1 files changed, 39 insertions, 2 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8d196a803820..e1d1825a2611 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3278,18 +3278,47 @@ static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
 	return true;
 }
 
+static int nr_pcp_free(struct per_cpu_pages *pcp, int high, int batch)
+{
+	int min_nr_free, max_nr_free;
+
+	/* Check for PCP disabled or boot pageset */
+	if (unlikely(high < batch))
+		return 1;
+
+	/* Leave at least pcp->batch pages on the list */
+	min_nr_free = batch;
+	max_nr_free = high - batch;
+
+	/*
+	 * Double the number of pages freed each time there is subsequent
+	 * freeing of pages without any allocation.
+	 */
+	batch <<= pcp->free_factor;
+	if (batch < max_nr_free)
+		pcp->free_factor++;
+	batch = clamp(batch, min_nr_free, max_nr_free);
+
+	return batch;
+}
+
 static void free_unref_page_commit(struct page *page, unsigned long pfn,
 				   int migratetype)
 {
 	struct zone *zone = page_zone(page);
 	struct per_cpu_pages *pcp;
+	int high;
 
 	__count_vm_event(PGFREE);
 	pcp = this_cpu_ptr(zone->per_cpu_pageset);
 	list_add(&page->lru, &pcp->lists[migratetype]);
 	pcp->count++;
-	if (pcp->count >= READ_ONCE(pcp->high))
-		free_pcppages_bulk(zone, READ_ONCE(pcp->batch), pcp);
+	high = READ_ONCE(pcp->high);
+	if (pcp->count >= high) {
+		int batch = READ_ONCE(pcp->batch);
+
+		free_pcppages_bulk(zone, nr_pcp_free(pcp, high, batch), pcp);
+	}
 }
 
 /*
@@ -3541,7 +3570,14 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
 	unsigned long flags;
 
 	local_lock_irqsave(&pagesets.lock, flags);
+
+	/*
+	 * On allocation, reduce the number of pages that are batch freed.
+	 * See nr_pcp_free() where free_factor is increased for subsequent
+	 * frees.
+	 */
 	pcp = this_cpu_ptr(zone->per_cpu_pageset);
+	pcp->free_factor >>= 1;
 	list = &pcp->lists[migratetype];
 	page = __rmqueue_pcplist(zone,  migratetype, alloc_flags, pcp, list);
 	local_unlock_irqrestore(&pagesets.lock, flags);
@@ -6737,6 +6773,7 @@ static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonesta
 	 */
 	pcp->high = BOOT_PAGESET_HIGH;
 	pcp->batch = BOOT_PAGESET_BATCH;
+	pcp->free_factor = 0;
 }
 
 static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high,