Make git-freeze bail out if the user has too much untracked data.

man/src/git-freeze.txt

Index: man/src/git-freeze.txt
diff --git a/man/src/git-freeze.txt b/man/src/git-freeze.txt
index 4a53832526fc0b1c50a7bf2b4f20759bee22706a..f9042519d4fb2db6eea66ac09ca4812cef1833de 100644
--- a/man/src/git-freeze.txt
+++ b/man/src/git-freeze.txt
@@ -26,10 +26,25 @@ with 'git add', 'git mv', 'git rm', etc.). A commit with the message
 `FREEZE.unindexed` will contain all changes which were not in your index at the
 time you ran git freeze (freshly modified files, new files, etc.).
 
+By default `git freeze` will only freeze up to 100MB of untracked files. See
+'CONFIGURATION VARIABLES' for more details.
+
+
 EXAMPLE
 -------
 demo:1[]
 
+
+CONFIGURATION VARIABLES
+-----------------------
+
+depot-tools.freeze-size-limit
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+This sets the size limit as an integer number of megabytes of untracked files
+that git-freeze will be willing to put in suspended animation. A 0 or negative
+limit disables the size-limit check entirely. *100* by default.
+
+
 SEE ALSO
 --------
 linkgit:git-thaw[1]