The key thing is that after memory growth in asm.js (but not wasm!) the typed array views get "neutered". Using them will then throw an error.
To avoid this, the simplest thing is to never keep typed array views around in your code. Instead, look at the global HEAP8 etc. views, and use them on demand. That is, avoid MyLongTermStorage.view = HEAP8.subarray(x, y); where that .view is going to be used over time. Instead, just do HEAP8.subarray(x, y) right where you need it. In wasm things are slightly different. Wasm memory growth will keep typed arrays alive to the previous size. The only problem is the views don't grow. So if you want to look at an object in the newly-allocated memory, a problem happens. The solution is, again, to avoid keeping around views, and to create views right when you need them etc. - Alon On Fri, Aug 23, 2019 at 5:32 AM Shachar Langbeheim <[email protected]> wrote: > Hi, > I have experienced these errors, which I understand that are related to > holding array buffers after memory growth: > TypeError: Cannot perform %TypedArray%.prototype.set on a neutered > ArrayBuffer > at Uint8Array.set (<anonymous>) > at Object.mmap (appWASM.js:2645) > at Object.mmap (appWASM.js:4347) > at __emscripten_syscall_mmap2 (appWASM.js:5232) > at ___syscall192 (appWASM.js:5242) > at ___mmap (:1234/wasm-function[10088]:208) > > Reading about this for a bit, I have a couple of questions. I know those > are a lot of questions, but I'm about to write a pretty memory-intensive > application, and I want to know what are my constraints and requirements. > If instead of answers there's some good reading materials about WASM memory > growth that is accessible to a layman I'd really appreciate a link. > > 1. What should I do when memory growth happens? > 1. How do I know that a memory growth event happened? > 2. Can I know what objects and buffers do I need to regenerate or > move? > 3. Can I know what triggered memory growth? > 4. What happens if a memory growth event happens on another thread, > while native code is running? > 2. What exactly happens to current memory and pointers during memory > growh? > 1. Might some of my native code pointers be made unusable? Can I > know what? > 2. In the native code, can these neutered arrays hold stack memory, > or only heap memory? > 3. Is there a way to check for WASM memory leaks in a running web > page? > 1. Is there some way to know how the WASM memory is allocated? Some > kind of memory map? > > Thanks in advance! > > -- > You received this message because you are subscribed to the Google Groups > "emscripten-discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/emscripten-discuss/CA%2B_KjGY6jxFBAfixfEC9kdp_Mwx4gdviR1PiR0ObQEcWcXvMGw%40mail.gmail.com > <https://groups.google.com/d/msgid/emscripten-discuss/CA%2B_KjGY6jxFBAfixfEC9kdp_Mwx4gdviR1PiR0ObQEcWcXvMGw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/emscripten-discuss/CAEX4NpSDJ6cPJ1%2BJzvSTcL7AUFrLSCrA%3DUSGf%2BHqY1D0Pjs6-A%40mail.gmail.com.
