On Fri, Jan 04, 2019 at 10:35:43PM +, Jason Gunthorpe wrote:
> Commit 2db76d7c3c6d ("lib/scatterlist: sg_page_iter: support sg lists w/o
> backing pages") introduced the sg_page_iter_dma_address() function without
> providing a way to use it in the general case. If the sg_dma_len is not
>
On Thu, Jan 17, 2019 at 10:30:01AM +0100, h...@lst.de wrote:
> On Wed, Jan 16, 2019 at 10:24:36AM -0700, Jason Gunthorpe wrote:
> > The fact is there is 0 industry interest in using RDMA on platforms
> > that can't do HW DMA cache coherency - the kernel syscalls required to
> > do the cache
On Thu, 2019-01-17 at 10:30 +0100, h...@lst.de wrote:
> On Wed, Jan 16, 2019 at 10:24:36AM -0700, Jason Gunthorpe wrote:
> > The fact is there is 0 industry interest in using RDMA on platforms
> > that can't do HW DMA cache coherency - the kernel syscalls required
> > to
> > do the cache flushing
On Wed, Jan 16, 2019 at 10:24:36AM -0700, Jason Gunthorpe wrote:
> The fact is there is 0 industry interest in using RDMA on platforms
> that can't do HW DMA cache coherency - the kernel syscalls required to
> do the cache flushing on the IO path would just destroy performance to
> the point of
On Wed, Jan 16, 2019 at 05:11:34PM +0100, h...@lst.de wrote:
> On Tue, Jan 15, 2019 at 02:25:01PM -0700, Jason Gunthorpe wrote:
> > RDMA needs something similar as well, in this case drivers take a
> > struct page * from get_user_pages() and need to have the DMA map fail
> > if the platform can't
On Wed, 16 Jan 2019 at 16:06, h...@lst.de wrote:
> On Wed, Jan 16, 2019 at 07:28:13AM +, Koenig, Christian wrote:
> > To summarize once more: We have an array of struct pages and want to
> > coherently map that to a device.
>
> And the answer to that is very simple: you can't. What is so
On Tue, Jan 15, 2019 at 02:25:01PM -0700, Jason Gunthorpe wrote:
> RDMA needs something similar as well, in this case drivers take a
> struct page * from get_user_pages() and need to have the DMA map fail
> if the platform can't DMA map in a way that does not require any
> additional DMA API calls
On Wed, Jan 16, 2019 at 07:28:13AM +, Koenig, Christian wrote:
> To summarize once more: We have an array of struct pages and want to
> coherently map that to a device.
And the answer to that is very simple: you can't. What is so hard
to understand about? If you want to map arbitrary
Am 15.01.19 um 22:25 schrieb Jason Gunthorpe:
On Tue, Jan 15, 2019 at 02:17:26PM +, Thomas Hellstrom wrote:
Hi, Christoph,
On Mon, 2019-01-14 at 10:48 +0100, Christoph Hellwig wrote:
On Thu, Jan 10, 2019 at 04:42:18PM -0700, Jason Gunthorpe wrote:
Changes since the RFC:
- Rework vmwgfx
On Wed, Jan 16, 2019 at 07:28:13AM +, Koenig, Christian wrote:
> Am 16.01.19 um 08:09 schrieb Thomas Hellstrom:
> > On Tue, 2019-01-15 at 21:58 +0100, h...@lst.de wrote:
> >> On Tue, Jan 15, 2019 at 07:13:11PM +, Koenig, Christian wrote:
> >>> Thomas is correct that the interface you
Am 16.01.19 um 08:09 schrieb Thomas Hellstrom:
> On Tue, 2019-01-15 at 21:58 +0100, h...@lst.de wrote:
>> On Tue, Jan 15, 2019 at 07:13:11PM +, Koenig, Christian wrote:
>>> Thomas is correct that the interface you propose here doesn't work
>>> at
>>> all for GPUs.
>>>
>>> The kernel driver is
On Tue, 2019-01-15 at 21:58 +0100, h...@lst.de wrote:
> On Tue, Jan 15, 2019 at 07:13:11PM +, Koenig, Christian wrote:
> > Thomas is correct that the interface you propose here doesn't work
> > at
> > all for GPUs.
> >
> > The kernel driver is not informed of flush/sync, but rather just
> >
On Tue, Jan 15, 2019 at 02:17:26PM +, Thomas Hellstrom wrote:
> Hi, Christoph,
>
> On Mon, 2019-01-14 at 10:48 +0100, Christoph Hellwig wrote:
> > On Thu, Jan 10, 2019 at 04:42:18PM -0700, Jason Gunthorpe wrote:
> > > > Changes since the RFC:
> > > > - Rework vmwgfx too [CH]
> > > > - Use a
On Tue, Jan 15, 2019 at 07:13:11PM +, Koenig, Christian wrote:
> Thomas is correct that the interface you propose here doesn't work at
> all for GPUs.
>
> The kernel driver is not informed of flush/sync, but rather just setups
> coherent mappings between system memory and devices.
