From: David Hildenbrand <david@redhat.com>
To: Alex Shi <alex.shi@linux.alibaba.com>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Michael S . Tsirkin" <mst@redhat.com>,
Sebastien Boeuf <sebastien.boeuf@intel.com>,
Samuel Ortiz <samuel.ortiz@intel.com>,
Robert Bradford <robert.bradford@intel.com>,
Luiz Capitulino <lcapitulino@redhat.com>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Alexander Potapenko <glider@google.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Anthony Yznaga <anthony.yznaga@oracle.com>,
Dan Williams <dan.j.williams@intel.com>,
Dave Young <dyoung@redhat.com>,
Igor Mammedov <imammedo@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Juergen Gross <jgross@suse.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Len Brown <lenb@kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@suse.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Oscar Salvador <osalvador@suse.com>,
Oscar Salvador <osalvador@suse.de>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Pavel Tatashin <pavel.tatashin@microsoft.com>,
Pingfan Liu <kernelfans@gmail.com>, Qian Cai <cai@lca.pw>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Stefan Hajnoczi <stefanha@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
Wei Yang <richard.weiyang@gmail.com>
Subject: Re: [PATCH RFC v4 00/13] virtio-mem: paravirtualized memory
Date: Fri, 5 Jun 2020 12:05:40 +0200 [thread overview]
Message-ID: <e1643897-ebd7-75f8-d271-44f62318aa66@redhat.com> (raw)
In-Reply-To: <6b4724bf-84b5-9880-5464-1908425d106d@redhat.com>
On 05.06.20 11:36, David Hildenbrand wrote:
> On 05.06.20 11:08, David Hildenbrand wrote:
>> On 05.06.20 10:55, Alex Shi wrote:
>>>
>>>
>>> 在 2020/1/9 下午9:48, David Hildenbrand 写道:
>>>> Ping,
>>>>
>>>> I'd love to get some feedback on
>>>>
>>>> a) The remaining MM bits from MM folks (especially, patch #6 and #8).
>>>> b) The general virtio infrastructure (esp. uapi in patch #2) from virtio
>>>> folks.
>>>>
>>>> I'm planning to send a proper v1 (!RFC) once I have all necessary MM
>>>> acks. In the meanwhile, I will do more testing and minor reworks (e.g.,
>>>> fix !CONFIG_NUMA compilation).
>>>
>>>
>>> Hi David,
>>>
>>> Thanks for your work!
>>>
>>> I am trying your https://github.com/davidhildenbrand/linux.git virtio-mem-v5
>>> which works fine for me, but just a 'DMA error' happens when a vm start with
>>> less than 2GB memory, Do I missed sth?
>>
>> Please use the virtio-mem-v4 branch for now, v5 is still under
>> construction (and might be scrapped completely if v4 goes upstream as is).
>>
>> Looks like a DMA issue. Your're hotplugging 1GB, which should not really
>> eat too much memory. There was a similar issue reported by Hui in [1],
>> which boiled down to wrong usage of the swiotlb parameter.
>>
>> In such cases you should always try to reproduce with hotplug of a
>> sam-sized DIMM. E.g., hotplugging a 1GB DIMM should result in the same
>> issue.
>>
>> What does your .config specify for CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE?
>>
>> I'll try to reproduce with v4 briefly.
>
> I guess I know what's happening here. In case we only have DMA memory
> when booting, we don't reserve swiotlb buffers. Once we hotplug memory
> and online ZONE_NORMAL, we don't have any swiotlb DMA bounce buffers to
> map such PFNs (total 0 (slots), used 0 (slots)).
>
> Can you try with "swiotlb=force" on the kernel cmdline?
Alternative, looks like you can specify "-m 2G,maxmem=16G,slots=1", to
create proper ACPI tables that indicate hotpluggable memory. (I'll have
to look into QEMU to figure out to always indicate hotpluggable memory
that way).
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-06-05 10:06 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-12 17:11 [PATCH RFC v4 00/13] virtio-mem: paravirtualized memory David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 01/13] ACPI: NUMA: export pxm_to_node David Hildenbrand
2019-12-12 21:43 ` Rafael J. Wysocki
2019-12-13 9:41 ` David Hildenbrand
2019-12-13 9:47 ` Rafael J. Wysocki
2019-12-12 17:11 ` [PATCH RFC v4 02/13] virtio-mem: Paravirtualized memory hotplug David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 03/13] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 04/13] mm: Export alloc_contig_range() / free_contig_range() David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 05/13] virtio-mem: Paravirtualized memory hotunplug part 2 David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 06/13] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE David Hildenbrand
2020-02-25 18:26 ` Alexander Duyck
2020-02-25 18:49 ` David Hildenbrand
2020-02-25 21:46 ` Alexander Duyck
2020-02-25 22:19 ` David Hildenbrand
2020-02-26 16:27 ` Alexander Duyck
2019-12-12 17:11 ` [PATCH RFC v4 07/13] virtio-mem: Allow to offline partially unplugged memory blocks David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 08/13] mm/memory_hotplug: Introduce offline_and_remove_memory() David Hildenbrand
2020-02-25 14:11 ` Michal Hocko
2020-02-25 14:27 ` David Hildenbrand
2020-03-02 12:48 ` Michal Hocko
2020-03-02 12:53 ` David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 09/13] virtio-mem: Offline and remove completely unplugged memory blocks David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 10/13] virtio-mem: Better retry handling David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 11/13] mm/vmscan: Move count_vm_event(DROP_SLAB) into drop_slab() David Hildenbrand
2020-02-25 14:13 ` Michal Hocko
2019-12-12 17:11 ` [PATCH RFC v4 12/13] mm/vmscan: Export drop_slab() and drop_slab_node() David Hildenbrand
2020-02-25 14:58 ` Michal Hocko
2020-02-25 15:09 ` David Hildenbrand
2020-02-25 17:06 ` Michal Hocko
2020-02-25 17:23 ` David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 13/13] virtio-mem: Drop slab objects when unplug continues to fail David Hildenbrand
2019-12-13 20:15 ` [PATCH RFC v4 00/13] virtio-mem: paravirtualized memory Konrad Rzeszutek Wilk
2019-12-16 11:03 ` David Hildenbrand
2019-12-24 6:58 ` teawater
2019-12-24 9:28 ` David Hildenbrand
2020-01-09 13:48 ` David Hildenbrand
2020-01-29 9:41 ` David Hildenbrand
2020-02-25 9:58 ` David Hildenbrand
2020-06-05 8:55 ` Alex Shi
2020-06-05 9:08 ` David Hildenbrand
2020-06-05 9:36 ` David Hildenbrand
2020-06-05 10:05 ` David Hildenbrand [this message]
2020-06-05 10:46 ` Alex Shi
2020-06-05 12:18 ` David Hildenbrand
2020-06-09 3:05 ` Alex Shi
2020-06-05 10:08 ` Alex Shi
2020-06-05 10:06 ` Alex Shi
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