guix - Wojtek's customized Guix

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-*- mode: org; coding: utf-8; -*-

#+TITLE: Hacking GNU Guix and Its Incredible Distro

Copyright © 2012, 2013, 2014, 2016, 2017, 2019 Ludovic Courtès <ludo@gnu.org>
Copyright © 2015, 2017 Mathieu Lirzin <mthl@gnu.org>
Copyright © 2017 Leo Famulari <leo@famulari.name>
Copyright © 2017 Arun Isaac <arunisaac@systemreboot.net>

  Copying and distribution of this file, with or without modification,
  are permitted in any medium without royalty provided the copyright
  notice and this notice are preserved.

* Contributing

See the manual for useful hacking information, either by running

  info -f doc/guix.info "Contributing"

or by checking the [[https://guix.gnu.org/manual/devel/en/html_node/Contributing.html][web copy of the manual]].

han 8 KiB typically represent ~70% of the entries in /gnu/store/.links but only contribute to ~4% of the space savings afforded by deduplication. Not considering these files for deduplication speeds up file insertion in the store and, more importantly, leaves 'removeUnusedLinks' with fewer entries to traverse, thereby speeding it up proportionally. Partly fixes <https://issues.guix.gnu.org/24937>. * config-daemon.ac: Remove symlink hard link check and CAN_LINK_SYMLINK definition. * guix/store/deduplication.scm (%deduplication-minimum-size): New variable. (deduplicate)[loop]: Do not recurse when FILE's size is below %DEDUPLICATION-MINIMUM-SIZE. (dump-port): New procedure. (dump-file/deduplicate)[hash]: Turn into... [dump-and-compute-hash]: ... this thunk. Call 'deduplicate' only when SIZE is greater than %DEDUPLICATION-MINIMUM-SIZE; otherwise call 'dump-port'. * nix/libstore/gc.cc (LocalStore::removeUnusedLinks): Drop files where st.st_size < deduplicationMinSize. * nix/libstore/local-store.hh (deduplicationMinSize): New declaration. * nix/libstore/optimise-store.cc (deduplicationMinSize): New variable. (LocalStore::optimisePath_): Return when PATH is a symlink or smaller than 'deduplicationMinSize'. * tests/derivations.scm ("identical files are deduplicated"): Produce files bigger than %DEDUPLICATION-MINIMUM-SIZE. * tests/nar.scm ("restore-file-set with directories (signed, valid)"): Likewise. * tests/store-deduplication.scm ("deduplicate, below %deduplication-minimum-size"): New test. ("deduplicate", "deduplicate, ENOSPC"): Produce files bigger than %DEDUPLICATION-MINIMUM-SIZE. * tests/store.scm ("substitute, deduplication"): Likewise. Ludovic Courtès 2020-06-25daemon: Correctly handle EMLINK corner case when deduplicating....Ludovic Courtès