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None of the files touched here are modules, and they are not exporting any symbols either -- so there is no need to be including the module.h. Builds of all the files remains successful. Even kernel/module.c does not need to include it, since it includes linux/moduleloader.h instead. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
1175 lines
30 KiB
C
1175 lines
30 KiB
C
/* sched.c - SPU scheduler.
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*
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* Copyright (C) IBM 2005
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* Author: Mark Nutter <mnutter@us.ibm.com>
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*
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* 2006-03-31 NUMA domains added.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#undef DEBUG
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/completion.h>
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#include <linux/vmalloc.h>
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#include <linux/smp.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/numa.h>
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#include <linux/mutex.h>
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#include <linux/notifier.h>
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#include <linux/kthread.h>
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#include <linux/pid_namespace.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <asm/io.h>
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#include <asm/mmu_context.h>
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#include <asm/spu.h>
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#include <asm/spu_csa.h>
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#include <asm/spu_priv1.h>
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#include "spufs.h"
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#define CREATE_TRACE_POINTS
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#include "sputrace.h"
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struct spu_prio_array {
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DECLARE_BITMAP(bitmap, MAX_PRIO);
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struct list_head runq[MAX_PRIO];
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spinlock_t runq_lock;
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int nr_waiting;
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};
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static unsigned long spu_avenrun[3];
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static struct spu_prio_array *spu_prio;
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static struct task_struct *spusched_task;
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static struct timer_list spusched_timer;
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static struct timer_list spuloadavg_timer;
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/*
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* Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
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*/
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#define NORMAL_PRIO 120
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/*
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* Frequency of the spu scheduler tick. By default we do one SPU scheduler
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* tick for every 10 CPU scheduler ticks.
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*/
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#define SPUSCHED_TICK (10)
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/*
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* These are the 'tuning knobs' of the scheduler:
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*
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* Minimum timeslice is 5 msecs (or 1 spu scheduler tick, whichever is
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* larger), default timeslice is 100 msecs, maximum timeslice is 800 msecs.
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*/
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#define MIN_SPU_TIMESLICE max(5 * HZ / (1000 * SPUSCHED_TICK), 1)
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#define DEF_SPU_TIMESLICE (100 * HZ / (1000 * SPUSCHED_TICK))
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#define MAX_USER_PRIO (MAX_PRIO - MAX_RT_PRIO)
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#define SCALE_PRIO(x, prio) \
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max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_SPU_TIMESLICE)
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/*
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* scale user-nice values [ -20 ... 0 ... 19 ] to time slice values:
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* [800ms ... 100ms ... 5ms]
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*
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* The higher a thread's priority, the bigger timeslices
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* it gets during one round of execution. But even the lowest
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* priority thread gets MIN_TIMESLICE worth of execution time.
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*/
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void spu_set_timeslice(struct spu_context *ctx)
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{
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if (ctx->prio < NORMAL_PRIO)
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ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE * 4, ctx->prio);
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else
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ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE, ctx->prio);
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}
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/*
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* Update scheduling information from the owning thread.
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*/
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void __spu_update_sched_info(struct spu_context *ctx)
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{
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/*
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* assert that the context is not on the runqueue, so it is safe
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* to change its scheduling parameters.
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*/
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BUG_ON(!list_empty(&ctx->rq));
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/*
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* 32-Bit assignments are atomic on powerpc, and we don't care about
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* memory ordering here because retrieving the controlling thread is
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* per definition racy.
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*/
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ctx->tid = current->pid;
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/*
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* We do our own priority calculations, so we normally want
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* ->static_prio to start with. Unfortunately this field
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* contains junk for threads with a realtime scheduling
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* policy so we have to look at ->prio in this case.
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*/
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if (rt_prio(current->prio))
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ctx->prio = current->prio;
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else
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ctx->prio = current->static_prio;
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ctx->policy = current->policy;
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/*
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* TO DO: the context may be loaded, so we may need to activate
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* it again on a different node. But it shouldn't hurt anything
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* to update its parameters, because we know that the scheduler
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* is not actively looking at this field, since it is not on the
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* runqueue. The context will be rescheduled on the proper node
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* if it is timesliced or preempted.
