Messages in this thread | | | Date | Fri, 8 Jan 2016 23:18:06 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH v4 2/3] common: DMA-mapping: add DMA_ATTR_NOHUGEPAGE attribute |
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On Fri, Jan 08, 2016 at 03:05:13PM -0800, Doug Anderson wrote: > 1. I have to go and touch all existing DMA-mapping code to set > DMA_ATTR_HUGE_PAGE. That will be a big patchset and touch more code, > making it more likely to break something. ...
Indeed, I was actually thinking of a positive "prefer/only use/force smaller pages" thing rather than "allow huge pages" as a way to get rid of the "no huge pages" negative as a way to get around that. It has the same meaning when set as DMA_ATTR_NO_HUGE_PAGE but avoids the problem of wondering what
!dma_get_attr(DMA_ATTR_NO_HUGE_PAGE, attrs)
means.
I wasn't thinking of DMA_ATTR_HUGE_PAGE as that would certainly be wrong when CONFIG_HAVE_DMA_ATTRS is disabled (when dma_get_attr() always returns 0.)
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