[PATCH/RFC 5/5] [PATCH] topology: add z196 cpu topology support

Heiko Carstens
2010-08-12T17:24:54Z

[-- Attachment #1: 05-topology-z196.diff --]
[-- Type: text/plain, Size: 9114 bytes --]

From: Heiko Carstens <heiko.carstens@de.ibm.com>

Use the extended cpu topology information that z196 machines provide
in order to make use of the new book scheduling domain.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
---

arch/s390/Kconfig | 7 +
arch/s390/include/asm/topology.h | 28 ++++++-
arch/s390/kernel/topology.c | 150 ++++++++++++++++++++++++---------------
3 files changed, 124 insertions(+), 61 deletions(-)

diff -urpN linux-2.6/arch/s390/include/asm/topology.h linux-2.6-patched/arch/s390/include/asm/topology.h
--- linux-2.6/arch/s390/include/asm/topology.h 2010-08-11 13:47:13.000000000 +0200
+++ linux-2.6-patched/arch/s390/include/asm/topology.h 2010-08-11 13:47:24.000000000 +0200
@@ -3,15 +3,33 @@

#include <linux/cpumask.h>

-#define mc_capable() (1)
-
-const struct cpumask *cpu_coregroup_mask(unsigned int cpu);
-
extern unsigned char cpu_core_id[NR_CPUS];
extern cpumask_t cpu_core_map[NR_CPUS];

+static inline const struct cpumask *cpu_coregroup_mask(unsigned int cpu)
+{
+ return &cpu_core_map[cpu];
+}
+
#define topology_core_id(cpu) (cpu_core_id[cpu])
#define topology_core_cpumask(cpu) (&cpu_core_map[cpu])
+#define mc_capable() (1)
+
+#ifdef CONFIG_SCHED_BOOK
+
+extern unsigned char cpu_book_id[NR_CPUS];
+extern cpumask_t cpu_book_map[NR_CPUS];
+
+static inline const struct cpumask *cpu_book_mask(unsigned int cpu)
+{
+ return &cpu_book_map[cpu];
+}
+
+#define topology_book_id(cpu) (cpu_book_id[cpu])
+#define topology_book_cpumask(cpu) (&cpu_book_map[cpu])
+#define book_capable() (1)
+
+#endif /* CONFIG_SCHED_BOOK */

int topology_set_cpu_management(int fc);
void topology_schedule_update(void);
@@ -30,6 +48,8 @@ static inline void s390_init_cpu_topolog
};
#endif

+#define SD_BOOK_INIT SD_CPU_INIT
+
#include <asm-generic/topology.h>

#endif /* _ASM_S390_TOPOLOGY_H */
diff -urpN linux-2.6/arch/s390/Kconfig linux-2.6-patched/arch/s390/Kconfig
--- linux-2.6/arch/s390/Kconfig 2010-08-11 13:47:13.000000000 +0200
+++ linux-2.6-patched/arch/s390/Kconfig 2010-08-11 13:47:24.000000000 +0200
@@ -198,6 +198,13 @@ config HOTPLUG_CPU
can be controlled through /sys/devices/system/cpu/cpu#.
Say N if you want to disable CPU hotplug.

+config SCHED_BOOK
+ bool "Book scheduler support"
+ depends on SMP
+ help
+ Book scheduler support improves the CPU scheduler's decision making
+ when dealing with machines that have several books.
+
config MATHEMU
bool "IEEE FPU emulation"
depends on MARCH_G5
diff -urpN linux-2.6/arch/s390/kernel/topology.c linux-2.6-patched/arch/s390/kernel/topology.c
--- linux-2.6/arch/s390/kernel/topology.c 2010-08-02 00:11:14.000000000 +0200
+++ linux-2.6-patched/arch/s390/kernel/topology.c 2010-08-11 13:47:24.000000000 +0200
@@ -57,8 +57,8 @@ struct tl_info {
union tl_entry tle[0];
};

