diff mbox series

[RFC,02/16] drm/ttm/pool: Fix ttm_pool_alloc error path

Message ID 20230215161405.187368-3-thomas.hellstrom@linux.intel.com (mailing list archive)
State New
Headers show
Series Add a TTM shrinker | expand

Commit Message

Thomas Hellstrom Feb. 15, 2023, 4:13 p.m. UTC
When hitting an error, the error path forgot to unmap dma mappings and
could call set_pages_wb() on already uncached pages.

Fix this by introducing a common __ttm_pool_free() function that
does the right thing.

Fixes: d099fc8f540a ("drm/ttm: new TT backend allocation pool v3")
Cc: Christian König <christian.koenig@amd.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Madhav Chauhan <madhav.chauhan@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/ttm/ttm_pool.c | 74 +++++++++++++++++++++-------------
 1 file changed, 45 insertions(+), 29 deletions(-)

Comments

Christian König Feb. 15, 2023, 5:31 p.m. UTC | #1
Am 15.02.23 um 17:13 schrieb Thomas Hellström:
> When hitting an error, the error path forgot to unmap dma mappings and

I don't see where this happens?

> could call set_pages_wb() on already uncached pages.

Yeah, but what's the problem?

Regards,
Christian.

>
> Fix this by introducing a common __ttm_pool_free() function that
> does the right thing.
>
> Fixes: d099fc8f540a ("drm/ttm: new TT backend allocation pool v3")
> Cc: Christian König <christian.koenig@amd.com>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Madhav Chauhan <madhav.chauhan@amd.com>
> Cc: Christian Koenig <christian.koenig@amd.com>
> Cc: Huang Rui <ray.huang@amd.com>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> ---
>   drivers/gpu/drm/ttm/ttm_pool.c | 74 +++++++++++++++++++++-------------
>   1 file changed, 45 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
> index aa116a7bbae3..1cc7591a9542 100644
> --- a/drivers/gpu/drm/ttm/ttm_pool.c
> +++ b/drivers/gpu/drm/ttm/ttm_pool.c
> @@ -367,6 +367,39 @@ static int ttm_pool_page_allocated(struct ttm_pool *pool, unsigned int order,
>   	return 0;
>   }
>   
> +static void __ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt,
> +			    struct page **caching_divide,
> +			    enum ttm_caching initial_caching,
> +			    enum ttm_caching subseq_caching,
> +			    pgoff_t num_pages)
> +{
> +	enum ttm_caching caching = subseq_caching;
> +	struct page **pages = tt->pages;
> +	unsigned int order;
> +	pgoff_t i, nr;
> +
> +	if (pool && caching_divide)
> +		caching = initial_caching;
> +
> +	for (i = 0; i < num_pages; i += nr, pages += nr) {
> +		struct ttm_pool_type *pt = NULL;
> +
> +		if (unlikely(caching_divide == pages))
> +			caching = subseq_caching;
> +
> +		order = ttm_pool_page_order(pool, *pages);
> +		nr = (1UL << order);
> +		if (tt->dma_address)
> +			ttm_pool_unmap(pool, tt->dma_address[i], nr);
> +
> +		pt = ttm_pool_select_type(pool, caching, order);
> +		if (pt)
> +			ttm_pool_type_give(pt, *pages);
> +		else
> +			ttm_pool_free_page(pool, caching, order, *pages);
> +	}
> +}
> +
>   /**
>    * ttm_pool_alloc - Fill a ttm_tt object
>    *
> @@ -386,8 +419,9 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
>   	dma_addr_t *dma_addr = tt->dma_address;
>   	struct page **caching = tt->pages;
>   	struct page **pages = tt->pages;
> +	enum ttm_caching page_caching;
>   	gfp_t gfp_flags = GFP_USER;
> -	unsigned int i, order;
> +	unsigned int order;
>   	struct page *p;
>   	int r;
>   
> @@ -410,6 +444,7 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
>   	     order = min_t(unsigned int, order, __fls(num_pages))) {
>   		struct ttm_pool_type *pt;
