[PATCH] mm/memory_hotplug: add add_pages() hotplug without linear mapping

[JÃrÃme Glisse]

For some memory hotplug we do not want the linear mapping to the
hotpluged physical range. Add a new helper that just do __add_pages()
and other arch specific bits if necessary.

Signed-off-by: Jéme Glisse <jglisse@xxxxxxxxxx>
---
 arch/x86/Kconfig      |  1 +
 arch/x86/mm/init_64.c | 17 ++++++++++++++++-
 mm/Kconfig            |  2 ++
 mm/memory_hotplug.c   | 18 ++++++++++++++++++
 4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cc98d5a..4024fee 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -25,6 +25,7 @@ config X86_64
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_SUPPORTS_INT128
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_HAS_ADD_PAGES
 	select HAVE_ARCH_SOFT_DIRTY
 	select MODULES_USE_ELF_RELA
 	select X86_DEV_DMA_OPS
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 15173d3..933032c 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -626,7 +626,7 @@ void __init paging_init(void)
  * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need
  * updating.
  */
-static void  update_end_of_memory_vars(u64 start, u64 size)
+static void update_end_of_memory_vars(u64 start, u64 size)
 {
 	unsigned long end_pfn = PFN_UP(start + size);
 
@@ -662,6 +662,21 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
 }
 EXPORT_SYMBOL_GPL(arch_add_memory);
 
+int add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
+		unsigned long nr_pages)
+{
+	int ret;
+
+	ret = __add_pages(nid, zone, phys_start_pfn, nr_pages);
+
+	if (!ret)
+		update_end_of_memory_vars(phys_start_pfn << PAGE_SHIFT,
+					  nr_pages << PAGE_SHIFT);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(add_pages);
+
 #define PAGE_INUSE 0xFD
 
 static void __meminit free_pagetable(struct page *page, int order)
diff --git a/mm/Kconfig b/mm/Kconfig
index 9b8fccb..d052ec1 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -707,3 +707,5 @@ config ARCH_USES_HIGH_VMA_FLAGS
 	bool
 config ARCH_HAS_PKEYS
 	bool
+config ARCH_HAS_ADD_PAGES
+	bool
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 295479b..bef772c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -576,6 +576,24 @@ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
 }
 EXPORT_SYMBOL_GPL(__add_pages);
 
+#ifndef ARCH_HAS_ADD_PAGES
+int add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
+		unsigned long nr_pages)
+{
+	int ret;
+
+	ret = __add_pages(nid, zone, phys_start_pfn, nr_pages);
+
+#ifdef CONFIG_X86_64
+	if (!ret)
+		update_end_of_memory_vars(phys_start_pfn << PAGE_SHIFT,
+					  nr_pages << PAGE_SHIFT);
+#endif
+	return ret;
+}
+EXPORT_SYMBOL_GPL(add_pages);
+#endif /* ARCH_HAS_ADD_PAGES */
+
 #ifdef CONFIG_MEMORY_HOTREMOVE
 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
 static int find_smallest_section_pfn(int nid, struct zone *zone,
-- 
2.7.4


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