On Wed, Apr 13, 2022 at 02:10:56PM +0100, Robin Murphy wrote:
> Are you sure? AFAICS swiotlb_map() does the right thing, and
> dma_direct_{sync,unmap} are working off the DMA address, which is that of
> the bounce slot when SWIOTLB is involved (not least, how would the
> is_swiotlb_buffer() chec
On 2022-04-13 05:59, Christoph Hellwig wrote:
On Wed, Apr 13, 2022 at 09:02:02AM +0800, Chao Gao wrote:
dma_direct_sync_single_for_cpu() also calls arch_sync_dma_for_cpu_all()
and arch_dma_mark_clean() in some cases. if SWIOTLB does sync internally,
should these two functions be called by SWIOTL
On Wed, Apr 13, 2022 at 01:46:06PM +0800, Chao Gao wrote:
> On Wed, Apr 13, 2022 at 06:59:58AM +0200, Christoph Hellwig wrote:
> >So for now I'd be happy with the one liner presented here, but
> >eventually the whole area could use an overhaul.
>
> Thanks. Do you want me to post a new version with
On Wed, Apr 13, 2022 at 06:59:58AM +0200, Christoph Hellwig wrote:
>So for now I'd be happy with the one liner presented here, but
>eventually the whole area could use an overhaul.
Thanks. Do you want me to post a new version with the Fixes tag or you
will take care of it?
Fixes: 55897af63091 ("d
On Wed, Apr 13, 2022 at 09:02:02AM +0800, Chao Gao wrote:
> dma_direct_sync_single_for_cpu() also calls arch_sync_dma_for_cpu_all()
> and arch_dma_mark_clean() in some cases. if SWIOTLB does sync internally,
> should these two functions be called by SWIOTLB?
>
> Personally, it might be better if s
On Tue, Apr 12, 2022 at 02:33:05PM +0100, Robin Murphy wrote:
>On 12/04/2022 12:38 pm, Chao Gao wrote:
>> When we looked into FIO performance with swiotlb enabled in VM, we found
>> swiotlb_bounce() is always called one more time than expected for each DMA
>> read request.
>>
>> It turns out that
On 12/04/2022 12:38 pm, Chao Gao wrote:
When we looked into FIO performance with swiotlb enabled in VM, we found
swiotlb_bounce() is always called one more time than expected for each DMA
read request.
It turns out that the bounce buffer is copied to original DMA buffer twice
after the completio
On Tue, Apr 12, 2022 at 07:38:05PM +0800, Chao Gao wrote:
>When we looked into FIO performance with swiotlb enabled in VM, we found
>swiotlb_bounce() is always called one more time than expected for each DMA
>read request.
>
>It turns out that the bounce buffer is copied to original DMA buffer twic
When we looked into FIO performance with swiotlb enabled in VM, we found
swiotlb_bounce() is always called one more time than expected for each DMA
read request.
It turns out that the bounce buffer is copied to original DMA buffer twice
after the completion of a DMA request (one is done by in
dma_
