[Request] Modify Tab Unloading on Low Memory

[savemyram]

Any way the code for the tab unloading functionality could be modified to unload tabs based on available memory? Right now, based on my understanding, it waits for a memory pressure call from the operating system before engaging this process. It would be cool if tab unloading could be based on when available physical memory on a Windows systems goes below a user definable threshold. Perhaps this threshold could be a tunable parameter in about:config. No idea what this could take on a programming level since I don't program, but this could take an already builtin functionality to the next level. I know about Auto Tab Discard, but that is based on inactivity. Here's to hoping someone might be willing to take this on. Would be more than happy to test a beta release if it was implemented.

[savemyram]

@K4sum1 Here's a link to the original source code the might be partly responsible for making this happen: https://searchfox.org/mozilla-central/rev/3f193a8bb0759058c2f9a9d7761ad73bc6ffd4b1/xpcom/base/AvailableMemoryWatcherWin.cpp

From what I understand, Windows unloads standby memory to use as free when processes need more. This is fine until standby memory that can be unloaded and free memory is gone, then Windows needs to page out older data to HDD or SSD. My goal with this request is to have the browser prevent this from happening, by calling the native tab unload function when available memory (Windows defines standby and free memory as available) is around 75%-80%. Right now I believe the code calls for unloading at 200 MB or less, but this is factoring in page file capacity which is what should be avoided.

[the-r3dacted]

This sounds like a good idea and probably how i would use my browser, but I'm not sure if I'd be able to do it alone.

[savemyram]

Yeah, I guess the big question is whether it would be worth having this as a parallel change to what's already there. Initially my thinking was to scrap the listening for a low memory pressure call from Windows and just poll "available memory" on an interval. What that interval should be, I'm not quite sure. Fives seconds...ten seconds? There would also probably have to be a loop of some kind, if there's not one already, where it would unload a tab, check if it's below threshold and continue unloading until in compliance with the threshold. Maybe a new about:config parameter of browser.low_physmem_threshold_percent could be added to make it user customizable.

[the-r3dacted]

I might be able to do a configurable preference with the current behavior. Although I'm not able to do it rn.

[savemyram]

That's okay, whenever you get around to it. Just keep me posted, because I definitely would like to test drive. :)

The cool thing is all the code for prioritizing which tab is eligible and should be unloaded first is already there. There just would need to be an addition trigger to call the unload.

[savemyram]

Any update on if and when this might be implemented?