Am 2021-06-15 um 8:18 a.m. schrieb Christian König:
> Am 15.06.21 um 14:11 schrieb Pan, Xinhui:
>>> 2021年6月15日 20:01，Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
>>> 写道：
>>>
>>> Am 15.06.21 um 13:57 schrieb xinhui pan:
>>>> Amdgpu set SG flag in populate callback. So TTM still count pages
>>>> in SG
>>>> BO.
>>> It's probably better to fix this instead. E.g. why does amdgpu
>>> modify the SG flag during populate and not during initial creation?
>>> That doesn't seem to make sense.
>> fair enough. Let me have a try.
>> No idea why we set SG flag in populate years ago.
>
> That's pretty recent IIRC. Felix moved the code around a bit to fix
> another problem.
I moved some code from populate/unpopulate to backend_bind/unbind for
attaching and detaching dmabufs. I didn't change the setting/unsetting
of SG flags for userptr BOs. That goes back all the way to 2015.
As far as I can tell, this is needed because userptr BOs are not created
as SG BOs. That's something I've also pointed out before.
Regards,
Felix
>
> Christian.
>
>>
>>> Christian.
>>>
>>>> One easy way to fix this is lets count pages after populate callback.
>>>>
>>>> We hit one issue that amdgpu alloc many SG BOs, but TTM try to do swap
>>>> again and again even if swapout does not swap SG BOs at all.
>>>>
>>>> Signed-off-by: xinhui pan <xinhui.pan@xxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/ttm/ttm_tt.c | 32 +++++++++++++-------------------
>>>> 1 file changed, 13 insertions(+), 19 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c
>>>> b/drivers/gpu/drm/ttm/ttm_tt.c
>>>> index a1a25410ec74..4fa0a8cd71c0 100644
>>>> --- a/drivers/gpu/drm/ttm/ttm_tt.c
>>>> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
>>>> @@ -317,13 +317,6 @@ int ttm_tt_populate(struct ttm_device *bdev,
>>>> if (ttm_tt_is_populated(ttm))
>>>> return 0;
>>>> - if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
>>>> - atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
>>>> - if (bdev->pool.use_dma32)
>>>> - atomic_long_add(ttm->num_pages,
>>>> - &ttm_dma32_pages_allocated);
>>>> - }
>>>> -
>>>> while (atomic_long_read(&ttm_pages_allocated) >
>>>> ttm_pages_limit ||
>>>> atomic_long_read(&ttm_dma32_pages_allocated) >
>>>> ttm_dma32_pages_limit) {
>>>> @@ -342,6 +335,13 @@ int ttm_tt_populate(struct ttm_device *bdev,
>>>> if (ret)
>>>> goto error;
>>>> + if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
>>>> + atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
>>>> + if (bdev->pool.use_dma32)
>>>> + atomic_long_add(ttm->num_pages,
>>>> + &ttm_dma32_pages_allocated);
>>>> + }
>>>> +
>>>> ttm_tt_add_mapping(bdev, ttm);
>>>> ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED;
>>>> if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
>>>> @@ -355,12 +355,6 @@ int ttm_tt_populate(struct ttm_device *bdev,
>>>> return 0;
>>>> error:
>>>> - if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
>>>> - atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
>>>> - if (bdev->pool.use_dma32)
>>>> - atomic_long_sub(ttm->num_pages,
>>>> - &ttm_dma32_pages_allocated);
>>>> - }
>>>> return ret;
>>>> }
>>>> EXPORT_SYMBOL(ttm_tt_populate);
>>>> @@ -384,12 +378,6 @@ void ttm_tt_unpopulate(struct ttm_device
>>>> *bdev, struct ttm_tt *ttm)
>>>> if (!ttm_tt_is_populated(ttm))
>>>> return;
>>>> - ttm_tt_clear_mapping(ttm);
>>>> - if (bdev->funcs->ttm_tt_unpopulate)
>>>> - bdev->funcs->ttm_tt_unpopulate(bdev, ttm);
>>>> - else
>>>> - ttm_pool_free(&bdev->pool, ttm);
>>>> -
>>>> if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
>>>> atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
>>>> if (bdev->pool.use_dma32)
>>>> @@ -397,6 +385,12 @@ void ttm_tt_unpopulate(struct ttm_device
>>>> *bdev, struct ttm_tt *ttm)
>>>> &ttm_dma32_pages_allocated);
>>>> }
>>>> + ttm_tt_clear_mapping(ttm);
>>>> + if (bdev->funcs->ttm_tt_unpopulate)
>>>> + bdev->funcs->ttm_tt_unpopulate(bdev, ttm);
>>>> + else
>>>> + ttm_pool_free(&bdev->pool, ttm);
>>>> +
>>>> ttm->page_flags &= ~TTM_PAGE_FLAG_PRIV_POPULATED;
>>>> }
>>>>
>
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