1308403 - Investigate disabling Ion compilation while we're in a low memory situation

Status: NEW

(Core :: JavaScript Engine: JIT, defect, P3)

Description

[Jon Coppeard (:jonco)]

Ion compilation consumes a lot of memory in order to improve execution speed.  We could disable this while there is an ongoing low memory situation.

Comment 1

[Jon Coppeard (:jonco)]

At the moment we receive a memory pressure event when the system enters a low memory state.  But I don't know if there's a way to tell when the situation changes and memory is available again.

gsvelto, do you know if there is a way to get an event when the low memory state ends too?  It sounds like there could be a tie-in here with the floating memory pressure trigger you mentioned in bug 1306128.

Comment 2

[Gabriele Svelto [:gsvelto] (PTO)]

Currently there's no way to tell when memory pressure is over and also we don't have a generic way of telling if memory pressure is ongoing or not (i.e. if the response from the previous memory pressure event had the desired effect or not).

Since I'm at it I'll add an event that indicates that memory pressure is over; it will be probably useful besides this use case.

Sadly enough we already had most of this in B2G-specific code but we never had the time to turn it into a generic facility.