[RFC v4 3/4] hotplug/drcinfo: Fix hot-add CPU issues
Nathan Fontenot
nfont at linux.vnet.ibm.com
Wed May 23 07:31:18 AEST 2018
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.
> +
> +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.
> + 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?
-Nathan
> + }
> + (*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;
>
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