diff --git a/SConstruct b/SConstruct
index ad6b6ee4451..88cd1494f14 100644
--- a/SConstruct
+++ b/SConstruct
@@ -557,9 +557,9 @@ class cache_progress:
         # decay since the ctime, and return a list with the entries
         # (filename, size, weight).
         current_time = time.time()
-        file_stat = [(x[0], x[1][0], x[1][0] * math.exp(self.exponent_scale * (x[1][1] - current_time))) for x in file_stat]
-        # Sort by highest weight (most sensible to keep) first
-        file_stat.sort(key=lambda x: x[2], reverse=True)
+        file_stat = [(x[0], x[1][0], (current_time - x[1][1])) for x in file_stat]
+        # Sort by the most resently accessed files (most sensible to keep) first
+        file_stat.sort(key=lambda x: x[2])
         # Search for the first entry where the storage limit is
         # reached
         sum, mark = 0, None
diff --git a/methods.py b/methods.py
index e861303e636..f9da6c8dd53 100644
--- a/methods.py
+++ b/methods.py
@@ -1755,16 +1755,16 @@ def precious_program(env, program, sources, **args):
     return program
 
 def add_shared_library(env, name, sources, **args):
-	library = env.SharedLibrary(name, sources, **args)
-	env.NoCache(library)
-	return library
+    library = env.SharedLibrary(name, sources, **args)
+    env.NoCache(library)
+    return library
 
 def add_library(env, name, sources, **args):
-	library = env.Library(name, sources, **args)
-	env.NoCache(library)
-	return library
+    library = env.Library(name, sources, **args)
+    env.NoCache(library)
+    return library
 
 def add_program(env, name, sources, **args):
-	program = env.Program(name, sources, **args)
-	env.NoCache(program)
-	return program
+    program = env.Program(name, sources, **args)
+    env.NoCache(program)
+    return program