Re: [PATCH v2 2/6] accel: accel_available() function

[Eduardo Habkost]

On Thu, Nov 26, 2020 at 10:06:03PM +0100, Claudio Fontana wrote:
> On 11/26/20 3:25 PM, Paolo Bonzini wrote:
> > On 26/11/20 15:13, Claudio Fontana wrote:
> >> One option I see is simply to document the behavior where
> >> accel_available() is declared in accel.h (ie do not use in fast
> >> path), as well as in accel_find() actually, so that both accel_find()
> >> and accel_available() are avoided in fast path and avoid being called
> >> frequently at runtime.
> >>
> >> Another option could be to remove the allocation completely, and use
> >> for example accel_find(ACCEL_CLASS_NAME("tcg")), or another option
> >> again would be to remove the allocation and use either a fixed buffer
> >> + snprintf, or alloca -like builtin code to use the stack, ...
> >>
> >> Not a big deal, but with a general utility and short name like
> >> accel_available(name) it might be tempting to use this more in the
> >> future?
> > 
> > I think it's just that the usecase is not that common.  "Is this 
> > accelerator compiled in the binary" is not something you need after 
> > startup (or if querying the monitor).
> > 
> > Paolo
> > 
> > 
> 
> A script that repeatedly uses the QMP interface to query for
> the status could generate fragmentation this way I think.

Is this a problem?  Today, execution of a "query-kvm" command
calls g_malloc() 37 times.

-- 
Eduardo