#9979 NORM 1.5-sof: tmpfs is too small

[Zarro Boogs per Child]

#9979: tmpfs is too small
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           Reporter:  pgf        |       Owner:  cjb                               
               Type:  defect     |      Status:  new                               
           Priority:  normal     |   Milestone:  1.5-software-update               
          Component:  distro     |     Version:  Development source as of this date
         Resolution:             |    Keywords:                                    
        Next_action:  never set  |    Verified:  0                                 
Deployment_affected:             |   Blockedby:                                    
           Blocking:             |  
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Comment(by Quozl):

 One can arrive at a limit for "good" numbers like so.

 There are 18 non-fstab tmpfs ... they are currently 1 megabyte each ...
 and would be 180 to 360 megabytes.  There are 3 fstab tmpfs ... up to 46
 megabytes each on current builds.

 So root could consume 318 to 498 megabytes of the 512 or 1024 megabytes
 available by writing files into the 18 tmpfs.

 For non-root user, there are four writable tmpfs on current builds, three
 times 46 megabytes plus 1 megabyte, a total of 140 megabytes.  Increasing
 that non-root user writable tmpfs to 20 megabytes is fairly low impact;
 they'd be able to consume only 160 megabytes of the 512 or 1024 megabytes
 available.

 Current builds consume about 60 megabytes of memory when booted to the
 Sugar shell ... excluding cache and buffers.

 So given 1024 megabytes available physical memory, subtract 60, subtract
 160, we're left with 804, which means that your 20 megabyte proposal won't
 allow local denial of service.

 The limit would be 1024 - 60 - (46 * 3) - n > 0, which means n is around
 820 megabytes.

 This is excluding something going wrong in root land.

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Ticket URL: <http://dev.laptop.org/ticket/9979#comment:1>
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