diff options
| author | John Garry <john.garry@huawei.com> | 2022-07-14 19:15:24 +0800 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2022-07-19 06:05:41 +0200 |
| commit | a229cc14f3395311b899e5e582b71efa8dd01df0 (patch) | |
| tree | c582777858d9da5c8d70cad910a04859b213fd8f /include/linux/dma-map-ops.h | |
| parent | 942a8186eb4451700dadd1d60a2e43ce67605991 (diff) | |
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>
Diffstat (limited to 'include/linux/dma-map-ops.h')
| -rw-r--r-- | include/linux/dma-map-ops.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 0d5b06b3a4a6..98ceba6fa848 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -69,6 +69,7 @@ struct dma_map_ops { int (*dma_supported)(struct device *dev, u64 mask); u64 (*get_required_mask)(struct device *dev); size_t (*max_mapping_size)(struct device *dev); + size_t (*opt_mapping_size)(void); unsigned long (*get_merge_boundary)(struct device *dev); }; |