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Date: Thu, 13 Apr 2017 10:03:46 -0700
From: Matthew Wilcox <willy@infradead.org>
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Subject: Re: [Qemu-devel] [PATCH v9 2/5] virtio-balloon:
 VIRTIO_BALLOON_F_BALLOON_CHUNKS
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Wei Wang <wei.w.wang@intel.com>, virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, david@redhat.com, dave.hansen@intel.com, cornelia.huck@de.ibm.com, akpm@linux-foundation.org, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, liliang.opensource@gmail.com

On Thu, Apr 13, 2017 at 07:34:19PM +0300, Michael S. Tsirkin wrote:
> So we don't need the bitmap to talk to host, it is just
> a data structure we chose to maintain lists of pages, right?
> OK as far as it goes but you need much better isolation for it.
> Build a data structure with APIs such as _init, _cleanup, _add, _clear,
> _find_first, _find_next.
> Completely unrelated to pages, it just maintains bits.
> Then use it here.

That sounds an awful lot like the xbitmap I wrote a few months ago ...

http://git.infradead.org/users/willy/linux-dax.git/commit/727e401bee5ad7d37e0077291d90cc17475c6392