>   
> +		page_caching = tt->caching;
>   		pt = ttm_pool_select_type(pool, tt->caching, order);
>   		p = pt ? ttm_pool_type_take(pt) : NULL;
>   		if (p) {
> @@ -418,6 +453,7 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
>   			if (r)
>   				goto error_free_page;
>   
> +			caching = pages;
>   			do {
>   				r = ttm_pool_page_allocated(pool, order, p,
>   							    &dma_addr,
> @@ -426,14 +462,15 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
>   				if (r)
>   					goto error_free_page;
>   
> +				caching = pages;
>   				if (num_pages < (1 << order))
>   					break;
>   
>   				p = ttm_pool_type_take(pt);
>   			} while (p);
> -			caching = pages;
>   		}
>   
> +		page_caching = ttm_cached;
>   		while (num_pages >= (1 << order) &&
>   		       (p = ttm_pool_alloc_page(pool, gfp_flags, order))) {
>   
> @@ -442,6 +479,7 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
>   							   tt->caching);
>   				if (r)
>   					goto error_free_page;
> +				caching = pages;
>   			}
>   			r = ttm_pool_page_allocated(pool, order, p, &dma_addr,
>   						    &num_pages, &pages);
> @@ -468,15 +506,12 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
>   	return 0;
>   
>   error_free_page:
> -	ttm_pool_free_page(pool, tt->caching, order, p);
> +	ttm_pool_free_page(pool, page_caching, order, p);
>   
>   error_free_all:
>   	num_pages = tt->num_pages - num_pages;
> -	for (i = 0; i < num_pages; ) {
> -		order = ttm_pool_page_order(pool, tt->pages[i]);
> -		ttm_pool_free_page(pool, tt->caching, order, tt->pages[i]);
> -		i += 1 << order;
> -	}
> +	__ttm_pool_free(pool, tt, caching, tt->caching, ttm_cached,
> +			num_pages);
>   
>   	return r;
>   }
> @@ -492,27 +527,8 @@ EXPORT_SYMBOL(ttm_pool_alloc);
>    */
>   void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
>   {
> -	unsigned int i;
> -
> -	for (i = 0; i < tt->num_pages; ) {
> -		struct page *p = tt->pages[i];
> -		unsigned int order, num_pages;
> -		struct ttm_pool_type *pt;
> -
> -		order = ttm_pool_page_order(pool, p);
> -		num_pages = 1ULL << order;
> -		if (tt->dma_address)
> -			ttm_pool_unmap(pool, tt->dma_address[i], num_pages);
> -
> -		pt = ttm_pool_select_type(pool, tt->caching, order);
> -		if (pt)
> -			ttm_pool_type_give(pt, tt->pages[i]);
> -		else
> -			ttm_pool_free_page(pool, tt->caching, order,
> -					   tt->pages[i]);
> -
> -		i += num_pages;
> -	}
> +	__ttm_pool_free(pool, tt, NULL, tt->caching, tt->caching,
> +			tt->num_pages);
>   
>   	while (atomic_long_read(&allocated_pages) > page_pool_size)
>   		ttm_pool_shrink();
Thomas Hellstrom Feb. 15, 2023, 6:02 p.m. UTC | #2
On Wed, 2023-02-15 at 18:31 +0100, Christian König wrote:
> Am 15.02.23 um 17:13 schrieb Thomas Hellström:
> > When hitting an error, the error path forgot to unmap dma mappings
> > and
> 
> I don't see where this happens?

From what I can tell, ttm_pool_page_allocated() maps the page for dma,
If we later hit an error, ttm_pool_free_page() will leak the mapping.

> 
> > could call set_pages_wb() on already uncached pages.
> 
> Yeah, but what's the problem?

Umm, at least if you try to set WC on an already WC'd page, the
set_pages_ code will spam dmesg with warnings. 
Not sure if set_pages_wb() on WB pages does the same, nor if it
issues unnecessary global cache / tlb flushes or whether that will
change in the future.
The point of avoiding the set_pages_wb() when already WB is you don't
have to check, and you don't have to care.

That said, the __ttm_pool_free() is used also in upcoming patches.

