Stefan Beller <sbel...@google.com> writes: > The problem comes from guessing the number of fds we're allowed to use. > At first I thought it was a fundamental issue with the code being broken, but > it turns out we just need a larger offset as we apparently have 9 files open > already, before the transaction even starts. > I did not expect the number to be that high, which is why I came up with the > arbitrary number of 8 (3 for stdin/out/err, maybe packed refs and reflog so I > guessed, 8 would do fine). > > I am not sure if the 9 is a constant or if it scales to some unknown > property yet. > So to make the series work, all we need is: > > - int remaining_fds = get_max_fd_limit() - 8; > + int remaining_fds = get_max_fd_limit() - 9; > > I am going to try to understand where the 9 comes from and resend the patches.
I have a suspicion that the above is an indication that the approach is fundamentally not sound. 9 may be OK in your test repository, but that may fail in a repository with different resource usage patterns. On the core management side, xmalloc() and friends retry upon failure, after attempting to free the resource. I wonder if your codepath can do something similar to that, perhaps? On the other hand, it may be that this "let's keep it open as long as possible, as creat-close-open-write-close is more expensive" may not be worth the complexity. I wonder if it might not be a bad idea to start with a simpler rule, e.g. "use creat-write-close for ref updates outside transactions, and creat-close-open-write-close for inside transactions, as that is likely to be multi-ref updates" or something stupid and simple like that? Michael? -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