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*/
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cpumask_copy(&ctx->cpus_allowed, tsk_cpus_allowed(current));
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/* Save the current cpu id for spu interrupt routing. */
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ctx->last_ran = raw_smp_processor_id();
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}
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void spu_update_sched_info(struct spu_context *ctx)
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{
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int node;
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if (ctx->state == SPU_STATE_RUNNABLE) {
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node = ctx->spu->node;
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/*
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* Take list_mutex to sync with find_victim().
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*/
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mutex_lock(&cbe_spu_info[node].list_mutex);
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__spu_update_sched_info(ctx);
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mutex_unlock(&cbe_spu_info[node].list_mutex);
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} else {
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__spu_update_sched_info(ctx);
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}
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}
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static int __node_allowed(struct spu_context *ctx, int node)
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{
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if (nr_cpus_node(node)) {
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const struct cpumask *mask = cpumask_of_node(node);
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if (cpumask_intersects(mask, &ctx->cpus_allowed))
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return 1;
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}
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return 0;
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}
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static int node_allowed(struct spu_context *ctx, int node)
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{
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int rval;
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spin_lock(&spu_prio->runq_lock);
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rval = __node_allowed(ctx, node);
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spin_unlock(&spu_prio->runq_lock);
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return rval;
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}
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void do_notify_spus_active(void)
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{
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int node;
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/*
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* Wake up the active spu_contexts.
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*
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* When the awakened processes see their "notify_active" flag is set,
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* they will call spu_switch_notify().
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*/
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for_each_online_node(node) {
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struct spu *spu;
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mutex_lock(&cbe_spu_info[node].list_mutex);
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list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
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if (spu->alloc_state != SPU_FREE) {
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struct spu_context *ctx = spu->ctx;
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set_bit(SPU_SCHED_NOTIFY_ACTIVE,
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&ctx->sched_flags);
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mb();
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wake_up_all(&ctx->stop_wq);
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}
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}
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mutex_unlock(&cbe_spu_info[node].list_mutex);
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}
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}
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/**
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* spu_bind_context - bind spu context to physical spu
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* @spu: physical spu to bind to
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* @ctx: context to bind
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*/
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static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
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{
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spu_context_trace(spu_bind_context__enter, ctx, spu);
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spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
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if (ctx->flags & SPU_CREATE_NOSCHED)
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atomic_inc(&cbe_spu_info[spu->node].reserved_spus);
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ctx->stats.slb_flt_base = spu->stats.slb_flt;
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ctx->stats.class2_intr_base = spu->stats.class2_intr;
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spu_associate_mm(spu, ctx->owner);
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spin_lock_irq(&spu->register_lock);
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spu->ctx = ctx;
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spu->flags = 0;
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ctx->spu = spu;
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ctx->ops = &spu_hw_ops;
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spu->pid = current->pid;
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spu->tgid = current->tgid;
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spu->ibox_callback = spufs_ibox_callback;
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spu->wbox_callback = spufs_wbox_callback;
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spu->stop_callback = spufs_stop_callback;
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spu->mfc_callback = spufs_mfc_callback;
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spin_unlock_irq(&spu->register_lock);
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spu_unmap_mappings(ctx);
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spu_switch_log_notify(spu, ctx, SWITCH_LOG_START, 0);
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spu_restore(&ctx->csa, spu);
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spu->timestamp = jiffies;
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spu_switch_notify(spu, ctx);
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ctx->state = SPU_STATE_RUNNABLE;
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spuctx_switch_state(ctx, SPU_UTIL_USER);
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}
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/*
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* Must be used with the list_mutex held.
