Re: 2.6.24-rc2-mm1 (memory hotplug x86_64/vmemmap fix)

[Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>]

On Thu, Nov 15, 2007 at 01:29:19PM +0900, KAMEZAWA Hiroyuki wrote:
> Fixes for memory hotplug compile and .section handling.
> 
> This patch fixes following bugs
> ==
> WARNING: vmlinux.o(.text+0x1d07c): Section mismatch: reference to .init.text:f
> ind_e820_area (between 'init_memory_mapping' and 'arch_add_memory')
> WARNING: vmlinux.o(.text+0x946b5): Section mismatch: reference to .init.text:
> __alloc_bootmem_node (between 'vmemmap_alloc_block' and 'vmemmap_pgd_populate')
> 
> ERROR: "memory_add_physaddr_to_nid" [drivers/acpi/acpi_memhotplug.ko] undefined!
> make[1]: *** [__modpost
> ==
> 
> This patch does
>  1. export memory_add_physaddr_to_nid().
>  2. changes __init to __init_refok find_early_table_space() (x86/mm/init_64.c)
>  3. changes __init_refok to __meminit in mm/sparse.c (This is bug.)
>  4. add wrapper function to call bootmem allocator without warning.
> 
>  After seeing "3", I thought simple __init_refok is dangerous and decided to
>  add wrapper function to call bootmem, is this style acceptable ?

Hi KAMEZAWA,

Thanks for the patch, it resolves memory_add_physaddr_to_nid() build
error for me.

 Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
 Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

 arch/x86/mm/init_64.c |    2 +-
 arch/x86/mm/srat_64.c |    1 +
 mm/sparse-vmemmap.c   |   13 ++++++++++++-
 mm/sparse.c           |   12 ++++++++++--
 4 files changed, 24 insertions(+), 4 deletions(-)

===================================================================
--- linux-2.6.24-rc2-mm1.orig/arch/x86/mm/srat_64.c
+++ linux-2.6.24-rc2-mm1/arch/x86/mm/srat_64.c
@@ -562,3 +562,4 @@ int memory_add_physaddr_to_nid(u64 start
 	return ret;
 }
 
+EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
Index: linux-2.6.24-rc2-mm1/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6.24-rc2-mm1.orig/arch/x86/mm/init_64.c
+++ linux-2.6.24-rc2-mm1/arch/x86/mm/init_64.c
@@ -319,7 +319,7 @@ static void __meminit phys_pud_init(pud_
 	__flush_tlb();
 } 
 
-static void __init find_early_table_space(unsigned long end)
+static void __init_refok find_early_table_space(unsigned long end)
 {
 	unsigned long puds, pmds, tables, start;
 
Index: linux-2.6.24-rc2-mm1/mm/sparse.c
===================================================================
--- linux-2.6.24-rc2-mm1.orig/mm/sparse.c
+++ linux-2.6.24-rc2-mm1/mm/sparse.c
@@ -55,7 +55,15 @@ static inline void set_section_nid(unsig
 #endif
 
 #ifdef CONFIG_SPARSEMEM_EXTREME
-static struct mem_section noinline __init_refok *sparse_index_alloc(int nid)
+/*
+ * for avoiding section mismatch.
+ */
+static void __init_refok *__call_bootmem_alloc(int nid, int array_size)
+{
+	return alloc_bootmem_node(NODE_DATA(nid), array_size);
+}
+
+static struct mem_section noinline __meminit *sparse_index_alloc(int nid)
 {
 	struct mem_section *section = NULL;
 	unsigned long array_size = SECTIONS_PER_ROOT *
@@ -64,7 +72,7 @@ static struct mem_section noinline __ini
 	if (slab_is_available())
 		section = kmalloc_node(array_size, GFP_KERNEL, nid);
 	else
-		section = alloc_bootmem_node(NODE_DATA(nid), array_size);
+		section = __call_bootmem_alloc(nid, array_size);
 
 	if (section)
 		memset(section, 0, array_size);
Index: linux-2.6.24-rc2-mm1/mm/sparse-vmemmap.c
===================================================================
--- linux-2.6.24-rc2-mm1.orig/mm/sparse-vmemmap.c
+++ linux-2.6.24-rc2-mm1/mm/sparse-vmemmap.c
@@ -30,6 +30,17 @@
 #include <asm/pgtable.h>
 
 /*
+ * wrapper for calling bootmem alloc from __meminit code.
+ */
+void __init_refok *__call_alloc_bootmem(int node,
+			int size, int align, int goal)
+{
+	return __alloc_bootmem_node(NODE_DATA(node), size, align, goal);
+}
+
+
+
+/*
  * Allocate a block of memory to be used to back the virtual memory map
  * or to back the page tables that are used to create the mapping.
  * Uses the main allocators if they are available, else bootmem.
@@ -44,7 +55,7 @@ void * __meminit vmemmap_alloc_block(uns
 			return page_address(page);
 		return NULL;
 	} else
-		return __alloc_bootmem_node(NODE_DATA(node), size, size,
+		return __call_alloc_bootmem(node, size, size,
 				__pa(MAX_DMA_ADDRESS));
 }