On 11/20/2012 05:37 PM, Wen Congyang wrote:
At 11/20/2012 02:58 PM, Jaegeuk Hanse Wrote:
On 11/20/2012 02:55 PM, Wen Congyang wrote:
At 11/20/2012 02:22 PM, Jaegeuk Hanse Wrote:
On 11/01/2012 05:44 PM, Wen Congyang wrote:
From: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But
even if
we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
So the patch add unregister_memory_section() into __remove_section().
Hi Yasuaki,
In order to review this patch, I should dig sparse memory codes in
advance. But I have some confuse of codes. Why need encode/decode mem
map instead of set mem_map to ms->section_mem_map directly?
The memmap is aligned, and the low bits are zero. We store some
information
in these bits. So we need to encode/decode memmap here.
Hi Congyang,
Thanks for you reponse. But I mean why return (unsigned long)(mem_map -
(section_nr_to_pfn(pnum))); in function sparse_encode_mem_map, and then
return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); in
funtion sparse_decode_mem_map instead of just store mem_map in
ms->section_mep_map directly.
I don't know why. I try to find the reason, but I don't find any
place to use the pfn stored in the mem_map except in the decode
function. Maybe the designer doesn't want us to access the mem_map
directly.
It seems that mem_map is per node, but pfn is real pfn.
you can check __page_to_pfn.
Thanks
Wen Congyang
Regards,
Jaegeuk
Thanks
Wen Congyang
Regards,
Jaegeuk
CC: David Rientjes <rientjes@xxxxxxxxxx>
CC: Jiang Liu <liuj97@xxxxxxxxx>
CC: Len Brown <len.brown@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>
---
mm/memory_hotplug.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index ca07433..66a79a7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -286,11 +286,14 @@ static int __meminit __add_section(int nid,
struct zone *zone,
#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 = -EINVAL;
+
+ 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)
--
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