[RFC v4 3/4] hotplug/drcinfo: Fix hot-add CPU issues
Michael Bringmann
mwb at linux.vnet.ibm.com
Wed May 23 11:14:45 AEST 2018
See below.
On 05/22/2018 04:31 PM, Nathan Fontenot wrote:
> On 05/22/2018 11:37 AM, Michael Bringmann wrote:
>> This patch applies a common parse function for the ibm,drc-info
>> property that can be modified by a callback function to the
>> hot-add CPU code. Candidate code is replaced by a call to the
>> parser including a pointer to a local context-specific functions,
>> and local data.
>>
>> In addition, a bug in the release of the previous patch set may
>> break things in some of the CPU DLPAR operations. For instance,
>> when attempting to hot-add a new CPU or set of CPUs, the original
>> patch failed to always properly calculate the available resources,
>> and aborted the operation.
>>
>> Signed-off-by: Michael Bringmann <mwb at linux.vnet.ibm.com>
>> Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmwar
>> e feature" -- end of patch series applied to powerpc next)
>> ---
>> Changes in V4:
>> -- Update code to account for latest kernel checkins.
>> -- Rebased to 4.17-rc5 kernel
>> -- Compress some more code
>> ---
>> arch/powerpc/platforms/pseries/hotplug-cpu.c | 118 +++++++++++++++++------
>> arch/powerpc/platforms/pseries/pseries_energy.c | 107 +++++++++++----------
>> 2 files changed, 141 insertions(+), 84 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> index 6ef77ca..ceacad9 100644
>> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> @@ -411,27 +411,63 @@ static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index)
>> return found;
>> }
>>
>> -static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
>> +static bool check_cpu_drc_index(struct device_node *parent,
>> + int (*cb)(struct of_drc_info *drc,
>> + void *data, void *not_used,
>> + int *ret_code),
>> + void *cdata)
>> {
>> bool found = false;
>> - int rc, index;
>>
>> - index = 0;
>> - while (!found) {
>> - u32 drc;
>> + if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
>> + if (drc_info_parser(parent, cb, "CPU", cdata))
>> + found = true;
>> + } else {
>> + int index = 0;
>>
>> - rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
>> - index++, &drc);
>> - if (rc)
>> - break;
>> + while (!found) {
>> + u32 drc;
>>
>> - if (drc == drc_index)
>> - found = true;
>> + if (of_property_read_u32_index(parent,
>> + "ibm,drc-indexes",
>> + index++, &drc))
>> + break;
>> + if (cb(NULL, cdata, &drc, NULL))
>> + found = true;
>> + }
>> }
>>
>> return found;
>> }
>>
>> +struct valid_drc_index_struct {
>> + u32 targ_drc_index;
>> +};
>
> Can you help me understand the need to encapsulate the drc_index as a struct.
At this point, it is consistency of use across all of the instances
of using 'walk_drc_info'. I believe that there were more values in
the structure earlier on.
