[Qemu-devel] Re: [RFC 0/7] Introduce hard dependency on glib

[Paolo Bonzini <pbonzini@redhat.com>]

On 01/24/2011 10:00 PM, Anthony Liguori wrote:
> Both the recent I/O loop and threadlet series have me concerned that we're
> digging ourselves deeper into the NIH hole.  I think it's time we look at
> something radical to let us borrow more code from existing projects instead of
> reinventing everything through trial and error.
>
> This series introduces a hard dependency on glib.  The initial use is portable
> threads but I see this as just the beginning.  Glib/Gobject offer many nice
> things including:
>
>   - portable threads
>   - IO library
>   - rich data structure support

These are where GLib shines.

>   - INI parser

Not compatible with our config files anyway.

>   - JSON parser

I think our JSON parser is much better than JsonGlib (which isn't anyway 
a part of GLib proper).

>   - generic type system
>   - object oriented infrastructure
>   - module system
>   - introspection to enable support for dynamic language bindings

See below.

> I see this series as the first step, followed by converting the I/O loop to
> a GMainLoop instance.  Once we're there, we can start making deeper use of
> GObjects including converting QDev to a GObject hierarchy.

I am not sure how these other bits will look like and maybe it won't 
make sense at all, but it doesn't matter.  The bits you posted are 
already a step in the right direction IMHO, and the same goes for 
converting the I/O loop to GMainLoop if you can pull that :) and using 
glib's thread pool.

(Regarding GMainLoop, my main worry is that we'd have to reinvent a lot 
of GSources to integrate properly with slirp, with QEMU's multiple 
clocks, and so on.  And GSources are black magic...).

I'd also add to the benefits a good multi-threaded memory allocator.

A small qualm I have is that glib (and GNOME in general) is one of the 
hardest pieces of free software to contribute to in my experience.  I 
have patches which had multiple acks and are still languishing after a 
year or so.  Still not an excuse for NIH.

Paolo