[RFC PATCH v2 5/13] memory-hotplug : does not release memory region in PAGES_PER_SECTION chunks

Yasuaki Ishimatsu
2012-07-03T05:58:45Z

Since applying a patch(de7f0cba96786c), release_mem_region() has been changed
as called in PAGES_PER_SECTION chunks because register_memory_resource() is
called in PAGES_PER_SECTION chunks by add_memory(). But it seems firmware
dependency. If CRS are written in the PAGES_PER_SECTION chunks in ACPI DSDT
Table, register_memory_resource() is called in PAGES_PER_SECTION chunks.
But if CRS are written in the DIMM unit in ACPI DSDT Table,
register_memory_resource() is called in DIMM unit. So release_mem_region()
should not be called in PAGES_PER_SECTION chunks. The patch fixes it.

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 | 13 +++++++++----
mm/memory_hotplug.c | 4 ++--
2 files changed, 11 insertions(+), 6 deletions(-)

Index: linux-3.5-rc4/mm/memory_hotplug.c
===================================================================
--- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-07-03 14:22:03.549198802 +0900
+++ linux-3.5-rc4/mm/memory_hotplug.c 2012-07-03 14:22:05.919169458 +0900
@@ -358,11 +358,11 @@ int __remove_pages(struct zone *zone, un
BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
BUG_ON(nr_pages % PAGES_PER_SECTION);

+ release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
+
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;
- release_mem_region(pfn << PAGE_SHIFT,
- PAGES_PER_SECTION << PAGE_SHIFT);
ret = __remove_section(zone, __pfn_to_section(pfn));
if (ret)
break;
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 14:21:45.641422678
+0900
+++ linux-3.5-rc4/arch/powerpc/platforms/pseries/hotplug-memory.c 2012-07-03 14:22:05.920169437 +0900
@@ -77,7 +77,8 @@ static int pseries_remove_memblock(unsig
{
unsigned long start, start_pfn;
struct zone *zone;
- int ret;
+ int i, ret;
+ int sections_to_remove;

start_pfn = base >> PAGE_SHIFT;

@@ -97,9 +98,13 @@ static int pseries_remove_memblock(unsig
* to sysfs "state" file and we can't remove sysfs entries
* while writing to it. So we have to defer it to here.
*/
- ret = __remove_pages(zone, start_pfn, memblock_size >> PAGE_SHIFT);
- if (ret)
- return ret;
+ 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);
+ if (ret)
+ return ret;
+ }

/*
* Update memory regions for memory remove