From: David Hildenbrand <david@redhat.com>
To: Dave Hansen <dave.hansen@intel.com>,
"Li, Liang Z" <liang.z.li@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Cc: "virtio-dev@lists.oasis-open.org"
<virtio-dev@lists.oasis-open.org>,
"mhocko@suse.com" <mhocko@suse.com>,
"mst@redhat.com" <mst@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"dgilbert@redhat.com" <dgilbert@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration
Date: Wed, 7 Dec 2016 17:21:53 +0100 [thread overview]
Message-ID: <2171e091-46ee-decd-7348-772555d3a5e3@redhat.com> (raw)
In-Reply-To: <0b83db29-ebad-2a70-8d61-756d33e33a48@intel.com>
>>>
>>> I did something similar. Filled the balloon with 15GB for a 16GB idle
>>> guest, by
>>> using bitmap, the madvise count was reduced to 605. when using the
>>> PFNs, the madvise count
>>> was 3932160. It means there are quite a lot consecutive bits in the
>>> bitmap.
>>> I didn't test for a guest with heavy memory workload.
>>
>> Would it then even make sense to go one step further and report {pfn,
>> length} combinations?
>>
>> So simply send over an array of {pfn, length}?
>
> Li's current patches do that. Well, maybe not pfn/length, but they do
> take a pfn and page-order, which fits perfectly with the kernel's
> concept of high-order pages.
So we can send length in powers of two. Still, I don't see any benefit
over a simple pfn/len schema. But I'll have a more detailed look at the
implementation first, maybe that will enlighten me :)
>
>> And it makes sense if you think about:
>>
>> a) hugetlb backing: The host may only be able to free huge pages (we
>> might want to communicate that to the guest later, that's another
>> story). Still we would have to send bitmaps full of 4k frames (512 bits
>> for 2mb frames). Of course, we could add a way to communicate that we
>> are using a different bitmap-granularity.
>
> Yeah, please read the patches. If they're not clear, then the
> descriptions need work, but this is done already.
>
I missed the page_shift, thanks for the hint.
--
David
next prev parent reply other threads:[~2016-12-07 16:22 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-30 8:43 [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 1/5] virtio-balloon: rework deflate to add page to a list Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 2/5] virtio-balloon: define new feature bit and head struct Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 3/5] virtio-balloon: speed up inflate/deflate process Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 4/5] virtio-balloon: define flags and head for host request vq Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 5/5] virtio-balloon: tell host vm's unused page info Liang Li
2016-11-30 19:15 ` Dave Hansen
2016-12-04 13:13 ` Li, Liang Z
2016-12-05 17:22 ` Dave Hansen
2016-12-06 4:47 ` Li, Liang Z
2016-12-06 8:40 ` [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration David Hildenbrand
2016-12-07 13:35 ` Li, Liang Z
2016-12-07 15:34 ` Dave Hansen
2016-12-09 3:09 ` Li, Liang Z
2016-12-07 15:42 ` David Hildenbrand
2016-12-07 15:45 ` Dave Hansen
2016-12-07 16:21 ` David Hildenbrand [this message]
2016-12-07 16:57 ` Dave Hansen
2016-12-07 18:38 ` [Qemu-devel] " Andrea Arcangeli
2016-12-07 18:44 ` Dave Hansen
2016-12-07 18:58 ` Andrea Arcangeli
2016-12-07 19:54 ` Dave Hansen
2016-12-07 20:28 ` Andrea Arcangeli
2016-12-09 4:45 ` Li, Liang Z
2016-12-09 4:53 ` Dave Hansen
2016-12-09 5:35 ` Li, Liang Z
2016-12-09 16:42 ` Andrea Arcangeli
2016-12-14 8:20 ` Li, Liang Z
2016-12-14 8:59 ` Li, Liang Z
2016-12-15 15:34 ` Dave Hansen
2016-12-15 15:54 ` Michael S. Tsirkin
2016-12-16 1:12 ` Li, Liang Z
2016-12-16 15:40 ` Andrea Arcangeli
2016-12-17 11:56 ` Li, Liang Z
2016-12-16 0:48 ` Li, Liang Z
2016-12-16 1:09 ` Dave Hansen
2016-12-16 1:38 ` Li, Liang Z
2016-12-16 1:40 ` Dave Hansen
2016-12-16 1:43 ` Li, Liang Z
2016-12-16 16:01 ` Andrea Arcangeli
2016-12-17 12:39 ` Li, Liang Z
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