Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/* sched.c - SPU scheduler.
 *
 * Copyright (C) IBM 2005
 * Author: Mark Nutter <mnutter@us.ibm.com>
 *
 * 2006-03-31	NUMA domains added.
 */
 
#undef DEBUG
 
#include <linux/errno.h>
#include <linux/sched/signal.h>
#include <linux/sched/loadavg.h>
#include <linux/sched/rt.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/vmalloc.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/numa.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/pid_namespace.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
 
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/spu.h>
#include <asm/spu_csa.h>
#include <asm/spu_priv1.h>
#include "spufs.h"
#define CREATE_TRACE_POINTS
#include "sputrace.h"
 
struct spu_prio_array {
<------>DECLARE_BITMAP(bitmap, MAX_PRIO);
<------>struct list_head runq[MAX_PRIO];
<------>spinlock_t runq_lock;
<------>int nr_waiting;
};
 
static unsigned long spu_avenrun[3];
static struct spu_prio_array *spu_prio;
static struct task_struct *spusched_task;
static struct timer_list spusched_timer;
static struct timer_list spuloadavg_timer;
 
/*
 * Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
 */
#define NORMAL_PRIO		120
 
/*
 * Frequency of the spu scheduler tick.  By default we do one SPU scheduler
 * tick for every 10 CPU scheduler ticks.
 */
#define SPUSCHED_TICK		(10)
 
/*
 * These are the 'tuning knobs' of the scheduler:
 *
 * Minimum timeslice is 5 msecs (or 1 spu scheduler tick, whichever is
 * larger), default timeslice is 100 msecs, maximum timeslice is 800 msecs.
 */
#define MIN_SPU_TIMESLICE	max(5 * HZ / (1000 * SPUSCHED_TICK), 1)
#define DEF_SPU_TIMESLICE	(100 * HZ / (1000 * SPUSCHED_TICK))
 
#define SCALE_PRIO(x, prio) \
<------>max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_SPU_TIMESLICE)
 
/*
 * scale user-nice values [ -20 ... 0 ... 19 ] to time slice values:
 * [800ms ... 100ms ... 5ms]
 *
 * The higher a thread's priority, the bigger timeslices
 * it gets during one round of execution. But even the lowest
 * priority thread gets MIN_TIMESLICE worth of execution time.
 */
void spu_set_timeslice(struct spu_context *ctx)
{
<------>if (ctx->prio < NORMAL_PRIO)
<------><------>ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE * 4, ctx->prio);
<------>else
<------><------>ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE, ctx->prio);
}
 
/*
 * Update scheduling information from the owning thread.
 */
void __spu_update_sched_info(struct spu_context *ctx)
{
<------>/*
<------> * assert that the context is not on the runqueue, so it is safe
<------> * to change its scheduling parameters.
<------> */
<------>BUG_ON(!list_empty(&ctx->rq));
 
<------>/*
<------> * 32-Bit assignments are atomic on powerpc, and we don't care about
<------> * memory ordering here because retrieving the controlling thread is
<------> * per definition racy.
<------> */
<------>ctx->tid = current->pid;
 
<------>/*
<------> * We do our own priority calculations, so we normally want
<------> * ->static_prio to start with. Unfortunately this field
<------> * contains junk for threads with a realtime scheduling
<------> * policy so we have to look at ->prio in this case.
<------> */
<------>if (rt_prio(current->prio))
<------><------>ctx->prio = current->prio;
<------>else
<------><------>ctx->prio = current->static_prio;
<------>ctx->policy = current->policy;
 
<------>/*
<------> * TO DO: the context may be loaded, so we may need to activate
<------> * it again on a different node. But it shouldn't hurt anything
<------> * to update its parameters, because we know that the scheduler
<------> * is not actively looking at this field, since it is not on the
<------> * runqueue. The context will be rescheduled on the proper node
<------> * if it is timesliced or preempted.
<------> */
<------>cpumask_copy(&ctx->cpus_allowed, current->cpus_ptr);
 
<------>/* Save the current cpu id for spu interrupt routing. */
<------>ctx->last_ran = raw_smp_processor_id();
}
 
void spu_update_sched_info(struct spu_context *ctx)
{
<------>int node;
 
<------>if (ctx->state == SPU_STATE_RUNNABLE) {
<------><------>node = ctx->spu->node;
 
<------><------>/*
<------><------> * Take list_mutex to sync with find_victim().
<------><------> */
<------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------>__spu_update_sched_info(ctx);
<------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------>} else {
<------><------>__spu_update_sched_info(ctx);
<------>}
}
 
static int __node_allowed(struct spu_context *ctx, int node)
{
<------>if (nr_cpus_node(node)) {
<------><------>const struct cpumask *mask = cpumask_of_node(node);
 
<------><------>if (cpumask_intersects(mask, &ctx->cpus_allowed))
<------><------><------>return 1;
<------>}
 
<------>return 0;
}
 
static int node_allowed(struct spu_context *ctx, int node)
{
<------>int rval;
 
