Re: [RFC v5 6/6] migration/memory: Update memory for assoc changes

[Michael Bringmann <mwb@linux.vnet.ibm.com>]

This patch was intended to apply the necessary changes for the
'ibm,dynamic-memory[-v2]' properties.  Before the advent of the
LMB representation, that code took up a lot more space.  At this
point, it has shrunk to only one line of unique change.  I was
hoping to include it here rather than create another patch.

But that can be done.

Michael

On 05/22/2018 04:11 PM, Thomas Falcon wrote:
> On 05/21/2018 12:52 PM, Michael Bringmann wrote:
>> migration/memory: This patch adds more recognition for changes to
>> the associativity of memory blocks described by the device-tree
>> properties and updates local and general kernel data structures to
>> reflect those changes.  These differences may include:
>>
>> * Evaluating 'ibm,dynamic-memory' properties when processing the
>>   topology of LPARS in Post Migration events.  Previous efforts
>>   only recognized whether a memory block's assignment had changed
>>   in the property.  Changes here include checking the aa_index
>>   values for each drc_index of the old/new LMBs and to 'readd'
>>   any block for which the setting has changed.
>>
>> * In an LPAR migration scenario, the "ibm,associativity-lookup-arrays"
>>   property may change.  In the event that a row of the array differs,
>>   locate all assigned memory blocks with that 'aa_index' and 're-add'
>>   them to the system memory block data structures.  In the process of
>>   the 're-add', the system routines will update the corresponding entry
>>   for the memory in the LMB structures and any other relevant kernel
>>   data structures.
>>
>> * Extend the previous work for the 'ibm,associativity-lookup-array'
>>   and 'ibm,dynamic-memory' properties to support the property
>>   'ibm,dynamic-memory-v2' by means of the DRMEM LMB interpretation
>>   code.
>>
>> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
>> ---
>> Changes in RFC:
>>   -- Simplify code to update memory nodes during mobility checks.
>>   -- Reuse code from DRMEM changes to scan for LMBs when updating
>>      aa_index
>>   -- Combine common code for properties 'ibm,dynamic-memory' and
>>      'ibm,dynamic-memory-v2' after integrating DRMEM features.
>>   -- Rearrange patches to co-locate memory property-related changes.
>>   -- Use new paired list iterator for the drmem info arrays.
>>   -- Use direct calls to add/remove memory from the update drconf
>>      function as those operations are only intended for user DLPAR
>>      ops, and should not occur during Migration reconfig notifier
>>      changes.
>>   -- Correct processing bug in processing of ibm,associativity-lookup-arrays
>>   -- Rebase to 4.17-rc5 kernel
>>   -- Apply minor code cleanups
>> ---
>>  arch/powerpc/platforms/pseries/hotplug-memory.c |  153 ++++++++++++++++++-----
>>  1 file changed, 121 insertions(+), 32 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
>> index c1578f5..ac329aa 100644
>> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
>> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
>> @@ -994,13 +994,11 @@ static int pseries_add_mem_node(struct device_node *np)
