0131-add-a-per-cpu-minimum-high-watermark-an-tune-batch-s.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan.van.de.ven@intel.com>
Date: Tue, 23 Nov 2021 17:38:50 +0000
Subject: [PATCH] add a per cpu minimum high watermark an tune batch size

make sure there's at least 1024 per cpu pages... a reasonably small
amount for todays system
---
 mm/page_alloc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e6f211dcf82e..0ea48434ac7d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6836,11 +6836,11 @@ static int zone_batchsize(struct zone *zone)
 
 	/*
 	 * The number of pages to batch allocate is either ~0.1%
-	 * of the zone or 1MB, whichever is smaller. The batch
+	 * of the zone or 4MB, whichever is smaller. The batch
 	 * size is striking a balance between allocation latency
 	 * and zone lock contention.
 	 */
-	batch = min(zone_managed_pages(zone) >> 10, SZ_1M / PAGE_SIZE);
+	batch = min(zone_managed_pages(zone) >> 10, 4 * SZ_1M / PAGE_SIZE);
 	batch /= 4;		/* We effectively *= 4 below */
 	if (batch < 1)
 		batch = 1;
-- 
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