powerpc/spufs: Allow gang to grow in size after it has been started

Submitted by Andre Detsch on Sept. 11, 2008, 11:38 p.m.


Message ID 200809112038.17055.adetsch@br.ibm.com
State Superseded
Delegated to: Jeremy Kerr
Headers show

Commit Message

Andre Detsch Sept. 11, 2008, 11:38 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>

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diff --git a/arch/powerpc/platforms/cell/spufs/context.c 
index 21ba409..c472519 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 
 	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);
+	}