Re: [PATCH v2] vmpressure: implement strict mode

[Andrew Morton]

On Wed, 26 Jun 2013 23:17:12 -0400 Luiz Capitulino <lcapitulino@xxxxxxxxxx> wrote:

> Currently, an eventfd is notified for the level it's registered for
> _plus_ higher levels.
> 
> This is a problem if an application wants to implement different
> actions for different levels. For example, an application might want
> to release 10% of its cache on level low, 50% on medium and 100% on
> critical. To do this, an application has to register a different
> eventfd for each pressure level. However, fd low is always going to
> be notified and and all fds are going to be notified on level critical.
> 
> Strict mode solves this problem by strictly notifiying an eventfd
> for the pressure level it registered for. This new mode is optional,
> by default we still notify eventfds on higher levels too.
> 

It didn't take long for this simple interface to start getting ugly :(
And having the fd operate in different modes is ugly.

Can we instead pass the level in the event payload?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/