Messages in this thread | | | Date | Tue, 18 Dec 2007 17:50:42 +0100 | From | Stefan Richter <> | Subject | Re: [RFC] dma: passing "attributes" to dma_map_* routines |
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akepner@sgi.com wrote: > Waaay back in October I sent some patches for passing additional > attributes to the dma_map_* routines: > > http://marc.info/?l=linux-kernel&m=119137949604365&w=2
Do I understand correctly?: A device and the CPUs communicate via two separate memory areas: A data buffer and a status FIFO. The NUMA interconnect may reorder accesses of the device to the areas. (Write accesses? Read accesses? Both?)
To ensure synchronization between device and CPUs, you want to mark a memory area which is to be dma-mapped with a flag which says: "Writes to the memory region will cause in-flight DMA to be flushed". Whose writes? A write access from the device or a write access from a CPU? -- Stefan Richter -=====-=-=== ==-- =--=- http://arcgraph.de/sr/
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