/Thomas


> 
> Regards,
> Christian.
> 
> > 
> > Fix this by introducing a common __ttm_pool_free() function that
> > does the right thing.
> > 
> > Fixes: d099fc8f540a ("drm/ttm: new TT backend allocation pool v3")
> > Cc: Christian König <christian.koenig@amd.com>
> > Cc: Dave Airlie <airlied@redhat.com>
> > Cc: Madhav Chauhan <madhav.chauhan@amd.com>
> > Cc: Christian Koenig <christian.koenig@amd.com>
> > Cc: Huang Rui <ray.huang@amd.com>
> > Cc: dri-devel@lists.freedesktop.org
> > Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> > ---
> >   drivers/gpu/drm/ttm/ttm_pool.c | 74 +++++++++++++++++++++--------
> > -----
> >   1 file changed, 45 insertions(+), 29 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/ttm/ttm_pool.c
> > b/drivers/gpu/drm/ttm/ttm_pool.c
> > index aa116a7bbae3..1cc7591a9542 100644
> > --- a/drivers/gpu/drm/ttm/ttm_pool.c
> > +++ b/drivers/gpu/drm/ttm/ttm_pool.c
> > @@ -367,6 +367,39 @@ static int ttm_pool_page_allocated(struct
> > ttm_pool *pool, unsigned int order,
> >         return 0;
> >   }
> >   
> > +static void __ttm_pool_free(struct ttm_pool *pool, struct ttm_tt
> > *tt,
> > +                           struct page **caching_divide,
> > +                           enum ttm_caching initial_caching,
> > +                           enum ttm_caching subseq_caching,
> > +                           pgoff_t num_pages)
> > +{
> > +       enum ttm_caching caching = subseq_caching;
> > +       struct page **pages = tt->pages;
> > +       unsigned int order;
> > +       pgoff_t i, nr;
> > +
> > +       if (pool && caching_divide)
> > +               caching = initial_caching;
> > +
> > +       for (i = 0; i < num_pages; i += nr, pages += nr) {
> > +               struct ttm_pool_type *pt = NULL;
> > +
> > +               if (unlikely(caching_divide == pages))
> > +                       caching = subseq_caching;
> > +
> > +               order = ttm_pool_page_order(pool, *pages);
> > +               nr = (1UL << order);
> > +               if (tt->dma_address)
> > +                       ttm_pool_unmap(pool, tt->dma_address[i],
> > nr);
> > +
> > +               pt = ttm_pool_select_type(pool, caching, order);
> > +               if (pt)
> > +                       ttm_pool_type_give(pt, *pages);
> > +               else
> > +                       ttm_pool_free_page(pool, caching, order,
> > *pages);
> > +       }
> > +}
> > +
> >   /**
> >    * ttm_pool_alloc - Fill a ttm_tt object
> >    *
> > @@ -386,8 +419,9 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > struct ttm_tt *tt,
> >         dma_addr_t *dma_addr = tt->dma_address;
> >         struct page **caching = tt->pages;
> >         struct page **pages = tt->pages;
> > +       enum ttm_caching page_caching;
> >         gfp_t gfp_flags = GFP_USER;
> > -       unsigned int i, order;
> > +       unsigned int order;
> >         struct page *p;
> >         int r;
> >   
> > @@ -410,6 +444,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > struct ttm_tt *tt,
> >              order = min_t(unsigned int, order, __fls(num_pages)))
> > {
> >                 struct ttm_pool_type *pt;
> >   
> > +               page_caching = tt->caching;
> >                 pt = ttm_pool_select_type(pool, tt->caching,
> > order);
> >                 p = pt ? ttm_pool_type_take(pt) : NULL;
> >                 if (p) {
> > @@ -418,6 +453,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > struct ttm_tt *tt,
> >                         if (r)
> >                                 goto error_free_page;
> >   
> > +                       caching = pages;
> >                         do {
> >                                 r = ttm_pool_page_allocated(pool,
> > order, p,
> >                                                            
