Re: [Qemu-devel] [PATCH v2 repost 4/7] virtio-balloon: speed up inflate/deflate process

[Michael S. Tsirkin]

On Wed, Jul 27, 2016 at 09:03:21AM -0700, Dave Hansen wrote:
> On 07/26/2016 06:23 PM, Liang Li wrote:
> > +   vb->pfn_limit = VIRTIO_BALLOON_PFNS_LIMIT;
> > +   vb->pfn_limit = min(vb->pfn_limit, get_max_pfn());
> > +   vb->bmap_len = ALIGN(vb->pfn_limit, BITS_PER_LONG) /
> > +            BITS_PER_BYTE + 2 * sizeof(unsigned long);
> > +   hdr_len = sizeof(struct balloon_bmap_hdr);
> > +   vb->bmap_hdr = kzalloc(hdr_len + vb->bmap_len, GFP_KERNEL);
> 
> This ends up doing a 1MB kmalloc() right?  That seems a _bit_ big.  How
> big was the pfn buffer before?


Yes I would limit this to 1G memory in a go, will result
in a 32KByte bitmap.

-- 
MST