[RFC PATCH 3/4] mm/hotplug: make __add_pages() iterate on memory_block and split __add_section()

[Wei Yang <richard.weiyang@gmail.com>]

Memory hotplug unit is memory_block which contains one or several
mem_section. The current logic is iterating on each mem_section and add or
adjust the memory_block every time.

This patch makes the __add_pages() iterate on memory_block and split
__add_section() to two functions: __add_section() and __add_memory_block().

The first one would take care of each section data and the second one would
register the memory_block at once, which makes the function more clear and
natural.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 drivers/base/memory.c | 17 +++++------------
 mm/memory_hotplug.c   | 27 +++++++++++++++++----------
 2 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index b54cfe9cd98b..468e5ad1bc87 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -705,19 +705,12 @@ int register_new_memory(int nid, struct mem_section *section)
 
 	mutex_lock(&mem_sysfs_mutex);
 
-	mem = find_memory_block(section);
-	if (mem) {
-		mem->section_count++;
-		put_device(&mem->dev);
-	} else {
-		ret = init_memory_block(&mem, section, MEM_OFFLINE);
-		if (ret)
-			goto out;
-		mem->section_count++;
-	}
+	ret = init_memory_block(&mem, section, MEM_OFFLINE);
+	if (ret)
+		goto out;
+	mem->section_count = sections_per_block;
 
-	if (mem->section_count == sections_per_block)
-		ret = register_mem_sect_under_node(mem, nid);
+	ret = register_mem_sect_under_node(mem, nid);
 out:
 	mutex_unlock(&mem_sysfs_mutex);
 	return ret;
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a79a83ec965f..14a08b980b59 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -302,8 +302,7 @@ void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
 }
 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
 
-static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
-		bool want_memblock)
+static int __meminit __add_section(int nid, unsigned long phys_start_pfn)
 {
 	int ret;
 	int i;
@@ -332,6 +331,18 @@ static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
 		SetPageReserved(page);
 	}
 
+	return 0;
+}
+
+static int __meminit __add_memory_block(int nid, unsigned long phys_start_pfn,
+		bool want_memblock)
+{
+	int ret;
+
+	ret = __add_section(nid, phys_start_pfn);
+	if (ret)
+		return ret;
+
 	if (!want_memblock)
 		return 0;
 
@@ -347,15 +358,10 @@ static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
 int __ref __add_pages(int nid, unsigned long phys_start_pfn,
 			unsigned long nr_pages, bool want_memblock)
 {
-	unsigned long i;
+	unsigned long pfn;
 	int err = 0;
-	int start_sec, end_sec;
 	struct vmem_altmap *altmap;
 
-	/* during initialize mem_map, align hot-added range to section */
-	start_sec = pfn_to_section_nr(phys_start_pfn);
-	end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
-
 	altmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn));
 	if (altmap) {
 		/*
@@ -370,8 +376,9 @@ int __ref __add_pages(int nid, unsigned long phys_start_pfn,
 		altmap->alloc = 0;
 	}
 
-	for (i = start_sec; i <= end_sec; i++) {
-		err = __add_section(nid, section_nr_to_pfn(i), want_memblock);
+	for (pfn; pfn < phys_start_pfn + nr_pages;
+			pfn += sections_per_block * PAGES_PER_SECTION) {
+		err = __add_memory_block(nid, pfn, want_memblock);
 
 		/*
 		 * EEXIST is finally dealt with by ioresource collision
-- 
2.11.0

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