Messages in this thread | | | Date | Tue, 28 Jun 2022 12:27:38 +0100 | Subject | Re: [PATCH v4 1/5] dma-mapping: Add dma_opt_mapping_size() | From | John Garry <> |
| |
On 28/06/2022 12:23, Robin Murphy wrote: >> + >> + size_t >> + dma_opt_mapping_size(struct device *dev); >> + >> +Returns the maximum optimal size of a mapping for the device. Mapping >> large >> +buffers may take longer so device drivers are advised to limit total DMA >> +streaming mappings length to the returned value. > > Nit: I'm not sure "advised" is necessarily the right thing to say in > general - that's only really true for a caller who cares about > throughput of churning through short-lived mappings more than anything > else, and doesn't take a significant hit overall from splitting up > larger requests. I do think it's good to clarify the exact context of > "optimal" here, but I'd prefer to be objectively clear that it's for > workloads where the up-front mapping overhead dominates.
Ok, sure, I can make that clear.
Thanks, John
| |