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From: Ingo Molnar <mingo@elte.hu>
To: huggie@earth.li, linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Subject: Re: Scheduler broken? sdhci issues with scheduling
Date: Fri, 29 Feb 2008 14:34:33 +0100	[thread overview]
Message-ID: <20080229133433.GA15532@elte.hu> (raw)
In-Reply-To: <20080229115256.GG24533@paranoidfreak.co.uk>


* Simon Huggins <huggie@earth.li> wrote:

> [ Please Cc me on replies ]
> 
> I had a bug with sdhci which Pierre Ossman looked at for me.
> 
> In the end essentially the fix was to use HZ=1000 and nothing else. 
> Pierre seemed to think that this was a bug in the scheduler.

does the patch below help, even if you keep HZ=100? This doesnt look 
like a scheduler issue, it's more of a timer/timing issue. Different HZ 
means different msleep() results - and the mmc code does a loop of small 
msleep delays.

	Ingo

-------------->
---
 drivers/mmc/core/core.h |    7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

Index: linux/drivers/mmc/core/core.h
===================================================================
--- linux.orig/drivers/mmc/core/core.h
+++ linux/drivers/mmc/core/core.h
@@ -36,12 +36,7 @@ void mmc_set_timing(struct mmc_host *hos
 
 static inline void mmc_delay(unsigned int ms)
 {
-	if (ms < 1000 / HZ) {
-		cond_resched();
-		mdelay(ms);
-	} else {
-		msleep(ms);
-	}
+	mdelay(ms);
 }
 
 void mmc_rescan(struct work_struct *work);

  reply	other threads:[~2008-02-29 13:34 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-29 11:52 Simon Huggins
2008-02-29 13:34 ` Ingo Molnar [this message]
2008-02-29 13:51   ` Ingo Molnar
2008-02-29 14:00     ` Ingo Molnar
2008-02-29 19:39       ` Simon Huggins
2008-02-29 20:39         ` Ingo Molnar
2008-03-01 12:42           ` Simon Huggins
2008-03-01 14:08             ` Pierre Ossman
2008-03-02 10:40 ` Pavel Machek
2008-03-02 18:04   ` Simon Huggins
2008-03-03 19:43   ` Pierre Ossman
2008-03-03 20:38     ` Pavel Machek
2008-03-03 21:05       ` Pierre Ossman
2008-03-13 21:17         ` Simon Huggins
2008-03-15 15:04           ` Pierre Ossman
2008-04-20 21:07             ` Simon Huggins

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