> -----Original Message-----
> From: ext Anton Vorontsov [mailto:anton.vorontsov@linaro.org]
> Sent: 08 June, 2012 10:59
... 
> a) Two more context swtiches;
> b) Serialization/deserialization of /proc/vmstat.
> 
> > It also will cause page trashing because user-space code could be pushed
> out from cache if VM decide.
> 
> This can solved by moving a "watcher" to a separate (daemon) process, and
> mlocking it. We do this in ulmkd.

Right. It but it has drawbacks as well e.g. ensure that daemon scheduled properly and propagate reaction decision outside ulmkd.
Also I understand your statement about "watcher" as probably you use one timer for daemon. 
Btw, in my variant (memnotify.c) I used only one timer, it is enough.
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