>
> In
Am 15.01.19 um 19:31 schrieb h...@lst.de:
> On Tue, Jan 15, 2019 at 06:03:39PM +, Thomas Hellstrom wrote:
>> In the graphics case, it's probably because it doesn't fit the graphics
>> use-cases:
>>
>> 1) Memory typically needs to be mappable by another device. (the "dma-
>> buf" interface)
>
On Tue, Jan 15, 2019 at 06:03:39PM +, Thomas Hellstrom wrote:
> In the graphics case, it's probably because it doesn't fit the graphics
> use-cases:
>
> 1) Memory typically needs to be mappable by another device. (the "dma-
> buf" interface)
And there is nothing preventing dma-buf sharing of
On Tue, 2019-01-15 at 16:20 +0100, h...@lst.de wrote:
> On Tue, Jan 15, 2019 at 03:24:55PM +0100, Christian König wrote:
> > Yeah, indeed. Bounce buffers are an absolute no-go for GPUs.
> >
> > If the DMA API finds that a piece of memory is not directly
> > accessible by
> > the GPU we need to
On Tue, Jan 15, 2019 at 03:24:55PM +0100, Christian König wrote:
> Yeah, indeed. Bounce buffers are an absolute no-go for GPUs.
>
> If the DMA API finds that a piece of memory is not directly accessible by
> the GPU we need to return an error and not try to use bounce buffers behind
> the
Am 15.01.19 um 15:17 schrieb Thomas Hellstrom:
Hi, Christoph,
On Mon, 2019-01-14 at 10:48 +0100, Christoph Hellwig wrote:
On Thu, Jan 10, 2019 at 04:42:18PM -0700, Jason Gunthorpe wrote:
Changes since the RFC:
- Rework vmwgfx too [CH]
- Use a distinct type for the DMA page iterator [CH]
- Do
Hi, Christoph,
On Mon, 2019-01-14 at 10:48 +0100, Christoph Hellwig wrote:
> On Thu, Jan 10, 2019 at 04:42:18PM -0700, Jason Gunthorpe wrote:
> > > Changes since the RFC:
> > > - Rework vmwgfx too [CH]
> > > - Use a distinct type for the DMA page iterator [CH]
> > > - Do not have a #ifdef [CH]
>
On Sat, Jan 12, 2019 at 01:03:05PM -0600, Shiraz Saleem wrote:
> On Sat, Jan 12, 2019 at 06:37:58PM +, Jason Gunthorpe wrote:
> > On Sat, Jan 12, 2019 at 12:27:05PM -0600, Shiraz Saleem wrote:
> > > On Fri, Jan 04, 2019 at 10:35:43PM +, Jason Gunthorpe wrote:
> > > > Commit 2db76d7c3c6d
On Thu, Jan 10, 2019 at 04:42:18PM -0700, Jason Gunthorpe wrote:
> > Changes since the RFC:
> > - Rework vmwgfx too [CH]
> > - Use a distinct type for the DMA page iterator [CH]
> > - Do not have a #ifdef [CH]
>
> ChristophH: Will you ack?
This looks generally fine.
>
> Are you still OK with
On Sat, Jan 12, 2019 at 01:03:05PM -0600, Shiraz Saleem wrote:
> Well I was trying convert the RDMA drivers to use your new iterator variant
> and saw the need for it in locations where we need virtual address of the
> pages
> contained in the SGEs.
As far as i can tell that pg_arr[i] value is
On Sat, Jan 12, 2019 at 06:37:58PM +, Jason Gunthorpe wrote:
> On Sat, Jan 12, 2019 at 12:27:05PM -0600, Shiraz Saleem wrote:
> > On Fri, Jan 04, 2019 at 10:35:43PM +, Jason Gunthorpe wrote:
> > > Commit 2db76d7c3c6d ("lib/scatterlist: sg_page_iter: support sg lists w/o
> > > backing
On Sat, Jan 12, 2019 at 12:27:05PM -0600, Shiraz Saleem wrote:
> On Fri, Jan 04, 2019 at 10:35:43PM +, Jason Gunthorpe wrote:
> > Commit 2db76d7c3c6d ("lib/scatterlist: sg_page_iter: support sg lists w/o
> > backing pages") introduced the sg_page_iter_dma_address() function without
> >
On Fri, Jan 04, 2019 at 10:35:43PM +, Jason Gunthorpe wrote:
> Commit 2db76d7c3c6d ("lib/scatterlist: sg_page_iter: support sg lists w/o
> backing pages") introduced the sg_page_iter_dma_address() function without
> providing a way to use it in the general case. If the sg_dma_len is not
>
On Fri, Jan 04, 2019 at 03:35:31PM -0700, Jason Gunthorpe wrote:
> Commit 2db76d7c3c6d ("lib/scatterlist: sg_page_iter: support sg lists w/o
> backing pages") introduced the sg_page_iter_dma_address() function without
> providing a way to use it in the general case. If the sg_dma_len is not
>
On Sat, Jan 05, 2019 at 10:37:17AM +0800, kbuild test robot wrote:
> Hi Jason,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on linus/master]
> [also build test ERROR on v4.20 next-20190103]
> [if your patch is applied to the wrong git tree, please drop us a note to
Hi Jason,
I love your patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v4.20 next-20190103]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
Commit 2db76d7c3c6d ("lib/scatterlist: sg_page_iter: support sg lists w/o
backing pages") introduced the sg_page_iter_dma_address() function without
providing a way to use it in the general case. If the sg_dma_len is not
equal to the dma_length callers cannot safely use the
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