Am 13.09.19 um 13:07 schrieb Thomas Hellström (VMware):
> On 9/13/19 12:53 PM, Koenig, Christian wrote:
>> Am 12.09.19 um 20:38 schrieb Thomas Hellström (VMware):
>>> From: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
>>>
>>> Commit 4daa4fba3a38 ("gpu: drm: ttm: Adding new return type
>>> vm_fault_t")
>>> broke TTM prefaulting. Since vmf_insert_mixed() typically always
>>> returns
>>> VM_FAULT_NOPAGE, prefaulting stops after the second PTE.
>>>
>>> Restore (almost) the original behaviour. Unfortunately we can no longer
>>> with the new vm_fault_t return type determine whether a prefaulting
>>> PTE insertion hit an already populated PTE, and terminate the insertion
>>> loop. Instead we continue with the pre-determined number of prefaults.
>>>
>>> Fixes: 4daa4fba3a38 ("gpu: drm: ttm: Adding new return type
>>> vm_fault_t")
>>> Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx>
>>> Cc: Christian König <christian.koenig@xxxxxxx>
>>> Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
>> Reviewed-by: Christian König <christian.koenig@xxxxxxx>
>>
>> Going to pick that up when Alex rebases our upstream branch.
>>
>> Christian.
>>
>>> ---
>>> drivers/gpu/drm/ttm/ttm_bo_vm.c | 16 +++++++---------
>>> 1 file changed, 7 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> index 5a580adeb9d1..aa18e8a53727 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> @@ -290,15 +290,13 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct
>>> vm_fault *vmf,
>>> else
>>> ret = vmf_insert_pfn(&cvma, address, pfn);
>>> - /*
>>> - * Somebody beat us to this PTE or prefaulting to
>>> - * an already populated PTE, or prefaulting error.
>>> - */
>>> -
>>> - if (unlikely((ret == VM_FAULT_NOPAGE && i > 0)))
>>> - break;
>>> - else if (unlikely(ret & VM_FAULT_ERROR))
>>> - goto out_io_unlock;
>>> + /* Never error on prefaulted PTEs */
>>> + if (unlikely((ret & VM_FAULT_ERROR))) {
>>> + if (i == 0)
>>> + goto out_io_unlock;
>>> + else
>
> We could perhaps skip that else. Let me know if you want me to respin.
I would rather like to keep it, when something goes wrong we should
really stop faulting in more.
Christian.
>
> /Thomas
>
>
>
>>> + break;
>>> + }
>>> address += PAGE_SIZE;
>>> if (unlikely(++page_offset >= page_last))
>
>
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
