[klibc] [PATCH] sysinfo() support

Kay Sievers kay.sievers at vrfy.org
Tue Apr 6 01:28:35 PDT 2004


On Mon, Apr 05, 2004 at 03:17:29PM -0700, Randy.Dunlap wrote:
> On Tue, 6 Apr 2004 00:19:06 +0200 Kay Sievers wrote:
> 
> | On Mon, Apr 05, 2004 at 12:36:37PM -0700, H. Peter Anvin wrote:
> | > Kay Sievers wrote:
> | > > Here is what we need for udev to get the seconds since uptime.
> | > > It implements the linux sysinfo system call.
> | > > 
> | > 
> | > Why does udev need this info?
> | 
> | We need a monotonically increasing time source independent from the
> | system time. The hotplug events are tagged with a timestamp to
> | determine its age for timeout handling. If we use time() or similar and
> | the init scripts are running ntpdate or changing the timezone from a
> | localtime BIOS clock, set by some other stupid OS, udev gets confused.
> | So I use the uptime seconds now, any better idea?
> 
> Uh, does that prevent (restrict) more than 1 hotplug event per second?

Oh, come on :)
No, it tags the event, waits for possibly missing sequences and runs all
in the right order. Every event for different DEVPATH is executed in
parallel and events for the same DEVPATH are executed one after the
other. If a sequence is missing (normally it never happens) the later events
are delayed by a maximum of 10 seconds.

Kay



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