[PATCH v07 2/9] hotplug/cpu: Add operation queuing function
Michael Bringmann
mwb at linux.vnet.ibm.com
Thu Jul 26 01:57:37 AEST 2018
See below.
On 07/23/2018 12:51 PM, Nathan Fontenot wrote:
> On 07/13/2018 03:18 PM, Michael Bringmann wrote:
>> migration/dlpar: This patch adds function dlpar_queue_action()
>> which will queued up information about a CPU/Memory 'readd'
>> operation according to resource type, action code, and DRC index.
>> At a subsequent point, the list of operations can be run/played
>> in series. Examples of such oprations include 'readd' of CPU
>> and Memory blocks identified as having changed their associativity
>> during an LPAR migration event. >
>> Signed-off-by: Michael Bringmann <mwb at linux.vnet.ibm.com>
>> ---
>> Changes in patch:
>> -- Correct drc_index before adding to pseries_hp_errorlog struct
>> -- Correct text of notice
>> -- Revise queuing model to save up all of the DLPAR actions for
>> later execution.
>> -- Restore list init statement missing from patch
>> -- Move call to apply queued operations into 'mobility.c'
>> -- Compress some code
>> -- Rename some of queueing function APIs
>> -- Revise implementation to push execution of queued operations
>> to a workqueue task.
>> -- Cleanup reference to outdated queuing operation.
>> ---
>> arch/powerpc/include/asm/rtas.h | 2 +
>> arch/powerpc/platforms/pseries/dlpar.c | 61 +++++++++++++++++++++++++++++
>> arch/powerpc/platforms/pseries/mobility.c | 4 ++
>> arch/powerpc/platforms/pseries/pseries.h | 2 +
>> 4 files changed, 69 insertions(+)
>>
>> diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
>> index 71e393c..4f601c7 100644
>> --- a/arch/powerpc/include/asm/rtas.h
>> +++ b/arch/powerpc/include/asm/rtas.h
>> @@ -310,12 +310,14 @@ struct pseries_hp_errorlog {
>> struct { __be32 count, index; } ic;
>> char drc_name[1];
>> } _drc_u;
>> + struct list_head list;
>> };
>>
>> #define PSERIES_HP_ELOG_RESOURCE_CPU 1
>> #define PSERIES_HP_ELOG_RESOURCE_MEM 2
>> #define PSERIES_HP_ELOG_RESOURCE_SLOT 3
>> #define PSERIES_HP_ELOG_RESOURCE_PHB 4
>> +#define PSERIES_HP_ELOG_RESOURCE_PMT 5
>>
>> #define PSERIES_HP_ELOG_ACTION_ADD 1
>> #define PSERIES_HP_ELOG_ACTION_REMOVE 2
>> diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
>> index a0b20c0..7264b8e 100644
>> --- a/arch/powerpc/platforms/pseries/dlpar.c
>> +++ b/arch/powerpc/platforms/pseries/dlpar.c
>> @@ -25,6 +25,7 @@
>> #include <asm/prom.h>
>> #include <asm/machdep.h>
>> #include <linux/uaccess.h>
>> +#include <linux/delay.h>
>> #include <asm/rtas.h>
>>
>> static struct workqueue_struct *pseries_hp_wq;
>> @@ -329,6 +330,8 @@ int dlpar_release_drc(u32 drc_index)
>> return 0;
>> }
>>
>> +static int dlpar_pmt(struct pseries_hp_errorlog *work);
>> +
>> static int handle_dlpar_errorlog(struct pseries_hp_errorlog *hp_elog)
>> {
>> int rc;
>> @@ -357,6 +360,9 @@ static int handle_dlpar_errorlog(struct pseries_hp_errorlog *hp_elog)
>> case PSERIES_HP_ELOG_RESOURCE_CPU:
>> rc = dlpar_cpu(hp_elog);
>> break;
>> + case PSERIES_HP_ELOG_RESOURCE_PMT:
>> + rc = dlpar_pmt(hp_elog);
>> + break;
>> default:
>> pr_warn_ratelimited("Invalid resource (%d) specified\n",
>> hp_elog->resource);
>> @@ -407,6 +413,61 @@ void queue_hotplug_event(struct pseries_hp_errorlog *hp_errlog,
>> }
>> }
>>
>> +LIST_HEAD(dlpar_delayed_list);
>> +
>> +int dlpar_queue_action(int resource, int action, u32 drc_index)
>> +{
