Re: Kernel panic: Route cache, RCU, possibly FIB trie.

From: Dipankar Sarma
Date: Tue Mar 21 2006 - 10:42:02 EST


On Tue, Mar 21, 2006 at 04:37:19PM +0100, Eric Dumazet wrote:
> Jesper Dangaard Brouer a écrit :
> >There is definitly high memory pressure on this machine!
> >Slab memory usage, range from 39Mb to 205Mb (at the moment on the
> >production servers).
> >
>
> Did you tried 2.6.16 ?
>
> It contains changes in kernel/rcupdate.c so that not too many RCU elems are
> queued (force_quiescent_state()). So in the case a rt_cache_flush is done,
> you have the guarantee all entries are not pushed into rcu at once.

Well, memory pressure or not, the oopses shouldn't be happening :)
Perhaps we should look at them before we work around memory
pressure through the rcu batch tuning stuff in 2.6.16 ?

One of the oopses looked like the rcu callback function pointer
getting corrupted indicating that it was double freed or
problem with RCU itself.

Thanks
Dipankar
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