[linux-audio-dev] malloc() in RT code considered not-so-harmful?

[Tim Hockin]

On Wed, Jul 14, 2004 at 05:58:25AM +0200, Ralf Beck wrote:
> Am Dienstag, 13. Juli 2004 22:50 schrieb Steve Harris:
> > On Tue, Jul 13, 2004 at 10:21:23 -0700, Joshua Haberman wrote:
> > > >Its not my experieince that you usually need to allocate memory in RT
> > > >threads, the times when I've seen it done are mostly <generalisation>
> > > >bacuase of bad design, excessive OO-ness or lack of knowledge of
> > > >alloca(3) </generalisation>.
> > >
> 
> malloc does not guarantee, that the allocated memory is locked into physical 
> memory.
> To say it short: A RT thread must NEVER call a function that might block!!

The point was that an RT-safe malloc() could be safe, but it indicates a
bad design.

If your app starts up, does malloc(1024*1024*32); walks through that
memory to page it in, then mlock()s it, you can write a "safe" malloc to
allocate from that memory.  But yuck.

Tim