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From: Andrew Morton <akpm@osdl.org>
To: James Bottomley <James.Bottomley@SteelEye.com>
Cc: johnstul@us.ibm.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fix get_jiffies_64 to work on voyager
Date: Tue, 6 Jan 2004 09:05:21 -0800	[thread overview]
Message-ID: <20040106090521.4a7ad2a0.akpm@osdl.org> (raw)
In-Reply-To: <1073406369.2047.33.camel@mulgrave>

James Bottomley <James.Bottomley@SteelEye.com> wrote:
>
> On Tue, 2004-01-06 at 10:19, Andrew Morton wrote:
> > Hm, OK.  I hit the same deadlock when running with the "don't require TSCs
> > to be synchronised in sched_clock()" patch from -mm.  The fix for that is
> > below.  I shall accelerate it.
> 
> Actually, I think we need to know why this is happening, since the use
> of these sequence locks is growing.

That would be nice.  Can you get a backtrace?

> On voyager I just put it down to HZ
> == 1000 being a bit much for my old pentium 66MHz processors, but if
> you've seen it on a much faster processor, that would tend to indicate
> there's some other problem at work here.

No, it was much simpler in my case: log_buf_len_setup() was accidentally
enabling interrupts early in boot and we were taking a timer interrupt
while holding a write lock on xtime_lock.  sched_clock() was requiring a
read lock and boom.


  reply	other threads:[~2004-01-06 17:05 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-06 16:04 [PATCH] fix get_jiffies_64 to work on voyager James Bottomley
2004-01-06 16:19 ` Andrew Morton
2004-01-06 16:26   ` James Bottomley
2004-01-06 17:05     ` Andrew Morton [this message]
2004-01-06 18:53       ` James Bottomley
2004-01-06 16:29   ` Linus Torvalds
2004-01-06 17:05     ` Andrew Morton
2004-01-06 17:11     ` Tim Schmielau
2004-01-06 17:22       ` Andrew Morton
2004-01-06 17:37         ` Tim Schmielau
2004-01-06 18:02       ` Linus Torvalds
2004-01-06 16:30   ` Tim Schmielau
2004-01-06 16:26 ` Linus Torvalds
2004-01-06 18:29   ` Paulo Marques
2004-01-06 18:46     ` Linus Torvalds
2004-01-06 19:04       ` Paulo Marques

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