<------>spin_lock(&spu_prio->runq_lock);
<------>rval = __node_allowed(ctx, node);
<------>spin_unlock(&spu_prio->runq_lock);
 
<------>return rval;
}
 
void do_notify_spus_active(void)
{
<------>int node;
 
<------>/*
<------> * Wake up the active spu_contexts.
<------> *
<------> * When the awakened processes see their "notify_active" flag is set,
<------> * they will call spu_switch_notify().
<------> */
<------>for_each_online_node(node) {
<------><------>struct spu *spu;
 
<------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------>list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
<------><------><------>if (spu->alloc_state != SPU_FREE) {
<------><------><------><------>struct spu_context *ctx = spu->ctx;
<------><------><------><------>set_bit(SPU_SCHED_NOTIFY_ACTIVE,
<------><------><------><------><------>&ctx->sched_flags);
<------><------><------><------>mb();
<------><------><------><------>wake_up_all(&ctx->stop_wq);
<------><------><------>}
<------><------>}
<------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------>}
}
 
/**
 * spu_bind_context - bind spu context to physical spu
 * @spu:	physical spu to bind to
 * @ctx:	context to bind
 */
static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
{
<------>spu_context_trace(spu_bind_context__enter, ctx, spu);
 
<------>spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 
<------>if (ctx->flags & SPU_CREATE_NOSCHED)
<------><------>atomic_inc(&cbe_spu_info[spu->node].reserved_spus);
 
<------>ctx->stats.slb_flt_base = spu->stats.slb_flt;
<------>ctx->stats.class2_intr_base = spu->stats.class2_intr;
 
<------>spu_associate_mm(spu, ctx->owner);
 
<------>spin_lock_irq(&spu->register_lock);
<------>spu->ctx = ctx;
<------>spu->flags = 0;
<------>ctx->spu = spu;
<------>ctx->ops = &spu_hw_ops;
<------>spu->pid = current->pid;
<------>spu->tgid = current->tgid;
<------>spu->ibox_callback = spufs_ibox_callback;
<------>spu->wbox_callback = spufs_wbox_callback;
<------>spu->stop_callback = spufs_stop_callback;
<------>spu->mfc_callback = spufs_mfc_callback;
<------>spin_unlock_irq(&spu->register_lock);
 
<------>spu_unmap_mappings(ctx);
 
<------>spu_switch_log_notify(spu, ctx, SWITCH_LOG_START, 0);
<------>spu_restore(&ctx->csa, spu);
<------>spu->timestamp = jiffies;
<------>spu_switch_notify(spu, ctx);
<------>ctx->state = SPU_STATE_RUNNABLE;
 
<------>spuctx_switch_state(ctx, SPU_UTIL_USER);
}
 
/*
 * Must be used with the list_mutex held.
 */
static inline int sched_spu(struct spu *spu)
{
<------>BUG_ON(!mutex_is_locked(&cbe_spu_info[spu->node].list_mutex));
 
<------>return (!spu->ctx || !(spu->ctx->flags & SPU_CREATE_NOSCHED));
}
 
static void aff_merge_remaining_ctxs(struct spu_gang *gang)
{
<------>struct spu_context *ctx;
 
<------>list_for_each_entry(ctx, &gang->aff_list_head, aff_list) {
<------><------>if (list_empty(&ctx->aff_list))
<------><------><------>list_add(&ctx->aff_list, &gang->aff_list_head);
<------>}
<------>gang->aff_flags |= AFF_MERGED;
}
 
static void aff_set_offsets(struct spu_gang *gang)
{
<------>struct spu_context *ctx;
<------>int offset;
 
<------>offset = -1;
<------>list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
<------><------><------><------><------><------><------><------>aff_list) {
<------><------>if (&ctx->aff_list == &gang->aff_list_head)
<------><------><------>break;
<------><------>ctx->aff_offset = offset--;
<------>}
 
<------>offset = 0;
<------>list_for_each_entry(ctx, gang->aff_ref_ctx->aff_list.prev, aff_list) {
<------><------>if (&ctx->aff_list == &gang->aff_list_head)
<------><------><------>break;
<------><------>ctx->aff_offset = offset++;
<------>}
 
<------>gang->aff_flags |= AFF_OFFSETS_SET;
}
 
static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
<------><------> int group_size, int lowest_offset)
{
<------>struct spu *spu;
<------>int node, n;
 
<------>/*
<------> * TODO: A better algorithm could be used to find a good spu to be
<------> *       used as reference location for the ctxs chain.
<------> */
<------>node = cpu_to_node(raw_smp_processor_id());
<------>for (n = 0; n < MAX_NUMNODES; n++, node++) {
<------><------>/*
<------><------> * "available_spus" counts how many spus are not potentially
<------><------> * going to be used by other affinity gangs whose reference
<------><------> * context is already in place. Although this code seeks to
<------><------> * avoid having affinity gangs with a summed amount of
<------><------> * contexts bigger than the amount of spus in the node,
<------><------> * this may happen sporadically. In this case, available_spus
<------><------> * becomes negative, which is harmless.
<------><------> */
<------><------>int available_spus;
 
