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Re: [PATCH 3/3] Avoid doing extra 'lstat()'s for d_type if we have an up-to-date cache entry

From
Linus Torvalds <torvalds@linux-foundation.org>
Date
Jul 9, 2009, 18:53 UTC
Message-ID
<alpine.LFD.2.01.0907091153130.3352@localhost.localdomain>
In-Reply-To
<7vab3d3dpc.fsf@alter.siamese.dyndns.org>
On Thu, 9 Jul 2009, Junio C Hamano wrote:
> 
> Would dir/a be marked as uptodate in the index, if somebody preloads the
> index, after the above sequence?  I hope not.
Index preloading does not care about directories. It does the standard
	if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY))
		continue;

and since it's all threaded (and the whole _point_ is that it's threaded), it can't do anything fancier. Our lstat cache is _not_ thread-safe.

But preloading isn't even the only thing to do that. All the merge logics also just do "ie_match_stat()", as does git checkout, although maybe the directory gets validated separately for those cases before recursion.

Looking at "ce_mark_uptodate()", I think diff-lib.c is the only one that actually does that whole "has_symlink_leading_path()" thing (in "check_removed()").

I guess we could make out lstat cache thread-safe, and have the callers pass in a per-thread "struct cache_def *". That would work well enough for preloading (and everybody else could just use some random static one and pass that in).

Added Kjetil to cc.
			Linus
Previous: Junio C HamanoNext: Linus Torvalds
Message 16 of 39 in “Too many 'stat' calls by git-status on Windows”
  1. Dmitry PotapovJul 7, 2009
  2. Ramsay JonesJul 8, 2009
  3. Linus TorvaldsJul 9, 2009
  4. Linus TorvaldsJul 9, 2009
  5. 1/3 Add 'fill_directory()' helper function for directory traversalLinus Torvalds, Jul 9, 2009
  6. 2/3 Simplify read_directory[_recursive]() argumentsLinus Torvalds, Jul 9, 2009
  7. 3/3 Avoid doing extra 'lstat()'s for d_type if we have an up-to-date cache entryLinus Torvalds, Jul 9, 2009
  8. Junio C HamanoJul 9, 2009
  9. Linus TorvaldsJul 9, 2009
  10. Junio C HamanoJul 9, 2009
  11. Linus TorvaldsJul 9, 2009
  12. Junio C HamanoJul 9, 2009
  13. Linus TorvaldsJul 9, 2009
  14. Linus TorvaldsJul 9, 2009
  15. Junio C HamanoJul 9, 2009
  16. Linus TorvaldsJul 9, 2009
  17. 4/3 Avoid using 'lstat()' to figure out directoriesLinus Torvalds, Jul 9, 2009
  18. 5/3 Prepare symlink caching for thread-safetyLinus Torvalds, Jul 9, 2009
  19. 6/3 Export thread-safe version of 'has_symlink_leading_path()'Linus Torvalds, Jul 9, 2009
  20. 7/3 Make index preloading check the whole path to the fileLinus Torvalds, Jul 9, 2009
  21. Linus TorvaldsJul 9, 2009
  22. Junio C HamanoJul 10, 2009
  23. Linus TorvaldsJul 10, 2009
  24. Linus TorvaldsJul 10, 2009
  25. Junio C HamanoJul 11, 2009
  26. Linus TorvaldsJul 11, 2009
  27. Kjetil BarvikJul 12, 2009
  28. Junio C HamanoJul 12, 2009
  29. Paolo BonziniJul 9, 2009
  30. Linus TorvaldsJul 9, 2009
  31. Linus TorvaldsJul 9, 2009
  32. Linus TorvaldsJul 10, 2009
  33. Junio C HamanoJul 9, 2009
  34. Dmitry PotapovJul 9, 2009
  35. Eric BlakeJul 9, 2009
  36. Dmitry PotapovJul 9, 2009
  37. Dmitry PotapovJul 10, 2009
  38. Dmitry PotapovJul 9, 2009
  39. Dmitry PotapovJul 9, 2009

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