From 5110459f181ef1f11200bb3dec61953f08cc49e7 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 5 Dec 2005 22:52:25 -0500 Subject: [PATCH] [PATCH] spufs: Improved SPU preemptability. This patch makes it easier to preempt an SPU context by having the scheduler hold ctx->state_sema for much shorter periods of time. As part of this restructuring, the control logic for the "run" operation is moved from arch/ppc64/kernel/spu_base.c to fs/spufs/file.c. Of course the base retains "bottom half" handlers for class{0,1} irqs. The new run loop will re-acquire an SPU if preempted. From: Mark Nutter Signed-off-by: Arnd Bergmann Signed-off-by: Paul Mackerras --- arch/powerpc/platforms/cell/spu_base.c | 93 +++----------- .../platforms/cell/spufs/backing_ops.c | 19 +++ arch/powerpc/platforms/cell/spufs/context.c | 5 +- arch/powerpc/platforms/cell/spufs/file.c | 117 ++++++++++++++++-- arch/powerpc/platforms/cell/spufs/hw_ops.c | 17 +++ arch/powerpc/platforms/cell/spufs/sched.c | 67 +++++----- arch/powerpc/platforms/cell/spufs/spufs.h | 5 + include/asm-powerpc/spu.h | 5 +- 8 files changed, 205 insertions(+), 123 deletions(-) diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c index 167580ce86..8abd4bd196 100644 --- a/arch/powerpc/platforms/cell/spu_base.c +++ b/arch/powerpc/platforms/cell/spu_base.c @@ -130,7 +130,8 @@ static int __spu_trap_data_map(struct spu *spu, unsigned long ea, u64 dsisr) spu->dar = ea; spu->dsisr = dsisr; mb(); - wake_up(&spu->stop_wq); + if (spu->stop_callback) + spu->stop_callback(spu); return 0; } @@ -151,7 +152,8 @@ static int __spu_trap_stop(struct spu *spu) { pr_debug("%s\n", __FUNCTION__); spu->stop_code = in_be32(&spu->problem->spu_status_R); - wake_up(&spu->stop_wq); + if (spu->stop_callback) + spu->stop_callback(spu); return 0; } @@ -159,7 +161,8 @@ static int __spu_trap_halt(struct spu *spu) { pr_debug("%s\n", __FUNCTION__); spu->stop_code = in_be32(&spu->problem->spu_status_R); - wake_up(&spu->stop_wq); + if (spu->stop_callback) + spu->stop_callback(spu); return 0; } @@ -190,12 +193,13 @@ spu_irq_class_0(int irq, void *data, struct pt_regs *regs) spu = data; spu->class_0_pending = 1; - wake_up(&spu->stop_wq); + if (spu->stop_callback) + spu->stop_callback(spu); return IRQ_HANDLED; } -static int +int spu_irq_class_0_bottom(struct spu *spu) { unsigned long stat; @@ -214,8 +218,10 @@ spu_irq_class_0_bottom(struct spu *spu) __spu_trap_error(spu); out_be64(&spu->priv1->int_stat_class0_RW, stat); - return 0; + + return (stat & 0x7) ? -EIO : 0; } +EXPORT_SYMBOL_GPL(spu_irq_class_0_bottom); static irqreturn_t spu_irq_class_1(int irq, void *data, struct pt_regs *regs) @@ -250,6 +256,7 @@ spu_irq_class_1(int irq, void *data, struct pt_regs *regs) return stat ? IRQ_HANDLED : IRQ_NONE; } +EXPORT_SYMBOL_GPL(spu_irq_class_1_bottom); static irqreturn_t spu_irq_class_2(int irq, void *data, struct pt_regs *regs) @@ -478,7 +485,7 @@ bad_area: return -EFAULT; } -static int spu_handle_pte_fault(struct spu *spu) +int spu_irq_class_1_bottom(struct spu *spu) { u64 ea, dsisr, access, error = 0UL; int ret = 0; @@ -508,76 +515,6 @@ static int spu_handle_pte_fault(struct spu *spu) return ret; } -static inline int spu_pending(struct spu *spu, u32 * stat) -{ - struct spu_problem __iomem *prob = spu->problem; - u64 pte_fault; - - *stat = in_be32(&prob->spu_status_R); - pte_fault = spu->dsisr & - (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED); - return (!