Messages in this thread | | | Date | Thu, 27 Jun 2013 15:02:31 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2] vmpressure: implement strict mode |
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On Wed, 26 Jun 2013 23:17:12 -0400 Luiz Capitulino <lcapitulino@redhat.com> 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?
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