Re: Hinted mmap(2) without MAP_FIXED can fail prematurely

[Johnny Billquist <bqt%softjar.se@localhost>]

On 2022-02-18 01:05, Michael van Elst wrote:
> bqt%softjar.se@localhost (Johnny Billquist) writes:
>
> > If it would ignore the hint, what's the point of the hint then?
>
> With MAP_FIXED it must use the hint, without it's just a best effort
> attempt.

Which then basically means that without MAP_FIXED, the hint don't really 
mean anything? It will take whatever address it can come up with, no 
matter what you put into the hint.

Which is what a hint of 0 should do. So I don't get that.
With MAP_FIXED, the hint needs to be exactly on a page boundary, which 
makes sense. Without MAP_FIXED, and with a hint, I would expect that 
things like rounding the address to the proper alignment, and so on, 
would be allowed, but not that it would just take any address. If I'm ok 
with it taking any random address, then I shouldn't provide a hint.

Anyway, that's just my reflections/thoughts on it.

  Johnny

--
Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt%softjar.se@localhost             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol