On Fri, May 22, 2026 at 2:31 PM Barry Song <[email protected]> wrote: > > > > > Again this is making me want to sit outside and sip on some lemonade and > > ice :) > > > > Yes - android processes are aggressively multi-threaded, sure of course. > > > > The missing bit here is the forking - what, where, why, when? > > > > I really want to know the what, where, why, and when > as well. But since most applications are not > open-source, it is basically a black hole for anyone > other than the owners of those apps. > > Let me try to do more investigation to understand what > is going on, although it is really hard. > To be honest, I would rather the Android framework > completely prohibit apps from calling fork(), if > possible. > > > And then you say zygote is sometimes multi-threaded but sometimes > > single-threaded, which is adding a whole bunch of confusion on top of all > > that. > > > > I don't find these stack trace dumps all that useful (though thanks of > > course for taking the time to gather them), I think we'd be better off with > > specific data on forking, in some _concise_ _summarised_ form, ideally with > > numbers. > > > > There's such a thing as too much information :)) > > This trace shows PF I/O in one thread overlapping > with a fork() call in another thread. > But as I explained, I really do not know what kind of > user behavior is behind it. > > > > > Anyway, again, please let's see a new _RFC_ with the approach proposed by > > Suren, with some _succinct_ data demonstrating _exactly_ what the problem > > is, so we can make some headway here. > > Okay, sure. Thanks for your patience.
Just checking in on the followup plans. IIUC the RFC mentioned will try to implement the solution we discussed at LSFMM: splitting VM_FAULT_RETRY into two flags - one for retrying under per-VMA locks and another one to fallback to mmap_lock. Barry, if you need any help or clarification, please do not hesitate to contact me. Thanks, Suren. > > > > > And now I'm off for a cornetto! :) > > Sounds good :) Enjoy your cornetto! > > Best Regards > Barry
