[POWERPC] spufs: optimize spu_run

There is no need to directly wake up contexts in spu_activate when
called from spu_run, so add a flag to surpress this wakeup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

5 files changed, 23 insertions, 12 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index 88a887186303..056a8ad02385 100644
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -163,7 +163,7 @@ int spu_acquire_exclusive(struct spu_context *ctx)
  *      Returns 0 and with the context locked on success
  *      Returns negative error and with the context _unlocked_ on failure.
  */
-int spu_acquire_runnable(struct spu_context *ctx)
+int spu_acquire_runnable(struct spu_context *ctx, unsigned long flags)
 {
         int ret = -EINVAL;
 
@@ -174,7 +174,7 @@ int spu_acquire_runnable(struct spu_context *ctx)
                  */
                 if (!ctx->owner)
                         goto out_unlock;
-                ret = spu_activate(ctx, 0);
+                ret = spu_activate(ctx, flags);
                 if (ret)
                         goto out_unlock;
         }
diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index a528020baa18..c729813043a6 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -164,7 +164,7 @@ static unsigned long spufs_ps_nopfn(struct vm_area_struct *vma,
         /* error here usually means a signal.. we might want to test
          * the error code more precisely though
          */
-        ret = spu_acquire_runnable(ctx);
+        ret = spu_acquire_runnable(ctx, 0);
         if (ret)
                 return NOPFN_REFAULT;
 
@@ -1306,7 +1306,7 @@ static ssize_t spufs_mfc_write(struct file *file, const char __user *buffer,
         if (ret)
                 goto out;
 
-        spu_acquire_runnable(ctx);
+        spu_acquire_runnable(ctx, 0);
         if (file->f_flags & O_NONBLOCK) {
                 ret = ctx->ops->send_mfc_command(ctx, &cmd);
         } else {
diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
index e1647311044b..a973e79e9fdc 100644
--- a/arch/powerpc/platforms/cell/spufs/run.c
+++ b/arch/powerpc/platforms/cell/spufs/run.c
@@ -143,7 +143,7 @@ static inline int spu_run_init(struct spu_context *ctx, u32 * npc)
         int ret;
         unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
 
-        ret = spu_acquire_runnable(ctx);
+        ret = spu_acquire_runnable(ctx, SPU_ACTIVATE_NOWAKE);
         if (ret)
                 return ret;
 
@@ -155,7 +155,7 @@ static inline int spu_run_init(struct spu_context *ctx, u32 * npc)
                         spu_release(ctx);
                         ret = spu_setup_isolated(ctx);
                         if (!ret)
-                                ret = spu_acquire_runnable(ctx);
+                                ret = spu_acquire_runnable(ctx, SPU_ACTIVATE_NOWAKE);
                 }
 
                 /* if userspace has set the runcntrl register (eg, to issue an
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 6f8e2257c5a6..07d0d095c62a 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -247,8 +247,8 @@ static void spu_prio_wait(struct spu_context *ctx)
 {
         DEFINE_WAIT(wait);
 
+        set_bit(SPU_SCHED_WAKE, &ctx->sched_flags);
         prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
-
         if (!signal_pending(current)) {
                 mutex_unlock(&ctx->state_mutex);
                 schedule();
@@ -256,6 +256,7 @@ static void spu_prio_wait(struct spu_context *ctx)
         }
         __set_current_state(TASK_RUNNING);
         remove_wait_queue(&ctx->stop_wq, &wait);
+        clear_bit(SPU_SCHED_WAKE, &ctx->sched_flags);
 }
 
 /**
@@ -275,7 +276,7 @@ static void spu_reschedule(struct spu *spu)
         best = sched_find_first_bit(spu_prio->bitmap);
         if (best < MAX_PRIO) {
                 struct spu_context *ctx = spu_grab_context(best);
-                if (ctx)
+                if (ctx && test_bit(SPU_SCHED_WAKE, &ctx->sched_flags))
                         wake_up(&ctx->stop_wq);
         }
         spin_unlock(&spu_prio->runq_lock);
@@ -315,7 +316,7 @@ static struct spu *spu_get_idle(struct spu_context *ctx)
  * add the context to the runqueue so it gets woken up once an spu
  * is available.
  */
-int spu_activate(struct spu_context *ctx, u64 flags)
+int spu_activate(struct spu_context *ctx, unsigned long flags)
 {
 
         if (ctx->spu)
@@ -331,7 +332,8 @@ int spu_activate(struct spu_context *ctx, u64 flags)
                 }
 
                 spu_add_to_rq(ctx);
-                spu_prio_wait(ctx);
+                if (!(flags & SPU_ACTIVATE_NOWAKE))
+                        spu_prio_wait(ctx);
                 spu_del_from_rq(ctx);
         } while (!signal_pending(current));
 
diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 7f5a4fc03c00..421f59167c55 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -39,6 +39,11 @@ enum {
 struct spu_context_ops;
 struct spu_gang;
 
+/* ctx->sched_flags */
+enum {
+        SPU_SCHED_WAKE = 0,
+};
+
 struct spu_context {
         struct spu *spu;                  /* pointer to a physical SPU */
         struct spu_state csa;             /* SPU context save area. */
@@ -77,6 +82,7 @@ struct spu_context {
 
         /* scheduler fields */
         struct list_head rq;
+        unsigned long sched_flags;
         int prio;
 };
 
@@ -179,10 +185,13 @@ int put_spu_context(struct spu_context *ctx);
 void spu_unmap_mappings(struct spu_context *ctx);
 
 void spu_forget(struct spu_context *ctx);
-int spu_acquire_runnable(struct spu_context *ctx);
+int spu_acquire_runnable(struct spu_context *ctx, unsigned long flags);
 void spu_acquire_saved(struct spu_context *ctx);
 int spu_acquire_exclusive(struct spu_context *ctx);
-int spu_activate(struct spu_context *ctx, u64 flags);
+enum {
+        SPU_ACTIVATE_NOWAKE = 1,
+};
+int spu_activate(struct spu_context *ctx, unsigned long flags);
 void spu_deactivate(struct spu_context *ctx);
 void spu_yield(struct spu_context *ctx);
 int __init spu_sched_init(void);