<------><------>node = (node < MAX_NUMNODES) ? node : 0;
<------><------>if (!node_allowed(ctx, node))
<------><------><------>continue;
 
<------><------>available_spus = 0;
<------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------>list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
<------><------><------>if (spu->ctx && spu->ctx->gang && !spu->ctx->aff_offset
<------><------><------><------><------>&& spu->ctx->gang->aff_ref_spu)
<------><------><------><------>available_spus -= spu->ctx->gang->contexts;
<------><------><------>available_spus++;
<------><------>}
<------><------>if (available_spus < ctx->gang->contexts) {
<------><------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------><------><------>continue;
<------><------>}
 
<------><------>list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
<------><------><------>if ((!mem_aff || spu->has_mem_affinity) &&
<------><------><------><------><------><------><------>sched_spu(spu)) {
<------><------><------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------><------><------><------>return spu;
<------><------><------>}
<------><------>}
<------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------>}
<------>return NULL;
}
 
static void aff_set_ref_point_location(struct spu_gang *gang)
{
<------>int mem_aff, gs, lowest_offset;
<------>struct spu_context *ctx;
<------>struct spu *tmp;
 
<------>mem_aff = gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM;
<------>lowest_offset = 0;
<------>gs = 0;
 
<------>list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
<------><------>gs++;
 
<------>list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
<------><------><------><------><------><------><------><------>aff_list) {
<------><------>if (&ctx->aff_list == &gang->aff_list_head)
<------><------><------>break;
<------><------>lowest_offset = ctx->aff_offset;
<------>}
 
<------>gang->aff_ref_spu = aff_ref_location(gang->aff_ref_ctx, mem_aff, gs,
<------><------><------><------><------><------><------>lowest_offset);
}
 
static struct spu *ctx_location(struct spu *ref, int offset, int node)
{
<------>struct spu *spu;
 
<------>spu = NULL;
<------>if (offset >= 0) {
<------><------>list_for_each_entry(spu, ref->aff_list.prev, aff_list) {
<------><------><------>BUG_ON(spu->node != node);
<------><------><------>if (offset == 0)
<------><------><------><------>break;
<------><------><------>if (sched_spu(spu))
<------><------><------><------>offset--;
<------><------>}
<------>} else {
<------><------>list_for_each_entry_reverse(spu, ref->aff_list.next, aff_list) {
<------><------><------>BUG_ON(spu->node != node);
<------><------><------>if (offset == 0)
<------><------><------><------>break;
<------><------><------>if (sched_spu(spu))
<------><------><------><------>offset++;
<------><------>}
<------>}
 
<------>return spu;
}
 
/*
 * affinity_check is called each time a context is going to be scheduled.
 * It returns the spu ptr on which the context must run.
 */
static int has_affinity(struct spu_context *ctx)
{
<------>struct spu_gang *gang = ctx->gang;
 
<------>if (list_empty(&ctx->aff_list))
<------><------>return 0;
 
<------>if (atomic_read(&ctx->gang->aff_sched_count) == 0)
<------><------>ctx->gang->aff_ref_spu = NULL;
 
<------>if (!gang->aff_ref_spu) {
<------><------>if (!(gang->aff_flags & AFF_MERGED))
<------><------><------>aff_merge_remaining_ctxs(gang);
<------><------>if (!(gang->aff_flags & AFF_OFFSETS_SET))
<------><------><------>aff_set_offsets(gang);
<------><------>aff_set_ref_point_location(gang);
<------>}
 
<------>return gang->aff_ref_spu != NULL;
}
 
/**
 * spu_unbind_context - unbind spu context from physical spu
 * @spu:	physical spu to unbind from
 * @ctx:	context to unbind
 */
static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
{
<------>u32 status;
 
<------>spu_context_trace(spu_unbind_context__enter, ctx, spu);
 
<------>spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 
 	if (spu->ctx->flags & SPU_CREATE_NOSCHED)
<------><------>atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
 
<------>if (ctx->gang)
<------><------>/*
<------><------> * If ctx->gang->aff_sched_count is positive, SPU affinity is
<------><------> * being considered in this gang. Using atomic_dec_if_positive
<------><------> * allow us to skip an explicit check for affinity in this gang
<------><------> */
<------><------>atomic_dec_if_positive(&ctx->gang->aff_sched_count);
 
<------>spu_switch_notify(spu, NULL);
<------>spu_unmap_mappings(ctx);
<------>spu_save(&ctx->csa, spu);
<------>spu_switch_log_notify(spu, ctx, SWITCH_LOG_STOP, 0);
 
<------>spin_lock_irq(&spu->register_lock);
<------>spu->timestamp = jiffies;
<------>ctx->state = SPU_STATE_SAVED;
<------>spu->ibox_callback = NULL;
<------>spu->wbox_callback = NULL;
<------>spu->stop_callback = NULL;
<------>spu->mfc_callback = NULL;
<------>spu->pid = 0;
<------>spu->tgid = 0;
<------>ctx->ops = &spu_backing_ops;
<------>spu->flags = 0;
<------>spu->ctx = NULL;
<------>spin_unlock_irq(&spu->register_lock);
 
