Actually i have access to a mmap'ed file that happen to have the DSO payload among other things. In practice i dont need memfd_create(), as passing the payload with the right offset within the mmaped file would do the trick.. But given its a file with much more data then just the DSO, by using something like memfd_create() i could make it easy for the OS, passing just the content of the DSO file.

Note that in my use case i will/can pass the file descriptors to the child process, so that's why memfd_create suited me well. But if you happen to know how i can just use the mmaped file, as long as i can point the exact offset to be readed, it will be much better, because it will be basically a zero-copy implementation of it.

(If memfd_create() could be created by passing the memory address, without the need to use a write() in the created fd, it would also be much less expensive)

Thank you for your tip, that is a really nice trick!