Felix Winkelmann <felix.winkelm...@bevuta.com> writes: > From: Andy Bennett <andy...@ashurst.eu.org> > Subject: mmap (was: Re: [Chicken-hackers] library unit restructuring) > Date: Wed, 09 Jul 2014 14:56:38 +0100 > >> Hi, >> >>> - memory-mapped-files >> >> Without wishing to hijack the entire thread, as an aside, is there any >> way of making memory mapped files play nicely with the CHICKEN scheduler >> and threading model? It's possible for memory mapped files to cause a >> page fault which will then wait for I/O and, as I understand it, that >> will block the entire runtime. > > Since nobody replied to this - I wouldn't know how this is done. I > guess there is some UNIX arcana that allows one to implement > non-blocking behaviour. As memory access will cause the blocking, we > can probably not check for this via poll/select. Do you have any > information about this? Is it possible to test whether a page is in > memory, and whether one can do the equivalent of a poll/select on > this?
IIRC mmap's flags MAP_NONBLOCK and MAP_POPULATE are linux specific and don't exist in all our other platforms, notably the *BSDs. Since mmap calls return a pointer to memory, the usual select/poll syscalls cannot be applied to it. (Also note that MAP_POPULATE is ignored in recent kernels even). Andy, can you elaborate on the blocking scenario you are seeing? HTH, Christian _______________________________________________ Chicken-hackers mailing list Chicken-hackers@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-hackers
