Re: [Linux-fbdev-devel] [PATCH 1/4 (updated)] ps3fb: thread updates

On Fri, 16 Feb 2007, Geert Uytterhoeven wrote:

On Fri, 16 Feb 2007, Christoph Hellwig wrote:

quoted

quoted

+	DEFINE_WAIT(wait);
+	DECLARE_WAIT_QUEUE_HEAD(wq);
+
+	while (!kthread_should_stop()) {
+		prepare_to_wait(&wq, &wait, TASK_INTERRUPTIBLE);
+		if (!ps3fb.is_kicked)
+			schedule();
+		finish_wait(&wq, &wait);
+		ps3fb.is_kicked = 0;
+		ps3fb_sync(0);	/* single buffer */

should probably be just:

	while (!kthread_should_stop()) {
		ps3fb_sync(0);
		schedule();
	}

given that you don't need a waitqueue and a spurious wakeup here
seems harmless.

Not always. If flipping is disabled, or external flip is enabled, you don't
want a spurious flip.

Looks like the waitqueue is needed. Without it ps3fbd runs at 100% CPU and +15
million loops per second.

Gr{oetje,eeting}s,

						Geert

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Geert Uytterhoeven -- Sony Network and Software Technology Center Europe (NSCE)
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