Messages in this thread | | | Date | Wed, 10 Sep 2008 16:52:49 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] x86: avoid unnecessary low zone allocation in AMD IOMMU's alloc_coherent |
| |
On Wed, Sep 10, 2008 at 11:39:00PM +0900, FUJITA Tomonori wrote:
> btw, in tip/x86/iommu, GART's alloc_coherent always does virtual > mappings to allocate a size-aligned memory (as DMA-mapping.txt > defines). > > Because someone strongly insisted, I modified GART's alloc_coherent to > do so but as I said again and again, it's completely meaningless (only > POWER IOMMU does it and drivers don't depend on such requirement). > > I guess that it would be better to do virtual mappings only when > necessary as the current mainline does since GART I/O space is > precious in some systems. But I don't care much. What's your opinion > (as a AMD developer)?
Very true. My original rewrite did the mapping only when necessary too. What were the reasons to do the mapping always?
Joerg
-- | AMD Saxony Limited Liability Company & Co. KG Operating | Wilschdorfer Landstr. 101, 01109 Dresden, Germany System | Register Court Dresden: HRA 4896 Research | General Partner authorized to represent: Center | AMD Saxony LLC (Wilmington, Delaware, US) | General Manager of AMD Saxony LLC: Dr. Hans-R. Deppe, Thomas McCoy
| |