Re: [PATCH v2 2/2] mmap-alloc: Include osdep.h before checking CONFIG_LINUX

[Peter Maydell]

On Mon, 16 Mar 2020 at 17:51, Eduardo Habkost <address@hidden> wrote:
> Yes, but both MAP_SYNC and MAP_SHARED_VALIDATE aren't available
> if the host is not Linux.
>
> Defining MAP_SYNC to 0 on MIPS would restore the existing
> behavior, so it seems like a reasonable step to fix the build
> failure.  But not even printing a warning when the host doesn't
> have MAP_SYNC (the existing behavior on MIPS and non-Linux) seems
> wrong.

The usual approach is that if you don't have the Linux-specific
feature available you quietly fall back to whatever the sensible
behaviour is for when the feature isn't present. We definitely
don't want to be printing warnings on non-Linux systems that
are effectively just saying "you're not running Linux". Same goes
for "host happens not to be running a bleeding-edge Linux kernel
and this feature isn't available yet".

thanks
-- PMM