#4945 NORM Never A: Debugging tools take half of free memory

Zarro Boogs per Child bugtracker at laptop.org
Sat Nov 17 14:08:18 EST 2007


#4945: Debugging tools take half of free memory
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  Reporter:  bert    |       Owner:  marco         
      Type:  defect  |      Status:  new           
  Priority:  normal  |   Milestone:  Never Assigned
 Component:  sugar   |     Version:                
Resolution:          |    Keywords:                
  Verified:  0       |  
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Comment(by AlbertCahalan):

 Replying to [comment:3 marco]:

 > And we should really give more priority to figure out a solution for
 memory sharing (do we have a ticket about it?).

 There was once a hack for merging pages of arbitrary processes. It was
 done many years ago, so bitrot has surely made the original patch useless,
 but the idea may work. It was for a heavily shared university server.

 There were two parts, user and kernel. The user part would use a checksum
 to find pages that were likely to be the same. The user part would then
 ask the kernel part to do an atomic byte-by-byte comparison and possibly
 merge the pages. Possibly the kernel-user split was a bad idea with
 regards to deadlocks; it was not common to have kernel-internal threads
 back then.

 It was thus possible to merge pages from processes which did not share
 security info and/or did not descend from each other via fork.

-- 
Ticket URL: <http://dev.laptop.org/ticket/4945#comment:6>
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