>> + struct pseries_hp_errorlog *hp_errlog;
>> +
>> + hp_errlog = kmalloc(sizeof(struct pseries_hp_errorlog), GFP_KERNEL);
>> + if (!hp_errlog)
>> + return -ENOMEM;
>> +
>> + hp_errlog->resource = resource;
>> + hp_errlog->action = action;
>> + hp_errlog->id_type = PSERIES_HP_ELOG_ID_DRC_INDEX;
>> + hp_errlog->_drc_u.drc_index = cpu_to_be32(drc_index);
>> +
>> + list_add_tail(&hp_errlog->list, &dlpar_delayed_list);
>> +
>> + return 0;
>> +}
>> +
>> +static int dlpar_pmt(struct pseries_hp_errorlog *work)
>> +{
>> + struct list_head *pos, *q;
>> +
>> + ssleep(15);
>> +
>> + list_for_each_safe(pos, q, &dlpar_delayed_list) {
>> + struct pseries_hp_errorlog *tmp;
>> +
>> + tmp = list_entry(pos, struct pseries_hp_errorlog, list);
>> + handle_dlpar_errorlog(tmp);
>> +
>> + list_del(pos);
>> + kfree(tmp);
>> +
>> + ssleep(10);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +int dlpar_queued_actions_run(void)
>> +{
>> + if (!list_empty(&dlpar_delayed_list)) {
>> + struct pseries_hp_errorlog hp_errlog;
>> +
>> + hp_errlog.resource = PSERIES_HP_ELOG_RESOURCE_PMT;
>> + hp_errlog.action = 0;
>> + hp_errlog.id_type = 0;
>> +
>> + queue_hotplug_event(&hp_errlog, 0, 0); > + }
>> + return 0;
>> +}
>
> I'm a bit confused by this. Is there a reason this needs to queue a
> hotplug event instead of just walking the list as is done in dlpar_pmt?
Up to this point, the operations have only been added to 'dlpar_delayed_list'.
This function separates the execution of the CPU readd and Memory readd
operations from the execution of 'migration store'. If we walk the list
here, then we add the execution time of all of the readd operations to
the time of 'migration store'. This is not a large problem in small
systems like we have in the Kernel Team. This may be a major issue though,
for production SAP HANA systems where we may be readding thousands of pages
of memory. By pushing the execution of the CPU readd and Memory readd
operations after, and separate, from the execution of 'migration store',
we do not delay the end of the operation or the return of the completion
status to an associated HMC.
>
> -Nathan
Michael
>
>> +
>> static int dlpar_parse_resource(char **cmd, struct pseries_hp_errorlog *hp_elog)
>> {
>> char *arg;
>> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
>> index f6364d9..d0d1cae 100644
>> --- a/arch/powerpc/platforms/pseries/mobility.c
>> +++ b/arch/powerpc/platforms/pseries/mobility.c
>> @@ -378,6 +378,10 @@ static ssize_t migration_store(struct class *class,
>> return rc;
>>
>> post_mobility_fixup();
>> +
>> + /* Apply any necessary changes identified during fixup */
>> + dlpar_queued_actions_run();
>> +
>> return count;
>> }
>>
>> diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
>> index 60db2ee..72ca996 100644
>> --- a/arch/powerpc/platforms/pseries/pseries.h
>> +++ b/arch/powerpc/platforms/pseries/pseries.h
>> @@ -61,6 +61,8 @@ extern struct device_node *dlpar_configure_connector(__be32,
>>
>> void queue_hotplug_event(struct pseries_hp_errorlog *hp_errlog,
>> struct completion *hotplug_done, int *rc);
>> +int dlpar_queue_action(int resource, int action, u32 drc_index);
>> +int dlpar_queued_actions_run(void);
>> #ifdef CONFIG_MEMORY_HOTPLUG
>> int dlpar_memory(struct pseries_hp_errorlog *hp_elog);
>> #else
>>
>
>
--
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
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