Re: [PATCH v10 01/17] iova: Export alloc_iova_fast() and free_iova_fast()

[Jason Wang]

在 2021/8/5 下午8:34, Yongji Xie 写道:
> > My main point, though, is that if you've already got something else
> > keeping track of the actual addresses, then the way you're using an
> > iova_domain appears to be something you could do with a trivial bitmap
> > allocator. That's why I don't buy the efficiency argument. The main
> > design points of the IOVA allocator are to manage large address spaces
> > while trying to maximise spatial locality to minimise the underlying
> > pagetable usage, and allocating with a flexible limit to support
> > multiple devices with different addressing capabilities in the same
> > address space. If none of those aspects are relevant to the use-case -
> > which AFAICS appears to be true here - then as a general-purpose
> > resource allocator it's rubbish and has an unreasonably massive memory
> > overhead and there are many, many better choices.
> OK, I get your point. Actually we used the genpool allocator in the
> early version. Maybe we can fall back to using it.


I think maybe you can share some perf numbers to see how much 
alloc_iova_fast() can help.

Thanks


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