[Crash-utility] [PATCH 07/16] MIPS: Fix display memory size issue

[Youling Tang]

On 03/10/2021 09:17 AM, HAGIO KAZUHITO(萩尾　一仁) wrote:
> -----Original Message-----
>> Hi, Vincent
>> Thank you for your reply and suggestion.
>>
>>
>> On 02/10/2021 09:59 PM, Vincent Whitchurch wrote:
>>
>>
>> 	On Tue, Jan 26, 2021 at 12:13:31PM +0100, Youling Tang wrote:
>>
>> 		"__node_data" instead of "node_data" is used in the MIPS architecture,
>> 		so "__node_data" is used to replace "node_data" to improve the use of
>> 		next_online_pgdat() functions in the MIPS architecture.
>>
>>
>> 	On my 32-bit MIPS dumps, MEMORY: works properly without this patch, but
>> 	they have contig_page_data instead of __node_data/node_data so they
>>
>> When the node_data/__node_data and pgdat_list symbols cannot be successfully
>> read from the kernel symbols, the contig_page_data symbol will be read. In
>> your 32-bit machine, there should be no node_data/__node_data, pgdat_list
>> symbols, and a single node, so the memory size can be displayed normally
>> without this patch.
>>
>>
>> 	shouldn't be affected by this code.  AFAICS only mach-loongson64 and
>> 	mach-ip27 have __node_data.
>>
>>
>> Yes, only mach-loongson64 and mach-ip27 use __node_data in the MIPS
>> architecture.
>>
>>
>>
>> 		E.g. Without this patch:
>> 		...
>> 		MEMORY: 0
>> 		...
>>
>>
>> 		With this patch:
>> 		...
>> 		MEMORY: 7.5 GB
>> 		...
>>
>> 		Signed-off-by: Huacai Chen <chenhuacai at loongson.cn> <mailto:chenhuacai at loongson.cn>
>> 		Signed-off-by: Youling Tang <tangyouling at loongson.cn> <mailto:tangyouling at loongson.cn>
>> 		---
>> 		 memory.c | 28 ++++++++++++++++++----------
>> 		 1 file changed, 18 insertions(+), 10 deletions(-)
>>
>> 		diff --git a/memory.c b/memory.c
>> 		index 33b0ca7..5347958 100644
>> 		--- a/memory.c
>> 		+++ b/memory.c
>> 		@@ -17820,22 +17820,28 @@ next_online_pgdat(int node)
>> 		         char buf[BUFSIZE];
>> 		 	ulong pgdat;
>>
>> 		+#ifndef __mips__
>> 		+#define NODE_DATA_VAR "node_data"
>> 		+#else
>> 		+#define NODE_DATA_VAR "__node_data"
>> 		+#endif
>>
>>
>> 	Is this really correct?  Doesn't __mips__ check the host architecture
>> 	when what we want to check here is the target?
>>
>> The results of filtering in the kernel code are as follows :
>> # grep -wnr "EXPORT_SYMBOL(node_data)"
>> arch/alpha/mm/numa.c:23:EXPORT_SYMBOL(node_data);
>> arch/arc/mm/init.c:37:EXPORT_SYMBOL(node_data);
>> arch/sparc/mm/init_64.c:1106:EXPORT_SYMBOL(node_data);
>> arch/powerpc/mm/numa.c:52:EXPORT_SYMBOL(node_data);
>> arch/s390/kernel/numa.c:18:EXPORT_SYMBOL(node_data);
>> arch/arm64/mm/numa.c:20:EXPORT_SYMBOL(node_data);
>> arch/x86/mm/numa.c:26:EXPORT_SYMBOL(node_data);
>>
>> # grep -wnr "EXPORT_SYMBOL(__node_data)"
>> arch/mips/sgi-ip27/ip27-memory.c:38:EXPORT_SYMBOL(__node_data);
>> arch/mips/loongson64/numa.c:33:EXPORT_SYMBOL(__node_data);
>>
>>
>> In the MIPS architecture, no platform uses node_data, only the __node_data
>> symbol. All other architectures use node_data symbols, so it should be
>> feasible to use __mips__ to determine the target (as long as it is a MIPS
>> architecture, use __node_data instead of node_data).
> OK.  Could you add a code comment about this to avoid confusion?
Ok. I will add the following comment, you see if it is feasible.

--- a/memory.c
+++ b/memory.c
@@ -17821,7 +17821,10 @@ next_online_pgdat(int node)
  {
          char buf[BUFSIZE];
         ulong pgdat;

+/*
+ * "__node_data" is used in the mips architecture,
+ * and "node_data" is used in other architectures.
+ */
  #ifndef __mips__
  #define NODE_DATA_VAR "node_data"
  #else

Thanks,
Youling
>
> Thanks,
> Kazu