>
>> +
>> +static int valid_drc_index_cb(struct of_drc_info *drc, void *idata,
>> + void *drc_index, int *ret_code)
>> +{
>> + struct valid_drc_index_struct *cdata = idata;
>> +
>> + if (drc) {
>> + if (!((drc->drc_index_start <= cdata->targ_drc_index) &&
>> + (cdata->targ_drc_index <= drc->last_drc_index)))
>> + return 0;
>> + } else {
>> + if (*((u32 *)drc_index) != cdata->targ_drc_index)
>> + return 0;
>> + }
>> + (*ret_code) = 1;
>> + return 1;
>> +}
>> +
>> +static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
>> +{
>> + struct valid_drc_index_struct cdata = { drc_index };
>> +
>> + return check_cpu_drc_index(parent, valid_drc_index_cb, &cdata);
>> +}
>> +
>> static ssize_t dlpar_cpu_add(u32 drc_index)
>> {
>> struct device_node *dn, *parent;
>> @@ -721,11 +757,43 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
>> return rc;
>> }
>>
>> +struct cpus_to_add_struct {
>> + struct device_node *parent;
>> + u32 *cpu_drcs;
>> + u32 cpus_to_add;
>> + u32 cpus_found;
>> +};
>> +
>> +static int cpus_to_add_cb(struct of_drc_info *drc, void *idata,
>> + void *drc_index, int *ret_code)
>> +{
>> + struct cpus_to_add_struct *cdata = idata;
>> +
>> + if (drc) {
>> + int k;
>> +
>> + for (k = 0; (k < drc->num_sequential_elems) &&
>> + (cdata->cpus_found < cdata->cpus_to_add); k++) {
>> + u32 idrc = drc->drc_index_start +
>> + (k * drc->sequential_inc);
>> +
>> + if (dlpar_cpu_exists(cdata->parent, idrc))
>> + continue;
>> + cdata->cpu_drcs[cdata->cpus_found++] = idrc;
>> + }
>> + } else {
>> + if (!dlpar_cpu_exists(cdata->parent, *((u32 *)drc_index)))
>> + cdata->cpu_drcs[cdata->cpus_found++] =
>> + *((u32 *)drc_index);
>> + }
>> + return 0;
>> +}
>> +
>> static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
>> {
>> struct device_node *parent;
>> - int cpus_found = 0;
>> - int index, rc;
>> + struct cpus_to_add_struct cdata = {
>> + NULL, cpu_drcs, cpus_to_add, 0 };
>>
>> parent = of_find_node_by_path("/cpus");
>> if (!parent) {
>> @@ -734,28 +802,14 @@ static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
>> return -1;
>> }
>>
>> - /* Search the ibm,drc-indexes array for possible CPU drcs to
>> - * add. Note that the format of the ibm,drc-indexes array is
>> - * the number of entries in the array followed by the array
>> - * of drc values so we start looking at index = 1.
>> + /* Search the appropriate property for possible CPU drcs to
>> + * add.
>> */
>> - index = 1;
>> - while (cpus_found < cpus_to_add) {
>> - u32 drc;
>> -
>> - rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
>> - index++, &drc);
>> - if (rc)
>> - break;
>> -
>> - if (dlpar_cpu_exists(parent, drc))
>> - continue;
>> -
>> - cpu_drcs[cpus_found++] = drc;
>> - }
>> + cdata.parent = parent;
>> + check_cpu_drc_index(parent, cpus_to_add_cb, &cdata);
>>
>> of_node_put(parent);
>> - return cpus_found;
>> + return cdata.cpus_found;
>> }
>>
>> static int dlpar_cpu_add_by_count(u32 cpus_to_add)
>> diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
>> index 5261975..d8d7750 100644
>> --- a/arch/powerpc/platforms/pseries/pseries_energy.c
>> +++ b/arch/powerpc/platforms/pseries/pseries_energy.c
>> @@ -36,6 +36,26 @@
>>
>> /* Helper Routines to convert between drc_index to cpu numbers */
>>
>> +struct cpu_to_drc_index_struct {
>> + u32 thread_index;
>> + u32 ret;
>> +};
>> +
>> +static int cpu_to_drc_index_cb(struct of_drc_info *drc, void *idata,
>> + void *not_used, int *ret_code)
>> +{
>> + struct cpu_to_drc_index_struct *cdata = idata;
>> + int ret = 0;
>> +
>> + if (cdata->thread_index < drc->last_drc_index) {
>
> Is this correct? You're comparing a thread index to a drc index.
I believe so. I will check when I retest this week, hopefully.
