From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH v11 3/6] virtio-balloon: VIRTIO_BALLOON_F_PAGE_CHUNKS
Date: Tue, 13 Jun 2017 10:59:07 -0700
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To: "Michael S. Tsirkin" <mst@redhat.com>, Wei Wang <wei.w.wang@intel.com>
Cc: aarcange@redhat.com, virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, amit.shah@redhat.com, liliang.opensource@gmail.com, linux-kernel@vger.kernel.org, Matthew Wilcox <willy@infradead.org>, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, cornelia.huck@de.ibm.com, pbonzini@redhat.com, akpm@linux-foundation.org, mgorman@techsingularity.net
List-Id: virtualization@lists.linuxfoundation.org

On 06/13/2017 10:56 AM, Michael S. Tsirkin wrote:
>> +/* The size of one page_bmap used to record inflated/deflated pages. */
>> +#define VIRTIO_BALLOON_PAGE_BMAP_SIZE	(8 * PAGE_SIZE)
> At this size, you probably want alloc_pages to avoid kmalloc
> overhead.

For slub, at least, kmalloc() just calls alloc_pages() basically
directly.  There's virtually no overhead.