Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757454AbZJSUJf (ORCPT ); Mon, 19 Oct 2009 16:09:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753486AbZJSUJf (ORCPT ); Mon, 19 Oct 2009 16:09:35 -0400 Received: from b.jim.sh ([75.150.123.26]:58069 "EHLO psychosis.jim.sh" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757414AbZJSUJe (ORCPT ); Mon, 19 Oct 2009 16:09:34 -0400 X-Greylist: delayed 365 seconds by postgrey-1.27 at vger.kernel.org; Mon, 19 Oct 2009 16:09:34 EDT Date: Mon, 19 Oct 2009 16:03:20 -0400 From: Jim Paris To: Geoff Levand Cc: Jens Axboe , Cell Broadband Engine OSS Development , Geert Uytterhoeven , linux-kernel@vger.kernel.org Subject: Re: [PATCH] block/ps3: Fix slow VRAM IO Message-ID: <20091019200320.GA30464@psychosis.jim.sh> References: <4ADCC4E3.8060104@am.sony.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ADCC4E3.8060104@am.sony.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1586 Lines: 51 Geoff Levand wrote: > > From: Hideyuki Sasaki > > The current PS3 VRAM driver uses msleep() to wait for completion > of RSX DMA transfers between system memory and VRAM. Depending > on the system timing, the processing delay and overhead of this > msleep() call can significantly impact VRAM driver IO. > > To avoid the condition, add a short duration (200 usec max) > udelay() polling loop before entering the msleep() polling > loop. > > Signed-off-by: Hideyuki Sasaki > Signed-off-by: Geoff Levand Acked-by: Jim Paris Thanks for tracking this down. -jim > --- > > drivers/block/ps3vram.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > --- a/drivers/block/ps3vram.c > +++ b/drivers/block/ps3vram.c > @@ -123,7 +123,15 @@ static int ps3vram_notifier_wait(struct > { > struct ps3vram_priv *priv = ps3_system_bus_get_drvdata(dev); > u32 *notify = ps3vram_get_notifier(priv->reports, NOTIFIER); > - unsigned long timeout = jiffies + msecs_to_jiffies(timeout_ms); > + unsigned long timeout; > + > + for (timeout = 20; timeout; timeout--) { > + if (!notify[3]) > + return 0; > + udelay(10); > + } > + > + timeout = jiffies + msecs_to_jiffies(timeout_ms); > > do { > if (!notify[3]) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/