Re: [PATCH v7u1 26/31] x86: Don't enable swiotlb if there is notenough ram for it

From: Shuah Khan
Date: Fri Jan 04 2013 - 17:25:52 EST

On Fri, Jan 4, 2013 at 3:10 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> On Fri, Jan 4, 2013 at 1:02 PM, Shuah Khan <shuahkhan@xxxxxxxxx> wrote:
>> Pani'cing the system doesn't sound like a good option to me in this
>> case. This change to disable swiotlb is made for kdump. However, with
>> this change several system fail to boot, unless crashkernel_low=72M is
>> specified.
> this patchset is new feature to put second kdump kernel above 4G.
I understand this is just one of the patches to implement the new
kdump feature. However, I think regression on existing behavior with a
panic is a bit of a big hammer. Thie change causes panic on systems
even when kdump is not enabled, if I understand it correctly.

Granted kdump gets enabled by several distros, but it is not a
required feature. However, expecting system to boot with devices that
require swiotlb fully functioning is a basic feature. So I would argue
that not breaking the basic functionality is a higher priority over
enabling kdump in this case.

-- Shuah
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