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Subject: Re: [PATCH v2] powerpc/mm: move a KERN_WARNING message to pr_debug()
To:     Michael Ellerman <mpe@ellerman.id.au>, linux-kernel@vger.kernel.org
Cc:     linuxppc-dev@lists.ozlabs.org,
        David Gibson <david@gibson.dropbear.id.au>,
        Christophe Leroy <christophe.leroy@c-s.fr>
References: <20190205202133.5048-1-lvivier@redhat.com>
 <8736p0kyiy.fsf@concordia.ellerman.id.au>
From:   Laurent Vivier <lvivier@redhat.com>
Message-ID: <866a19ec-93b2-de04-d8a3-11858fcaacea@redhat.com>
Date:   Thu, 7 Feb 2019 10:13:47 +0100
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On 07/02/2019 05:33, Michael Ellerman wrote:
> Hi Laurent,
> 
> I'm not sure I'm convinced about this one. It seems like we're just
> throwing away the warning because it's annoying.
> 
> Laurent Vivier <lvivier@redhat.com> writes:
>> resize_hpt_for_hotplug() reports a warning when it cannot
>> increase the hash page table ("Unable to resize hash page
>> table to target order") but this is not blocking and
>> can make user thinks something has not worked properly.
> 
> Something did not work properly, the resize didn't work properly. Right?
> 
>> As we move the message to the debug area, report again the
>> ENODEV error.
>>
>> If the operation cannot be done the real error message
>> will be reported by arch_add_memory() if create_section_mapping()
>> fails.
> 
> Can you explain that more. Isn't the fact that the resize failed "the
> real error message"?

In arch_add_memory(), after calling resize_hpt_for_hotplug() it calls
create_section_mapping() and if create_section_mapping() fails we will
have the error message "Unable to create mapping for hot added memory"
and the real exit (EFAULT).

> 
>> Fixes: 7339390d772dd
>>        powerpc/pseries: Don't give a warning when HPT resizing isn't available
> 
> This should all be on one line, and formatted as:
> 
> Fixes: 7339390d772d ("powerpc/pseries: Don't give a warning when HPT resizing isn't available")
> 
> See Documentation/process/submitting-patches.rst for more info and how
> to configure git to do it automatically for you.

Thank you, I didn't know the format was documented.

Thanks,
Laurent