[tor-bugs] #7176 [Core Tor/Tor]: Reduced TOR memory consumption for embedded devices

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#7176: Reduced TOR memory consumption for embedded devices
-------------------------------------------------+-------------------------
 Reporter:  cypherpunks                          |          Owner:
     Type:  enhancement                          |         Status:
                                                 |  needs_information
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.2.x-final
Component:  Core Tor/Tor                         |        Version:  Tor:
                                                 |  unspecified
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-client, embedded, low-memory,    |  Actual Points:
  sponsor8-maybe, review-group-18                |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
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Changes (by nickm):

 * status:  needs_review => needs_information


Comment:

 > (Are we sure the license on these is cool?)

 I'm not sure we can merge these at all.  The tor-openwrt_0.2.3.19-rc-3.tgz
 file from which they are taken is confusing: It has a GPLv2 LICENSE file
 in its toplevel, and I can't tell whether they wanted that license to
 apply to their patches or not.

 I'm going to try to find out to see if anybody from Access Now can make a
 definitive statement here before I consider them for real merge or
 revision.  Alternatively, if we can't get clarity on the licensing terms,
 we may need to recreate similar work independently in the time-honored
 manner.

 Here is what the patches seem to be trying to do:
   0001-anon_mmap: instead of using a journal file and keeping journaled
 descs in ram, tries to use mmap stuff to append them to the mmap on disk.
   0001-persistent_keys_in_etc: Changes where keys are stored. This should
 be replaced with a separate KeyDirectory torrc option.
   001-rebuild_when_big_dropped: Changes some logic in
 should_rebuild_md_cache() to rebuild the cache more aggressively.
   001-shorter_desc_lifetime: Lowers TOLERATE_MICRODESC_AGE.  This is risky
 and should only be done after analysis of microdescriptor lifetime. Also
 lowers ROUTER_MAX_AGE and OLD_ROUTER_DESC_MAX_AGE.
   002-gzipped-cache: Stores microdescriptors and routerdescs compressed
 with gzip, uses anonymous mmap for decompressing them. May have sync/flush
 issues.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/7176#comment:11>
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