On Fri, 2008-01-25 at 04:09 -0700, Andreas Dilger wrote:

On Jan 24, 2008  17:25 -0700, Zan Lynx wrote:

quoted

Have y'all been following the /dev/mem_notify patches?
http://article.gmane.org/gmane.linux.kernel/628653

Having the notification be via poll() is a very restrictive processing
model.  Having the notification be via a signal means that any kind of
process (and not just those that are event loop driven) can register
a callback at some arbitrary point in the code and be notified.  I
don't object to the poll() interface, but it would be good to have a
signal mechanism also.

The commentary on the mem_notify threads claimed that the signal is
easily provided by setting up the file handle for SIGIO.

Yeah.  Here it is...copied from email written by KOSAKI Motohiro:

implement FASYNC capability to /dev/mem_notify.

<usage example>
        fd = open("/dev/mem_notify", O_RDONLY);

        fcntl(fd, F_SETOWN, getpid());

        flags = fcntl(fd, F_GETFL);
        fcntl(fd, F_SETFL, flags|FASYNC);  /* when low memory, receive SIGIO */
</usage example>
-- 
Zan Lynx [off-list ref]