Messages in this thread | | | Date | Sat, 2 Mar 2002 00:27:40 +0000 (GMT) | From | Julian Anastasov <> | Subject | Re: OOPS: Multipath routing 2.4.17 |
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Hello,
Kain wrote:
> impossible 888 > divide error: 0000
> > > EIP; c024c5ea <fib_select_multipath+5a/a0> <===== > Trace; c02232e8 <ip_route_output_slow+318/670>
There is no write locking in fib_select_multipath, combined with high rate of route resolutions and ... boom, fi->fib_power is 0:
w = jiffies % fi->fib_power;
What about a different algorithm to apply weighted round robin (idea mostly from LVS), something like this code (entirely not tested) where fi->fib_power is not used and where fib_sync_up and fib_sync_down don't need to play with nh_power on nh_flags change:
void fib_select_multipath(const struct rt_key *key, struct fib_result *res) { struct fib_info *fi = res->fi; int w = -1, sel = 0;
write_lock(&fib_info_lock);
repeat:
change_nexthops(fi) { if (nh->nh_power > w && !(nh->nh_flags&RTNH_F_DEAD)) { w = nh->nh_power; sel = nhsel; } } endfor_nexthops(fi); if (w > 0) { fi->fib_nh[sel].nh_power--; write_unlock(&fib_info_lock); res->nh_sel = sel; return; }
if (!w) { change_nexthops(fi) { if (!(nh->nh_flags&RTNH_F_DEAD)) { nh->nh_power = nh->nh_weight; } } endfor_nexthops(fi); w = -1; goto repeat; }
write_unlock(&fib_info_lock);
#if 1 printk(KERN_CRIT "impossible 888\n"); #endif return; }
Regards
-- Julian Anastasov <ja@ssi.bg>
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