<------>spu_associate_mm(spu, NULL);
 
<------>ctx->stats.slb_flt +=
<------><------>(spu->stats.slb_flt - ctx->stats.slb_flt_base);
<------>ctx->stats.class2_intr +=
<------><------>(spu->stats.class2_intr - ctx->stats.class2_intr_base);
 
<------>/* This maps the underlying spu state to idle */
<------>spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
<------>ctx->spu = NULL;
 
<------>if (spu_stopped(ctx, &status))
<------><------>wake_up_all(&ctx->stop_wq);
}
 
/**
 * spu_add_to_rq - add a context to the runqueue
 * @ctx:       context to add
 */
static void __spu_add_to_rq(struct spu_context *ctx)
{
<------>/*
<------> * Unfortunately this code path can be called from multiple threads
<------> * on behalf of a single context due to the way the problem state
<------> * mmap support works.
<------> *
<------> * Fortunately we need to wake up all these threads at the same time
<------> * and can simply skip the runqueue addition for every but the first
<------> * thread getting into this codepath.
<------> *
<------> * It's still quite hacky, and long-term we should proxy all other
<------> * threads through the owner thread so that spu_run is in control
<------> * of all the scheduling activity for a given context.
<------> */
<------>if (list_empty(&ctx->rq)) {
<------><------>list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]);
<------><------>set_bit(ctx->prio, spu_prio->bitmap);
<------><------>if (!spu_prio->nr_waiting++)
<------><------><------>mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
<------>}
}
 
static void spu_add_to_rq(struct spu_context *ctx)
{
<------>spin_lock(&spu_prio->runq_lock);
<------>__spu_add_to_rq(ctx);
<------>spin_unlock(&spu_prio->runq_lock);
}
 
static void __spu_del_from_rq(struct spu_context *ctx)
{
<------>int prio = ctx->prio;
 
<------>if (!list_empty(&ctx->rq)) {
<------><------>if (!--spu_prio->nr_waiting)
<------><------><------>del_timer(&spusched_timer);
<------><------>list_del_init(&ctx->rq);
 
<------><------>if (list_empty(&spu_prio->runq[prio]))
<------><------><------>clear_bit(prio, spu_prio->bitmap);
<------>}
}
 
void spu_del_from_rq(struct spu_context *ctx)
{
<------>spin_lock(&spu_prio->runq_lock);
<------>__spu_del_from_rq(ctx);
<------>spin_unlock(&spu_prio->runq_lock);
}
 
static void spu_prio_wait(struct spu_context *ctx)
{
<------>DEFINE_WAIT(wait);
 
<------>/*
<------> * The caller must explicitly wait for a context to be loaded
<------> * if the nosched flag is set.  If NOSCHED is not set, the caller
<------> * queues the context and waits for an spu event or error.
<------> */
<------>BUG_ON(!(ctx->flags & SPU_CREATE_NOSCHED));
 
<------>spin_lock(&spu_prio->runq_lock);
<------>prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
<------>if (!signal_pending(current)) {
<------><------>__spu_add_to_rq(ctx);
<------><------>spin_unlock(&spu_prio->runq_lock);
<------><------>mutex_unlock(&ctx->state_mutex);
<------><------>schedule();
<------><------>mutex_lock(&ctx->state_mutex);
<------><------>spin_lock(&spu_prio->runq_lock);
<------><------>__spu_del_from_rq(ctx);
<------>}
<------>spin_unlock(&spu_prio->runq_lock);
<------>__set_current_state(TASK_RUNNING);
<------>remove_wait_queue(&ctx->stop_wq, &wait);
}
 
static struct spu *spu_get_idle(struct spu_context *ctx)
{
<------>struct spu *spu, *aff_ref_spu;
<------>int node, n;
 
<------>spu_context_nospu_trace(spu_get_idle__enter, ctx);
 
<------>if (ctx->gang) {
<------><------>mutex_lock(&ctx->gang->aff_mutex);
<------><------>if (has_affinity(ctx)) {
<------><------><------>aff_ref_spu = ctx->gang->aff_ref_spu;
<------><------><------>atomic_inc(&ctx->gang->aff_sched_count);
<------><------><------>mutex_unlock(&ctx->gang->aff_mutex);
<------><------><------>node = aff_ref_spu->node;
 
<------><------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------><------>spu = ctx_location(aff_ref_spu, ctx->aff_offset, node);
<------><------><------>if (spu && spu->alloc_state == SPU_FREE)
<------><------><------><------>goto found;
<------><------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
 
<------><------><------>atomic_dec(&ctx->gang->aff_sched_count);
<------><------><------>goto not_found;
<------><------>}
<------><------>mutex_unlock(&ctx->gang->aff_mutex);
<------>}
<------>node = cpu_to_node(raw_smp_processor_id());
<------>for (n = 0; n < MAX_NUMNODES; n++, node++) {
<------><------>node = (node < MAX_NUMNODES) ? node : 0;
<------><------>if (!node_allowed(ctx, node))
<------><------><------>continue;
 
