Re: [PATCH 19/32] target: Convert to rbtree for se_dev_entry in se_node_acl

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On 12/16/2013 01:40 PM, Nicholas A. Bellinger wrote:
On Fri, 2013-12-13 at 15:59 -0800, Andy Grover wrote:
Instead of an array, use a rbtree. Less memory use on average, and
can allow >255 entries. We go from O(1) to O(log n) on lookups. If this
shows up on profiling (it won't) then transition to other kernel lookup
methods is straightforward from here.


Ugh.

There is no reason to be using rbtrees in a performance critical path
here.

The number of pointer lookups is what ends up hurting the most vs. a
flat array, so given that 256 LUNs per endpoint is currently not an
issue, and there is no hard limit on the number of endpoints with
virtual addressing, I don't see the benefit of this patch.

NAK.

What does virtual addressing mean in this context? I'm not familiar -- so instead of reporting 257+ luns per tpg, it would get split up somehow?

-- Andy

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