1644252 - Clarify in code and docs that accumulations in GeckoViewStreamingTelemetry's SendBatch could deadlock

Status: RESOLVED FIXED

(Toolkit :: Telemetry, task, P1)

Description

[Chris H-C :chutten]

As :froydnj mentioned today on Slack, SendBatch could deadlock if something inside it decided to accumulate.

Most of it is framework level stuff like nsTArray's SwapElements but it isn't unreasonable that NS_DispatchToMainThread might one day decide to accumulate something and stream it over the GV Streaming bridge for Fenix reporting.

At this point I don't think there's much we'll want to do in code to prevent it (there are multiple barriers to adding measurements that would cause the deadlocks, and Project FOG will provide a better way to get metrics from Gecko out via Fenix's Glean in the medium term) but let's at least document the possibility.

Comment 1

[Chris H-C :chutten]

Attachment: Bug 1644252 - Make note of deadlock potential in gv streaming telemetry r?janerik!

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a5ee74afa9be
Make note of deadlock potential in gv streaming telemetry r=janerik

Comment 3

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/a5ee74afa9be