Messages in this thread | | | Subject | Re: [PATCH] iommu/dma: Zero pages manually in a length of scatterlist | From | Robin Murphy <> | Date | Tue, 6 Nov 2018 14:39:26 +0000 |
| |
On 05/11/2018 14:58, Christoph Hellwig wrote: > On Fri, Nov 02, 2018 at 04:36:13PM -0700, Nicolin Chen wrote: >>> What if the pages came from highmem? I know that doesn't happen on arm64 >>> today, but the point of this code *is* to be generic, and other users will >>> arrive eventually. >> >> Hmm, so it probably should use sg_miter_start/stop() too? Looking >> at the flush routine doing in PAGE_SIZE for each iteration, would >> be possible to map and memset contiguous pages together? Actually >> the flush routine might be also optimized if we can map contiguous >> pages. > > FYI, I have patches I plan to submit soon that gets rid of the > struct scatterlist use in this code to simplify it:
...and I have some significant objections to that simplification which I plan to respond with ;)
(namely that it defaults the whole higher-order page allocation business which will have varying degrees of performance impact on certain cases)
Robin.
| |