[PATCH 4/5] drm/ttm: add ttm_sg_tt_init

[He, Roger]

Patch 1: Acked-by: Roger He <Hongbo.He at amd.com>

Patch 2~5: Reviewed-by: Roger He <Hongbo.He at amd.com>

-----Original Message-----
From: dri-devel [mailto:dri-devel-bounces at lists.freedesktop.org] On Behalf Of Christian K?nig
Sent: Monday, March 05, 2018 8:07 PM
To: dri-devel at lists.freedesktop.org; amd-gfx at lists.freedesktop.org; Ben Skeggs <bskeggs at redhat.com>; Ilia Mirkin <imirkin at alum.mit.edu>; nouveau <nouveau at lists.freedesktop.org>
Subject: Re: [PATCH 4/5] drm/ttm: add ttm_sg_tt_init

Ping?

Am 27.02.2018 um 13:07 schrieb Christian König:
> Hi guys,
>
> at least on amdgpu and radeon the page array allocated by 
> ttm_dma_tt_init is completely unused in the case of DMA-buf sharing.
> So I'm trying to get rid of that by only allocating the DMA address 
> array.
>
> Now the only other user of DMA-buf together with ttm_dma_tt_init is 
> Nouveau. So my question is are you guys using the page array anywhere 
> in your kernel driver in case of a DMA-buf sharing?
>
> If no then I could just make this the default behavior for all drivers 
> and save quite a bit of memory for everybody.
>
> Thanks,
> Christian.
>
> Am 27.02.2018 um 12:49 schrieb Christian König:
>> This allows drivers to only allocate dma addresses, but not a page 
>> array.
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/ttm/ttm_tt.c | 54
>> ++++++++++++++++++++++++++++++++++++--------
>>   include/drm/ttm/ttm_tt.h     |  2 ++
>>   2 files changed, 47 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c 
>> b/drivers/gpu/drm/ttm/ttm_tt.c index 8e0b525cda00..971133106ec2 
>> 100644
>> --- a/drivers/gpu/drm/ttm/ttm_tt.c
>> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
>> @@ -108,6 +108,16 @@ static int
>> ttm_dma_tt_alloc_page_directory(struct ttm_dma_tt *ttm)
>>       return 0;
>>   }
>>   +static int ttm_sg_tt_alloc_page_directory(struct ttm_dma_tt *ttm)
>> +{
>> +    ttm->dma_address = kvmalloc_array(ttm->ttm.num_pages,
>> +                      sizeof(*ttm->dma_address),
>> +                      GFP_KERNEL | __GFP_ZERO);
>> +    if (!ttm->dma_address)
>> +        return -ENOMEM;
>> +    return 0;
>> +}
>> +
>>   #ifdef CONFIG_X86
>>   static inline int ttm_tt_set_page_caching(struct page *p,
>>                         enum ttm_caching_state c_old, @@ -227,8 
>> +237,8 @@ void ttm_tt_destroy(struct ttm_tt *ttm)
>>       ttm->func->destroy(ttm);
>>   }
>>   -int ttm_tt_init(struct ttm_tt *ttm, struct ttm_bo_device *bdev,
>> -        unsigned long size, uint32_t page_flags)
>> +void ttm_tt_init_fields(struct ttm_tt *ttm, struct ttm_bo_device 
>> +*bdev,
>> +            unsigned long size, uint32_t page_flags)
>>   {
>>       ttm->bdev = bdev;
>>       ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; @@ 
>> -236,6 +246,12 @@ int ttm_tt_init(struct ttm_tt *ttm, struct 
>> ttm_bo_device *bdev,
>>       ttm->page_flags = page_flags;
>>       ttm->state = tt_unpopulated;
>>       ttm->swap_storage = NULL;
>> +}
>> +
>> +int ttm_tt_init(struct ttm_tt *ttm, struct ttm_bo_device *bdev,
>> +        unsigned long size, uint32_t page_flags) {
>> +    ttm_tt_init_fields(ttm, bdev, size, page_flags);
>>         if (ttm_tt_alloc_page_directory(ttm)) {
>>           ttm_tt_destroy(ttm);
>> @@ -258,12 +274,7 @@ int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, 
>> struct ttm_bo_device *bdev,
>>   {
>>       struct ttm_tt *ttm = &ttm_dma->ttm;
>>   -    ttm->bdev = bdev;
>> -    ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
>> -    ttm->caching_state = tt_cached;
>> -    ttm->page_flags = page_flags;
>> -    ttm->state = tt_unpopulated;
>> -    ttm->swap_storage = NULL;
>> +    ttm_tt_init_fields(ttm, bdev, size, page_flags);
>>         INIT_LIST_HEAD(&ttm_dma->pages_list);
>>       if (ttm_dma_tt_alloc_page_directory(ttm_dma)) { @@ -275,11 
>> +286,36 @@ int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct 
>> ttm_bo_device *bdev,
>>   }
>>   EXPORT_SYMBOL(ttm_dma_tt_init);
>>   +int ttm_sg_tt_init(struct ttm_dma_tt *ttm_dma, struct 
>> ttm_bo_device *bdev,
>> +           unsigned long size, uint32_t page_flags) {
>> +    struct ttm_tt *ttm = &ttm_dma->ttm;
>> +    int ret;
>> +
>> +    ttm_tt_init_fields(ttm, bdev, size, page_flags);
>> +
>> +    INIT_LIST_HEAD(&ttm_dma->pages_list);
>> +    if (page_flags & TTM_PAGE_FLAG_SG)
>> +        ret = ttm_sg_tt_alloc_page_directory(ttm_dma);
>> +    else
>> +        ret = ttm_dma_tt_alloc_page_directory(ttm_dma);
>> +    if (ret) {
>> +        ttm_tt_destroy(ttm);
>> +        pr_err("Failed allocating page table\n");
>> +        return -ENOMEM;
>> +    }
>> +    return 0;
>> +}
>> +EXPORT_SYMBOL(ttm_sg_tt_init);
>> +
>>   void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma)
>>   {
>>       struct ttm_tt *ttm = &ttm_dma->ttm;
>>   -    kvfree(ttm->pages);
>> +    if (ttm->pages)
>> +        kvfree(ttm->pages);
>> +    else
>> +        kvfree(ttm_dma->dma_address);
>>       ttm->pages = NULL;
>>       ttm_dma->dma_address = NULL;
>>   }
>> diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h 
>> index 9c78556b488e..1cf316a4257c 100644
>> --- a/include/drm/ttm/ttm_tt.h
>> +++ b/include/drm/ttm/ttm_tt.h
>> @@ -163,6 +163,8 @@ int ttm_tt_init(struct ttm_tt *ttm, struct 
>> ttm_bo_device *bdev,
>>           unsigned long size, uint32_t page_flags);
>>   int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct 
>> ttm_bo_device *bdev,
>>               unsigned long size, uint32_t page_flags);
>> +int ttm_sg_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_bo_device
>> *bdev,
>> +           unsigned long size, uint32_t page_flags);
>>     /**
>>    * ttm_tt_fini
>

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