> > &dma_addr,
> > @@ -426,14 +462,15 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > struct ttm_tt *tt,
> >                                 if (r)
> >                                         goto error_free_page;
> >   
> > +                               caching = pages;
> >                                 if (num_pages < (1 << order))
> >                                         break;
> >   
> >                                 p = ttm_pool_type_take(pt);
> >                         } while (p);
> > -                       caching = pages;
> >                 }
> >   
> > +               page_caching = ttm_cached;
> >                 while (num_pages >= (1 << order) &&
> >                        (p = ttm_pool_alloc_page(pool, gfp_flags,
> > order))) {
> >   
> > @@ -442,6 +479,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > struct ttm_tt *tt,
> >                                                            tt-
> > >caching);
> >                                 if (r)
> >                                         goto error_free_page;
> > +                               caching = pages;
> >                         }
> >                         r = ttm_pool_page_allocated(pool, order, p,
> > &dma_addr,
> >                                                     &num_pages,
> > &pages);
> > @@ -468,15 +506,12 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > struct ttm_tt *tt,
> >         return 0;
> >   
> >   error_free_page:
> > -       ttm_pool_free_page(pool, tt->caching, order, p);
> > +       ttm_pool_free_page(pool, page_caching, order, p);
> >   
> >   error_free_all:
> >         num_pages = tt->num_pages - num_pages;
> > -       for (i = 0; i < num_pages; ) {
> > -               order = ttm_pool_page_order(pool, tt->pages[i]);
> > -               ttm_pool_free_page(pool, tt->caching, order, tt-
> > >pages[i]);
> > -               i += 1 << order;
> > -       }
> > +       __ttm_pool_free(pool, tt, caching, tt->caching, ttm_cached,
> > +                       num_pages);
> >   
> >         return r;
> >   }
> > @@ -492,27 +527,8 @@ EXPORT_SYMBOL(ttm_pool_alloc);
> >    */
> >   void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
> >   {
> > -       unsigned int i;
> > -
> > -       for (i = 0; i < tt->num_pages; ) {
> > -               struct page *p = tt->pages[i];
> > -               unsigned int order, num_pages;
> > -               struct ttm_pool_type *pt;
> > -
> > -               order = ttm_pool_page_order(pool, p);
> > -               num_pages = 1ULL << order;
> > -               if (tt->dma_address)
> > -                       ttm_pool_unmap(pool, tt->dma_address[i],
> > num_pages);
> > -
> > -               pt = ttm_pool_select_type(pool, tt->caching,
> > order);
> > -               if (pt)
> > -                       ttm_pool_type_give(pt, tt->pages[i]);
> > -               else
> > -                       ttm_pool_free_page(pool, tt->caching,
> > order,
> > -                                          tt->pages[i]);
> > -
> > -               i += num_pages;
> > -       }
> > +       __ttm_pool_free(pool, tt, NULL, tt->caching, tt->caching,
> > +                       tt->num_pages);
> >   
> >         while (atomic_long_read(&allocated_pages) > page_pool_size)
> >                 ttm_pool_shrink();
>
Christian König Feb. 15, 2023, 6:26 p.m. UTC | #3
Am 15.02.23 um 19:02 schrieb Thomas Hellström:
> On Wed, 2023-02-15 at 18:31 +0100, Christian König wrote:
>> Am 15.02.23 um 17:13 schrieb Thomas Hellström:
>>> When hitting an error, the error path forgot to unmap dma mappings
>>> and
>> I don't see where this happens?
>  From what I can tell, ttm_pool_page_allocated() maps the page for dma,
> If we later hit an error, ttm_pool_free_page() will leak the mapping.