<------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------>list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
<------><------><------>if (spu->alloc_state == SPU_FREE)
<------><------><------><------>goto found;
<------><------>}
<------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------>}
 
 not_found:
<------>spu_context_nospu_trace(spu_get_idle__not_found, ctx);
<------>return NULL;
 
 found:
<------>spu->alloc_state = SPU_USED;
<------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------>spu_context_trace(spu_get_idle__found, ctx, spu);
<------>spu_init_channels(spu);
<------>return spu;
}
 
/**
 * find_victim - find a lower priority context to preempt
 * @ctx:	candidate context for running
 *
 * Returns the freed physical spu to run the new context on.
 */
static struct spu *find_victim(struct spu_context *ctx)
{
<------>struct spu_context *victim = NULL;
<------>struct spu *spu;
<------>int node, n;
 
<------>spu_context_nospu_trace(spu_find_victim__enter, ctx);
 
<------>/*
<------> * Look for a possible preemption candidate on the local node first.
<------> * If there is no candidate look at the other nodes.  This isn't
<------> * exactly fair, but so far the whole spu scheduler tries to keep
<------> * a strong node affinity.  We might want to fine-tune this in
<------> * the future.
<------> */
 restart:
<------>node = cpu_to_node(raw_smp_processor_id());
<------>for (n = 0; n < MAX_NUMNODES; n++, node++) {
<------><------>node = (node < MAX_NUMNODES) ? node : 0;
<------><------>if (!node_allowed(ctx, node))
<------><------><------>continue;
 
<------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------>list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
<------><------><------>struct spu_context *tmp = spu->ctx;
 
<------><------><------>if (tmp && tmp->prio > ctx->prio &&
<------><------><------>    !(tmp->flags & SPU_CREATE_NOSCHED) &&
<------><------><------>    (!victim || tmp->prio > victim->prio)) {
<------><------><------><------>victim = spu->ctx;
<------><------><------>}
<------><------>}
<------><------>if (victim)
<------><------><------>get_spu_context(victim);
<------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
 
<------><------>if (victim) {
<------><------><------>/*
<------><------><------> * This nests ctx->state_mutex, but we always lock
<------><------><------> * higher priority contexts before lower priority
<------><------><------> * ones, so this is safe until we introduce
<------><------><------> * priority inheritance schemes.
<------><------><------> *
<------><------><------> * XXX if the highest priority context is locked,
<------><------><------> * this can loop a long time.  Might be better to
<------><------><------> * look at another context or give up after X retries.
<------><------><------> */
<------><------><------>if (!mutex_trylock(&victim->state_mutex)) {
<------><------><------><------>put_spu_context(victim);
<------><------><------><------>victim = NULL;
<------><------><------><------>goto restart;
<------><------><------>}
 
<------><------><------>spu = victim->spu;
<------><------><------>if (!spu || victim->prio <= ctx->prio) {
<------><------><------><------>/*
<------><------><------><------> * This race can happen because we've dropped
<------><------><------><------> * the active list mutex.  Not a problem, just
<------><------><------><------> * restart the search.
<------><------><------><------> */
<------><------><------><------>mutex_unlock(&victim->state_mutex);
<------><------><------><------>put_spu_context(victim);
<------><------><------><------>victim = NULL;
<------><------><------><------>goto restart;
<------><------><------>}
 
<------><------><------>spu_context_trace(__spu_deactivate__unload, ctx, spu);
 
<------><------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------><------>cbe_spu_info[node].nr_active--;
<------><------><------>spu_unbind_context(spu, victim);
<------><------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
 
<------><------><------>victim->stats.invol_ctx_switch++;
<------><------><------>spu->stats.invol_ctx_switch++;
<------><------><------>if (test_bit(SPU_SCHED_SPU_RUN, &victim->sched_flags))
<------><------><------><------>spu_add_to_rq(victim);
 
<------><------><------>mutex_unlock(&victim->state_mutex);
<------><------><------>put_spu_context(victim);
 
<------><------><------>return spu;
<------><------>}
<------>}
 
<------>return NULL;
}
 
static void __spu_schedule(struct spu *spu, struct spu_context *ctx)
{
<------>int node = spu->node;
<------>int success = 0;
 
<------>spu_set_timeslice(ctx);
 
<------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------>if (spu->ctx == NULL) {
<------><------>spu_bind_context(spu, ctx);
<------><------>cbe_spu_info[node].nr_active++;
<------><------>spu->alloc_state = SPU_USED;
<------><------>success = 1;
<------>}
<------>mutex_unlock(&cbe_spu_info[node].list_mutex);
 
<------>if (success)
<------><------>wake_up_all(&ctx->run_wq);
<------>else
<------><------>spu_add_to_rq(ctx);
}
 
static void spu_schedule(struct spu *spu, struct spu_context *ctx)
{
<------>/* not a candidate for interruptible because it's called either
<------>   from the scheduler thread or from spu_deactivate */
<------>mutex_lock(&ctx->state_mutex);
<------>if (ctx->state == SPU_STATE_SAVED)
<------><------>__spu_schedule(spu, ctx);
<------>spu_release(ctx);
}
 
