Jesper Dangaard Brouer writes:
> > It is almost certainly the cause of your crashes, that code
> > is still extremely raw and that's why it is listed as "EXPERIMENTAL".
>
> It seems your are right :-) (and I'll take more care of using experimental
> code on production again). The machine, has now been running for 34 hours
> without crashing. The strange thing is that I'm running the same kernel
> on 30 other (similar) machines, which have not crashed. (I do suspect the
> specific traffic load pattern to influence this)
Sounds good... seems like Dave did the the correct analysis.
> BUT, I do think I have noticed another problem in the garbage collection
> code (route.c), that causes the garbage collector (almost) never to
> garbage collect.
We're trying to avoid most/all periodic GC in hi-flow systems and just to
do GC as new entries are created. We use the patch below to create et another
(unfortunately) /proc entry to better control this. ip_rt_gc_max_chain_length
it also decreases the threshhold for this from 8 to 4 for this.
Cheers.
--ro
--- linux-2.6.14.5/net/ipv4/route.c.orig 2006-01-02 14:24:00.000000000 +0100
+++ linux-2.6.14.5/net/ipv4/route.c 2006-01-02 15:26:29.000000000 +0100
@@ -126,6 +126,7 @@
static int ip_rt_error_cost = HZ;
static int ip_rt_error_burst = 5 * HZ;
static int ip_rt_gc_elasticity = 8;
+static int ip_rt_gc_max_chain_length = 4;
static int ip_rt_mtu_expires = 10 * 60 * HZ;
static int ip_rt_min_pmtu = 512 + 20 + 20;
static int ip_rt_min_advmss = 256;
@@ -977,7 +978,7 @@
* The second limit is less certain. At the moment it allows
* only 2 entries per bucket. We will see.
*/
- if (chain_length > ip_rt_gc_elasticity) {
+ if (chain_length > ip_rt_gc_max_chain_length) {
*candp = cand->u.rt_next;
rt_free(cand);
}
@@ -3017,6 +3018,14 @@
.proc_handler = &proc_dointvec,
},
{
+ .ctl_name = NET_IPV4_ROUTE_GC_MAX_CHAIN_LENGTH,
+ .procname = "gc_max_chain_length",
+ .data = &ip_rt_gc_max_chain_length,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
.ctl_name = NET_IPV4_ROUTE_MTU_EXPIRES,
.procname = "mtu_expires",
.data = &ip_rt_mtu_expires,
--- linux-2.6.14.5/include/linux/sysctl.h.orig 2006-01-02 14:46:55.000000000 +0100
+++ linux-2.6.14.5/include/linux/sysctl.h 2006-01-02 14:47:01.000000000 +0100
@@ -375,6 +375,7 @@
NET_IPV4_ROUTE_MIN_ADVMSS=17,
NET_IPV4_ROUTE_SECRET_INTERVAL=18,
NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS=19,
+ NET_IPV4_ROUTE_GC_MAX_CHAIN_LENGTH=20,
};
enum
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