Re: [PATCH 1/1] nm-dns-dnsmasq: clear cache when dns server changes

[Thomas Haller <thaller redhat com>]

On Tue, 2016-11-29 at 20:23 +0100, Christian Hesse wrote:
> Thomas Haller <thaller redhat com> on Tue, 2016/11/29 17:51:
> > On Tue, 2016-11-29 at 15:03 +0100, Christian Hesse wrote:
> > > From: Christian Hesse <mail eworm de>
> > >
> > > A new DNS may have different data for us. So tell dnsmasq to
> > > clear
> > > the
> > > cache when servers change.
> >
> > we currently always do a ClearCache call after SetServerEx.
> >
> > How does this relate to your patch? Does --clear-on-reload make the
> > ClearCache call unnecessary? Why is ClearCache not sufficient?
>
> Oops, missed that in my logs (and did not find the code)... You are
> right,
> cache is cleared.
>
> Either of both is just fine and it works as-is. So ignore my patch.

Hi,

clear-on-reload might be better:

  - it saves the explicit call for ClearCache (less code, and possibly
    less runtime-overhead).
  - depending on how --clear-on-reload is implemented, it might be 
    race-free and clear the cache atomically when setting new servers.


IMO, i would apply the patch, and possibly a follow-up to drop the
ClearCache call. But I don't know dnsmasq well enough to be sure that
that is indeed correct...


Any opinions?


Thomas

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