[Crash-utility] [PATCH] Fix for the "kmem -i" option on Linux 5.0

[Kazuhito Hagio]

On 3/8/2019 3:13 PM, Dave Anderson wrote:
> 
> 
> ----- Original Message -----
>> Fix for the "kmem -i" option on Linux 5.0 and later kernels that
>> contain commit ca79b0c211af63fa3276f0e3fd7dd9ada2439839, titled
>> "mm: convert totalram_pages and totalhigh_pages variables to atomic".
>> Without the patch, the command prints some incorrect values, and
>> besides doesn't print high/low memory information on kernels which
>> are configured with CONFIG_HIGHMEM.
> 
> Hi Kazu,
> 
> Thanks again -- the patch is queued for crash-7.2.6:
> 
>   https://github.com/crash-utility/crash/commit/942d813cda354a5f4234fd36e9c6734140e3ffcb
> 
> Dave

Hi Dave,

Thank you for the quick response as always!
That's very helpful for me to test makedumpfile :)

Kazu

> 
> 
>> crash> kmem -i
>>                  PAGES        TOTAL      PERCENTAGE
>>     TOTAL MEM  -4395174638254716088  53602483503169.4 GB         ----
>>          FREE   398314       1.5 GB    0% of TOTAL MEM
>>          USED  -4395174638255114402  53602483503167.9 GB    0% of TOTAL MEM
>> ...
>>
>> Tested with 5.0 and 4.20 Fedora kernels for x86_64 and x86.
>>
>> Signed-off-by: Kazuhito Hagio <k-hagio at ab.jp.nec.com>
>> ---
>>  memory.c | 75 +++++++++++++++++++++++++++-----------------------------
>>  1 file changed, 36 insertions(+), 39 deletions(-)
>>
>> diff --git a/memory.c b/memory.c
>> index 9c1019a..ab561b3 100644
>> --- a/memory.c
>> +++ b/memory.c
>> @@ -910,26 +910,40 @@ vm_init(void)
>>  	if (IS_VMALLOC_ADDR(vt->mem_map))
>>  		vt->flags |= V_MEM_MAP;
>>  	vt->total_pages = BTOP(VTOP(vt->high_memory));
>> -	switch (get_syment_array("totalram_pages", sp_array, 2))
>> -	{
>> -	case 1:
>> -		get_symbol_data("totalram_pages", sizeof(ulong),
>> -			&vt->totalram_pages);
>> -		break;
>> -	case 2:
>> -		if (!(readmem(sp_array[0]->value, KVADDR,
>> -		    &value1, sizeof(ulong),
>> -		    "totalram_pages #1", RETURN_ON_ERROR)))
>> +
>> +	if (symbol_exists("_totalram_pages")) {
>> +		readmem(symbol_value("_totalram_pages") +
>> +			OFFSET(atomic_t_counter), KVADDR,
>> +			&vt->totalram_pages, sizeof(ulong),
>> +			"_totalram_pages", FAULT_ON_ERROR);
>> +	} else {
>> +		switch (get_syment_array("totalram_pages", sp_array, 2))
>> +		{
>> +		case 1:
>> +			get_symbol_data("totalram_pages", sizeof(ulong),
>> +				&vt->totalram_pages);
>>  			break;
>> -                if (!(readmem(sp_array[1]->value, KVADDR,
>> -                    &value2, sizeof(ulong),
>> -		    "totalram_pages #2", RETURN_ON_ERROR)))
>> -                        break;
>> -		vt->totalram_pages = MAX(value1, value2);
>> -		break;
>> +		case 2:
>> +			if (!(readmem(sp_array[0]->value, KVADDR,
>> +			    &value1, sizeof(ulong),
>> +			    "totalram_pages #1", RETURN_ON_ERROR)))
>> +				break;
>> +			if (!(readmem(sp_array[1]->value, KVADDR,
>> +			    &value2, sizeof(ulong),
>> +			    "totalram_pages #2", RETURN_ON_ERROR)))
