T12641: Refactor KFileProtocol::copy

[David Faure]

dfaure added a comment.


  I don't really understand the relation to ksmserver, surely kioslaves are not part of session management.
  
  I also don't really understand what would happen in the new event loop (select/poll) of the kioslave while the non-blocking I/O is happening. It's not like the slave can handle other commands in parallel. Slaves are in a separate process exactly so that they can block.
  
  Regarding O_DIRECT, I have some doubts. The man page you linked to, says
  
    In summary, O_DIRECT is a potentially powerful tool that should be used with caution. It is recommended that applications treat use of O_DIRECT as a performance option which is disabled by default.
    "The thing that has always disturbed me about O_DIRECT is that the whole interface is just stupid, and was probably designed by a deranged monkey on some serious mind-controlling substances."--Linus"`
  
  Are you sure you want to use that? :-)
  More precisely, it says it will break with NFS (in some cases).
  And it sounds like a bad buffer size with O_DIRECT will slow things down (too many direct writes instead of buffering).
  Overall, I'd say -- did you check what the `cp` source code does? That's what we're competing against :-)

TASK DETAIL
  https://phabricator.kde.org/T12641

To: meven, dfaure
Cc: apol, dfaure, #frameworks, #dolphin, ognarb, broulik, meven, pberestov, iasensio, fprice, LeGast00n, cblack, MrPepe, fbampaloukas, alexde, GB_2, Codezela, feverfew, michaelh, spoorun, navarromorales, firef, ngraham, andrebarros, bruns, emmanuelp, mikesomov
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