lkml.org 
[lkml]   [2018]   [Nov]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] iommu/dma: Zero pages manually in a length of scatterlist
From
Date
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.

\
 
 \ /
  Last update: 2018-11-06 15:40    [W:0.074 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site