Re: [PATCH 03/21] mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option

On 04/21/20 at 12:09pm, Mike Rapoport wrote:

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diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index fc0aad0bc1f5..e67dc501576a 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c

@@ -1372,11 +1372,7 @@ check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
 
 static int __init cmdline_parse_movable_node(char *p)
 {
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 	movable_node_enabled = true;
-#else
-	pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
-#endif

Wondering if this change will impact anything. Before, those ARCHes with
CONFIG_HAVE_MEMBLOCK_NODE_MAP support movable_node. With this patch
applied, those ARCHes which don't support CONFIG_HAVE_MEMBLOCK_NODE_MAP
can also have 'movable_node' specified in kernel cmdline.

quoted

 	return 0;
 }
 early_param("movable_node", cmdline_parse_movable_node);

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1ac775bfc9cf..4530e9cfd9f7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c

@@ -335,7 +335,6 @@ static unsigned long nr_kernel_pages __initdata;
 static unsigned long nr_all_pages __initdata;
 static unsigned long dma_reserve __initdata;
 
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
 static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
 static unsigned long required_kernelcore __initdata;

Does it mean those ARCHes which don't support
CONFIG_HAVE_MEMBLOCK_NODE_MAP before, will have 'kernelcore=' and
'movablecore=' now, and will have MOVABLE zone?

I hesitated a lot about whether to hide the kernelcore/movablecore and
related code behind an #ifdef.
In the end I've decided to keep the code compiled unconditionally as it
is anyway __init and no sane person would pass "kernelcore=" to the
kernel on a UMA system.

I see. Then maybe can do something if someone complains about it
in the future, e.g warn out with a message in
cmdline_parse_movable_node(), cmdline_parse_kernelcore().

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@@ -348,7 +347,6 @@ static bool mirrored_kernelcore __meminitdata;
 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
 int movable_zone;
 EXPORT_SYMBOL(movable_zone);
-#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 
 #if MAX_NUMNODES > 1
 unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;

@@ -1499,8 +1497,7 @@ void __free_pages_core(struct page *page, unsigned int order)
 	__free_pages(page, order);
 }
 
-#if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
-	defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
+#ifdef CONFIG_NEED_MULTIPLE_NODES
 
 static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
 

@@ -1542,7 +1539,7 @@ int __meminit early_pfn_to_nid(unsigned long pfn)
 
 	return nid;
 }
-#endif
+#endif /* CONFIG_NEED_MULTIPLE_NODES */
 
 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
 /* Only safe to use early in boot when initialisation is single-threaded */

@@ -5924,7 +5921,6 @@ void __ref build_all_zonelists(pg_data_t *pgdat)
 static bool __meminit
 overlap_memmap_init(unsigned long zone, unsigned long *pfn)
 {
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 	static struct memblock_region *r;
 
 	if (mirrored_kernelcore && zone == ZONE_MOVABLE) {

@@ -5940,7 +5936,6 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn)
 			return true;
 		}
 	}
-#endif
 	return false;
 }
 

@@ -6573,8 +6568,7 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
 	return nr_absent;
 }
 
-#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
-static inline unsigned long __init zone_spanned_pages_in_node(int nid,
+static inline unsigned long __init compat_zone_spanned_pages_in_node(int nid,

Is it compact zone which has continuous memory region, and the
compat here is typo? Or it's compatible zone? The name seems a little
confusing, or I miss something.

It's 'compat' from 'compatibility'. This is kinda "the old way" and the
version that was defined when CONFIG_HAVE_MEMBLOCK_NODE_MAP=y is the
"new way", so I picked 'compat' for backwards compatibility. 
Anyway, it will go away later in pacth 19. 

Got it, thanks for telling.

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 					unsigned long zone_type,
 					unsigned long node_start_pfn,
 					unsigned long node_end_pfn,

@@ -6593,7 +6587,7 @@ static inline unsigned long __init zone_spanned_pages_in_node(int nid,
 	return zones_size[zone_type];
 }
 
-static inline unsigned long __init zone_absent_pages_in_node(int nid,
+static inline unsigned long __init compat_zone_absent_pages_in_node(int nid,
 						unsigned long zone_type,
 						unsigned long node_start_pfn,
 						unsigned long node_end_pfn,

@@ -6605,13 +6599,12 @@ static inline unsigned long __init zone_absent_pages_in_node(int nid,
 	return zholes_size[zone_type];
 }
 
-#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
-
 static void __init calculate_node_totalpages(struct pglist_data *pgdat,
 						unsigned long node_start_pfn,
 						unsigned long node_end_pfn,
 						unsigned long *zones_size,
-						unsigned long *zholes_size)
+						unsigned long *zholes_size,
+						bool compat)
 {
 	unsigned long realtotalpages = 0, totalpages = 0;
 	enum zone_type i;

