comment 2

[Matt Woodrow (:mattwoodrow)]

Attachment: Bug 1617434 - Move reserved client creation to parent-side with DocumentChannel. r?perry,asuth

Rather than creating a ClientSource in the content process for the initial URL, this changes us to just create the ClientInfo in the parent, as we do for redirects.

Depends on D63805

Comment 3

[Matt Woodrow (:mattwoodrow)]

Attachment: Bug 1617434 - Don't recreate ClientSource when we process switch. r?perry,asuth

Now that we're guaranteed to not have an existing ClientSource in the old process, we no longer need to allocate a new ClientInfo in the new process.
This lets us just create a ClientSource around the ClientInfo already on the channel (exactly as we do for same-process loads), and we no longer need to reconcile changes with the parent.

Depends on D63807

Comment 4

[Matt Woodrow (:mattwoodrow)]

Attachment: Bug 1617434 - Simplify ClientChannelHelperChild. r?perry,asuth

Depends on D63808

Comment 5

[Matt Woodrow (:mattwoodrow)]

Attachment: Bug 1617434 - Share code where possible in ClientChannelHelper. r?perry,asuth

Depends on D63809

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1563faa24d15
Split ClientChannelHelper into three separate classes instead of having a mode variable. r=perry
https://hg.mozilla.org/integration/autoland/rev/c5f1f70efb88
Move reserved client creation to parent-side with DocumentChannel. r=perry

Comment 7

[Dorel Luca [:dluca]]

Backed out 7 changesets (bug 1617500, bug 1617789, bug 1617434) for build bustage in dom/clients/manager/ClientChannelHelper.cpp

Log:
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=291144779&repo=autoland&lineNumber=28560

Push with failures:
https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&revision=1a62904bfcb7345ea90841e179e8aea5e88ffac8

Backout:
https://hg.mozilla.org/integration/autoland/rev/d9db62e5092eaeefb7049b150bdd775016c9a62d

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3e91b3805158
Split ClientChannelHelper into three separate classes instead of having a mode variable. r=perry
https://hg.mozilla.org/integration/autoland/rev/c0f15f00e1c6
Move reserved client creation to parent-side with DocumentChannel. r=perry

Comment 9

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/3e91b3805158
https://hg.mozilla.org/mozilla-central/rev/c0f15f00e1c6

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a4b2284d5325
Don't recreate ClientSource when we process switch. r=perry
https://hg.mozilla.org/integration/autoland/rev/2c557fca99ed
Simplify ClientChannelHelperChild. r=perry
https://hg.mozilla.org/integration/autoland/rev/713b5f2a3735
Share code where possible in ClientChannelHelper. r=perry

Comment 11

[Oana Pop-Rus]

https://hg.mozilla.org/mozilla-central/rev/a4b2284d5325
https://hg.mozilla.org/mozilla-central/rev/2c557fca99ed
https://hg.mozilla.org/mozilla-central/rev/713b5f2a3735