Alfred,
You've brought this up before. This looks familiar to your earlier
post(s) regarding how to "abuse m_ext." Mind you, I may be mistaken, but
that would be because this isn't being made awfully clear.
Earlier you talked about forcing a custom free routine to be called
even in the case of mbuf clusters, and we devised a way.
Are you suggesting now to have a custom free routine called when your
mbuf is freed (i.e. even when it is a non-M_EXT mbuf?)
If that's so, I would urge you to re-examine the code because doing
something like that would be generally wrong. I say "generally" because
I'm always open to exceptions, as you know. So please clarify.
On Tue, 12 Dec 2000, Alfred Perlstein wrote:
> Ok, so I'm trying to rid FreeBSD of the unp_gc() junk in uipc_usrreq.c
> I just realized why I'm leaking file descriptors:
>
> Only mbufs with external storage can have a 'free' function, the
> problem is that for the most part when passing a single fd I'm only
> using a single mbuf to pass my data around, my ext_free routine is
> probably never called, and on top of that I'm probably corrupting
> my mbuf by using it when I shouldn't be.
>
> This is terrible, what should be a simple free() hook is now my
> worst nightmare. A couple of options come to mind:
>
> a) always have a free hook, the extra if (m->m_freehook != NULL)
> check can't be that expensive.
> b) a macro to make an mbuf into an mbuf cluster that points to itself,
> it should check to see if it has enough room to shuffle the data
> and return an error if it can't accomidate both the data and the
> expanded mbug header.
>
> I like 'a' but would be willing to deal with 'b' as we've never
> had a need for this, although that would mean copying about the
> size of an mbuf in the worst case when a subsystem needs this
> facility.
>
> Suggestions? Comments?
>
> --
> -Alfred Perlstein - [[EMAIL PROTECTED]|[EMAIL PROTECTED]]
> "I have the heart of a child; I keep it in a jar on my desk."
>
>
Bosko Milekic
[EMAIL PROTECTED]
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