Ah, I see. Good point.

>
>>> could call set_pages_wb() on already uncached pages.
>> Yeah, but what's the problem?
> Umm, at least if you try to set WC on an already WC'd page, the
> set_pages_ code will spam dmesg with warnings.
> Not sure if set_pages_wb() on WB pages does the same, nor if it
> issues unnecessary global cache / tlb flushes or whether that will
> change in the future.
> The point of avoiding the set_pages_wb() when already WB is you don't
> have to check, and you don't have to care.

Please just open code the error handling then. That helper function 
looks horrible complicated to me.

Alternatively we could have a free function for a range of pages.

Regards,
Christian.


>
> That said, the __ttm_pool_free() is used also in upcoming patches.
>
> /Thomas
>
>
>> Regards,
>> Christian.
>>
>>> Fix this by introducing a common __ttm_pool_free() function that
>>> does the right thing.
>>>
>>> Fixes: d099fc8f540a ("drm/ttm: new TT backend allocation pool v3")
>>> Cc: Christian König <christian.koenig@amd.com>
>>> Cc: Dave Airlie <airlied@redhat.com>
>>> Cc: Madhav Chauhan <madhav.chauhan@amd.com>
>>> Cc: Christian Koenig <christian.koenig@amd.com>
>>> Cc: Huang Rui <ray.huang@amd.com>
>>> Cc: dri-devel@lists.freedesktop.org
>>> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
>>> ---
>>>    drivers/gpu/drm/ttm/ttm_pool.c | 74 +++++++++++++++++++++--------
>>> -----
>>>    1 file changed, 45 insertions(+), 29 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/ttm/ttm_pool.c
>>> b/drivers/gpu/drm/ttm/ttm_pool.c
>>> index aa116a7bbae3..1cc7591a9542 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_pool.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_pool.c
>>> @@ -367,6 +367,39 @@ static int ttm_pool_page_allocated(struct
>>> ttm_pool *pool, unsigned int order,
>>>          return 0;
>>>    }
>>>    
>>> +static void __ttm_pool_free(struct ttm_pool *pool, struct ttm_tt
>>> *tt,
>>> +                           struct page **caching_divide,
>>> +                           enum ttm_caching initial_caching,
>>> +                           enum ttm_caching subseq_caching,
>>> +                           pgoff_t num_pages)
>>> +{
>>> +       enum ttm_caching caching = subseq_caching;
>>> +       struct page **pages = tt->pages;
>>> +       unsigned int order;
>>> +       pgoff_t i, nr;
>>> +
>>> +       if (pool && caching_divide)
>>> +               caching = initial_caching;
>>> +
>>> +       for (i = 0; i < num_pages; i += nr, pages += nr) {
>>> +               struct ttm_pool_type *pt = NULL;
>>> +
>>> +               if (unlikely(caching_divide == pages))
>>> +                       caching = subseq_caching;
>>> +
>>> +               order = ttm_pool_page_order(pool, *pages);
>>> +               nr = (1UL << order);
>>> +               if (tt->dma_address)
>>> +                       ttm_pool_unmap(pool, tt->dma_address[i],
>>> nr);
>>> +
>>> +               pt = ttm_pool_select_type(pool, caching, order);
>>> +               if (pt)
>>> +                       ttm_pool_type_give(pt, *pages);
>>> +               else
>>> +                       ttm_pool_free_page(pool, caching, order,
>>> *pages);
>>> +       }
>>> +}
>>> +
>>>    /**
>>>     * ttm_pool_alloc - Fill a ttm_tt object
>>>     *
>>> @@ -386,8 +419,9 @@ int ttm_pool_alloc(struct ttm_pool *pool,
>>> struct ttm_tt *tt,
>>>          dma_addr_t *dma_addr = tt->dma_address;
>>>          struct page **caching = tt->pages;
>>>          struct page **pages = tt->pages;
>>> +       enum ttm_caching page_caching;
>>>          gfp_t gfp_flags = GFP_USER;
>>> -       unsigned int i, order;
>>> +       unsigned int order;
>>>          struct page *p;
>>>          int r;
>>>    
>>> @@ -410,6 +444,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
>>> struct ttm_tt *tt,
>>>               order = min_t(unsigned int, order, __fls(num_pages)))
>>> {
>>>                  struct ttm_pool_type *pt;
>>>    
>>> +               page_caching = tt->caching;
>>>                  pt = ttm_pool_select_type(pool, tt->caching,
>>> order);
>>>                  p = pt ? ttm_pool_type_take(pt) : NULL;
>>>                  if (p) {
>>> @@ -418,6 +453,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
>>> struct ttm_tt *tt,
>>>                          if (r)
>>>                                  goto error_free_page;
>>>    
>>> +                       caching = pages;
>>>                          do {
>>>                                  r = ttm_pool_page_allocated(pool,
>>> order, p,
>>>                                                             
