From: Nitesh Narayan Lal <nitesh@redhat.com>
To: Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Alexander Duyck <alexander.duyck@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
kvm@vger.kernel.org, david@redhat.com, dave.hansen@intel.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, yang.zhang.wz@gmail.com,
pagupta@redhat.com, riel@surriel.com, konrad.wilk@oracle.com,
lcapitulino@redhat.com, wei.w.wang@intel.com,
aarcange@redhat.com, pbonzini@redhat.com,
dan.j.williams@intel.com
Subject: Re: [PATCH v2 QEMU] virtio-balloon: Provide a interface for "bubble hinting"
Date: Thu, 25 Jul 2019 07:57:35 -0400 [thread overview]
Message-ID: <bbfe0fbb-dd23-ed5c-01b3-493ae804942f@redhat.com> (raw)
In-Reply-To: <6218af96d7d55935f2cf607d47680edc9b90816e.camel@linux.intel.com>
On 7/24/19 4:18 PM, Alexander Duyck wrote:
> On Wed, 2019-07-24 at 15:02 -0400, Michael S. Tsirkin wrote:
>> On Wed, Jul 24, 2019 at 10:12:10AM -0700, Alexander Duyck wrote:
>>> From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>>>
>>> Add support for what I am referring to as "bubble hinting". Basically the
>>> idea is to function very similar to how the balloon works in that we
>>> basically end up madvising the page as not being used. However we don't
>>> really need to bother with any deflate type logic since the page will be
>>> faulted back into the guest when it is read or written to.
>>>
>>> This is meant to be a simplification of the existing balloon interface
>>> to use for providing hints to what memory needs to be freed. I am assuming
>>> this is safe to do as the deflate logic does not actually appear to do very
>>> much other than tracking what subpages have been released and which ones
>>> haven't.
>>>
>>> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>>> ---
>>> hw/virtio/virtio-balloon.c | 40 +++++++++++++++++++++++
>>> include/hw/virtio/virtio-balloon.h | 2 +
>>> include/standard-headers/linux/virtio_balloon.h | 1 +
>>> 3 files changed, 42 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
>>> index 2112874055fb..70c0004c0f88 100644
>>> --- a/hw/virtio/virtio-balloon.c
>>> +++ b/hw/virtio/virtio-balloon.c
>>> @@ -328,6 +328,39 @@ static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
>>> balloon_stats_change_timer(s, 0);
>>> }
>>>
>>> +static void virtio_bubble_handle_output(VirtIODevice *vdev, VirtQueue *vq)
>>> +{
>>> + VirtQueueElement *elem;
>>> +
>>> + while ((elem = virtqueue_pop(vq, sizeof(VirtQueueElement)))) {
>>> + unsigned int i;
>>> +
>>> + for (i = 0; i < elem->in_num; i++) {
>>> + void *addr = elem->in_sg[i].iov_base;
>>> + size_t size = elem->in_sg[i].iov_len;
>>> + ram_addr_t ram_offset;
>>> + size_t rb_page_size;
>>> + RAMBlock *rb;
>>> +
>>> + if (qemu_balloon_is_inhibited())
>>> + continue;
>>> +
>>> + rb = qemu_ram_block_from_host(addr, false, &ram_offset);
>>> + rb_page_size = qemu_ram_pagesize(rb);
>>> +
>>> + /* For now we will simply ignore unaligned memory regions */
>>> + if ((ram_offset | size) & (rb_page_size - 1))
>>> + continue;
>>> +
>>> + ram_block_discard_range(rb, ram_offset, size);
>> I suspect this needs to do like the migration type of
>> hinting and get disabled if page poisoning is in effect.
>> Right?
> Shouldn't something like that end up getting handled via
> qemu_balloon_is_inhibited, or did I miss something there? I assumed cases
> like that would end up setting qemu_balloon_is_inhibited to true, if that
> isn't the case then I could add some additional conditions. I would do it
> in about the same spot as the qemu_balloon_is_inhibited check.
Just wondering if you have tried running these patches in an environment with
directly assigned devices? Ideally, I would expect qemu_balloon_is_inhibited()
to take care of it.
>
>
--
Thanks
Nitesh
next prev parent reply other threads:[~2019-07-25 11:57 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-24 16:54 [PATCH v2 0/5] mm / virtio: Provide support for page hinting Alexander Duyck
2019-07-24 16:56 ` [PATCH v2 1/5] mm: Adjust shuffle code to allow for future coalescing Alexander Duyck
2019-07-24 16:58 ` [PATCH v2 2/5] mm: Move set/get_pcppage_migratetype to mmzone.h Alexander Duyck
2019-07-24 17:00 ` [PATCH v2 3/5] mm: Use zone and order instead of free area in free_list manipulators Alexander Duyck
2019-07-24 17:03 ` [PATCH v2 4/5] mm: Introduce Hinted pages Alexander Duyck
2019-07-25 8:53 ` David Hildenbrand
2019-07-25 11:46 ` Nitesh Narayan Lal
2019-07-25 11:54 ` David Hildenbrand
2019-07-25 15:59 ` Alexander Duyck
2019-07-25 16:48 ` David Hildenbrand
2019-07-25 17:38 ` Alexander Duyck
2019-07-25 18:32 ` David Hildenbrand
2019-07-25 20:37 ` Alexander Duyck
2019-07-25 20:44 ` David Hildenbrand
2019-07-26 12:24 ` Nitesh Narayan Lal
2019-07-26 16:38 ` Alexander Duyck
2019-07-24 17:05 ` [PATCH v2 5/5] virtio-balloon: Add support for providing page hints to host Alexander Duyck
2019-07-24 19:02 ` Michael S. Tsirkin
2019-07-24 19:07 ` Nitesh Narayan Lal
2019-07-24 19:26 ` Michael S. Tsirkin
2019-07-24 20:37 ` Alexander Duyck
2019-07-24 20:43 ` Michael S. Tsirkin
2019-07-25 14:44 ` Nitesh Narayan Lal
2019-07-25 14:54 ` Michael S. Tsirkin
2019-07-25 14:56 ` Alexander Duyck
2019-07-25 14:59 ` Michael S. Tsirkin
2019-07-25 17:42 ` Nitesh Narayan Lal
2019-07-25 19:54 ` Alexander Duyck
2019-07-24 17:12 ` [PATCH v2 QEMU] virtio-balloon: Provide a interface for "bubble hinting" Alexander Duyck
2019-07-24 19:02 ` Michael S. Tsirkin
2019-07-24 20:18 ` Alexander Duyck
2019-07-24 20:29 ` Nitesh Narayan Lal
2019-07-24 20:42 ` Michael S. Tsirkin
2019-07-29 16:58 ` Alexander Duyck
2019-07-29 19:25 ` Michael S. Tsirkin
2019-07-29 20:21 ` Alexander Duyck
2019-07-29 20:49 ` Michael S. Tsirkin
2019-07-29 21:37 ` Alexander Duyck
2019-07-29 22:11 ` Michael S. Tsirkin
2019-07-24 20:46 ` Michael S. Tsirkin
2019-07-24 21:14 ` Alexander Duyck
2019-07-25 11:57 ` Nitesh Narayan Lal [this message]
2019-07-25 14:57 ` Alexander Duyck
2019-07-24 21:38 ` Michael S. Tsirkin
2019-07-24 22:03 ` Alexander Duyck
2019-07-24 22:08 ` Michael S. Tsirkin
2019-07-24 22:27 ` Alexander Duyck
2019-07-25 6:07 ` Michael S. Tsirkin
2019-07-25 11:35 ` Nitesh Narayan Lal
2019-07-25 15:05 ` Alexander Duyck
2019-07-25 15:16 ` Michael S. Tsirkin
2019-07-25 16:16 ` Alexander Duyck
2019-07-25 17:19 ` Michael S. Tsirkin
2019-07-25 18:25 ` Nitesh Narayan Lal
2019-07-25 20:00 ` Alexander Duyck
2019-07-25 20:14 ` Nitesh Narayan Lal
2019-07-24 18:40 ` [PATCH v2 0/5] mm / virtio: Provide support for page hinting Nitesh Narayan Lal
2019-07-24 18:41 ` David Hildenbrand
2019-07-24 19:31 ` Michael S. Tsirkin
2019-07-24 19:47 ` David Hildenbrand
2019-07-24 19:54 ` Nitesh Narayan Lal
2019-07-24 21:32 ` Michael S. Tsirkin
2019-07-24 19:24 ` Michael S. Tsirkin
2019-07-24 20:27 ` Alexander Duyck
2019-07-24 20:38 ` Nitesh Narayan Lal
2019-07-24 21:00 ` Alexander Duyck
2019-07-25 12:08 ` Nitesh Narayan Lal
2019-07-24 20:38 ` Michael S. Tsirkin
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