Hi Kosaki-san,
2012/06/28 14:26, KOSAKI Motohiro wrote:
On Wed, Jun 27, 2012 at 1:44 AM, Yasuaki Ishimatsu
<isimatu.yasuaki@xxxxxxxxxxxxxx> wrote:
When offline_pages() is called to offlined memory, the function fails since
all memory has been offlined. In this case, the function should succeed.
The patch adds the check function into offline_pages().
I don't understand your point. I think following misoperation should
fail. Otherwise
administrator have no way to know their fault.
$ echo offline > memoryN/state
$ echo offline > memoryN/state
In general, we don't like to ignore an error except the standard require it.
I understood the intention of previous mail (why the caller can't check it? ).
I'll move memory_is_offline() to caller side.
CC: Len Brown <len.brown@xxxxxxxxx>
CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
CC: Paul Mackerras <paulus@xxxxxxxxx>
CC: Christoph Lameter <cl@xxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
CC: Wen Congyang <wency@xxxxxxxxxxxxxx>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
---
drivers/base/memory.c | 20 ++++++++++++++++++++
include/linux/memory.h | 1 +
mm/memory_hotplug.c | 5 +++++
3 files changed, 26 insertions(+)
Index: linux-3.5-rc4/drivers/base/memory.c
===================================================================
--- linux-3.5-rc4.orig/drivers/base/memory.c 2012-06-26 13:28:16.726211752 +0900
+++ linux-3.5-rc4/drivers/base/memory.c 2012-06-26 13:34:22.423639904 +0900
@@ -70,6 +70,26 @@ void unregister_memory_isolate_notifier(
}
EXPORT_SYMBOL(unregister_memory_isolate_notifier);
+bool memory_is_offline(unsigned long start_pfn, unsigned long end_pfn)
I dislike this function name. 'memory' is too vague to me.
O.K.
I retry to change the name of the function.
+{
+ struct memory_block *mem;
+ struct mem_section *section;
+ unsigned long pfn, section_nr;
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ section_nr = pfn_to_section_nr(pfn);
+ section = __nr_to_section(section_nr);
+ mem = find_memory_block(section);
This seems to have strong sparse dependency.
Thanks.
I will consider other CONFIG_.
Thanks.
Yasuaki Ishimatsu
Hm, I wonder why memory-hotplug.c can enable when X86_64_ACPI_NUMA.
# eventually, we can have this option just 'select SPARSEMEM'
config MEMORY_HOTPLUG
bool "Allow for memory hot-add"
depends on SPARSEMEM || X86_64_ACPI_NUMA
+ if (!mem)
+ continue;
+ if (mem->state == MEM_OFFLINE)
+ continue;
+ return false;
+ }
+
+ return true;
+}
+
/*
* register_memory - Setup a sysfs device for a memory block
*/
Index: linux-3.5-rc4/include/linux/memory.h
===================================================================
--- linux-3.5-rc4.orig/include/linux/memory.h 2012-06-25 04:53:04.000000000 +0900
+++ linux-3.5-rc4/include/linux/memory.h 2012-06-26 13:34:22.424639891 +0900
@@ -120,6 +120,7 @@ extern int memory_isolate_notify(unsigne
extern struct memory_block *find_memory_block_hinted(struct mem_section *,
struct memory_block *);
extern struct memory_block *find_memory_block(struct mem_section *);
+extern bool memory_is_offline(unsigned long start_pfn, unsigned long end_pfn);
#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
enum mem_add_context { BOOT, HOTPLUG };
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
Index: linux-3.5-rc4/mm/memory_hotplug.c
===================================================================
--- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-06-26 13:28:16.743211538 +0900
+++ linux-3.5-rc4/mm/memory_hotplug.c 2012-06-26 13:48:38.264940468 +0900
@@ -887,6 +887,11 @@ static int __ref offline_pages(unsigned
lock_memory_hotplug();
+ if (memory_is_offline(start_pfn, end_pfn)) {
+ ret = 0;
+ goto out;
+ }
+
zone = page_zone(pfn_to_page(start_pfn));
node = zone_to_nid(zone);
nr_pages = end_pfn - start_pfn;
--
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