[07/18] powerpc/spufs: Allow gang to grow in size after it has been started

Submitted by Andre Detsch on Dec. 10, 2008, 7:40 p.m.

Details

Message ID 200812101740.53135.adetsch@br.ibm.com
State RFC
Headers show

Commit Message

Andre Detsch Dec. 10, 2008, 7:40 p.m.
Just deactivate it, add the new context, and let the calling thread
drives its reactivation.  It needs to be unscheduled, since it may
no longer fit or it may need to be migrated to a different node.

Signed-off-by: Luke Browning <lukebrowning@us.ibm.com>
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
---
 arch/powerpc/platforms/cell/spufs/context.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

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diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index b810050..d3887fe 100644
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -57,6 +57,17 @@  struct spu_context *alloc_spu_context(struct spu_gang *gang)
 	if (spu_init_csa(&ctx->csa))
 		goto out_free_gang;
 
+	/* If the gang is running, it needs to be stopped, since we have a
+	 * new context that needs to be gang scheduled.  Gangs are allowed
+	 * to grow and shrink over time, but they are unscheduled when it
+	 * happens as the gang may need to migrated to a different node.
+	 */
+	if (atomic_read(&gang->nstarted)) {
+		mutex_lock(&gang->mutex);
+		spu_deactivate(gang);
+		mutex_unlock(&gang->mutex);
+	}
+
 	spin_lock_init(&ctx->mmio_lock);
 	mutex_init(&ctx->mapping_lock);
 	kref_init(&ctx->kref);