Re: [PATCH v20 4/7] virtio-balloon: VIRTIO_BALLOON_F_SG

From: Wei Wang
Date: Wed Jan 03 2018 - 03:58:39 EST


On 01/03/2018 10:29 AM, Tetsuo Handa wrote:
Matthew Wilcox wrote:
The radix tree convention is objectively awful, which is why I'm working
to change it. Specifying the GFP flags at radix tree initialisation time
rather than allocation time leads to all kinds of confusion. The preload
API is a pretty awful workaround, and it will go away once the XArray
is working correctly. That said, there's no alternative to it without
making XBitmap depend on XArray, and I don't want to hold you up there.
So there's an xb_preload for the moment.
I'm ready to propose cvbmp shown below as an alternative to xbitmap (but
specialized for virtio-balloon case). Wei, can you do some benchmarking
between xbitmap and cvbmp?
----------------------------------------
cvbmp: clustered values bitmap

I don't think we need to replace xbitmap, at least at this stage. The new implementation doesn't look simpler at all, and virtio-balloon has worked well with xbitmap.

I would suggest you to send out the new implementation for discussion after this series ends, and justify with better performance results if you could get.

Best,
Wei