>>  	return (ret < 0) ? -EINVAL : 0;
>>  }
>>
>> -static int pseries_update_drconf_memory(struct of_reconfig_data *pr)
>> +static int pseries_update_drconf_memory(struct drmem_lmb_info *new_dinfo)
>>  {
>> -	struct of_drconf_cell_v1 *new_drmem, *old_drmem;
>> +	struct drmem_lmb *old_lmb, *new_lmb;
>>  	unsigned long memblock_size;
>> -	u32 entries;
>> -	__be32 *p;
>> -	int i, rc = -EINVAL;
>> +	int rc = 0;
>>
>>  	if (rtas_hp_event)
>>  		return 0;
>> @@ -1009,42 +1007,124 @@ static int pseries_update_drconf_memory(struct of_reconfig_data *pr)
>>  	if (!memblock_size)
>>  		return -EINVAL;
>>
>> -	p = (__be32 *) pr->old_prop->value;
>> -	if (!p)
>> -		return -EINVAL;
>> +	/* Arrays should have the same size and DRC indexes */
>> +	for_each_pair_drmem_lmb(drmem_info, old_lmb, new_dinfo, new_lmb) {
>>
>> -	/* The first int of the property is the number of lmb's described
>> -	 * by the property. This is followed by an array of of_drconf_cell
>> -	 * entries. Get the number of entries and skip to the array of
>> -	 * of_drconf_cell's.
>> -	 */
>> -	entries = be32_to_cpu(*p++);
>> -	old_drmem = (struct of_drconf_cell_v1 *)p;
>> -
>> -	p = (__be32 *)pr->prop->value;
>> -	p++;
>> -	new_drmem = (struct of_drconf_cell_v1 *)p;
>> +		if (new_lmb->drc_index != old_lmb->drc_index)
>> +			continue;
>>
>> -	for (i = 0; i < entries; i++) {
>> -		if ((be32_to_cpu(old_drmem[i].flags) & DRCONF_MEM_ASSIGNED) &&
>> -		    (!(be32_to_cpu(new_drmem[i].flags) & DRCONF_MEM_ASSIGNED))) {
>> +		if ((old_lmb->flags & DRCONF_MEM_ASSIGNED) &&
>> +		    (!(new_lmb->flags & DRCONF_MEM_ASSIGNED))) {
>>  			rc = pseries_remove_memblock(
>> -				be64_to_cpu(old_drmem[i].base_addr),
>> -						     memblock_size);
>> +				old_lmb->base_addr, memblock_size);
>>  			break;
>> -		} else if ((!(be32_to_cpu(old_drmem[i].flags) &
>> -			    DRCONF_MEM_ASSIGNED)) &&
>> -			    (be32_to_cpu(new_drmem[i].flags) &
>> -			    DRCONF_MEM_ASSIGNED)) {
>> -			rc = memblock_add(be64_to_cpu(old_drmem[i].base_addr),
>> -					  memblock_size);
>> +		} else if ((!(old_lmb->flags & DRCONF_MEM_ASSIGNED)) &&
>> +			   (new_lmb->flags & DRCONF_MEM_ASSIGNED)) {
>> +			rc = memblock_add(old_lmb->base_addr,
>> +					memblock_size);
>>  			rc = (rc < 0) ? -EINVAL : 0;
>>  			break;
>> +		} else if ((old_lmb->aa_index != new_lmb->aa_index) &&
>> +			   (new_lmb->flags & DRCONF_MEM_ASSIGNED)) {
>> +			dlpar_queue_action(PSERIES_HP_ELOG_RESOURCE_MEM,
>> +					   PSERIES_HP_ELOG_ACTION_READD,
>> +					   new_lmb->drc_index);
>>  		}
>>  	}
>>  	return rc;
>>  }
>>
>> +static void pseries_update_ala_memory_aai(int aa_index)
>> +{
>> +	struct drmem_lmb *lmb;
>> +
>> +	/* Readd all LMBs which were previously using the
>> +	 * specified aa_index value.
>> +	 */
>> +	for_each_drmem_lmb(lmb) {
>> +		if ((lmb->aa_index == aa_index) &&
>> +			(lmb->flags & DRCONF_MEM_ASSIGNED)) {
>> +			dlpar_queue_action(PSERIES_HP_ELOG_RESOURCE_MEM,
>> +					   PSERIES_HP_ELOG_ACTION_READD,
>> +					   lmb->drc_index);
>> +		}
>> +	}
>> +}
>> +
>> +struct assoc_arrays {
>> +	u32 n_arrays;
>> +	u32 array_sz;
>> +	const __be32 *arrays;
>> +};
>> +
>> +static int pseries_update_ala_memory(struct of_reconfig_data *pr)