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*/
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static inline int sched_spu(struct spu *spu)
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{
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BUG_ON(!mutex_is_locked(&cbe_spu_info[spu->node].list_mutex));
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return (!spu->ctx || !(spu->ctx->flags & SPU_CREATE_NOSCHED));
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}
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static void aff_merge_remaining_ctxs(struct spu_gang *gang)
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{
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struct spu_context *ctx;
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list_for_each_entry(ctx, &gang->aff_list_head, aff_list) {
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if (list_empty(&ctx->aff_list))
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list_add(&ctx->aff_list, &gang->aff_list_head);
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}
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gang->aff_flags |= AFF_MERGED;
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}
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static void aff_set_offsets(struct spu_gang *gang)
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{
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struct spu_context *ctx;
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int offset;
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offset = -1;
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list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
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aff_list) {
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if (&ctx->aff_list == &gang->aff_list_head)
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break;
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ctx->aff_offset = offset--;
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}
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offset = 0;
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list_for_each_entry(ctx, gang->aff_ref_ctx->aff_list.prev, aff_list) {
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if (&ctx->aff_list == &gang->aff_list_head)
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break;
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ctx->aff_offset = offset++;
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}
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gang->aff_flags |= AFF_OFFSETS_SET;
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}
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static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
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int group_size, int lowest_offset)
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{
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struct spu *spu;
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int node, n;
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/*
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* TODO: A better algorithm could be used to find a good spu to be
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* used as reference location for the ctxs chain.
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*/
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node = cpu_to_node(raw_smp_processor_id());
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for (n = 0; n < MAX_NUMNODES; n++, node++) {
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/*
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* "available_spus" counts how many spus are not potentially
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* going to be used by other affinity gangs whose reference
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* context is already in place. Although this code seeks to
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* avoid having affinity gangs with a summed amount of
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* contexts bigger than the amount of spus in the node,
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* this may happen sporadically. In this case, available_spus
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* becomes negative, which is harmless.
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*/
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int available_spus;
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node = (node < MAX_NUMNODES) ? node : 0;
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if (!node_allowed(ctx, node))
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continue;
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available_spus = 0;
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mutex_lock(&cbe_spu_info[node].list_mutex);
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list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
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if (spu->ctx && spu->ctx->gang && !spu->ctx->aff_offset
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&& spu->ctx->gang->aff_ref_spu)
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available_spus -= spu->ctx->gang->contexts;
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available_spus++;
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}
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if (available_spus < ctx->gang->contexts) {
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mutex_unlock(&cbe_spu_info[node].list_mutex);
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continue;
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}
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list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
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if ((!mem_aff || spu->has_mem_affinity) &&
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sched_spu(spu)) {
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mutex_unlock(&cbe_spu_info[node].list_mutex);
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return spu;
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}
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}
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mutex_unlock(&cbe_spu_info[node].list_mutex);
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}
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return NULL;
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}
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static void aff_set_ref_point_location(struct spu_gang *gang)
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{
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int mem_aff, gs, lowest_offset;
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struct spu_context *ctx;
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struct spu *tmp;
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mem_aff = gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM;
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lowest_offset = 0;
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gs = 0;
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list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
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gs++;
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list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
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aff_list) {
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if (&ctx->aff_list == &gang->aff_list_head)
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break;
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lowest_offset = ctx->aff_offset;
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}
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gang->aff_ref_spu = aff_ref_location(gang->aff_ref_ctx, mem_aff, gs,
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lowest_offset);
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}
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static struct spu *ctx_location(struct spu *ref, int offset, int node)
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{
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struct spu *spu;
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spu = NULL;
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if (offset >= 0) {
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list_for_each_entry(spu, ref->aff_list.prev, aff_list) {
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BUG_ON(spu->node != node);
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if (offset == 0)
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break;
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if (sched_spu(spu))
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offset--;
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}
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} else {
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list_for_each_entry_reverse(spu, ref->aff_list.next, aff_list) {
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BUG_ON(spu->node != node);
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if (offset == 0)
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break;
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if (sched_spu(spu))
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offset++;
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}
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}
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return spu;
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}
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/*
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* affinity_check is called each time a context is going to be scheduled.
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* It returns the spu ptr on which the context must run.
