I noticed that I had this problem again after a vagrant halt, vagrant up cycle.  The reason I did the halt was that it was non-responsive, so it's possible it was already wrong even before the halt.

Actual total and usage (when I have enough memory to do the free command, took a couple retries):

===
vagrant@mediawiki-vagrant:~$ free -m
             total       used       free     shared    buffers     cached
Mem:           993        938         55         20          0         25
-/+ buffers/cache:        912         81
Swap:            0          0          0

===
Roles:

===
Available roles:

  accountinfo              * guidedtour               * popups                  
  analytics                  gwtoolset                  proofreadpage           
  antispam                   hadoop                     renameuser              
  antispoof                  hive                       scholarships            
  apisandbox                 https                      scribunto               
  apparmor                   hue                        simple_miser            
  babel                      imagemetrics               simple_performant       
* betafeatures               interwiki                  sitematrix              
  centralauth                jsduck                     svg                     
  centralnotice              jsonconfig                 templatedata            
  chromium                   mantle                     textextracts            
  cirrussearch               massmessage                thumb_on_404            
  cite                     * math                       timedmediahandler       
  cldr                       mathsearch                 translate               
* codeeditor                 mleb                       uls                     
* cologneblue                mobileapp                  uploadwizard            
  commons                    mobilefrontend             urlshortener            
  commonsmetadata          * modern                     usermerge               
  confirmedit                molhandler               * vectorbeta              
  doublewiki               * monobook                 * visualeditor            
* echo                       multimedia                 wikidata                
  education                * multimediaviewer           wikidiff2               
* eventlogging               navigationtiming         * wikieditor              
  featuredfeeds              newusermessage             wikihiero               
* flow                       oauth                      wikilove                
  fss                        oozie                    * wikimediaevents         
  fundraising                pagedtiffhandler           wikimediaincubator      
* gadgets                  * pageimages                 wikimetrics             
  gadgets2                   pagetriage                 wikitech                
  geodata                  * parserfunctions            xhprof                  
  geshi                    * parsoid                    zend                    
* gettingstarted             pdfhandler                 zero                    
  globalcssjs                phptags                                            
  graph                      poem                                               
===

.settings.yaml

===
---
git_user: ''
vagrant_ram: 2048
puppet_debug: true
===

vagrant.d/10-cirrussearch.yaml:
===
# Vagrant settings
# Managed by puppet. Local changes will be lost on next puppet run.
vagrant_ram: 2000
forward_ports:
    9200: 9200
===