/**
 * spu_unschedule - remove a context from a spu, and possibly release it.
 * @spu:	The SPU to unschedule from
 * @ctx:	The context currently scheduled on the SPU
 * @free_spu	Whether to free the SPU for other contexts
 *
 * Unbinds the context @ctx from the SPU @spu. If @free_spu is non-zero, the
 * SPU is made available for other contexts (ie, may be returned by
 * spu_get_idle). If this is zero, the caller is expected to schedule another
 * context to this spu.
 *
 * Should be called with ctx->state_mutex held.
 */
static void spu_unschedule(struct spu *spu, struct spu_context *ctx,
<------><------>int free_spu)
{
<------>int node = spu->node;
 
<------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------>cbe_spu_info[node].nr_active--;
<------>if (free_spu)
<------><------>spu->alloc_state = SPU_FREE;
<------>spu_unbind_context(spu, ctx);
<------>ctx->stats.invol_ctx_switch++;
<------>spu->stats.invol_ctx_switch++;
<------>mutex_unlock(&cbe_spu_info[node].list_mutex);
}
 
/**
 * spu_activate - find a free spu for a context and execute it
 * @ctx:	spu context to schedule
 * @flags:	flags (currently ignored)
 *
 * Tries to find a free spu to run @ctx.  If no free spu is available
 * add the context to the runqueue so it gets woken up once an spu
 * is available.
 */
int spu_activate(struct spu_context *ctx, unsigned long flags)
{
<------>struct spu *spu;
 
<------>/*
<------> * If there are multiple threads waiting for a single context
<------> * only one actually binds the context while the others will
<------> * only be able to acquire the state_mutex once the context
<------> * already is in runnable state.
<------> */
<------>if (ctx->spu)
<------><------>return 0;
 
spu_activate_top:
<------>if (signal_pending(current))
<------><------>return -ERESTARTSYS;
 
<------>spu = spu_get_idle(ctx);
<------>/*
<------> * If this is a realtime thread we try to get it running by
<------> * preempting a lower priority thread.
<------> */
<------>if (!spu && rt_prio(ctx->prio))
<------><------>spu = find_victim(ctx);
<------>if (spu) {
<------><------>unsigned long runcntl;
 
<------><------>runcntl = ctx->ops->runcntl_read(ctx);
<------><------>__spu_schedule(spu, ctx);
<------><------>if (runcntl & SPU_RUNCNTL_RUNNABLE)
<------><------><------>spuctx_switch_state(ctx, SPU_UTIL_USER);
 
<------><------>return 0;
<------>}
 
<------>if (ctx->flags & SPU_CREATE_NOSCHED) {
<------><------>spu_prio_wait(ctx);
<------><------>goto spu_activate_top;
<------>}
 
<------>spu_add_to_rq(ctx);
 
<------>return 0;
}
 
/**
 * grab_runnable_context - try to find a runnable context
 *
 * Remove the highest priority context on the runqueue and return it
 * to the caller.  Returns %NULL if no runnable context was found.
 */
static struct spu_context *grab_runnable_context(int prio, int node)
{
<------>struct spu_context *ctx;
<------>int best;
 
<------>spin_lock(&spu_prio->runq_lock);
<------>best = find_first_bit(spu_prio->bitmap, prio);
<------>while (best < prio) {
<------><------>struct list_head *rq = &spu_prio->runq[best];
 
<------><------>list_for_each_entry(ctx, rq, rq) {
<------><------><------>/* XXX(hch): check for affinity here as well */
<------><------><------>if (__node_allowed(ctx, node)) {
<------><------><------><------>__spu_del_from_rq(ctx);
<------><------><------><------>goto found;
<------><------><------>}
<------><------>}
<------><------>best++;
<------>}
<------>ctx = NULL;
 found:
<------>spin_unlock(&spu_prio->runq_lock);
<------>return ctx;
}
 
static int __spu_deactivate(struct spu_context *ctx, int force, int max_prio)
{
<------>struct spu *spu = ctx->spu;
<------>struct spu_context *new = NULL;
 
<------>if (spu) {
<------><------>new = grab_runnable_context(max_prio, spu->node);
<------><------>if (new || force) {
<------><------><------>spu_unschedule(spu, ctx, new == NULL);
<------><------><------>if (new) {
<------><------><------><------>if (new->flags & SPU_CREATE_NOSCHED)
<------><------><------><------><------>wake_up(&new->stop_wq);
<------><------><------><------>else {
<------><------><------><------><------>spu_release(ctx);
<------><------><------><------><------>spu_schedule(spu, new);
<------><------><------><------><------>/* this one can't easily be made
<------><------><------><------><------>   interruptible */
<------><------><------><------><------>mutex_lock(&ctx->state_mutex);
<------><------><------><------>}
<------><------><------>}
<------><------>}
<------>}
 