>
>> + cdata->ret = drc->drc_index_start +
>> + (cdata->thread_index * drc->sequential_inc);
>> + ret = 1;
>> + }
>> + (*ret_code) = ret;
>> + return ret;
>> +}
>> +
>> static u32 cpu_to_drc_index(int cpu)
>> {
>> struct device_node *dn = NULL;
>> @@ -51,30 +71,14 @@ static u32 cpu_to_drc_index(int cpu)
>> thread_index = cpu_core_index_of_thread(cpu);
>>
>> if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
>> - struct property *info = NULL;
>> - struct of_drc_info drc;
>> - int j;
>> - u32 num_set_entries;
>> - const __be32 *value;
>> -
>> - info = of_find_property(dn, "ibm,drc-info", NULL);
>> - if (info == NULL)
>> - goto err_of_node_put;
>> + struct cpu_to_drc_index_struct cdata = {
>> + thread_index, 0 };
>>
>> - value = info->value;
>> - num_set_entries = of_read_number(value++, 1);
>> -
>> - for (j = 0; j < num_set_entries; j++) {
>> -
>> - of_read_drc_info_cell(&info, &value, &drc);
>> - if (strncmp(drc.drc_type, "CPU", 3))
>> - goto err;
>> -
>> - if (thread_index < drc.last_drc_index)
>> - break;
>> - }
>> -
>> - ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
>> + rc = drc_info_parser(dn, &cpu_to_drc_index_cb,
>> + "CPU", &cdata);
>> + if (rc < 0)
>> + goto err_of_node_put;
>> + ret = cdata.ret;
>> } else {
>> const __be32 *indexes;
>>
>> @@ -100,11 +104,33 @@ static u32 cpu_to_drc_index(int cpu)
>> return ret;
>> }
>>
>> +struct drc_index_to_cpu_struct {
>> + u32 drc_index;
>> + u32 thread_index;
>> + u32 cpu;
>> +};
>> +
>> +static int drc_index_to_cpu_cb(struct of_drc_info *drc,
>> + void *idata, void *not_used, int *ret_code)
>> +{
>> + struct drc_index_to_cpu_struct *cdata = idata;
>> +
>> + if (cdata->drc_index > drc->last_drc_index) {
>> + cdata->cpu += drc->num_sequential_elems;
>> + } else {
>> + cdata->cpu += ((cdata->drc_index - drc->drc_index_start) /
>> + drc->sequential_inc);
>> + cdata->thread_index = cpu_first_thread_of_core(cdata->cpu);
>
> Should this return 1 here to avoid continuing to walk the drc_info entries?
Yes.
>
> -Nathan
Michael
>
>> + }
>> + (*ret_code) = 0;
>> + return 0;
>> +}
>> +
>> static int drc_index_to_cpu(u32 drc_index)
>> {
>> struct device_node *dn = NULL;
>> const int *indexes;
>> - int thread_index = 0, cpu = 0;
>> + int thread_index = 0;
>> int rc = 1;
>>
>> dn = of_find_node_by_path("/cpus");
>> @@ -112,36 +138,13 @@ static int drc_index_to_cpu(u32 drc_index)
>> goto err;
>>
>> if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
>> - struct property *info = NULL;
>> - struct of_drc_info drc;
>> - int j;
>> - u32 num_set_entries;
>> - const __be32 *value;
>> -
>> - info = of_find_property(dn, "ibm,drc-info", NULL);
>> - if (info == NULL)
>> - goto err_of_node_put;
>> -
>> - value = info->value;
>> - num_set_entries = of_read_number(value++, 1);
>> -
>> - for (j = 0; j < num_set_entries; j++) {
>> + struct drc_index_to_cpu_struct cdata = {
>> + drc_index, 0, 0 };
>>
>> - of_read_drc_info_cell(&info, &value, &drc);
>> - if (strncmp(drc.drc_type, "CPU", 3))
>> - goto err;
>> + rc = drc_info_parser(dn, &drc_index_to_cpu_cb,
>> + "CPU", &cdata);
>> + thread_index = cdata.thread_index;
>>
>> - if (drc_index > drc.last_drc_index) {
>> - cpu += drc.num_sequential_elems;
>> - continue;
>> - }
>> - cpu += ((drc_index - drc.drc_index_start) /
>> - drc.sequential_inc);
>> -
>> - thread_index = cpu_first_thread_of_core(cpu);
>> - rc = 0;
>> - break;
>> - }
>> } else {
>> unsigned long int i;
>>
>
>
--
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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