#3605 HIGH Trial-3: Donut doesn't accurately show memory usage

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#3605: Donut doesn't accurately show memory usage
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  Reporter:  AlexL   |       Owner:  marco  
      Type:  defect  |      Status:  new    
  Priority:  high    |   Milestone:  Trial-3
 Component:  sugar   |     Version:         
Resolution:          |    Keywords:  relnote
  Verified:  0       |  
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Comment(by danw):

 Doing "ps aux|grep Journal", deleting 10 or 20 journal entries, and then
 doing "ps aux|grep Journal" again shows that the Journal's memory usage
 according to ps *does* increase when you delete entries.  Likewise, adding
 up just the anonymous (ie, heap memory) mappings from pmap for the journal
 also shows steadily increasing usage as you delete things. So the donut
 *is* telling the truth: the journal is steadily using more and more
 memory.

 As for the exact percentages, ps/top's "%MEM" column measures the
 percentage of *total* RAM used, while the activity ring ignores the RAM
 used by system processes. So you shouldn't expect them to match.

 That said, I can't explain why the journal would take up 1/3 of the ring
 with an RSS of 30M and 100M free memory. The actual measured memory usage
 should be less than the RSS, so it should take up less than 1/4 of the
 ring. So there seems to be some degree of measurement error here, and it
 might even be that the measurement error is getting worse as the journal
 uses more memory.

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Ticket URL: <https://dev.laptop.org/ticket/3605#comment:6>
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