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

Re: [PATCH 11/11] walker.c: use ref transaction for ref updates

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Apr 19, 2014, 19:48 UTC
Message-ID
<5352D31A.6000107@alum.mit.edu>
In-Reply-To
<1397763987-4453-12-git-send-email-sahlberg@google.com>
On 04/17/2014 09:46 PM, Ronnie Sahlberg wrote:
> Switch to using ref transactions in walker_fetch(). As part of the refactoring
> to use ref transactions we also fix a potential memory leak where in the
> original code if write_ref_sha1() would fail we would end up returning from
> the function without free()ing the msg string.

I don't have time to review this last patch this evening, but one thing struck me. It seems like the old code went to extra effort to lock all the write_ref references early in the function, whereas your modified version doesn't lock them until later. Have you verified that you are not opening a possible race condition? If so, your commit message should justify that it isn't a problem. In other words, what does the code do between the old time of locking and the new time of locking and why doesn't it care whether the references are locked?

Aside from my other comments, patches 01-10 in the series looked fine. Thanks!

Michael
-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/
Previous: Ronnie SahlbergNext: Junio C Hamano
Message 22 of 24 in “Use ref transactions from most callers”
  1. 00/11 Use ref transactions from most callersRonnie Sahlberg, Apr 17, 2014
  2. 01/11 refs.c: constify the sha arguments for ref_transaction_create|delete|updateRonnie Sahlberg, Apr 17, 2014
  3. Michael HaggertyApr 19, 2014
  4. 02/11 refs.c: change ref_transaction_update() to do error checking and return statusRonnie Sahlberg, Apr 17, 2014
  5. Michael HaggertyApr 19, 2014
  6. Jonathan NiederApr 25, 2014
  7. 03/11 refs.c: change ref_transaction_create to do error checking and return statusRonnie Sahlberg, Apr 17, 2014
  8. Michael HaggertyApr 19, 2014
  9. 04/11 refs.c: ref_transaction_delete to check for error and return statusRonnie Sahlberg, Apr 17, 2014
  10. Michael HaggertyApr 19, 2014
  11. 05/11 tag.c: use ref transactions when doing updatesRonnie Sahlberg, Apr 17, 2014
  12. Michael HaggertyApr 19, 2014
  13. 06/11 replace.c: use the ref transaction functions for updatesRonnie Sahlberg, Apr 17, 2014
  14. Michael HaggertyApr 19, 2014
  15. 07/11 commit.c: use ref transactions for updatesRonnie Sahlberg, Apr 17, 2014
  16. Michael HaggertyApr 19, 2014
  17. Ronnie SahlbergApr 21, 2014
  18. 08/11 sequencer.c: use ref transactions for all ref updatesRonnie Sahlberg, Apr 17, 2014
  19. 09/11 fast-import.c: change update_branch to use ref transactionsRonnie Sahlberg, Apr 17, 2014
  20. 10/11 branch.c: use ref transaction for all ref updatesRonnie Sahlberg, Apr 17, 2014
  21. 11/11 walker.c: use ref transaction for ref updatesRonnie Sahlberg, Apr 17, 2014
  22. Michael HaggertyApr 19, 2014
  23. Junio C HamanoApr 21, 2014
  24. Ronnie SahlbergApr 21, 2014

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.