Re: (ITS#8976) LMDB > use posix_madvise(3) instead of madvise(3) for SmartOS

[matthieu.guegan@smile-suisse.com]

On Fri, Feb 15, 2019 at 3:56 PM Howard Chu <hyc@symas.com> wrote:
>
> mguegan@virtua.ch wrote:
> > Full_Name: Matthieu Guegan
> > Version: current
> > OS: SmartOS
> > URL:
> > Submission from: (NULL) (109.190.148.77)
> >
> >
> > Hi,
> >
> > In order to compile knot[1] on SmartOS, I have done a series of little patches.
> > One of them is linked to the LMDB project, which redirects me here.
> >
> > The idea is to tell SmartOS (and I think the SunOS family) to make use of
> > posix_madvise(3), instead of madvise(3) as implementation on this OS[2] is
> > different than, for example, the Linux[3] one.
> >
> > So, I kindly ask you to take a look at the merge request of the knot project[4],
> > in particular the `src/contrib/lmdb/mdb.c` patch (that's just a ifdef
> > modification) : would it be possible to apply this patch directly in this
> > repository ?
>
> I see no functional difference between your references [2] and [3].
> What is the benefit of this patch?

Well, the Solaris/SunOS's madvise(3) is defined with an old `caddr_t`
type whereas Linux (and *BSD OSes too) use a more modern approach with
`void *`.
On the `knot` project, which embed the lmdb part of openldap,
compilation failed when using madvise(3) on SmartOS, so I did a
replacement with posix_madvise(3) which uses the `void *` argument
too.
I don't know what's the best way to handle this case, that's why I ask here.

> >
> > Thanks
> >
> >
> > [1] https://www.knot-dns.cz/
> > [2] https://docs.oracle.com/cd/E36784_01/html/E36874/madvise-3c.html
> > [3] http://man7.org/linux/man-pages/man2/madvise.2.html
> > [4] https://gitlab.labs.nic.cz/knot/knot-dns/merge_requests/979/diffs?commit_id=64cd2cfdb76d7299beb5a5561bc65162c2ec8a06
> >
> >
>
>
> --
>   -- Howard Chu
>   CTO, Symas Corp.           http://www.symas.com
>   Director, Highland Sun     http://highlandsun.com/hyc/
>   Chief Architect, OpenLDAP  http://www.openldap.org/project/