From 6bc0a31cf9576d800cb3c0cba86aef0407171664 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@techsingularity.net>
Date: Fri, 11 Feb 2022 18:32:16 +0000
Subject: [PATCH] mm/page_alloc: Track range of active PCP lists during bulk
free
References: bnc#1193239,bnc#1193199,bnc#1193329
Patch-mainline: v5.18-rc1
Git-commit: 35b6d770e6334aa470080570f0f81c8b74a07afd
free_pcppages_bulk() frees pages in a round-robin fashion. Originally,
this was dealing only with migratetypes but storing high-order pages
means that there can be many more empty lists that are uselessly
checked. Track the minimum and maximum active pindex to reduce the
search space.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/page_alloc.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6a2446851fc4..b69337042a0c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1435,6 +1435,8 @@ static void free_pcppages_bulk(struct zone *zone, int count,
struct per_cpu_pages *pcp)
{
int pindex = 0;
+ int min_pindex = 0;
+ int max_pindex = NR_PCP_LISTS - 1;
int batch_free = 0;
int nr_freed = 0;
unsigned int order;
@@ -1460,13 +1462,20 @@ static void free_pcppages_bulk(struct zone *zone, int count,
*/
do {
batch_free++;
- if (++pindex == NR_PCP_LISTS)
- pindex = 0;
+ if (++pindex > max_pindex)
+ pindex = min_pindex;
list = &pcp->lists[pindex];
- } while (list_empty(list));
+ if (!list_empty(list))
+ break;
+
+ if (pindex == max_pindex)
+ max_pindex--;
+ if (pindex == min_pindex)
+ min_pindex++;
+ } while (1);
/* This is the only non-empty list. Free them all. */
- if (batch_free == NR_PCP_LISTS)
+ if (batch_free >= max_pindex - min_pindex)
batch_free = count;
order = pindex_to_order(pindex);