<------>return new != NULL;
}
 
/**
 * spu_deactivate - unbind a context from it's physical spu
 * @ctx:	spu context to unbind
 *
 * Unbind @ctx from the physical spu it is running on and schedule
 * the highest priority context to run on the freed physical spu.
 */
void spu_deactivate(struct spu_context *ctx)
{
<------>spu_context_nospu_trace(spu_deactivate__enter, ctx);
<------>__spu_deactivate(ctx, 1, MAX_PRIO);
}
 
/**
 * spu_yield -	yield a physical spu if others are waiting
 * @ctx:	spu context to yield
 *
 * Check if there is a higher priority context waiting and if yes
 * unbind @ctx from the physical spu and schedule the highest
 * priority context to run on the freed physical spu instead.
 */
void spu_yield(struct spu_context *ctx)
{
<------>spu_context_nospu_trace(spu_yield__enter, ctx);
<------>if (!(ctx->flags & SPU_CREATE_NOSCHED)) {
<------><------>mutex_lock(&ctx->state_mutex);
<------><------>__spu_deactivate(ctx, 0, MAX_PRIO);
<------><------>mutex_unlock(&ctx->state_mutex);
<------>}
}
 
static noinline void spusched_tick(struct spu_context *ctx)
{
<------>struct spu_context *new = NULL;
<------>struct spu *spu = NULL;
 
<------>if (spu_acquire(ctx))
<------><------>BUG();	/* a kernel thread never has signals pending */
 
<------>if (ctx->state != SPU_STATE_RUNNABLE)
<------><------>goto out;
<------>if (ctx->flags & SPU_CREATE_NOSCHED)
<------><------>goto out;
<------>if (ctx->policy == SCHED_FIFO)
<------><------>goto out;
 
<------>if (--ctx->time_slice && test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
<------><------>goto out;
 
<------>spu = ctx->spu;
 
<------>spu_context_trace(spusched_tick__preempt, ctx, spu);
 
<------>new = grab_runnable_context(ctx->prio + 1, spu->node);
<------>if (new) {
<------><------>spu_unschedule(spu, ctx, 0);
<------><------>if (test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
<------><------><------>spu_add_to_rq(ctx);
<------>} else {
<------><------>spu_context_nospu_trace(spusched_tick__newslice, ctx);
<------><------>if (!ctx->time_slice)
<------><------><------>ctx->time_slice++;
<------>}
out:
<------>spu_release(ctx);
 
<------>if (new)
<------><------>spu_schedule(spu, new);
}
 
/**
 * count_active_contexts - count nr of active tasks
 *
 * Return the number of tasks currently running or waiting to run.
 *
 * Note that we don't take runq_lock / list_mutex here.  Reading
 * a single 32bit value is atomic on powerpc, and we don't care
 * about memory ordering issues here.
 */
static unsigned long count_active_contexts(void)
{
<------>int nr_active = 0, node;
 
<------>for (node = 0; node < MAX_NUMNODES; node++)
<------><------>nr_active += cbe_spu_info[node].nr_active;
<------>nr_active += spu_prio->nr_waiting;
 
<------>return nr_active;
}
 
/**
 * spu_calc_load - update the avenrun load estimates.
 *
 * No locking against reading these values from userspace, as for
 * the CPU loadavg code.
 */
static void spu_calc_load(void)
{
<------>unsigned long active_tasks; /* fixed-point */
 
<------>active_tasks = count_active_contexts() * FIXED_1;
<------>spu_avenrun[0] = calc_load(spu_avenrun[0], EXP_1, active_tasks);
<------>spu_avenrun[1] = calc_load(spu_avenrun[1], EXP_5, active_tasks);
<------>spu_avenrun[2] = calc_load(spu_avenrun[2], EXP_15, active_tasks);
}
 
static void spusched_wake(struct timer_list *unused)
{
<------>mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
<------>wake_up_process(spusched_task);
}
 
static void spuloadavg_wake(struct timer_list *unused)
{
<------>mod_timer(&spuloadavg_timer, jiffies + LOAD_FREQ);
<------>spu_calc_load();
}
 
static int spusched_thread(void *unused)
{
<------>struct spu *spu;
<------>int node;
 
<------>while (!kthread_should_stop()) {
<------><------>set_current_state(TASK_INTERRUPTIBLE);
<------><------>schedule();
<------><------>for (node = 0; node < MAX_NUMNODES; node++) {
<------><------><------>struct mutex *mtx = &cbe_spu_info[node].list_mutex;
 
<------><------><------>mutex_lock(mtx);
<------><------><------>list_for_each_entry(spu, &cbe_spu_info[node].spus,
<------><------><------><------><------>cbe_list) {
<------><------><------><------>struct spu_context *ctx = spu->ctx;
 
