Re: [PATCH v4 2/6] iova: Allow rcache range upper limit to be flexible

2021-08-02 Thread Robin Murphy
On 2021-08-02 16:23, John Garry wrote: On 02/08/2021 16:01, Will Deacon wrote: On Wed, Jul 14, 2021 at 06:36:39PM +0800, John Garry wrote: Some LLDs may request DMA mappings whose IOVA length exceeds that of the current rcache upper limit. What's an LLD? low-level driver maybe I'll stick

Re: [PATCH v4 2/6] iova: Allow rcache range upper limit to be flexible

2021-08-02 Thread John Garry
On 02/08/2021 16:01, Will Deacon wrote: On Wed, Jul 14, 2021 at 06:36:39PM +0800, John Garry wrote: Some LLDs may request DMA mappings whose IOVA length exceeds that of the current rcache upper limit. What's an LLD? low-level driver maybe I'll stick with simply "drivers" This means that

Re: [PATCH v4 2/6] iova: Allow rcache range upper limit to be flexible

2021-08-02 Thread Will Deacon
On Wed, Jul 14, 2021 at 06:36:39PM +0800, John Garry wrote: > Some LLDs may request DMA mappings whose IOVA length exceeds that of the > current rcache upper limit. What's an LLD? > This means that allocations for those IOVAs will never be cached, and > always must be allocated and freed from the

[PATCH v4 2/6] iova: Allow rcache range upper limit to be flexible

2021-07-14 Thread John Garry
Some LLDs may request DMA mappings whose IOVA length exceeds that of the current rcache upper limit. This means that allocations for those IOVAs will never be cached, and always must be allocated and freed from the RB tree per DMA mapping cycle. This has a significant effect on performance, more s