[RFC PATCH v2 7/13] memory-hotplug : remove_memory calls __remove_pages

Yasuaki Ishimatsu
2012-07-03T06:00:57Z

The patch adds __remove_pages() to remove_memory(). Then the range of
phys_start_pfn argument and nr_pages argument in __remove_pagse() may
have different zone. So zone argument is removed from __remove_pages()
and __remove_pages() caluculates zone in each section.

When CONFIG_SPARSEMEM_VMEMMAP is defined, there is no way to remove a memmap.
So __remove_section only calls unregister_memory_section().

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

---
arch/powerpc/platforms/pseries/hotplug-memory.c | 5 +----
include/linux/memory_hotplug.h | 3 +--
mm/memory_hotplug.c | 20 +++++++++++++-------
3 files changed, 15 insertions(+), 13 deletions(-)

Index: linux-3.5-rc4/mm/memory_hotplug.c
===================================================================
--- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-07-03 14:22:05.919169458 +0900
+++ linux-3.5-rc4/mm/memory_hotplug.c 2012-07-03 14:22:10.170116406 +0900
@@ -275,11 +275,14 @@ static int __meminit __add_section(int n
#ifdef CONFIG_SPARSEMEM_VMEMMAP
static int __remove_section(struct zone *zone, struct mem_section *ms)
{
- /*
- * XXX: Freeing memmap with vmemmap is not implement yet.
- * This should be removed later.
- */
- return -EBUSY;
+ int ret;
+
+ if (!valid_section(ms))
+ return ret;
+
+ ret = unregister_memory_section(ms);
+
+ return ret;
}
#else
static int __remove_section(struct zone *zone, struct mem_section *ms)
@@ -346,11 +349,11 @@ EXPORT_SYMBOL_GPL(__add_pages);
* sure that pages are marked reserved and zones are adjust properly by
* calling offline_pages().
*/
-int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
- unsigned long nr_pages)
+int __remove_pages(unsigned long phys_start_pfn, unsigned long nr_pages)
{
unsigned long i, ret = 0;
int sections_to_remove;
+ struct zone *zone;

/*
* We can only remove entire sections
@@ -363,6 +366,7 @@ int __remove_pages(struct zone *zone, un
sections_to_remove = nr_pages / PAGES_PER_SECTION;
for (i = 0; i < sections_to_remove; i++) {
unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
+ zone = page_zone(pfn_to_page(pfn));
ret = __remove_section(zone, __pfn_to_section(pfn));
if (ret)
break;
@@ -664,6 +668,8 @@ int remove_memory(int nid, u64 start, u6
lock_memory_hotplug();
/* remove memmap entry */
firmware_map_remove(start, start + size - 1, "System RAM");
+
+ __remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT);
unlock_memory_hotplug();
return 0;

Index: linux-3.5-rc4/include/linux/memory_hotplug.h
===================================================================
--- linux-3.5-rc4.orig/include/linux/memory_hotplug.h 2012-07-03 14:21:58.330264047 +0900
+++ linux-3.5-rc4/include/linux/memory_hotplug.h 2012-07-03 14:22:10.170116406 +0900
@@ -89,8 +89,7 @@ extern bool is_pageblock_removable_noloc
/* reasonably generic interface to expand the physical pages in a zone */
extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages);
-extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
- unsigned long nr_pages);
+extern int __remove_pages(unsigned long start_pfn, unsigned long nr_pages);

#ifdef CONFIG_NUMA
extern int memory_add_physaddr_to_nid(u64 start);
Index: linux-3.5-rc4/arch/powerpc/platforms/pseries/hotplug-memory.c
===================================================================
--- linux-3.5-rc4.orig/arch/powerpc/platforms/pseries/hotplug-memory.c 2012-07-03 14:22:05.920169437
+0900
+++ linux-3.5-rc4/arch/powerpc/platforms/pseries/hotplug-memory.c 2012-07-03 14:22:10.172116353 +0900
@@ -76,7 +76,6 @@ unsigned long memory_block_size_bytes(vo
static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
{
unsigned long start, start_pfn;
- struct zone *zone;
int i, ret;
int sections_to_remove;

@@ -87,8 +86,6 @@ static int pseries_remove_memblock(unsig
return 0;
}

- zone = page_zone(pfn_to_page(start_pfn));
-
/*
* Remove section mappings and sysfs entries for the
* section of the memory we are removing.
@@ -101,7 +98,7 @@ static int pseries_remove_memblock(unsig
sections_to_remove = (memblock_size >> PAGE_SHIFT) / PAGES_PER_SECTION;
for (i = 0; i < sections_to_remove; i++) {
unsigned long pfn = start_pfn + i * PAGES_PER_SECTION;
- ret = __remove_pages(zone, start_pfn, PAGES_PER_SECTION);
+ ret = __remove_pages(start_pfn, PAGES_PER_SECTION);
if (ret)
return ret;
}