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

[Christian König <christian.koenig@xxxxxxx>]

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@xxxxxxx>
> > ---
> >   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

_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel