1663418 - Get rid of the O(n^2) loop in ChromeUtils::RequestProcessInfo

Status: RESOLVED FIXED

(Core :: DOM: Content Processes, defect)

Comment 1

[David Teller [:Yoric] - still alive but not very active]

Attachment: Bug 1663418 - Faster path for ContentProcess in RequestProcInfo;r?froydnj

Prior to this patch, RequestProcInfo attempts to examine all processes from mozilla::ipc::GeckoChildProcessHost::GetAll callbacks.

This causes two issues:

• lifetime management for raw ContentProcess* used during the callbacks works but is complicated to audit;
• for each GeckoChildProcessHost identified as a ContentProcess, we need to perform a linear lookup within content processes during each callback, which makes the code O(n^2) where n is the number of content processes.

This patch rewrites this section of RequestProcInfo by splitting it as follows:

1. We use the same GeckoChildProcessHost::GetAll callback to examine non-ContentProcess, without any lookup.
2. We use the list of ContentProcess to examine ContentProcesses, without any lookup.

New code is a bit longer (138 loc vs. 115) but not as deeply nested, which should be an acceptable tradeoff.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b0e9cfc9e157
Faster path for ContentProcess in RequestProcInfo;r=froydnj

Comment 3

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/b0e9cfc9e157