>> +{
>> +	struct assoc_arrays new_ala, old_ala;
>> +	__be32 *p;
>> +	int i, lim;
>> +
>> +	if (rtas_hp_event)
>> +		return 0;
>> +
>> +	/*
>> +	 * The layout of the ibm,associativity-lookup-arrays
>> +	 * property is a number N indicating the number of
>> +	 * associativity arrays, followed by a number M
>> +	 * indicating the size of each associativity array,
>> +	 * followed by a list of N associativity arrays.
>> +	 */
>> +
>> +	p = (__be32 *) pr->old_prop->value;
>> +	if (!p)
>> +		return -EINVAL;
>> +	old_ala.n_arrays = of_read_number(p++, 1);
>> +	old_ala.array_sz = of_read_number(p++, 1);
>> +	old_ala.arrays = p;
>> +
>> +	p = (__be32 *) pr->prop->value;
>> +	if (!p)
>> +		return -EINVAL;
>> +	new_ala.n_arrays = of_read_number(p++, 1);
>> +	new_ala.array_sz = of_read_number(p++, 1);
>> +	new_ala.arrays = p;
>> +
> 
> I don't know how often associativity lookup arrays needs to be parsed, but maybe it would be helpful to create a helper function to parse those here.
> 
>> +	lim = (new_ala.n_arrays > old_ala.n_arrays) ? old_ala.n_arrays :
>> +			new_ala.n_arrays;
>> +
>> +	if (old_ala.array_sz == new_ala.array_sz) {
>> +
>> +		/* Reset any entries where the old and new rows
>> +		 * the array have changed.
>> +		 */
>> +		for (i = 0; i < lim; i++) {
>> +			int index = (i * new_ala.array_sz);
>> +
>> +			if (!memcmp(&old_ala.arrays[index],
>> +				&new_ala.arrays[index],
>> +				new_ala.array_sz))
>> +				continue;
>> +
>> +			pseries_update_ala_memory_aai(i);
>> +		}
>> +
>> +		/* Reset any entries representing the extra rows.
>> +		 * There shouldn't be any, but just in case ...
>> +		 */
>> +		for (i = lim; i < new_ala.n_arrays; i++)
>> +			pseries_update_ala_memory_aai(i);
>> +
>> +	} else {
>> +		/* Update all entries representing these rows;
>> +		 * as all rows have different sizes, none can
>> +		 * have equivalent values.
>> +		 */
>> +		for (i = 0; i < lim; i++)
>> +			pseries_update_ala_memory_aai(i);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  static int pseries_memory_notifier(struct notifier_block *nb,
>>  				   unsigned long action, void *data)
>>  {
>> @@ -1059,8 +1139,17 @@ static int pseries_memory_notifier(struct notifier_block *nb,
>>  		err = pseries_remove_mem_node(rd->dn);
>>  		break;
>>  	case OF_RECONFIG_UPDATE_PROPERTY:
>> -		if (!strcmp(rd->prop->name, "ibm,dynamic-memory"))
>> -			err = pseries_update_drconf_memory(rd);
>> +		if (!strcmp(rd->prop->name, "ibm,dynamic-memory") ||
>> +		    !strcmp(rd->prop->name, "ibm,dynamic-memory-v2")) {
>> +			struct drmem_lmb_info *dinfo =
>> +				drmem_lmbs_init(rd->prop);
>> +			if (!dinfo)
>> +				return -EINVAL;
>> +			err = pseries_update_drconf_memory(dinfo);
>> +			drmem_lmbs_free(dinfo);
> 
> Is this block above related to the other associativity changes?  It seems to be an update for dynamic-memory-v2, so should probably be in a separate patch.
> 
> Thanks,
> Tom
> 
>> +		} else if (!strcmp(rd->prop->name,
>> +				"ibm,associativity-lookup-arrays"))
>> +			err = pseries_update_ala_memory(rd);
>>  		break;
>>  	}
>>  	return notifier_from_errno(err);
> 
> 
> 

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