| /* sched.c - SPU scheduler. |
| * |
| * Copyright (C) IBM 2005 |
| * Author: Mark Nutter <mnutter@us.ibm.com> |
| * |
| * 2006-03-31 NUMA domains added. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2, or (at your option) |
| * any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #undef DEBUG |
| |
| #include <linux/errno.h> |
| #include <linux/sched.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, tsk_cpus_allowed(current)); |
| |
| /* 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; |
| 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 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); |
| } |
| } |
| |
| #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), |
| task_active_pid_ns(current)->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); |
| } |