---

yaml --- r: 258935 b: refs/heads/master c: 45ebb84 h: refs/heads/master i: 258933: 4bc87a3 258931: 78e511b 258927: a550dfd v: v3
git-mirror · Jul 26, 2011 · d47e275 · d47e275
1 parent e8f69c1
commit d47e275
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Showing 2 changed files with 12 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 53bb01f593d50188c8d638f89db96f9b6b042bcd
+refs/heads/master: 45ebb840257b060ec54416aebffd9747e210962c
diff --git a/trunk/mm/thrash.c b/trunk/mm/thrash.c
@@ -67,6 +67,17 @@ void grab_swap_token(struct mm_struct *mm)
 	if (!swap_token_mm)
 		goto replace_token;
 
+	/*
+	 * Usually, we don't need priority aging because long interval faults
+	 * makes priority decrease quickly. But there is one exception. If the
+	 * token owner task is sleeping, it never make long interval faults.
+	 * Thus, we need a priority aging mechanism instead. The requirements
+	 * of priority aging are
+	 *  1) An aging interval is reasonable enough long. Too short aging
+	 *     interval makes quick swap token lost and decrease performance.
+	 *  2) The swap token owner task have to get priority aging even if
+	 *     it's under sleep.
+	 */
 	if ((global_faults - last_aging) > TOKEN_AGING_INTERVAL) {
 		swap_token_mm->token_priority /= 2;
 		last_aging = global_faults;