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yaml --- r: 625 b: refs/heads/master c: 8e30f27 h: refs/heads/master i: 623: 4506dff v: v3
git-mirror · May 1, 2005 · 73de519 · 73de519
1 parent 6143c44
commit 73de519
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 81b4082dc7666e2bc5ec229d8e837f3bafb96883
+refs/heads/master: 8e30f272a93ec9c1d5c305c5040dfaebc880499d
diff --git a/trunk/mm/page_alloc.c b/trunk/mm/page_alloc.c
@@ -1671,6 +1671,18 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
 		if (batch < 1)
 			batch = 1;
 
+		/*
+		 * Clamp the batch to a 2^n - 1 value. Having a power
+		 * of 2 value was found to be more likely to have
+		 * suboptimal cache aliasing properties in some cases.
+		 *
+		 * For example if 2 tasks are alternately allocating
+		 * batches of pages, one task can end up with a lot
+		 * of pages of one half of the possible page colors
+		 * and the other with pages of the other colors.
+		 */
+		batch = (1 << fls(batch + batch/2)) - 1;
+
 		for (cpu = 0; cpu < NR_CPUS; cpu++) {
 			struct per_cpu_pages *pcp;