Re: [PATCH] hostmem: don't use mbind() if host-nodes is epmty

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 5/11/20 9:24 PM, Igor Mammedov wrote:
> On Mon, 11 May 2020 18:00:01 +0200
> Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
> 
>> Hi Eduardo,
>>
>> On 5/4/20 5:44 PM, Eduardo Habkost wrote:
>>> On Thu, Apr 30, 2020 at 11:46:06AM -0400, Igor Mammedov wrote:
>>>> Since 5.0 QEMU uses hostmem backend for allocating main guest RAM.
>>>> The backend however calls mbind() which is typically NOP
>>>> in case of default policy/absent host-nodes bitmap.
>>>> However when runing in container with black-listed mbind()
>>>> syscall, QEMU fails to start with error
>>>>    "cannot bind memory to host NUMA nodes: Operation not permitted"
>>>> even when user hasn't provided host-nodes to pin to explictly
>>>> (which is the case with -m option)
>>>>
>>>> To fix issue, call mbind() only in case when user has provided
>>>> host-nodes explicitly (i.e. host_nodes bitmap is not empty).
>>>> That should allow to run QEMU in containers with black-listed
>>>> mbind() without memory pinning. If QEMU provided memory-pinning
>>>> is required user still has to white-list mbind() in container
>>>> configuration.
>>>>
>>>> Reported-by: Manuel Hohmann <mhohmann@physnet.uni-hamburg.de>
>>>> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
>>>
>>> Queued on machine-next, thanks!
>>
>> I've been debugging this issue again today and figured it was not
>> merged, if possible can you add the "Cc: qemu-stable@nongnu.org" tag
>> before sending your pull request?
> it's CCed already, so my impression was that will should picked up once it was reviewed.

Correct, however some distributions find easier to grep for the 'Cc: 
qemu-stable@nongnu.org' merged tag before qemu-stable is released.

> 
>>
>> Thanks,
>>
>> Phil.
>>
>