-struct core_info {
- struct core_info *next;
+struct mask_info {
+ struct mask_info *next;
unsigned char id;
cpumask_t mask;
};
@@ -66,7 +66,6 @@ struct core_info {
static int topology_enabled;
static void topology_work_fn(struct work_struct *work);
static struct tl_info *tl_info;
-static struct core_info core_info;
static int machine_has_topology;
static struct timer_list topology_timer;
static void set_topology_timer(void);
@@ -74,38 +73,37 @@ static DECLARE_WORK(topology_work, topol
/* topology_lock protects the core linked list */
static DEFINE_SPINLOCK(topology_lock);

+static struct mask_info core_info;
cpumask_t cpu_core_map[NR_CPUS];
unsigned char cpu_core_id[NR_CPUS];

-static cpumask_t cpu_coregroup_map(unsigned int cpu)
+#ifdef CONFIG_SCHED_BOOK
+static struct mask_info book_info;
+cpumask_t cpu_book_map[NR_CPUS];
+unsigned char cpu_book_id[NR_CPUS];
+#endif
+
+static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
{
- struct core_info *core = &core_info;
- unsigned long flags;
cpumask_t mask;

cpus_clear(mask);
if (!topology_enabled || !machine_has_topology)
return cpu_possible_map;
- spin_lock_irqsave(&topology_lock, flags);
- while (core) {
- if (cpu_isset(cpu, core->mask)) {
- mask = core->mask;
+ while (info) {
+ if (cpu_isset(cpu, info->mask)) {
+ mask = info->mask;
break;
}
- core = core->next;
+ info = info->next;
}
- spin_unlock_irqrestore(&topology_lock, flags);
if (cpus_empty(mask))
mask = cpumask_of_cpu(cpu);
return mask;
}

-const struct cpumask *cpu_coregroup_mask(unsigned int cpu)
-{
- return &cpu_core_map[cpu];
-}
-
-static void add_cpus_to_core(struct tl_cpu *tl_cpu, struct core_info *core)
+static void add_cpus_to_mask(struct tl_cpu *tl_cpu, struct mask_info *book,
+ struct mask_info *core)
{
unsigned int cpu;

@@ -117,23 +115,35 @@ static void add_cpus_to_core(struct tl_c

rcpu = CPU_BITS - 1 - cpu + tl_cpu->origin;
for_each_present_cpu(lcpu) {
- if (cpu_logical_map(lcpu) == rcpu) {
- cpu_set(lcpu, core->mask);
- cpu_core_id[lcpu] = core->id;
- smp_cpu_polarization[lcpu] = tl_cpu->pp;
- }
+ if (cpu_logical_map(lcpu) != rcpu)
+ continue;
+#ifdef CONFIG_SCHED_BOOK
+ cpu_set(lcpu, book->mask);
+ cpu_book_id[lcpu] = book->id;
+#endif
+ cpu_set(lcpu, core->mask);
+ cpu_core_id[lcpu] = core->id;
+ smp_cpu_polarization[lcpu] = tl_cpu->pp;
}
}
}

-static void clear_cores(void)
+static void clear_masks(void)
{
- struct core_info *core = &core_info;
+ struct mask_info *info;

- while (core) {
- cpus_clear(core->mask);
- core = core->next;
+ info = &core_info;
+ while (info) {
+ cpus_clear(info->mask);
+ info = info->next;
+ }
+#ifdef CONFIG_SCHED_BOOK
+ info = &book_info;
+ while (info) {
+ cpus_clear(info->mask);
+ info = info->next;
}
+#endif
}

static union tl_entry *next_tle(union tl_entry *tle)
@@ -146,29 +156,36 @@ static union tl_entry *next_tle(union tl

static void tl_to_cores(struct tl_info *info)
{
+#ifdef CONFIG_SCHED_BOOK
+ struct mask_info *book = &book_info;
+#else
+ struct mask_info *book = NULL;
+#endif
+ struct mask_info *core = &core_info;
union tl_entry *tle, *end;
- struct core_info *core = &core_info;
+

