Re: [PATCH 0/2] Support direct I/O read and write for memory allocated by dmabuf

[Lei Liu <liulei.rjpt@vivo.com>]

在 2024/7/10 22:14, Christian König 写道:
> Am 10.07.24 um 15:57 schrieb Lei Liu:
>> Use vm_insert_page to establish a mapping for the memory allocated
>> by dmabuf, thus supporting direct I/O read and write; and fix the
>> issue of incorrect memory statistics after mapping dmabuf memory.
>
> Well big NAK to that! Direct I/O is intentionally disabled on DMA-bufs.

Hello! Could you explain why direct_io is disabled on DMABUF? Is there 
any historical reason for this?

>
> We already discussed enforcing that in the DMA-buf framework and this 
> patch probably means that we should really do that.
>
> Regards,
> Christian.

Thank you for your response. With the application of AI large model 
edgeification, we urgently need support for direct_io on DMABUF to read 
some very large files. Do you have any new solutions or plans for this?

Regards,
Lei Liu.

>
>>
>> Lei Liu (2):
>>    mm: dmabuf_direct_io: Support direct_io for memory allocated by 
>> dmabuf
>>    mm: dmabuf_direct_io: Fix memory statistics error for dmabuf 
>> allocated
>>      memory with direct_io support
>>
>>   drivers/dma-buf/heaps/system_heap.c |  5 +++--
>>   fs/proc/task_mmu.c                  |  8 +++++++-
>>   include/linux/mm.h                  |  1 +
>>   mm/memory.c                         | 15 ++++++++++-----
>>   mm/rmap.c                           |  9 +++++----
>>   5 files changed, 26 insertions(+), 12 deletions(-)
>>
>