Re: [PATCH] ipvs: Make the synchronization interval controllable

[Sven Wegener]

On Wed, 6 Feb 2008, David Rientjes wrote:

> On Wed, 6 Feb 2008, Sven Wegener wrote:
>
> > diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
> > index 948378d..9b57ad3 100644
> > --- a/net/ipv4/ipvs/ip_vs_sync.c
> > +++ b/net/ipv4/ipvs/ip_vs_sync.c
> > @@ -143,6 +143,8 @@ char ip_vs_backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];
> >  /* multicast addr */
> >  static struct sockaddr_in mcast_addr;
> >
> > +/* milliseconds between synchronization runs */
> > +int sysctl_ip_vs_sync_interval = 1000;
> >
> >  static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
> >  {
>
> How useful is a negative ip_vs_sync_interval?

Negative values will be converted to MAX_JIFFY_OFFSET by msecs_to_jiffies 
and result in a very long interval. A too long interval will be a good way 
to get your system OOM. We could use an unsigned int or even restrict the 
value with proc_dointvec_minmax. I'd prefer the latter, that's what I 
already had in my mind and it also protects from unintentionally choosing 
a too long interval.

Sven
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