On 30 Nov 2022, at 15:13, Hannes Mehnert <han...@mehnert.org> wrote: > > ## `mmap` available on `Mirage_block.S` (dinosaure, > https://github.com/mirage/mirage-block/issues/53) > - dinosaure has an implementation to get a part of the block (similar to > mmap), without being in the Lwt monad > - at the moment, read is in Lwt.t, i.e. does not block, but returns the > filled page(s) > - dinosaure needs a blocking function that returns the data > - the solo5 interface is already blocking (and synchronous), > mirage-block-solo5 adds the asynchronous stuff > - christiano mentions that it could be done with locking > - maybe develop a block read-only interface with a synchronous read
In general, having "automatic" scheduling via mmap is a bad idea for anything non-trivial, since you slow to a crawl when under memory pressure and having a lot of page faults. There's no way a caller can determine whether or not a set of accesses will result in a blocking fetch or not. It may be workable for a read-only mmap, but... why do you want it? To get out of Lwt allocations? Anil