(*stat & 0x1) || pte_fault || spu->class_0_pending) ? 1 : 0; -} - -int spu_run(struct spu *spu) -{ - struct spu_problem __iomem *prob; - struct spu_priv1 __iomem *priv1; - struct spu_priv2 __iomem *priv2; - u32 status; - int ret; - - prob = spu->problem; - priv1 = spu->priv1; - priv2 = spu->priv2; - - /* Let SPU run. */ - eieio(); - out_be32(&prob->spu_runcntl_RW, SPU_RUNCNTL_RUNNABLE); - - do { - ret = wait_event_interruptible(spu->stop_wq, - spu_pending(spu, &status)); - - if (spu->dsisr & - (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)) - ret = spu_handle_pte_fault(spu); - - if (spu->class_0_pending) - spu_irq_class_0_bottom(spu); - - if (!ret && signal_pending(current)) - ret = -ERESTARTSYS; - - } while (!ret && !(status & - (SPU_STATUS_STOPPED_BY_STOP | - SPU_STATUS_STOPPED_BY_HALT))); - - /* Ensure SPU is stopped. */ - out_be32(&prob->spu_runcntl_RW, SPU_RUNCNTL_STOP); - eieio(); - while (in_be32(&prob->spu_status_R) & SPU_STATUS_RUNNING) - cpu_relax(); - - out_be64(&priv2->slb_invalidate_all_W, 0); - out_be64(&priv1->tlb_invalidate_entry_W, 0UL); - eieio(); - - /* Check for SPU breakpoint. */ - if (unlikely(current->ptrace & PT_PTRACED)) { - status = in_be32(&prob->spu_status_R); - - if ((status & SPU_STATUS_STOPPED_BY_STOP) - && status >> SPU_STOP_STATUS_SHIFT == 0x3fff) { - force_sig(SIGTRAP, current); - ret = -ERESTARTSYS; - } - } - - return ret; -} -EXPORT_SYMBOL_GPL(spu_run); - static void __iomem * __init map_spe_prop(struct device_node *n, const char *name) { @@ -693,9 +630,9 @@ static int __init create_spu(struct device_node *spe) out_be64(&spu->priv1->mfc_sdr_RW, mfspr(SPRN_SDR1)); out_be64(&spu->priv1->mfc_sr1_RW, 0x33); - init_waitqueue_head(&spu->stop_wq); spu->ibox_callback = NULL; spu->wbox_callback = NULL; + spu->stop_callback = NULL; down(&spu_mutex); spu->number = number++; diff --git a/arch/powerpc/platforms/cell/spufs/backing_ops.c b/arch/powerpc/platforms/cell/spufs/backing_ops.c index caf0984064..66567c1099 100644 --- a/arch/powerpc/platforms/cell/spufs/backing_ops.c +++ b/arch/powerpc/platforms/cell/spufs/backing_ops.c @@ -232,6 +232,23 @@ static char *spu_backing_get_ls(struct spu_context *ctx) return ctx->csa.lscsa->ls; } +static void spu_backing_runcntl_write(struct spu_context *ctx, u32 val) +{ + spin_lock(&ctx->csa.register_lock); + ctx->csa.prob.spu_runcntl_RW = val; + if (val & SPU_RUNCNTL_RUNNABLE) { + ctx->csa.prob.spu_status_R |= SPU_STATUS_RUNNING; + } else { + ctx->csa.prob.spu_status_R &= ~SPU_STATUS_RUNNING; + } + spin_unlock(&ctx->csa.register_lock); +} + +static void spu_backing_runcntl_stop(struct spu_context *ctx) +{ + spu_backing_runcntl_write(ctx, SPU_RUNCNTL_STOP); +} + struct spu_context_ops spu_backing_ops = { .mbox_read = spu_backing_mbox_read, .mbox_stat_read = spu_backing_mbox_stat_read, @@ -249,4 +266,6 @@ struct spu_context_ops spu_backing_ops = { .npc_write = spu_backing_npc_write, .status_read = spu_backing_status_read, .get_ls = spu_backing_get_ls, + .runcntl_write = spu_backing_runcntl_write, + .runcntl_stop = spu_backing_runcntl_stop, }; diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c index 5d6195fc10..0d88a1c24f 100644 --- a/arch/powerpc/platforms/cell/spufs/context.c +++ b/arch/powerpc/platforms/cell/spufs/context.c @@ -45,6 +45,7 @@ struct spu_context *alloc_spu_context(struct address_space *local_store) init_rwsem(&ctx->state_sema); init_waitqueue_head(&ctx->ibox_wq); init_waitqueue_head(&ctx->wbox_wq); + init_waitqueue_head(&ctx->stop_wq); ctx->ibox_fasync = NULL; ctx->wbox_fasync = NULL; ctx->state = SPU_STATE_SAVED; @@ -105,7 +106,7 @@ void spu_release(struct spu_context *ctx) up_read(&ctx->state_sema); } -static void spu_unmap_mappings(struct spu_context *ctx) +void spu_unmap_mappings(struct spu_context *ctx) { unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1); } @@ -126,7 +127,6 @@ int spu_acquire_runnable(struct spu_context *ctx) down_write(&ctx->state_sema); if (ctx->state == SPU_STATE_SAVED) { - spu_unmap_mappings(ctx); ret = spu_activate(ctx, 0); ctx->state = SPU_STATE_RUNNABLE; } @@ -154,7 +154,6 @@ void spu_acquire_saved(struct spu_context *ctx) down_write(&ctx->state_sema); if (ctx->state == SPU_STATE_RUNNABLE) { - spu_unmap_mappings(ctx); spu_deactivate(ctx); ctx->state = SPU_STATE_SAVED; } diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c index 0fe1feccc0..af5adc3722 100644 --- a/arch/powerpc/platforms/cell/spufs/file.c +++ b/arch/powerpc/platforms/cell/spufs/file.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -540,26 +541,122 @@ static struct file_operations spufs_wbox_stat_fops = { .read = spufs_wbox_stat_read, }; -long spufs_run_spu(struct file *file, struct spu_context *ctx, - u32 *npc, u32 *status) +/* interrupt-level stop callback function. */ +void spufs_stop_callback(struct spu *spu) +{ + struct spu_context *ctx = spu->ctx; + + wake_up_all(&ctx->stop_wq); +} + +static inline int spu_stopped(struct spu_context *ctx, u32 * stat) +{ + struct spu *spu; + u64 pte_fault; + + *stat = ctx->ops->status_read(ctx); + if (ctx->state != SPU_STATE_RUNNABLE) + return 1; + spu = ctx->spu; + pte_fault = spu->dsisr & + (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED); + return (!(*stat & 0x1) || pte_fault || spu->class_0_pending) ? 1 : 0; +} + +static inline int spu_run_init(struct spu_context *ctx, u32 * npc, + u32 * status) { int ret; - ret = spu_acquire_runnable(ctx); - if (ret) + if ((ret = spu_acquire_runnable(ctx)) != 0) return ret; - ctx->ops->npc_write(ctx, *npc); + ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE); + return 0; +} - ret = spu_run(ctx->spu); - - if (!ret) - ret = ctx->ops->status_read(ctx); +static inline int spu_run_fini(struct spu_context *ctx, u32 * npc, + u32 * status) +{ + int ret = 0; + *status = ctx->ops->status_read(ctx); *npc = ctx->ops->npc_read(ctx); - spu_release(ctx); + + if (signal_pending(current)) + ret = -ERESTARTSYS; + if (unlikely(current->ptrace & PT_PTRACED)) { + if ((*status & SPU_STATUS_STOPPED_BY_STOP) + && (*status >> SPU_STOP_STATUS_SHIFT) == 0x3fff) { + force_sig(SIGTRAP, current); + ret = -ERESTARTSYS; + } + } + return ret; +} + +static inline int spu_reacquire_runnable(struct spu_context *ctx, u32 *npc, + u32 *status) +{ + int ret; + + if ((ret = spu_run_fini(ctx, npc, status)) != 0) + return ret; + if (*status & (SPU_STATUS_STOPPED_BY_STOP | + SPU_STATUS_STOPPED_BY_HALT)) { + return *status; + } + if ((ret = spu_run_init(ctx, npc, status)) != 0) + return ret; + return 0; +} + +static inline int spu_process_events(struct spu_context *ctx) +{ + struct spu *spu = ctx->spu; + u64 pte_fault = MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED; + int ret = 0; + + if (spu->dsisr & pte_fault) + ret = spu_irq_class_1_bottom(spu); + if (spu->class_0_pending) + ret = spu_irq_class_0_bottom(spu); + if (!ret && signal_pending(current)) + ret = -ERESTARTSYS; + return ret; +} + +long spufs_run_spu(struct file *file, struct spu_context *ctx, + u32 * npc, u32 * status) +{ + int ret; + + if ((ret = spu_run_init(ctx, npc, status)) != 0) + return ret; + + do { + ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, status)); + if (unlikely(ret)) + break; + if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) { + ret = spu_reacquire_runnable(ctx, npc, status); + if (ret) { + return ret; + } + continue; + } + ret = spu_process_events(ctx); + + } while (!ret && !(*status & (SPU_STATUS_STOPPED_BY_STOP | + SPU_STATUS_STOPPED_BY_HALT))); + + ctx->ops->runcntl_stop(ctx); + ret = spu_run_fini(ctx, npc, status); + if (!ret) + ret = *status; spu_yield(ctx); + return ret; } diff --git a/arch/powerpc/platforms/cell/spufs/hw_ops.c b/arch/powerpc/platforms/cell/spufs/hw_ops.c index 2e90cae98a..68812415ee 100644 --- a/arch/powerpc/platforms/cell/spufs/hw_ops.c +++ b/arch/powerpc/platforms/cell/spufs/hw_ops.c @@ -186,6 +186,21 @@ static char *spu_hw_get_ls(struct spu_context *ctx) return ctx->spu->local_store; } +static void spu_hw_runcntl_write(struct spu_context *ctx, u32 val) +{ + eieio(); + out_be32(&ctx->spu->problem->spu_runcntl_RW, val); +} + +static void spu_hw_runcntl_stop(struct spu_context *ctx) +{ + spin_lock_irq(&ctx->spu->register_lock); + out_be32(&ctx->spu->problem->spu_runcntl_RW, SPU_RUNCNTL_STOP); + while (in_be32(&ctx->spu->problem->spu_status_R) & SPU_STATUS_RUNNING) + cpu_relax(); + spin_unlock_irq(&ctx->spu->register_lock); +} + struct spu_context_ops spu_hw_ops = { .mbox_read = spu_hw_mbox_read, .mbox_stat_read = spu_hw_mbox_stat_read, @@ -203,4 +218,6 @@ struct spu_context_ops spu_hw_ops = { .npc_write = spu_hw_npc_write, .status_read = spu_hw_status_read, .get_ls = spu_hw_get_ls, + .runcntl_write = spu_hw_runcntl_write, + .runcntl_stop = spu_hw_runcntl_stop, }; diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c index 575027062b..e2f10b5b8a 100644 --- a/arch/powerpc/platforms/cell/spufs/sched.c +++ b/arch/powerpc/platforms/cell/spufs/sched.c @@ -119,7 +119,8 @@ static void prio_wakeup(struct spu_runqueue *rq) } } -static void