Searched hist:a229cc14f3395311b899e5e582b71efa8dd01df0 (Results 1 – 2 of 2) sorted by relevance
| /linux/Documentation/core-api/ |
| H A D | dma-api.rst | diff a229cc14f3395311b899e5e582b71efa8dd01df0 Thu Jul 14 13:15:24 CEST 2022 John Garry <john.garry@huawei.com> dma-mapping: add dma_opt_mapping_size()
Streaming DMA mapping involving an IOMMU may be much slower for larger
total mapping size. This is because every IOMMU DMA mapping requires an
IOVA to be allocated and freed. IOVA sizes above a certain limit are not
cached, which can have a big impact on DMA mapping performance.
Provide an API for device drivers to know this "optimal" limit, such that
they may try to produce mapping which don't exceed it.
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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| /linux/kernel/dma/ |
| H A D | mapping.c | diff a229cc14f3395311b899e5e582b71efa8dd01df0 Thu Jul 14 13:15:24 CEST 2022 John Garry <john.garry@huawei.com> dma-mapping: add dma_opt_mapping_size()
Streaming DMA mapping involving an IOMMU may be much slower for larger
total mapping size. This is because every IOMMU DMA mapping requires an
IOVA to be allocated and freed. IOVA sizes above a certain limit are not
cached, which can have a big impact on DMA mapping performance.
Provide an API for device drivers to know this "optimal" limit, such that
they may try to produce mapping which don't exceed it.
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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