![Martin Schwidefsky](/assets/img/avatar_default.png)
The multi-threading facility is introduced with the z13 processor family. This patch adds code to detect the multi-threading facility. With the facility enabled each core will surface multiple hardware threads to the system. Each hardware threads looks like a normal CPU to the operating system with all its registers and properties. The SCLP interface reports the SMT topology indirectly via the maximum thread id. Each reported CPU in the result of a read-scp-information is a core representing a number of hardware threads. To reflect the reduced CPU capacity if two hardware threads run on a single core the MT utilization counter set is used to normalize the raw cputime obtained by the CPU timer deltas. This scaled cputime is reported via the taskstats interface. The normal /proc/stat numbers are based on the raw cputime and are not affected by the normalization. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
508 lines
11 KiB
C
508 lines
11 KiB
C
/*
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* Copyright IBM Corp. 2007, 2011
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* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
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*/
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#define KMSG_COMPONENT "cpu"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/workqueue.h>
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#include <linux/bootmem.h>
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#include <linux/cpuset.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/cpu.h>
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#include <linux/smp.h>
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#include <linux/mm.h>
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#include <asm/sysinfo.h>
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#define PTF_HORIZONTAL (0UL)
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#define PTF_VERTICAL (1UL)
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#define PTF_CHECK (2UL)
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struct mask_info {
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struct mask_info *next;
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unsigned char id;
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cpumask_t mask;
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};
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static void set_topology_timer(void);
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static void topology_work_fn(struct work_struct *work);
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static struct sysinfo_15_1_x *tl_info;
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static int topology_enabled = 1;
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static DECLARE_WORK(topology_work, topology_work_fn);
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/* topology_lock protects the socket and book linked lists */
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static DEFINE_SPINLOCK(topology_lock);
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static struct mask_info socket_info;
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static struct mask_info book_info;
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struct cpu_topology_s390 cpu_topology[NR_CPUS];
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EXPORT_SYMBOL_GPL(cpu_topology);
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static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
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{
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cpumask_t mask;
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cpumask_copy(&mask, cpumask_of(cpu));
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if (!topology_enabled || !MACHINE_HAS_TOPOLOGY)
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return mask;
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for (; info; info = info->next) {
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if (cpumask_test_cpu(cpu, &info->mask))
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return info->mask;
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}
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return mask;
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}
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static cpumask_t cpu_thread_map(unsigned int cpu)
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{
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cpumask_t mask;
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int i;
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cpumask_copy(&mask, cpumask_of(cpu));
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if (!topology_enabled || !MACHINE_HAS_TOPOLOGY)
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return mask;
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cpu -= cpu % (smp_cpu_mtid + 1);
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for (i = 0; i <= smp_cpu_mtid; i++)
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if (cpu_present(cpu + i))
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cpumask_set_cpu(cpu + i, &mask);
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return mask;
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}
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static struct mask_info *add_cpus_to_mask(struct topology_core *tl_core,
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struct mask_info *book,
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struct mask_info *socket,
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int one_socket_per_cpu)
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{
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unsigned int core;
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for_each_set_bit(core, &tl_core->mask[0], TOPOLOGY_CORE_BITS) {
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unsigned int rcore;
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int lcpu, i;
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rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
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lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
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if (lcpu < 0)
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continue;
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for (i = 0; i <= smp_cpu_mtid; i++) {
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cpu_topology[lcpu + i].book_id = book->id;
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cpu_topology[lcpu + i].core_id = rcore;
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cpu_topology[lcpu + i].thread_id = lcpu + i;
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cpumask_set_cpu(lcpu + i, &book->mask);
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cpumask_set_cpu(lcpu + i, &socket->mask);
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if (one_socket_per_cpu)
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cpu_topology[lcpu + i].socket_id = rcore;
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else
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cpu_topology[lcpu + i].socket_id = socket->id;
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smp_cpu_set_polarization(lcpu + i, tl_core->pp);
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}
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if (one_socket_per_cpu)
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socket = socket->next;
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}
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return socket;
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}
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static void clear_masks(void)
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{
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struct mask_info *info;
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info = &socket_info;
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while (info) {
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cpumask_clear(&info->mask);
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info = info->next;
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}
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info = &book_info;
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while (info) {
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cpumask_clear(&info->mask);
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info = info->next;
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}
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}
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static union topology_entry *next_tle(union topology_entry *tle)
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{
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if (!tle->nl)
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return (union topology_entry *)((struct topology_core *)tle + 1);
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return (union topology_entry *)((struct topology_container *)tle + 1);
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}
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static void __tl_to_masks_generic(struct sysinfo_15_1_x *info)
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{
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struct mask_info *socket = &socket_info;
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struct mask_info *book = &book_info;
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union topology_entry *tle, *end;
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tle = info->tle;
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end = (union topology_entry *)((unsigned long)info + info->length);
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while (tle < end) {
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switch (tle->nl) {
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case 2:
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book = book->next;
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book->id = tle->container.id;
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break;
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case 1:
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socket = socket->next;
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socket->id = tle->container.id;
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break;
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case 0:
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add_cpus_to_mask(&tle->cpu, book, socket, 0);
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break;
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default:
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clear_masks();
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return;
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}