prio_wait(struct spu_runqueue *rq, u64 flags) +static void prio_wait(struct spu_runqueue *rq, struct spu_context *ctx, + u64 flags) { int prio = current->prio; wait_queue_head_t *wq = &rq->prio.waitq[prio]; @@ -130,9 +131,11 @@ static void prio_wait(struct spu_runqueue *rq, u64 flags) prepare_to_wait_exclusive(wq, &wait, TASK_INTERRUPTIBLE); if (!signal_pending(current)) { up(&rq->sem); + up_write(&ctx->state_sema); pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__, current->pid, current->prio); schedule(); + down_write(&ctx->state_sema); down(&rq->sem); } finish_wait(wq, &wait); @@ -173,7 +176,9 @@ static inline void bind_context(struct spu *spu, struct spu_context *ctx) mm_needs_global_tlbie(spu->mm); spu->ibox_callback = spufs_ibox_callback; spu->wbox_callback = spufs_wbox_callback; + spu->stop_callback = spufs_stop_callback; mb(); + spu_unmap_mappings(ctx); spu_restore(&ctx->csa, spu); } @@ -181,10 +186,12 @@ static inline void unbind_context(struct spu *spu, struct spu_context *ctx) { pr_debug("%s: unbind pid=%d SPU=%d\n", __FUNCTION__, spu->pid, spu->number); + spu_unmap_mappings(ctx); spu_save(&ctx->csa, spu); ctx->state = SPU_STATE_SAVED; spu->ibox_callback = NULL; spu->wbox_callback = NULL; + spu->stop_callback = NULL; spu->mm = NULL; spu->pid = 0; spu->prio = MAX_PRIO; @@ -196,37 +203,35 @@ static inline void unbind_context(struct spu *spu, struct spu_context *ctx) static struct spu *preempt_active(struct spu_runqueue *rq) { struct list_head *p; - struct spu_context *ctx; - struct spu *spu; + struct spu *worst, *spu; - /* Future: implement real preemption. For now just - * boot a lower priority ctx that is in "detached" - * state, i.e. on a processor but not currently in - * spu_run(). - */ + worst = list_entry(rq->active_list.next, struct spu, sched_list); list_for_each(p, &rq->active_list) { spu = list_entry(p, struct spu, sched_list); - if (current->prio < spu->prio) { - ctx = spu->ctx; - if (down_write_trylock(&ctx->state_sema)) { - if (ctx->state != SPU_STATE_RUNNABLE) { - up_write(&ctx->state_sema); - continue; - } - pr_debug("%s: booting pid=%d from SPU %d\n", - __FUNCTION__, spu->pid, spu->number); - del_active(rq, spu); - up(&rq->sem); - unbind_context(spu, ctx); - up_write(&ctx->state_sema); - return spu; - } + if (spu->prio > worst->prio) { + worst = spu; + } + } + if (current->prio < worst->prio) { + struct spu_context *ctx = worst->ctx; + + spu = worst; + if (down_write_trylock(&ctx->state_sema)) { + pr_debug("%s: booting pid=%d from SPU %d\n", + __FUNCTION__, spu->pid, spu->number); + del_active(rq, spu); + up(&rq->sem); + wake_up_all(&ctx->stop_wq); + ctx->ops->runcntl_stop(ctx); + unbind_context(spu, ctx); + up_write(&ctx->state_sema); + return spu; } } return NULL; } -static struct spu *get_idle_spu(u64 flags) +static struct spu *get_idle_spu(struct spu_context *ctx, u64 flags) { struct spu_runqueue *rq; struct spu *spu = NULL; @@ -255,7 +260,7 @@ static struct spu *get_idle_spu(u64 flags) if ((spu = preempt_active(rq)) != NULL) return spu; } - prio_wait(rq, flags); + prio_wait(rq, ctx, flags); if (signal_pending(current)) { prio_wakeup(rq); spu = NULL; @@ -322,7 +327,7 @@ int spu_activate(struct spu_context *ctx, u64 flags) if (ctx->spu) return 0; - spu = get_idle_spu(flags); + spu = get_idle_spu(ctx, flags); if (!spu) return (signal_pending(current)) ? -ERESTARTSYS : -EAGAIN; bind_context(spu, ctx); @@ -347,17 +352,19 @@ void spu_deactivate(struct spu_context *ctx) void spu_yield(struct spu_context *ctx) { struct spu *spu; + int need_yield = 0; - if (!down_write_trylock(&ctx->state_sema)) - return; + down_write(&ctx->state_sema); spu = ctx->spu; - if ((ctx->state == SPU_STATE_RUNNABLE) && - (sched_find_first_bit(spu->rq->prio.bitmap) <= current->prio)) { + if (spu && (sched_find_first_bit(spu->rq->prio.bitmap) < MAX_PRIO)) { pr_debug("%s: yielding SPU %d\n", __FUNCTION__, spu->number); spu_deactivate(ctx); ctx->state = SPU_STATE_SAVED; + need_yield = 1; } up_write(&ctx->state_sema); + if (unlikely(need_yield)) + yield(); } int __init spu_sched_init(void) diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h index 93c6a05375..20f4e51d10 100644 --- a/arch/powerpc/platforms/cell/spufs/spufs.h +++ b/arch/powerpc/platforms/cell/spufs/spufs.h @@ -51,6 +51,7 @@ struct spu_context { struct kref kref; wait_queue_head_t ibox_wq; wait_queue_head_t wbox_wq; + wait_queue_head_t stop_wq; struct fasync_struct *ibox_fasync; struct fasync_struct *wbox_fasync; struct spu_context_ops *ops; @@ -74,6 +75,8 @@ struct spu_context_ops { void (*npc_write) (struct spu_context * ctx, u32 data); u32(*status_read) (struct spu_context * ctx); char*(*get_ls) (struct spu_context * ctx); + void (*runcntl_write) (struct spu_context * ctx, u32 data); + void (*runcntl_stop) (struct spu_context * ctx); }; extern struct spu_context_ops spu_hw_ops; @@ -99,6 +102,7 @@ struct spu_context * alloc_spu_context(struct address_space *local_store); void destroy_spu_context(struct kref *kref); struct spu_context * get_spu_context(struct spu_context *ctx); int put_spu_context(struct spu_context *ctx); +void spu_unmap_mappings(struct spu_context *ctx); void spu_forget(struct spu_context *ctx); void spu_acquire(struct spu_context *ctx); @@ -118,5 +122,6 @@ size_t spu_ibox_read(struct spu_context *ctx, u32 *data); /* irq callback funcs. */ void spufs_ibox_callback(struct spu *spu); void spufs_wbox_callback(struct spu *spu); +void spufs_stop_callback(struct spu *spu); #endif diff --git a/include/asm-powerpc/spu.h b/include/asm-powerpc/spu.h index 092ec97be3..dd91ed8563 100644 --- a/include/asm-powerpc/spu.h +++ b/include/asm-powerpc/spu.h @@ -135,9 +135,9 @@ struct spu { spinlock_t register_lock; u32 stop_code; - wait_queue_head_t stop_wq; void (* wbox_callback)(struct spu *spu); void (* ibox_callback)(struct spu *spu); + void (* stop_callback)(struct spu *spu); char irq_c0[8]; char irq_c1[8]; @@ -146,7 +146,8 @@ struct spu { struct spu *spu_alloc(void); void spu_free(struct spu *spu); -int spu_run(struct spu *spu); +int spu_irq_class_0_bottom(struct spu *spu); +int spu_irq_class_1_bottom(struct spu *spu); extern struct spufs_calls { asmlinkage long (*create_thread)(const char __user *name, -- 2.39.5