>> +				break;
>> +			vt->totalram_pages = MAX(value1, value2);
>> +			break;
>> +		}
>>  	}
>>  
>> -	if (symbol_exists("totalhigh_pages")) {
>> +	if (symbol_exists("_totalhigh_pages")) {
>> +		readmem(symbol_value("_totalhigh_pages") +
>> +			OFFSET(atomic_t_counter), KVADDR,
>> +			&vt->totalhigh_pages, sizeof(ulong),
>> +			"_totalhigh_pages", FAULT_ON_ERROR);
>> +		vt->total_pages += vt->totalhigh_pages;
>> +	} else if (symbol_exists("totalhigh_pages")) {
>>  	        switch (get_syment_array("totalhigh_pages", sp_array, 2))
>>  	        {
>>  	        case 1:
>> @@ -8169,7 +8183,6 @@ dump_kmeminfo(void)
>>  	long nr_file_pages, nr_slab;
>>  	ulong swapper_space_nrpages;
>>  	ulong pct;
>> -	ulong value1, value2;
>>  	uint tmp;
>>  	struct meminfo meminfo;
>>  	struct gnu_request req;
>> @@ -8177,7 +8190,6 @@ dump_kmeminfo(void)
>>          ulong get_totalram;
>>          ulong get_buffers;
>>          ulong get_slabs;
>> -        struct syment *sp_array[2];
>>  	char buf[BUFSIZE];
>>  
>>  
>> @@ -8210,7 +8222,8 @@ dump_kmeminfo(void)
>>           *    Prior to 2.3.36, count all mem_map pages minus the reserved
>>           ones.
>>           *    From 2.3.36 onwards, use "totalram_pages" if set.
>>  	 */
>> -	if (symbol_exists("totalram_pages")) {
>> +	if (symbol_exists("totalram_pages") ||
>> +	    symbol_exists("_totalram_pages")) {
>>  		totalram_pages = vt->totalram_pages ?
>>  			vt->totalram_pages : get_totalram;
>>  	} else
>> @@ -8362,25 +8375,9 @@ dump_kmeminfo(void)
>>  	fprintf(fp, "%13s  %7ld  %11s  %3ld%% of TOTAL MEM\n",
>>  		"SLAB", get_slabs, pages_to_size(get_slabs, buf), pct);
>>  
>> -        if (symbol_exists("totalhigh_pages")) {
>> -	        switch (get_syment_array("totalhigh_pages", sp_array, 2))
>> -	        {
>> -	        case 1:
>> -	                get_symbol_data("totalhigh_pages", sizeof(ulong),
>> -	                        &totalhigh_pages);
>> -	                break;
>> -	        case 2:
>> -	                if (!(readmem(sp_array[0]->value, KVADDR,
>> -	                    &value1, sizeof(ulong),
>> -	                    "totalhigh_pages #1", RETURN_ON_ERROR)))
>> -	                        break;
>> -	                if (!(readmem(sp_array[1]->value, KVADDR,
>> -	                    &value2, sizeof(ulong),
>> -	                    "totalhigh_pages #2", RETURN_ON_ERROR)))
>> -	                        break;
>> -	                totalhigh_pages = MAX(value1, value2);
>> -	                break;
>> -	        }
>> +	if (symbol_exists("totalhigh_pages") ||
>> +	    symbol_exists("_totalhigh_pages")) {
>> +		totalhigh_pages = vt->totalhigh_pages;
>>  
>>  		pct = totalhigh_pages ?
>>  			(totalhigh_pages * 100)/totalram_pages : 0;
>> --
>> 2.17.0
>>
>> --
>> Crash-utility mailing list
>> Crash-utility at redhat.com
>> https://www.redhat.com/mailman/listinfo/crash-utility
>>
> 
> --
> Crash-utility mailing list
> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility
>