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tle = next_tle(tle);
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}
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}
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static void __tl_to_masks_z10(struct sysinfo_15_1_x *info)
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{
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struct mask_info *socket = &socket_info;
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struct mask_info *book = &book_info;
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union topology_entry *tle, *end;
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tle = info->tle;
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end = (union topology_entry *)((unsigned long)info + info->length);
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while (tle < end) {
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switch (tle->nl) {
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case 1:
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book = book->next;
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book->id = tle->container.id;
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break;
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case 0:
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socket = add_cpus_to_mask(&tle->cpu, book, socket, 1);
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break;
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default:
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clear_masks();
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return;
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}
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tle = next_tle(tle);
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}
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}
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static void tl_to_masks(struct sysinfo_15_1_x *info)
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{
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struct cpuid cpu_id;
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spin_lock_irq(&topology_lock);
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get_cpu_id(&cpu_id);
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clear_masks();
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switch (cpu_id.machine) {
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case 0x2097:
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case 0x2098:
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__tl_to_masks_z10(info);
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break;
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default:
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__tl_to_masks_generic(info);
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}
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spin_unlock_irq(&topology_lock);
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}
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static void topology_update_polarization_simple(void)
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{
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int cpu;
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mutex_lock(&smp_cpu_state_mutex);
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for_each_possible_cpu(cpu)
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smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
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mutex_unlock(&smp_cpu_state_mutex);
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}
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static int ptf(unsigned long fc)
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{
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int rc;
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asm volatile(
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" .insn rre,0xb9a20000,%1,%1\n"
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" ipm %0\n"
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" srl %0,28\n"
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: "=d" (rc)
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: "d" (fc) : "cc");
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return rc;
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}
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int topology_set_cpu_management(int fc)
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{
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int cpu, rc;
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if (!MACHINE_HAS_TOPOLOGY)
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return -EOPNOTSUPP;
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if (fc)
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rc = ptf(PTF_VERTICAL);
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else
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rc = ptf(PTF_HORIZONTAL);
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if (rc)
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return -EBUSY;
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for_each_possible_cpu(cpu)
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smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
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return rc;
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}
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static void update_cpu_masks(void)
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{
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unsigned long flags;
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int cpu;
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spin_lock_irqsave(&topology_lock, flags);
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for_each_possible_cpu(cpu) {
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cpu_topology[cpu].thread_mask = cpu_thread_map(cpu);
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cpu_topology[cpu].core_mask = cpu_group_map(&socket_info, cpu);
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cpu_topology[cpu].book_mask = cpu_group_map(&book_info, cpu);
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if (!MACHINE_HAS_TOPOLOGY) {
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cpu_topology[cpu].thread_id = cpu;
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cpu_topology[cpu].core_id = cpu;
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cpu_topology[cpu].socket_id = cpu;
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cpu_topology[cpu].book_id = cpu;
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}
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}
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spin_unlock_irqrestore(&topology_lock, flags);
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}
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void store_topology(struct sysinfo_15_1_x *info)
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{
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if (topology_max_mnest >= 3)
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stsi(info, 15, 1, 3);
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else
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stsi(info, 15, 1, 2);
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}
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int arch_update_cpu_topology(void)
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{
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struct sysinfo_15_1_x *info = tl_info;
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struct device *dev;
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int cpu;
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if (!MACHINE_HAS_TOPOLOGY) {
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update_cpu_masks();
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topology_update_polarization_simple();
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return 0;
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}
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store_topology(info);
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tl_to_masks(info);
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update_cpu_masks();
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for_each_online_cpu(cpu) {
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dev = get_cpu_device(cpu);
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kobject_uevent(&dev->kobj, KOBJ_CHANGE);
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}
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return 1;
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}
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static void topology_work_fn(struct work_struct *work)
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{
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rebuild_sched_domains();
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}
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void topology_schedule_update(void)
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{
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schedule_work(&topology_work);
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}
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static void topology_timer_fn(unsigned long ignored)
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{
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if (ptf(PTF_CHECK))
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topology_schedule_update();
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set_topology_timer();
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}
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static struct timer_list topology_timer =
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TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);
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static atomic_t topology_poll = ATOMIC_INIT(0);
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static void set_topology_timer(void)
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{
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if (atomic_add_unless(&topology_poll, -1, 0))
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mod_timer(&topology_timer, jiffies + HZ / 10);
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else
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mod_timer(&topology_timer, jiffies + HZ * 60);
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}
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void topology_expect_change(void)
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{
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if (!MACHINE_HAS_TOPOLOGY)
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return;
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/* This is racy, but it doesn't matter since it is just a heuristic.