>>> &dma_addr,
>>> @@ -426,14 +462,15 @@ int ttm_pool_alloc(struct ttm_pool *pool,
>>> struct ttm_tt *tt,
>>>                                  if (r)
>>>                                          goto error_free_page;
>>>    
>>> +                               caching = pages;
>>>                                  if (num_pages < (1 << order))
>>>                                          break;
>>>    
>>>                                  p = ttm_pool_type_take(pt);
>>>                          } while (p);
>>> -                       caching = pages;
>>>                  }
>>>    
>>> +               page_caching = ttm_cached;
>>>                  while (num_pages >= (1 << order) &&
>>>                         (p = ttm_pool_alloc_page(pool, gfp_flags,
>>> order))) {
>>>    
>>> @@ -442,6 +479,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
>>> struct ttm_tt *tt,
>>>                                                             tt-
>>>> caching);
>>>                                  if (r)
>>>                                          goto error_free_page;
>>> +                               caching = pages;
>>>                          }
>>>                          r = ttm_pool_page_allocated(pool, order, p,
>>> &dma_addr,
>>>                                                      &num_pages,
>>> &pages);
>>> @@ -468,15 +506,12 @@ int ttm_pool_alloc(struct ttm_pool *pool,
>>> struct ttm_tt *tt,
>>>          return 0;
>>>    
>>>    error_free_page:
>>> -       ttm_pool_free_page(pool, tt->caching, order, p);
>>> +       ttm_pool_free_page(pool, page_caching, order, p);
>>>    
>>>    error_free_all:
>>>          num_pages = tt->num_pages - num_pages;
>>> -       for (i = 0; i < num_pages; ) {
>>> -               order = ttm_pool_page_order(pool, tt->pages[i]);
>>> -               ttm_pool_free_page(pool, tt->caching, order, tt-
>>>> pages[i]);
>>> -               i += 1 << order;
>>> -       }
>>> +       __ttm_pool_free(pool, tt, caching, tt->caching, ttm_cached,
>>> +                       num_pages);
>>>    
>>>          return r;
>>>    }
>>> @@ -492,27 +527,8 @@ EXPORT_SYMBOL(ttm_pool_alloc);
>>>     */
>>>    void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
>>>    {
>>> -       unsigned int i;
>>> -
>>> -       for (i = 0; i < tt->num_pages; ) {
>>> -               struct page *p = tt->pages[i];
>>> -               unsigned int order, num_pages;
>>> -               struct ttm_pool_type *pt;
>>> -
>>> -               order = ttm_pool_page_order(pool, p);
>>> -               num_pages = 1ULL << order;
>>> -               if (tt->dma_address)
>>> -                       ttm_pool_unmap(pool, tt->dma_address[i],
>>> num_pages);
>>> -
>>> -               pt = ttm_pool_select_type(pool, tt->caching,
>>> order);
>>> -               if (pt)
>>> -                       ttm_pool_type_give(pt, tt->pages[i]);
>>> -               else
>>> -                       ttm_pool_free_page(pool, tt->caching,
>>> order,
>>> -                                          tt->pages[i]);
>>> -
>>> -               i += num_pages;
>>> -       }
>>> +       __ttm_pool_free(pool, tt, NULL, tt->caching, tt->caching,
>>> +                       tt->num_pages);
>>>    
>>>          while (atomic_long_read(&allocated_pages) > page_pool_size)
>>>                  ttm_pool_shrink();
Thomas Hellstrom Feb. 15, 2023, 6:51 p.m. UTC | #4
On Wed, 2023-02-15 at 19:26 +0100, Christian König wrote:
> Am 15.02.23 um 19:02 schrieb Thomas Hellström:
> > On Wed, 2023-02-15 at 18:31 +0100, Christian König wrote:
> > > Am 15.02.23 um 17:13 schrieb Thomas Hellström:
> > > > When hitting an error, the error path forgot to unmap dma
> > > > mappings
> > > > and
> > > I don't see where this happens?
> >  From what I can tell, ttm_pool_page_allocated() maps the page for
> > dma,
> > If we later hit an error, ttm_pool_free_page() will leak the
> > mapping.
> 
> Ah, I see. Good point.
> 
> > 
> > > > could call set_pages_wb() on already uncached pages.
> > > Yeah, but what's the problem?
> > Umm, at least if you try to set WC on an already WC'd page, the
> > set_pages_ code will spam dmesg with warnings.
> > Not sure if set_pages_wb() on WB pages does the same, nor if it
> > issues unnecessary global cache / tlb flushes or whether that will
> > change in the future.
> > The point of avoiding the set_pages_wb() when already WB is you
> > don't
> > have to check, and you don't have to care.
> 
> Please just open code the error handling then. That helper function 
> looks horrible complicated to me.
> 
> Alternatively we could have a free function for a range of pages.

