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poll for it (i.e. if we can't acquire the lock, then let the main select() loop wait for at most a few seconds and then try again). This improves parallelism: if two nix-store processes are both trying to build a path at the same time, the second one shouldn't block; it should first see if it can build other goals. Also, it prevents the deadlocks that have been occuring in Hydra lately, where a process waits for a lock held by another process that's waiting for a lock held by the first. The downside is that polling isn't really elegant, but POSIX doesn't provide a way to wait for locks in a select() loop. The only solution would be to spawn a thread for each lock to do a blocking fcntl() and then signal the main thread, but that would require pthreads. |
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|---|---|---|
| blacklisting | ||
| corepkgs | ||
| doc | ||
| externals | ||
| make | ||
| misc | ||
| scripts | ||
| src | ||
| tests | ||
| aterm-gc.supp | ||
| AUTHORS | ||
| bootstrap.sh | ||
| ChangeLog | ||
| configure.ac | ||
| COPYING | ||
| INSTALL | ||
| Makefile.am | ||
| nix.conf.example | ||
| nix.spec.in | ||
| README | ||
| release.nix | ||
| substitute.mk | ||
| version | ||
Nix is a purely functional package manager. For installation and usage instructions, please read the manual, which can be found in `docs/manual/manual.html', and additionally at the Nix website at <http://nixos.org/>. Acknowledgments This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit (http://www.OpenSSL.org/).