[dpdk-dev] [RFC] hash/lpm: return NULL if the object exists
Olivier Matz
olivier.matz at 6wind.com
Fri Mar 25 11:32:47 CET 2016
Hi Bruce,
On 03/15/2016 01:25 PM, Olivier Matz wrote:
> Seen by trying to fix the func_reentrancy autotest. The test
> was doing the following on several cores in parallel:
>
> name = "common_name";
> do several times {
> obj = allocate_an_object(name) // obj = ring, mempool, hash, lpm, ...
> if (obj == NULL && lookup(name) == NULL)
> return TEST_FAIL;
> }
>
> Issues:
>
> 1/ rings, mempools, hashs API are not coherent
> rings and mempool return NULL if the object does not exist
> hash and lpm return an object that was allocated allocated if
> it already was allocated
>
> 2/ The hash/lpm API looks dangerous: when an object is returned,
> the user does not know if it should be freed or not (no refcnt)
>
> 3/ There are some possible race conditions in cuckoo_hash as the
> lock is not held in rte_hash_create(). We could find some cases
> where NULL is returned when the object already exists (ex: when
> rte_ring_create() fails).
>
> This patch tries to rationalize the APIs of lpm and hash.
>
> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
Sorry, I forgot to CC you in the first mail. Do you have any opinion
about this rfc patch?
Thanks,
Olivier
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