From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: miaox@cn.fujitsu.com
Cc: Ingo Molnar <mingo@elte.hu>, Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched: fair-group: fix a Div0 error of the fair group scheduler
Date: Mon, 28 Apr 2008 10:33:45 +0200 [thread overview]
Message-ID: <1209371625.13978.1.camel@twins> (raw)
In-Reply-To: <48158A78.5010904@cn.fujitsu.com>
On Mon, 2008-04-28 at 16:27 +0800, Miao Xie wrote:
> I'm sorry, I didn't explained clearly.Though echoing ULONG_MAX value into
> cpu.shares causes Div0 error, this error was not caused by the above code.
> It is caused by the following code.
>
> calc_delta_mine()
> ->lw->inv_weight = (WMULT_CONST-lw->weight/2) / (lw->weight+1);
>
> And besides, the Div0 error caused by echoing ULONG_MAX occured on the UP system
> or on SMP system with only one cpu.
>
> So this patch fixes the bug caused by echoing a number which was less than the number
> of processores into the "cpu.shares" file, but doesn't fix the bug caused by echoing
> ULONG_MAX.
Ah, ok. But I guess we run into other problems with weights that heavy,
but we should not crash.
Ok, I'll ACK your initial patch
next prev parent reply other threads:[~2008-04-28 8:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-28 4:54 [PATCH] sched: fair-group: fix a Div0 error of the fair group scheduler Miao Xie
2008-04-28 5:45 ` Peter Zijlstra
2008-04-28 8:27 ` Miao Xie
2008-04-28 8:33 ` Peter Zijlstra [this message]
2008-04-28 8:34 ` Peter Zijlstra
2008-04-28 12:51 ` Ingo Molnar
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