From ab08ebea9b12f8bda931d6107d540ab3c18f9a4e Mon Sep 17 00:00:00 2001
From: Simon Xue <xxm@rock-chips.com>
Date: Tue, 15 Apr 2025 10:46:04 +0800
Subject: [PATCH] mm: defer init highmem page when
 CONFIG_ROCKCHIP_THUNDER_BOOT_DEFER_FREE_MEMBLOCK=y

Change-Id: I41527559ee66786826da7c3c9763804b91226bcf
Signed-off-by: Simon Xue <xxm@rock-chips.com>
---
 mm/internal.h   |  5 +++++
 mm/memblock.c   | 53 ++++++++++++++++++++++++++++++++++++++++++++++++-
 mm/page_alloc.c | 30 ++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/mm/internal.h b/mm/internal.h
index 2229c9198912..ac8795a89858 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -371,6 +371,11 @@ extern void memblock_free_pages(struct page *page, unsigned long pfn,
 					unsigned int order);
 #ifdef CONFIG_ROCKCHIP_THUNDER_BOOT_DEFER_FREE_MEMBLOCK
 extern void __init rk_free_pages_core(struct page *page, unsigned int order);
+extern unsigned long __init rk_deferred_init_pages(struct zone *zone,
+						   unsigned long pfn,
+						   unsigned long end_pfn);
+extern bool __meminit rk_defer_init_hpages(int nid, unsigned long zone_idx,
+				unsigned long pfn, unsigned long end_pfn);
 #endif
 extern void __free_pages_core(struct page *page, unsigned int order);
 extern void prep_compound_page(struct page *page, unsigned int order);
diff --git a/mm/memblock.c b/mm/memblock.c
index c89b37563872..5358ce52ee3c 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -124,7 +124,19 @@ static int __init early_defer_free_block_size(char *p)
 }
 
 early_param("defer_free_block_size", early_defer_free_block_size);
-#endif
+
+/* deferred highpage stuff */
+struct rk_defered_highpage_info {
+	unsigned long pfn_start;
+	unsigned long pfn_end;
+	struct zone *zone;
+};
+
+#define RK_DHPI_NUM_MAX 3
+
+static struct rk_defered_highpage_info rk_dhpi[RK_DHPI_NUM_MAX];
+static int rk_dhpi_num;
+#endif /* CONFIG_ROCKCHIP_THUNDER_BOOT_DEFER_FREE_MEMBLOCK */
 
 unsigned long max_low_pfn;
 unsigned long min_low_pfn;
@@ -2106,9 +2118,48 @@ static void __init rk_free_highpages(void)
 #endif
 }
 
+bool __meminit rk_defer_init_hpages(int nid, unsigned long zone_idx,
+			unsigned long pfn, unsigned long end_pfn)
+{
+	struct pglist_data *pdata = NODE_DATA(nid);
+	struct zone *zone = &pdata->node_zones[zone_idx];
+
+	if (rk_dhpi_num >= RK_DHPI_NUM_MAX) {
+		pr_err("too much deferred page zone\n");
+		return false;
+	}
+
+	if (strstr(zone->name, "HighMem")) {
+		pr_debug("%s, zone : %s, pfn[0x%lx-0x%lx]\n", __func__,
+			 zone->name, pfn, end_pfn);
+		rk_dhpi[rk_dhpi_num].pfn_start = pfn;
+		rk_dhpi[rk_dhpi_num].pfn_end = end_pfn;
+		rk_dhpi[rk_dhpi_num].zone = zone;
+		rk_dhpi_num++;
+
+		return true;
+	}
+	return false;
+}
+
 int __init defer_free_memblock(void *unused)
 {
 	int i;
+	unsigned long nr_pages = 0;
+
+	pr_debug("%s, rk_dhpi_num = %d\n", __func__, rk_dhpi_num);
+
+	for (i = 0; i < rk_dhpi_num; i++) {
+		struct zone *zone = rk_dhpi[i].zone;
+		unsigned long start_pfn = rk_dhpi[i].pfn_start;
+		unsigned long end_pfn = rk_dhpi[i].pfn_end;
+
+		pr_info("%s, zone : %s, pfn[0x%lx-0x%lx]\n", __func__,
+			zone->name, start_pfn, end_pfn);
+		nr_pages += rk_deferred_init_pages(zone, start_pfn, end_pfn);
+	}
+
+	pr_debug("%s, deferred_nr_page = 0x%lx\n", __func__, nr_pages);
 
 	for (i = 0; i < db_count; i++) {
 		pr_debug("%s: start = %ld, end = %ld\n",
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7ecce8b38753..e463adea6504 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1822,6 +1822,31 @@ void __init rk_free_pages_core(struct page *page, unsigned int order)
 		totalhigh_pages_add(1 << order);
 #endif
 }
+
+unsigned long __init rk_deferred_init_pages(struct zone *zone,
+					    unsigned long pfn,
+					    unsigned long end_pfn)
+{
+	int nid = zone_to_nid(zone);
+	unsigned long nr_pages = 0;
+	int zid = zone_idx(zone);
+	struct page *page = NULL;
+
+	for (; pfn < end_pfn; pfn++) {
+		if (!page || pageblock_aligned(pfn))
+			page = pfn_to_page(pfn);
+		else
+			page++;
+
+		__init_single_page(page, pfn, zid, nid, true);
+		nr_pages++;
+
+		/* Call cond_resched() only once every 8 pages */
+		if ((nr_pages & 7) == 0)
+			cond_resched();
+	}
+	return (nr_pages);
+}
 #endif /* CONFIG_ROCKCHIP_THUNDER_BOOT_DEFER_FREE_MEMBLOCK */
 
 /*
@@ -6830,6 +6855,11 @@ void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone
 	}
 #endif
 
+#ifdef CONFIG_ROCKCHIP_THUNDER_BOOT_DEFER_FREE_MEMBLOCK
+	if (rk_defer_init_hpages(nid, zone, start_pfn, end_pfn))
+		return;
+#endif
+
 #ifdef CONFIG_ROCKCHIP_THUNDER_BOOT
 	/* Zero all page struct in advance */
 	memset(pfn_to_page(start_pfn), 0, sizeof(struct page) * size);