[PATCH v3 7/12] Use stop machine to update cpu maps
Benjamin Herrenschmidt
benh at kernel.crashing.org
Tue Apr 23 10:24:48 EST 2013
On Mon, 2013-04-22 at 13:41 -0500, Nathan Fontenot wrote:
> From: Jesse Larrew <jlarrew at linux.vnet.ibm.com>
>
> Platform events such as partition migration or the new PRRN firmware
> feature can cause the NUMA characteristics of a CPU to change, and these
> changes will be reflected in the device tree nodes for the affected
> CPUs.
>
> This patch registers a handler for Open Firmware device tree updates
> and reconfigures the CPU and node maps whenever the associativity
> changes. Currently, this is accomplished by marking the affected CPUs in
> the cpu_associativity_changes_mask and allowing
> arch_update_cpu_topology() to retrieve the new associativity information
> using hcall_vphn().
>
> Protecting the NUMA cpu maps from concurrent access during an update
> operation will be addressed in a subsequent patch in this series.
I see no more mention of stop_machine() ... is the patch subject stale ?
Cheers,
Ben.
> Signed-off-by: Nathan Fontenot <nfont at linux.vnet.ibm.com>
> ---
>
> arch/powerpc/include/asm/firmware.h | 3
> arch/powerpc/include/asm/prom.h | 1
> arch/powerpc/mm/numa.c | 99 ++++++++++++++++++++++--------
> arch/powerpc/platforms/pseries/firmware.c | 1
> 4 files changed, 79 insertions(+), 25 deletions(-)
>
> Index: powerpc/arch/powerpc/include/asm/prom.h
> ===================================================================
> --- powerpc.orig/arch/powerpc/include/asm/prom.h 2013-04-15 14:03:52.000000000 -0500
> +++ powerpc/arch/powerpc/include/asm/prom.h 2013-04-15 14:04:47.000000000 -0500
> @@ -128,6 +128,7 @@
> #define OV5_CMO 0x0480 /* Cooperative Memory Overcommitment */
> #define OV5_XCMO 0x0440 /* Page Coalescing */
> #define OV5_TYPE1_AFFINITY 0x0580 /* Type 1 NUMA affinity */
> +#define OV5_PRRN 0x0540 /* Platform Resource Reassignment */
> #define OV5_PFO_HW_RNG 0x0E80 /* PFO Random Number Generator */
> #define OV5_PFO_HW_842 0x0E40 /* PFO Compression Accelerator */
> #define OV5_PFO_HW_ENCR 0x0E20 /* PFO Encryption Accelerator */
> Index: powerpc/arch/powerpc/mm/numa.c
> ===================================================================
> --- powerpc.orig/arch/powerpc/mm/numa.c 2013-04-15 14:04:46.000000000 -0500
> +++ powerpc/arch/powerpc/mm/numa.c 2013-04-15 14:06:20.000000000 -0500
> @@ -1257,7 +1257,8 @@
> static u8 vphn_cpu_change_counts[NR_CPUS][MAX_DISTANCE_REF_POINTS];
> static cpumask_t cpu_associativity_changes_mask;
> static int vphn_enabled;
> -static void set_topology_timer(void);
> +static int prrn_enabled;
> +static void reset_topology_timer(void);
>
> /*
> * Store the current values of the associativity change counters in the
> @@ -1293,11 +1294,9 @@
> */
> static int update_cpu_associativity_changes_mask(void)
> {
> - int cpu, nr_cpus = 0;
> + int cpu;
> cpumask_t *changes = &cpu_associativity_changes_mask;
>
> - cpumask_clear(changes);
> -
> for_each_possible_cpu(cpu) {
> int i, changed = 0;
> u8 *counts = vphn_cpu_change_counts[cpu];
> @@ -1311,11 +1310,10 @@
> }
> if (changed) {
> cpumask_set_cpu(cpu, changes);
> - nr_cpus++;
> }
> }
>
> - return nr_cpus;
> + return cpumask_weight(changes);
> }
>
> /*
> @@ -1416,7 +1414,7 @@
> unsigned int associativity[VPHN_ASSOC_BUFSIZE] = {0};
> struct device *dev;
>
> - for_each_cpu(cpu,&cpu_associativity_changes_mask) {
> + for_each_cpu(cpu, &cpu_associativity_changes_mask) {
> vphn_get_associativity(cpu, associativity);
> nid = associativity_to_nid(associativity);
>
> @@ -1438,6 +1436,7 @@
> dev = get_cpu_device(cpu);
> if (dev)
> kobject_uevent(&dev->kobj, KOBJ_CHANGE);
> + cpumask_clear_cpu(cpu, &cpu_associativity_changes_mask);
> changed = 1;
> }
>
> @@ -1457,37 +1456,80 @@
>
> static void topology_timer_fn(unsigned long ignored)
> {
> - if (!vphn_enabled)
> - return;
> - if (update_cpu_associativity_changes_mask() > 0)
> + if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))
> topology_schedule_update();
> - set_topology_timer();
> + else if (vphn_enabled) {
> + if (update_cpu_associativity_changes_mask() > 0)
> + topology_schedule_update();
> + reset_topology_timer();
> + }
> }
> static struct timer_list topology_timer =
> TIMER_INITIALIZER(topology_timer_fn, 0, 0);
>
> -static void set_topology_timer(void)
> +static void reset_topology_timer(void)
> {
> topology_timer.data = 0;
> topology_timer.expires = jiffies + 60 * HZ;
> - add_timer(&topology_timer);
> + mod_timer(&topology_timer, topology_timer.expires);
> +}
> +
> +static void stage_topology_update(int core_id)
> +{
> + cpumask_or(&cpu_associativity_changes_mask,
> + &cpu_associativity_changes_mask, cpu_sibling_mask(core_id));
> + reset_topology_timer();
> }
>
> +static int dt_update_callback(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct of_prop_reconfig *update;
> + int rc = NOTIFY_DONE;
> +
> + switch (action) {
> + case OF_RECONFIG_ADD_PROPERTY:
> + case OF_RECONFIG_UPDATE_PROPERTY:
> + update = (struct of_prop_reconfig *)data;
> + if (!of_prop_cmp(update->dn->type, "cpu")) {
> + u32 core_id;
> + of_property_read_u32(update->dn, "reg", &core_id);
> + stage_topology_update(core_id);
> + rc = NOTIFY_OK;
> + }
> + break;
> + }
> +
> + return rc;
> +}
> +
> +static struct notifier_block dt_update_nb = {
> + .notifier_call = dt_update_callback,
> +};
> +
> /*
> - * Start polling for VPHN associativity changes.