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*/
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static int has_affinity(struct spu_context *ctx)
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{
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struct spu_gang *gang = ctx->gang;
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if (list_empty(&ctx->aff_list))
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return 0;
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if (atomic_read(&ctx->gang->aff_sched_count) == 0)
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ctx->gang->aff_ref_spu = NULL;
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if (!gang->aff_ref_spu) {
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if (!(gang->aff_flags & AFF_MERGED))
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aff_merge_remaining_ctxs(gang);
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if (!(gang->aff_flags & AFF_OFFSETS_SET))
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aff_set_offsets(gang);
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aff_set_ref_point_location(gang);
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}
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return gang->aff_ref_spu != NULL;
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}
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/**
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* spu_unbind_context - unbind spu context from physical spu
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* @spu: physical spu to unbind from
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* @ctx: context to unbind
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*/
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static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
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{
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u32 status;
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spu_context_trace(spu_unbind_context__enter, ctx, spu);
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spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
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if (spu->ctx->flags & SPU_CREATE_NOSCHED)
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atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
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if (ctx->gang)
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/*
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* If ctx->gang->aff_sched_count is positive, SPU affinity is
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* being considered in this gang. Using atomic_dec_if_positive
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* allow us to skip an explicit check for affinity in this gang
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*/
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atomic_dec_if_positive(&ctx->gang->aff_sched_count);
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spu_switch_notify(spu, NULL);
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spu_unmap_mappings(ctx);
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spu_save(&ctx->csa, spu);
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spu_switch_log_notify(spu, ctx, SWITCH_LOG_STOP, 0);
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spin_lock_irq(&spu->register_lock);
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spu->timestamp = jiffies;
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ctx->state = SPU_STATE_SAVED;
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spu->ibox_callback = NULL;
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spu->wbox_callback = NULL;
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spu->stop_callback = NULL;
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spu->mfc_callback = NULL;
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spu->pid = 0;
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spu->tgid = 0;
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ctx->ops = &spu_backing_ops;
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spu->flags = 0;
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spu->ctx = NULL;
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spin_unlock_irq(&spu->register_lock);
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spu_associate_mm(spu, NULL);
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ctx->stats.slb_flt +=
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(spu->stats.slb_flt - ctx->stats.slb_flt_base);
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ctx->stats.class2_intr +=
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(spu->stats.class2_intr - ctx->stats.class2_intr_base);
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/* This maps the underlying spu state to idle */
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spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
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ctx->spu = NULL;
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if (spu_stopped(ctx, &status))
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wake_up_all(&ctx->stop_wq);
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}
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/**
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* spu_add_to_rq - add a context to the runqueue
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* @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: canidate 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;
|
|
CALC_LOAD(spu_avenrun[0], EXP_1, active_tasks);
|
|
CALC_LOAD(spu_avenrun[1], EXP_5, active_tasks);
|
|
CALC_LOAD(spu_avenrun[2], EXP_15, active_tasks);
|
|
}
|
|
|
|
static void spusched_wake(unsigned long data)
|
|
{
|
|
mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
|
|
wake_up_process(spusched_task);
|
|
}
|
|
|
|
static void spuloadavg_wake(unsigned long data)
|
|
{
|
|
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 timespec ts;
|
|
struct spu *spu;
|
|
enum spu_utilization_state old_state;
|
|
int node;
|
|
|
|
ktime_get_ts(&ts);
|
|
curtime = timespec_to_ns(&ts);
|
|
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);
|
|
}
|
|
}
|
|
|
|
#define LOAD_INT(x) ((x) >> FSHIFT)
|
|
#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
|
|
|
|
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),
|
|
current->nsproxy->pid_ns->last_pid);
|
|
return 0;
|
|
}
|
|
|
|
static int spu_loadavg_open(struct inode *inode, struct file *file)
|
|
{
|
|
return single_open(file, show_spu_loadavg, NULL);
|
|
}
|
|
|
|
static const struct file_operations spu_loadavg_fops = {
|
|
.open = spu_loadavg_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = single_release,
|
|
};
|
|
|
|
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);
|
|
|
|
setup_timer(&spusched_timer, spusched_wake, 0);
|
|
setup_timer(&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("spu_loadavg", 0, NULL, &spu_loadavg_fops);
|
|
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);
|
|
}
|