Date: Mon, 7 Feb 2011 11:04:51 -0500
From: Vivek Goyal <vgoyal@redhat.com>
To: "Haefliger, Juerg" <Juerg.Haefliger@hp.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: Block IO throttling disabled in distros
Message-ID: <20110207160451.GH7437@redhat.com>
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On Mon, Feb 07, 2011 at 03:33:38PM +0000, Haefliger, Juerg wrote:
> Hi,
> 
> Both RHEL6 and Ubuntu 10.10 have block IO throttling disabled in their kernels. Does anybody know why that is? Are there performance or stability issues with the throttling controller or does it somehow negatively interfere with the rest of the kernel and/or system?

Block IO throttling support was not even upstream at that time hence
you don't see it. 

I have not heard about any stability issues so far. Of course more testing
will reveal that.

The only thing I have thinking is that should we limit the number of bios
queued per IO context on the device. Currently there is no such limit
and one can queue up as many bios as one want to.

Thanks
Vivek
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