[POWERPC] spusched: Update scheduling paramters on every spu_run

Update scheduling information on every spu_run to allow for setting
threads to realtime priority just before running them.  This requires
some slightly ugly code in spufs_run_spu because we can just update
the information unlocked if the spu is not runnable, but we need to
acquire the active_mutex when it is runnable to protect against
find_victim.  This locking scheme requires opencoding
spu_acquire_runnable in spufs_run_spu which actually is a nice cleanup
all by itself.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 002b40af4a77..3707c7fdbdee 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -96,6 +96,33 @@ void spu_set_timeslice(struct spu_context *ctx)
                 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)
+{
+        /*
+         * We do our own priority calculations, so we normally want
+         * ->static_prio to start with. Unfortunately thies 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;
+}
+
+void spu_update_sched_info(struct spu_context *ctx)
+{
+        int node = ctx->spu->node;
+
+        mutex_lock(&spu_prio->active_mutex[node]);
+        __spu_update_sched_info(ctx);
+        mutex_unlock(&spu_prio->active_mutex[node]);
+}
+
 static inline int node_allowed(int node)
 {
         cpumask_t mask;