spin_lock_irq(&topology_lock);
- clear_cores();
+ clear_masks();
tle = info->tle;
end = (union tl_entry *)((unsigned long)info + info->length);
while (tle < end) {
switch (tle->nl) {
- case 5:
- case 4:
- case 3:
+#ifdef CONFIG_SCHED_BOOK
case 2:
+ book = book->next;
+ book->id = tle->container.id;
break;
+#endif
case 1:
core = core->next;
core->id = tle->container.id;
break;
case 0:
- add_cpus_to_core(&tle->cpu, core);
+ add_cpus_to_mask(&tle->cpu, book, core);
break;
default:
- clear_cores();
+ clear_masks();
machine_has_topology = 0;
goto out;
}
@@ -221,10 +238,29 @@ int topology_set_cpu_management(int fc)

static void update_cpu_core_map(void)
{
+ unsigned long flags;
int cpu;

- for_each_possible_cpu(cpu)
- cpu_core_map[cpu] = cpu_coregroup_map(cpu);
+ spin_lock_irqsave(&topology_lock, flags);
+ for_each_possible_cpu(cpu) {
+ cpu_core_map[cpu] = cpu_group_map(&core_info, cpu);
+#ifdef CONFIG_SCHED_BOOK
+ cpu_book_map[cpu] = cpu_group_map(&book_info, cpu);
+#endif
+ }
+ spin_unlock_irqrestore(&topology_lock, flags);
+}
+
+static void store_topology(struct tl_info *info)
+{
+#ifdef CONFIG_SCHED_BOOK
+ int rc;
+
+ rc = stsi(info, 15, 1, 3);
+ if (rc != -ENOSYS)
+ return;
+#endif
+ stsi(info, 15, 1, 2);
}

int arch_update_cpu_topology(void)
@@ -238,7 +274,7 @@ int arch_update_cpu_topology(void)
topology_update_polarization_simple();
return 0;
}
- stsi(info, 15, 1, 2);
+ store_topology(info);
tl_to_cores(info);
update_cpu_core_map();
for_each_online_cpu(cpu) {
@@ -299,12 +335,24 @@ out:
}
__initcall(init_topology_update);

+static void alloc_masks(struct tl_info *info, struct mask_info *mask, int offset)
+{
+ int i, nr_masks;
+
+ nr_masks = info->mag[NR_MAG - offset];
+ for (i = 0; i < info->mnest - offset; i++)
+ nr_masks *= info->mag[NR_MAG - offset - 1 - i];
+ nr_masks = max(nr_masks, 1);
+ for (i = 0; i < nr_masks; i++) {
+ mask->next = alloc_bootmem(sizeof(struct mask_info));
+ mask = mask->next;
+ }
+}
+
void __init s390_init_cpu_topology(void)
{
unsigned long long facility_bits;
struct tl_info *info;
- struct core_info *core;
- int nr_cores;
int i;

if (stfle(&facility_bits, 1) <= 0)
@@ -315,25 +363,13 @@ void __init s390_init_cpu_topology(void)

tl_info = alloc_bootmem_pages(PAGE_SIZE);
info = tl_info;
- stsi(info, 15, 1, 2);
-
- nr_cores = info->mag[NR_MAG - 2];
- for (i = 0; i < info->mnest - 2; i++)
- nr_cores *= info->mag[NR_MAG - 3 - i];
-
+ store_topology(info);
pr_info("The CPU configuration topology of the machine is:");
for (i = 0; i < NR_MAG; i++)
printk(" %d", info->mag[i]);
printk(" / %d\n", info->mnest);
-
- core = &core_info;
- for (i = 0; i < nr_cores; i++) {
- core->next = alloc_bootmem(sizeof(struct core_info));
- core = core->next;
- if (!core)
- goto error;
- }
- return;
-error:
- machine_has_topology = 0;
+ alloc_masks(info, &core_info, 2);
+#ifdef CONFIG_SCHED_BOOK
+ alloc_masks(info, &book_info, 3);
+#endif
}