[B.A.T.M.A.N.] performance patches (v2)

Sven Eckelmann sven.eckelmann at gmx.de
Sat Dec 4 20:42:14 CET 2010


Marek Lindner wrote:
> Hi,
> 
> I continued improving the the performance patches which results in the
> first usable version. I tested it in a VM environment as well as on real
> hardware and did not encounter problematic behavior anymore.

I looked through your patches and have some small suggestions. First I would 
like to move the hashtable-functions related patches to the front. This would 
make it possible to send a new version of batman-adv to David S. Miller 
without adding to many changes (so maybe he doesn't get too angry this time).

Then you missed hashtable_t::elements of the hash implementation which are 
only needed for the resize implementation (now it is only a wom :) ). The 
hash_iterate function is also still there.... I would like to remove it 
completely. hash_remove only rcu locked the list - but we must spinlock here 
to prevent double frees. kref_put of data directly after call_rcu for bucket 
could lead to invalid memory access when a rcu protected region still accesses 
the bucket which isn't removed yet (but the data in the bucket was already 
removed). Unneeded(?) hlist_empty checks. Missing conversation of neigh_node 
hlist operations to _rcu. Missing rcu_read_unlock's. Missing correct refcnt 
for neigh_list

I would rework some of those parts and resend all patches again to the mailing 
list. This doesn't mean that I have checked everything.... some of the patches 
were just too "wirr" and this is a first try to get it in the right direction. 
It still needs a lot of cleanup and testing. For example neigh_list stuff and 
the kref_put after call_rcu is complete unfixed and I also didn't finish the 
complete patchset.... maybe will continue with it when the patchset is cleaned 
up.

Best regards,
	Sven
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