> + * Start polling for associativity changes.
> */
> int start_topology_update(void)
> {
> int rc = 0;
>
> - /* Disabled until races with load balancing are fixed */
> - if (0 && firmware_has_feature(FW_FEATURE_VPHN) &&
> - get_lppaca()->shared_proc) {
> - vphn_enabled = 1;
> - setup_cpu_associativity_change_counters();
> - init_timer_deferrable(&topology_timer);
> - set_topology_timer();
> - rc = 1;
> + if (firmware_has_feature(FW_FEATURE_PRRN)) {
> + if (!prrn_enabled) {
> + prrn_enabled = 1;
> + vphn_enabled = 0;
> + rc = of_reconfig_notifier_register(&dt_update_nb);
> + }
> + } else if (0 && firmware_has_feature(FW_FEATURE_VPHN) &&
> + get_lppaca()->shared_proc) {
> + /* Disabled until races with load balancing are fixed */
> + if (!vphn_enabled) {
> + prrn_enabled = 0;
> + vphn_enabled = 1;
> + setup_cpu_associativity_change_counters();
> + init_timer_deferrable(&topology_timer);
> + reset_topology_timer();
> + }
> }
>
> return rc;
> @@ -1499,7 +1541,16 @@
> */
> int stop_topology_update(void)
> {
> - vphn_enabled = 0;
> - return del_timer_sync(&topology_timer);
> + int rc = 0;
> +
> + if (prrn_enabled) {
> + prrn_enabled = 0;
> + rc = of_reconfig_notifier_unregister(&dt_update_nb);
> + } else if (vphn_enabled) {
> + vphn_enabled = 0;
> + rc = del_timer_sync(&topology_timer);
> + }
> +
> + return rc;
> }
> #endif /* CONFIG_PPC_SPLPAR */
> Index: powerpc/arch/powerpc/include/asm/firmware.h
> ===================================================================
> --- powerpc.orig/arch/powerpc/include/asm/firmware.h 2013-04-15 14:03:52.000000000 -0500
> +++ powerpc/arch/powerpc/include/asm/firmware.h 2013-04-15 14:04:47.000000000 -0500
> @@ -52,6 +52,7 @@
> #define FW_FEATURE_SET_MODE ASM_CONST(0x0000000040000000)
> #define FW_FEATURE_BEST_ENERGY ASM_CONST(0x0000000080000000)
> #define FW_FEATURE_TYPE1_AFFINITY ASM_CONST(0x0000000100000000)
> +#define FW_FEATURE_PRRN ASM_CONST(0x0000000200000000)
>
> #ifndef __ASSEMBLY__
>
> @@ -67,7 +68,7 @@
> FW_FEATURE_MULTITCE | FW_FEATURE_SPLPAR | FW_FEATURE_LPAR |
> FW_FEATURE_CMO | FW_FEATURE_VPHN | FW_FEATURE_XCMO |
> FW_FEATURE_SET_MODE | FW_FEATURE_BEST_ENERGY |
> - FW_FEATURE_TYPE1_AFFINITY,
> + FW_FEATURE_TYPE1_AFFINITY | FW_FEATURE_PRRN,
> FW_FEATURE_PSERIES_ALWAYS = 0,
> FW_FEATURE_POWERNV_POSSIBLE = FW_FEATURE_OPAL | FW_FEATURE_OPALv2,
> FW_FEATURE_POWERNV_ALWAYS = 0,
> Index: powerpc/arch/powerpc/platforms/pseries/firmware.c
> ===================================================================
> --- powerpc.orig/arch/powerpc/platforms/pseries/firmware.c 2013-04-15 14:03:52.000000000 -0500
> +++ powerpc/arch/powerpc/platforms/pseries/firmware.c 2013-04-15 14:04:47.000000000 -0500
> @@ -113,6 +113,7 @@
> static __initdata struct vec5_fw_feature
> vec5_fw_features_table[FIRMWARE_MAX_FEATURES] = {
> {FW_FEATURE_TYPE1_AFFINITY, OV5_TYPE1_AFFINITY},
> + {FW_FEATURE_PRRN, OV5_PRRN},
> };
>
> void __init fw_vec5_feature_init(const char *vec5, unsigned long len)
>
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