git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: comparing file contents in is_exact_match?

From
Linus Torvalds <torvalds@osdl.org>
Date
Jul 18, 2006, 15:37 UTC
Message-ID
<Pine.LNX.4.64.0607180837260.3386@evo.osdl.org>
In-Reply-To
<f36b08ee0607180238i34cde4deib17426f121ae269e@mail.gmail.com>
On Tue, 18 Jul 2006, Yakov Lerner wrote:
> 
> How about making this parameter (do-use-mmap  vs  not-use-mmap)
> a *runtime*  parameter  ?

The thing is, there are really two different kinds of users, and one of them in particular (the pack-file case) shouldn't have the problems under Windows at all (because the pack-files aren't moved), and have a much bigger reason to use mmap in the first place (because accesses will be sparse, so reading the whole file is wasteful).

The other user was the index file, and _that_ one is the one that gets renamed (to replace the previous index file), and that one is also not ever read only partially, so using "read()" instead of mmap is much less of an issue.

So I really think we should just basically always mmap the pack-files (it should work everywhere), and make NO_MMAP just trigger on the other cases.

		Linus
Previous: Johannes SchindelinNext: Alex Riesen
Message 24 of 32 in “comparing file contents in is_exact_match?”
  1. Martin WaitzJul 6, 2006
  2. Junio C HamanoJul 6, 2006
  3. Martin WaitzJul 6, 2006
  4. Junio C HamanoJul 6, 2006
  5. Martin WaitzJul 6, 2006
  6. Martin WaitzJul 6, 2006
  7. Florian WeimerJul 7, 2006
  8. Johannes SchindelinJul 8, 2006
  9. Florian WeimerJul 16, 2006
  10. Johannes SchindelinJul 16, 2006
  11. Yakov LernerJul 16, 2006
  12. Alex RiesenJul 16, 2006
  13. Florian WeimerJul 17, 2006
  14. Johannes SchindelinJul 17, 2006
  15. Linus TorvaldsJul 17, 2006
  16. Johannes SchindelinJul 17, 2006
  17. Linus TorvaldsJul 17, 2006
  18. Martin WaitzJul 17, 2006
  19. Alex RiesenJul 17, 2006
  20. Geert BoschJul 17, 2006
  21. Linus TorvaldsJul 17, 2006
  22. Yakov LernerJul 18, 2006
  23. Johannes SchindelinJul 18, 2006
  24. Linus TorvaldsJul 18, 2006
  25. Alex RiesenJul 18, 2006
  26. Juergen RuehleJul 17, 2006
  27. Johannes SchindelinJul 17, 2006
  28. Juergen RuehleJul 17, 2006
  29. Yakov LernerJul 17, 2006
  30. Juergen RuehleJul 17, 2006
  31. Yakov LernerJul 18, 2006
  32. Yakov LernerJul 17, 2006

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.