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* Worst case is that we poll in a higher frequency for a bit longer.
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*/
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if (atomic_read(&topology_poll) > 60)
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return;
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atomic_add(60, &topology_poll);
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set_topology_timer();
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}
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static int __init early_parse_topology(char *p)
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{
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if (strncmp(p, "off", 3))
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return 0;
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topology_enabled = 0;
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return 0;
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}
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early_param("topology", early_parse_topology);
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static void __init alloc_masks(struct sysinfo_15_1_x *info,
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struct mask_info *mask, int offset)
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{
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int i, nr_masks;
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nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
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for (i = 0; i < info->mnest - offset; i++)
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nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
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nr_masks = max(nr_masks, 1);
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for (i = 0; i < nr_masks; i++) {
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mask->next = alloc_bootmem_align(
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roundup_pow_of_two(sizeof(struct mask_info)),
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roundup_pow_of_two(sizeof(struct mask_info)));
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mask = mask->next;
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}
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}
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void __init s390_init_cpu_topology(void)
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{
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struct sysinfo_15_1_x *info;
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int i;
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if (!MACHINE_HAS_TOPOLOGY)
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return;
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tl_info = alloc_bootmem_pages(PAGE_SIZE);
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info = tl_info;
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store_topology(info);
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pr_info("The CPU configuration topology of the machine is:");
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for (i = 0; i < TOPOLOGY_NR_MAG; i++)
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printk(KERN_CONT " %d", info->mag[i]);
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printk(KERN_CONT " / %d\n", info->mnest);
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alloc_masks(info, &socket_info, 1);
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alloc_masks(info, &book_info, 2);
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}
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static int cpu_management;
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static ssize_t dispatching_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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ssize_t count;
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mutex_lock(&smp_cpu_state_mutex);
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count = sprintf(buf, "%d\n", cpu_management);
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mutex_unlock(&smp_cpu_state_mutex);
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return count;
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}
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static ssize_t dispatching_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t count)
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{
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int val, rc;
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char delim;
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if (sscanf(buf, "%d %c", &val, &delim) != 1)
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return -EINVAL;
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if (val != 0 && val != 1)
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return -EINVAL;
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rc = 0;
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get_online_cpus();
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mutex_lock(&smp_cpu_state_mutex);
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if (cpu_management == val)
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goto out;
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rc = topology_set_cpu_management(val);
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if (rc)
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goto out;
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cpu_management = val;
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topology_expect_change();
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out:
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mutex_unlock(&smp_cpu_state_mutex);
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put_online_cpus();
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return rc ? rc : count;
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}
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static DEVICE_ATTR(dispatching, 0644, dispatching_show,
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dispatching_store);
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static ssize_t cpu_polarization_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int cpu = dev->id;
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ssize_t count;
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mutex_lock(&smp_cpu_state_mutex);
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switch (smp_cpu_get_polarization(cpu)) {
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case POLARIZATION_HRZ:
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count = sprintf(buf, "horizontal\n");
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break;
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case POLARIZATION_VL:
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count = sprintf(buf, "vertical:low\n");
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break;
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case POLARIZATION_VM:
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count = sprintf(buf, "vertical:medium\n");
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break;
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case POLARIZATION_VH:
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count = sprintf(buf, "vertical:high\n");
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break;
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default:
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count = sprintf(buf, "unknown\n");
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break;
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}
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mutex_unlock(&smp_cpu_state_mutex);
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return count;
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}
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static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
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static struct attribute *topology_cpu_attrs[] = {
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&dev_attr_polarization.attr,
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NULL,
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};
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static struct attribute_group topology_cpu_attr_group = {
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.attrs = topology_cpu_attrs,
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};
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int topology_cpu_init(struct cpu *cpu)
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{
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return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
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}
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const struct cpumask *cpu_thread_mask(int cpu)
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{
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return &cpu_topology[cpu].thread_mask;
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}
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const struct cpumask *cpu_coregroup_mask(int cpu)
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{
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return &cpu_topology[cpu].core_mask;
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}
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static const struct cpumask *cpu_book_mask(int cpu)
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{
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return &cpu_topology[cpu].book_mask;
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}
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static struct sched_domain_topology_level s390_topology[] = {
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{ cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
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{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
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{ cpu_book_mask, SD_INIT_NAME(BOOK) },
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{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
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{ NULL, },
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};
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static int __init topology_init(void)
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{
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if (MACHINE_HAS_TOPOLOGY)
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set_topology_timer();
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else
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topology_update_polarization_simple();
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return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
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}
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device_initcall(topology_init);
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static int __init early_topology_init(void)
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{
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set_sched_topology(s390_topology);
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return 0;
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}
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early_initcall(early_topology_init);
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