From 94fd46fa1c4655a609b3a67bef447c9547eb5080 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Sat, 14 Jun 2008 16:02:31 +0000
Subject: [PATCH] * Note.

---
 src/libstore/gc.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index b30f78b33..c46cc817b 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -123,7 +123,11 @@ Path addPermRoot(const Path & _storePath, const Path & _gcRoot,
         createSymlink(gcRoot, storePath, false);
     }
 
-    /* Check that the root can be found by the garbage collector. */
+    /* Check that the root can be found by the garbage collector.
+       !!! This can be very slow on machines that have many roots.
+       Instead of reading all the roots, it would be more efficient to
+       check if the root is in a directory in or linked from the
+       gcroots directory. */
     if (queryBoolSetting("gc-check-reachability", true)) {
         Roots roots = store->findRoots();
         if (roots.find(gcRoot) == roots.end())