Open Stack

Hi, I'd like you to take a look at this patch for potential
DocImpact.
https://review.openstack.org/27160

Log:
commit e289dd0fa9659f260dea0545a5fff68e6ea63143
Author: Alvaro Lopez Garcia <aloga at ifca.unican.es>
Date:   Thu Apr 18 17:28:27 2013 +0200

    Normalize the scheduler weights instead of using raw values.
    
    Currently the weighter is using the raw values instead of normalizing
    them. This makes difficult to properly use multipliers for establishing
    the relative importance between two wheigters (one big magnitude could
    shade a smaller one).
    
    This commit introduces weight normalization so that we can apply
    multipliers easily. The commit does not change the behaviour per-se
    since currently we only have 1 weighter. All the weights will be
    normalized between 0.0 and 1.0, so that the final weight for a host
    will be:
    
        weight = w1_multiplier * norm(w1) + w2_multiplier * norm(w2) + ...
    
    Also, a new "ram_weight_inverse" flag has been introduced for the
    RAMWeighter. Before, the weigther stated that to change the behaviour
    to "stacking" instead of "spreading", a negative multiplier would do
    the trick but this is not true when using more that one weighter.
    
    DocImpact
    
    Change-Id: I81bf90898d3cb81541f4390596823cc00106eb20