How can we ensure that long-running applications (even if theoretical), that may load and unload an unlimited number of new modules over time (f.e. routes in a web page specified by 3rd parties as time progresses), not leak memory?
Even if it is theoretical, I don't like the thought of something that only ever allocates memory that will never be freed. Is someone working on a solution for this? #!/JoePea On Wed, Jul 1, 2020 at 6:16 AM Mark S. Miller <[email protected]> wrote: > > No, definitely not. The table from specifiers to module instances is indexed > by specifiers. Specifiers are strings, so this table is not weak. It is not a > "cache" in the sense that it is allowed to drop things. Rather it is a > registry of module instances. Only a registry as a whole can be gc'ed, and > which point that context is no longer around for instantiating or > reinstantiating modules. > > As you suggest, if it could drop things because of GC that it would then need > to regenerate, that would expose the non-determinism of gc. That would be a > big deal. We carefully designed WeakMaps so that gc was non-observable. > WeakMaps introduce no observable non-determinism. WeakRefs alone expose the > non-determinism of gc, and are kept well quarantined from the rest of the > language. > > > On Tue, Jun 30, 2020 at 5:42 PM #!/JoePea <[email protected]> wrote: >> >> I am curious: can modules be garbage collected if the exports are not >> references by anything anymore? And if so, will the module be >> re-evaluated the next time it is imported? >> >> I haven't tried an experiment to answer this yet. I'll be back to post >> findings if someone doesn't post an official answer first. >> >> I'm thinking about code longevity. For example, if we make >> long-running web-based applications with many routes and features (for >> sake of example imagine a desktop environment, or a MMORPG game, with >> apps or components that are loaded within the same context). Over >> time, if imports are not collected, then it means we have a memory >> leak. >> >> Imagine, for example, an infinite-universe MMORPG where you can land >> on different planets where the code for features of a planet are >> provided by third parties as ES Modules. I know, this might not be a >> safe idea to import any code into an app, but just imagine it for sake >> of example (imagine we have a continuous integration system to test >> and verify code security, or something, before that code is allowed to >> be consumed in the app). Imagine you play this app for many many days, >> and visit many places, and you leave the app running the whole time >> (because farming for resources is disabled if the app is not running, >> or something). >> >> I would imagine that we want unused modules (when we leave a planet, >> for example) to be (destroyed) garbage collected so that we don't >> waste memory. >> >> #!/JoePea >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss > > > > -- > Cheers, > --MarkM _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
