[PATCH v04 3/5] migration/memory: Add hotplug READD_MULTIPLE

[Michael Bringmann]

On 10/10/2018 11:59 AM, Nathan Fontenot wrote:
> On 10/09/2018 03:36 PM, Michael Bringmann wrote:
>> migration/memory: This patch adds a new pseries hotplug action
>> for CPU and memory operations, PSERIES_HP_ELOG_ACTION_READD_MULTIPLE.
>> This is a variant of the READD operation which performs the action
>> upon multiple instances of the resource at one time.  The operation
>> is to be triggered by device-tree analysis of updates by RTAS events
>> analyzed by 'migation_store' during post-migration processing.  It
>> will be used for memory updates, initially.
>>
>> Signed-off-by: Michael Bringmann <mwb at linux.vnet.ibm.com>
>> ---
>> Changes in v04:
>>   -- Move init of 'lmb->internal_flags' in init_drmem_v2_lmbs to
>>      previous patch.
>>   -- Pull in implementation of dlpar_memory_readd_multiple() to go
>>      with operation flag.
>> ---
>>  arch/powerpc/include/asm/rtas.h                 |    1 +
>>  arch/powerpc/platforms/pseries/hotplug-memory.c |   31 +++++++++++++++++++++++
>>  2 files changed, 32 insertions(+)
>>
>> diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
>> index 0183e95..cc00451 100644
>> --- a/arch/powerpc/include/asm/rtas.h
>> +++ b/arch/powerpc/include/asm/rtas.h
>> @@ -333,6 +333,7 @@ struct pseries_hp_errorlog {
>>  #define PSERIES_HP_ELOG_ACTION_ADD	1
>>  #define PSERIES_HP_ELOG_ACTION_REMOVE	2
>>  #define PSERIES_HP_ELOG_ACTION_READD	3
>> +#define PSERIES_HP_ELOG_ACTION_READD_MULTIPLE	4
>>
>>  #define PSERIES_HP_ELOG_ID_DRC_NAME	1
>>  #define PSERIES_HP_ELOG_ID_DRC_INDEX	2
>> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
>> index 9a15d39..bf2420a 100644
>> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
>> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
>> @@ -546,6 +546,30 @@ static int dlpar_memory_readd_by_index(u32 drc_index)
>>  	return rc;
>>  }
>>
>> +static int dlpar_memory_readd_multiple(void)
>> +{
>> +	struct drmem_lmb *lmb;
>> +	int rc;
>> +
>> +	pr_info("Attempting to update multiple LMBs\n");
>> +
>> +	for_each_drmem_lmb(lmb) {
>> +		if (drmem_lmb_update(lmb)) {
>> +			rc = dlpar_remove_lmb(lmb);
>> +
>> +			if (!rc) {
>> +				rc = dlpar_add_lmb(lmb);
>> +				if (rc)
>> +					dlpar_release_drc(lmb->drc_index);
>> +			}
> 
> The work you're doing here is essentially the same that is done in
> dlpar_memory_readd_by_index(). Perhaps pulling the commin bits of both
> routines into a helper routine. This could include the success/failure
> messages in dlpar_memory_readd_by_index()

Really, only the interior of the loop is common to the two functions.
Creating a helper that incorporated the loop would mean either several
helper functions customized to each path (and a lot more code).
Or a common helper function that does everything for both paths, and
would be harder to understand/maintain.

It would be a lot cleaner to put the common loop interior into a helper function,
and retain the other two functions with their unique loop + test + extra
operations.  I will update with this method.

> 
> -Nathan

Michael

> 
>> +
>> +			drmem_remove_lmb_update(lmb);
>> +		}
>> +	}
>> +
>> +	return rc;
>> +}
>> +
>>  static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
>>  {
>>  	struct drmem_lmb *lmb, *start_lmb, *end_lmb;
>> @@ -646,6 +670,10 @@ static int dlpar_memory_readd_by_index(u32 drc_index)
>>  {
>>  	return -EOPNOTSUPP;
>>  }
>> +static int dlpar_memory_readd_multiple(void)
>> +{
>> +	return -EOPNOTSUPP;
>> +}
>>
>>  static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
>>  {
>> @@ -923,6 +951,9 @@ int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
>>  		drc_index = hp_elog->_drc_u.drc_index;
>>  		rc = dlpar_memory_readd_by_index(drc_index);
>>  		break;
>> +	case PSERIES_HP_ELOG_ACTION_READD_MULTIPLE:
>> +		rc = dlpar_memory_readd_multiple();
>> +		break;
>>  	default:
>>  		pr_err("Invalid action (%d) specified\n", hp_elog->action);
>>  		rc = -EINVAL;
>>
> 
> 

-- 
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line  363-5196
External: (512) 286-5196
Cell:       (512) 466-0650
mwb at linux.vnet.ibm.com