[ofa-general] Re: [PATCH 2/3] remove ib pkey gid and lmc cache

[Yosef Etigin]

Michael S. Tsirkin wrote:
>>Quoting Yosef Etigin <yosefe at voltaire.com>:
>>Subject: Re: [PATCH 2/3] remove ib pkey gid and lmc cache
>>
>>Michael S. Tsirkin wrote:
>>
>>>>+ * ib_query_lmc() returns the LID mask control associated
>>>>+ * with port @port_num
>>>>+ */
>>>>+int ib_query_lmc(struct ib_device *device, u8 port_num, u8 *lmc);
>>>>+
>>>
>>>
>>>I don't think we need this one in ib_verbs.h - it just does query_port once.
>>>Let's keep the API simple. The only user is in mad.c - move
>>>it there and make it static.
>>>
>>>
>>
>>why keep ib_query_lmc anyway if we won't use it?
> 
> 
> Actually, I think I see a problem with changing
> ib_get_cached_lmc -> ib_query_lmc: it is called on data path in mad.c.
> Calling ib_query_port there will slow down MAD processing significantly,
> because it's hard to driver to cache all of portinfo state
> (e.g. how do you cache phys_state?).
> 
> But mad.c is actually seeing all MADs, too, so maybe the right thing
> is to cache lmc directly there.
> 
So how about mad.c will use the cache for now (like mthca), and will
have a lmc cache of its own after the cache is really removed?