<------><------><------><------>if (ctx) {
<------><------><------><------><------>get_spu_context(ctx);
<------><------><------><------><------>mutex_unlock(mtx);
<------><------><------><------><------>spusched_tick(ctx);
<------><------><------><------><------>mutex_lock(mtx);
<------><------><------><------><------>put_spu_context(ctx);
<------><------><------><------>}
<------><------><------>}
<------><------><------>mutex_unlock(mtx);
<------><------>}
<------>}
 
<------>return 0;
}
 
void spuctx_switch_state(struct spu_context *ctx,
<------><------>enum spu_utilization_state new_state)
{
<------>unsigned long long curtime;
<------>signed long long delta;
<------>struct spu *spu;
<------>enum spu_utilization_state old_state;
<------>int node;
 
<------>curtime = ktime_get_ns();
<------>delta = curtime - ctx->stats.tstamp;
 
<------>WARN_ON(!mutex_is_locked(&ctx->state_mutex));
<------>WARN_ON(delta < 0);
 
<------>spu = ctx->spu;
<------>old_state = ctx->stats.util_state;
<------>ctx->stats.util_state = new_state;
<------>ctx->stats.tstamp = curtime;
 
<------>/*
<------> * Update the physical SPU utilization statistics.
<------> */
<------>if (spu) {
<------><------>ctx->stats.times[old_state] += delta;
<------><------>spu->stats.times[old_state] += delta;
<------><------>spu->stats.util_state = new_state;
<------><------>spu->stats.tstamp = curtime;
<------><------>node = spu->node;
<------><------>if (old_state == SPU_UTIL_USER)
<------><------><------>atomic_dec(&cbe_spu_info[node].busy_spus);
<------><------>if (new_state == SPU_UTIL_USER)
<------><------><------>atomic_inc(&cbe_spu_info[node].busy_spus);
<------>}
}
 
static int show_spu_loadavg(struct seq_file *s, void *private)
{
<------>int a, b, c;
 
<------>a = spu_avenrun[0] + (FIXED_1/200);
<------>b = spu_avenrun[1] + (FIXED_1/200);
<------>c = spu_avenrun[2] + (FIXED_1/200);
 
<------>/*
<------> * Note that last_pid doesn't really make much sense for the
<------> * SPU loadavg (it even seems very odd on the CPU side...),
<------> * but we include it here to have a 100% compatible interface.
<------> */
<------>seq_printf(s, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
<------><------>LOAD_INT(a), LOAD_FRAC(a),
<------><------>LOAD_INT(b), LOAD_FRAC(b),
<------><------>LOAD_INT(c), LOAD_FRAC(c),
<------><------>count_active_contexts(),
<------><------>atomic_read(&nr_spu_contexts),
<------><------>idr_get_cursor(&task_active_pid_ns(current)->idr) - 1);
<------>return 0;
};
 
int __init spu_sched_init(void)
{
<------>struct proc_dir_entry *entry;
<------>int err = -ENOMEM, i;
 
<------>spu_prio = kzalloc(sizeof(struct spu_prio_array), GFP_KERNEL);
<------>if (!spu_prio)
<------><------>goto out;
 
<------>for (i = 0; i < MAX_PRIO; i++) {
<------><------>INIT_LIST_HEAD(&spu_prio->runq[i]);
<------><------>__clear_bit(i, spu_prio->bitmap);
<------>}
<------>spin_lock_init(&spu_prio->runq_lock);
 
<------>timer_setup(&spusched_timer, spusched_wake, 0);
<------>timer_setup(&spuloadavg_timer, spuloadavg_wake, 0);
 
<------>spusched_task = kthread_run(spusched_thread, NULL, "spusched");
<------>if (IS_ERR(spusched_task)) {
<------><------>err = PTR_ERR(spusched_task);
<------><------>goto out_free_spu_prio;
<------>}
 
<------>mod_timer(&spuloadavg_timer, 0);
 
<------>entry = proc_create_single("spu_loadavg", 0, NULL, show_spu_loadavg);
<------>if (!entry)
<------><------>goto out_stop_kthread;
 
<------>pr_debug("spusched: tick: %d, min ticks: %d, default ticks: %d\n",
<------><------><------>SPUSCHED_TICK, MIN_SPU_TIMESLICE, DEF_SPU_TIMESLICE);
<------>return 0;
 
 out_stop_kthread:
<------>kthread_stop(spusched_task);
 out_free_spu_prio:
<------>kfree(spu_prio);
 out:
<------>return err;
}
 
void spu_sched_exit(void)
{
<------>struct spu *spu;
<------>int node;
 
<------>remove_proc_entry("spu_loadavg", NULL);
 
<------>del_timer_sync(&spusched_timer);
<------>del_timer_sync(&spuloadavg_timer);
<------>kthread_stop(spusched_task);
 
<------>for (node = 0; node < MAX_NUMNODES; node++) {
<------><------>mutex_lock(&cbe_spu_info[node].list_mutex);
<------><------>list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list)
<------><------><------>if (spu->alloc_state != SPU_FREE)
<------><------><------><------>spu->alloc_state = SPU_FREE;
<------><------>mutex_unlock(&cbe_spu_info[node].list_mutex);
<------>}
<------>kfree(spu_prio);
}