[PATCH v3] ALSA: control: Add memory consumption limit to user controls

[Takashi Iwai]

On Sat, 10 Apr 2021 10:20:16 +0200,
Takashi Sakamoto wrote:
> 
> On Fri, Apr 09, 2021 at 06:09:02PM +0200, Takashi Iwai wrote:
> > On Fri, 09 Apr 2021 12:59:10 +0200,
> > Takashi Iwai wrote:
> > > 
> > > On Fri, 09 Apr 2021 04:27:35 +0200,
> > > Takashi Sakamoto wrote:
> > > > 
> > > > 4. Add `max_user_ctl_alloc_size` kobject attribute to the control device
> > > > 
> > > > In the patch, a new module parameter 'max_user_ctl_alloc_size' is added.
> > > > In the item, I use the value of this parameter as initial value per
> > > > control device. The value per control device can be changed via sysfs
> > > > node.
> > > > 
> > > > The `max_user_ctl_alloc_size` is really the attribute of control device,
> > > > so I think it acceptable. Additionally, 'curr_user_ctl_alloc_size' is
> > > > also added so that userspace applications get current status.
> > > 
> > > So that's the primary purpose?  Then it makes sense, yeah.
> > 
> > You meant something like below, right?
> 
> If you were carefully reading my items in the order, you would have
> realized that the patch includes problem to share attribute group
> table between several modules...

Which several modules...?  The control API is mandatory, hence it
can't be separated from each card core stuff.  So splitting to another
module makes no sense, as I already replied earlier.

> Device attribute is one of userspace interface expected to be stable. I'd
> like to avoid careless changes which our known developer tends to do.

Sure, it has to be set on stone once after put in the tree.
However, currently it's just a brain storming phase, and no need to
grumble for a dreadful future vision.


Takashi