@@ -6619,17 +6612,38 @@ static void __init calculate_node_totalpages(struct pglist_data *pgdat,
 	for (i = 0; i < MAX_NR_ZONES; i++) {
 		struct zone *zone = pgdat->node_zones + i;
 		unsigned long zone_start_pfn, zone_end_pfn;
+		unsigned long spanned, absent;
 		unsigned long size, real_size;
 
-		size = zone_spanned_pages_in_node(pgdat->node_id, i,
-						  node_start_pfn,
-						  node_end_pfn,
-						  &zone_start_pfn,
-						  &zone_end_pfn,
-						  zones_size);
-		real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
-						  node_start_pfn, node_end_pfn,
-						  zholes_size);
+		if (compat) {
+			spanned = compat_zone_spanned_pages_in_node(
+						pgdat->node_id, i,
+						node_start_pfn,
+						node_end_pfn,
+						&zone_start_pfn,
+						&zone_end_pfn,
+						zones_size);
+			absent = compat_zone_absent_pages_in_node(
+						pgdat->node_id, i,
+						node_start_pfn,
+						node_end_pfn,
+						zholes_size);
+		} else {
+			spanned = zone_spanned_pages_in_node(pgdat->node_id, i,
+						node_start_pfn,
+						node_end_pfn,
+						&zone_start_pfn,
+						&zone_end_pfn,
+						zones_size);
+			absent = zone_absent_pages_in_node(pgdat->node_id, i,
+						node_start_pfn,
+						node_end_pfn,
+						zholes_size);
+		}
+
+		size = spanned;
+		real_size = size - absent;
+
 		if (size)
 			zone->zone_start_pfn = zone_start_pfn;
 		else

@@ -6929,10 +6943,8 @@ static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
 	 */
 	if (pgdat == NODE_DATA(0)) {
 		mem_map = NODE_DATA(0)->node_mem_map;
-#if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
 		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
 			mem_map -= offset;
-#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 	}
 #endif
 }

@@ -6949,9 +6961,10 @@ static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
 static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
 #endif
 
-void __init free_area_init_node(int nid, unsigned long *zones_size,
-				   unsigned long node_start_pfn,
-				   unsigned long *zholes_size)
+static void __init __free_area_init_node(int nid, unsigned long *zones_size,
+					 unsigned long node_start_pfn,
+					 unsigned long *zholes_size,
+					 bool compat)
 {
 	pg_data_t *pgdat = NODE_DATA(nid);
 	unsigned long start_pfn = 0;

@@ -6963,16 +6976,16 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
 	pgdat->node_id = nid;
 	pgdat->node_start_pfn = node_start_pfn;
 	pgdat->per_cpu_nodestats = NULL;
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
-	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
-	pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
-		(u64)start_pfn << PAGE_SHIFT,
-		end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
-#else
-	start_pfn = node_start_pfn;
-#endif
+	if (!compat) {
+		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
+		pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
+			(u64)start_pfn << PAGE_SHIFT,
+			end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
+	} else {
+		start_pfn = node_start_pfn;
+	}
 	calculate_node_totalpages(pgdat, start_pfn, end_pfn,
-				  zones_size, zholes_size);
+				  zones_size, zholes_size, compat);
 
 	alloc_node_mem_map(pgdat);
 	pgdat_set_deferred_range(pgdat);

@@ -6980,6 +6993,14 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
 	free_area_init_core(pgdat);
 }
 
+void __init free_area_init_node(int nid, unsigned long *zones_size,
+				unsigned long node_start_pfn,
+				unsigned long *zholes_size)
+{
+	__free_area_init_node(nid, zones_size, node_start_pfn, zholes_size,
+			      true);
+}
+
 #if !defined(CONFIG_FLAT_NODE_MEM_MAP)
 /*
  * Initialize all valid struct pages in the range [spfn, epfn) and mark them

@@ -7063,8 +7084,6 @@ static inline void __init init_unavailable_mem(void)
 }
 #endif /* !CONFIG_FLAT_NODE_MEM_MAP */
 
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
-
 #if MAX_NUMNODES > 1
 /*
  * Figure out the number of possible node ids.

@@ -7493,8 +7512,8 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 	init_unavailable_mem();
 	for_each_online_node(nid) {
 		pg_data_t *pgdat = NODE_DATA(nid);
-		free_area_init_node(nid, NULL,
-				find_min_pfn_for_node(nid), NULL);
+		__free_area_init_node(nid, NULL,
+				      find_min_pfn_for_node(nid), NULL, false);
 
 		/* Any memory on that node */
 		if (pgdat->node_present_pages)

@@ -7559,8 +7578,6 @@ static int __init cmdline_parse_movablecore(char *p)
 early_param("kernelcore", cmdline_parse_kernelcore);
 early_param("movablecore", cmdline_parse_movablecore);
 
-#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
-
 void adjust_managed_page_count(struct page *page, long count)
 {
 	atomic_long_add(count, &page_zone(page)->managed_pages);

-- 
2.25.1

-- 
Sincerely yours,
Mike.