OK, I'll see if this is doable without adding a tremendous amount of
code.

/Thomas


> 
> Regards,
> Christian.
> 
> 
> > 
> > That said, the __ttm_pool_free() is used also in upcoming patches.
> > 
> > /Thomas
> > 
> > 
> > > Regards,
> > > Christian.
> > > 
> > > > Fix this by introducing a common __ttm_pool_free() function
> > > > that
> > > > does the right thing.
> > > > 
> > > > Fixes: d099fc8f540a ("drm/ttm: new TT backend allocation pool
> > > > v3")
> > > > Cc: Christian König <christian.koenig@amd.com>
> > > > Cc: Dave Airlie <airlied@redhat.com>
> > > > Cc: Madhav Chauhan <madhav.chauhan@amd.com>
> > > > Cc: Christian Koenig <christian.koenig@amd.com>
> > > > Cc: Huang Rui <ray.huang@amd.com>
> > > > Cc: dri-devel@lists.freedesktop.org
> > > > Signed-off-by: Thomas Hellström
> > > > <thomas.hellstrom@linux.intel.com>
> > > > ---
> > > >    drivers/gpu/drm/ttm/ttm_pool.c | 74 +++++++++++++++++++++---
> > > > -----
> > > > -----
> > > >    1 file changed, 45 insertions(+), 29 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/ttm/ttm_pool.c
> > > > b/drivers/gpu/drm/ttm/ttm_pool.c
> > > > index aa116a7bbae3..1cc7591a9542 100644
> > > > --- a/drivers/gpu/drm/ttm/ttm_pool.c
> > > > +++ b/drivers/gpu/drm/ttm/ttm_pool.c
> > > > @@ -367,6 +367,39 @@ static int ttm_pool_page_allocated(struct
> > > > ttm_pool *pool, unsigned int order,
> > > >          return 0;
> > > >    }
> > > >    
> > > > +static void __ttm_pool_free(struct ttm_pool *pool, struct
> > > > ttm_tt
> > > > *tt,
> > > > +                           struct page **caching_divide,
> > > > +                           enum ttm_caching initial_caching,
> > > > +                           enum ttm_caching subseq_caching,
> > > > +                           pgoff_t num_pages)
> > > > +{
> > > > +       enum ttm_caching caching = subseq_caching;
> > > > +       struct page **pages = tt->pages;
> > > > +       unsigned int order;
> > > > +       pgoff_t i, nr;
> > > > +
> > > > +       if (pool && caching_divide)
> > > > +               caching = initial_caching;
> > > > +
> > > > +       for (i = 0; i < num_pages; i += nr, pages += nr) {
> > > > +               struct ttm_pool_type *pt = NULL;
> > > > +
> > > > +               if (unlikely(caching_divide == pages))
> > > > +                       caching = subseq_caching;
> > > > +
> > > > +               order = ttm_pool_page_order(pool, *pages);
> > > > +               nr = (1UL << order);
> > > > +               if (tt->dma_address)
> > > > +                       ttm_pool_unmap(pool, tt-
> > > > >dma_address[i],
> > > > nr);
> > > > +
> > > > +               pt = ttm_pool_select_type(pool, caching,
> > > > order);
> > > > +               if (pt)
> > > > +                       ttm_pool_type_give(pt, *pages);
> > > > +               else
> > > > +                       ttm_pool_free_page(pool, caching,
> > > > order,
> > > > *pages);
> > > > +       }
> > > > +}
> > > > +
> > > >    /**
> > > >     * ttm_pool_alloc - Fill a ttm_tt object
> > > >     *
> > > > @@ -386,8 +419,9 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > > > struct ttm_tt *tt,
> > > >          dma_addr_t *dma_addr = tt->dma_address;
> > > >          struct page **caching = tt->pages;
> > > >          struct page **pages = tt->pages;
> > > > +       enum ttm_caching page_caching;
> > > >          gfp_t gfp_flags = GFP_USER;
> > > > -       unsigned int i, order;
> > > > +       unsigned int order;
> > > >          struct page *p;
> > > >          int r;
> > > >    
> > > > @@ -410,6 +444,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > > > struct ttm_tt *tt,
> > > >               order = min_t(unsigned int, order,
> > > > __fls(num_pages)))
> > > > {
> > > >                  struct ttm_pool_type *pt;
> > > >    
> > > > +               page_caching = tt->caching;
> > > >                  pt = ttm_pool_select_type(pool, tt->caching,
> > > > order);
> > > >                  p = pt ? ttm_pool_type_take(pt) : NULL;
> > > >                  if (p) {
> > > > @@ -418,6 +453,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > > > struct ttm_tt *tt,
> > > >                          if (r)
> > > >                                  goto error_free_page;
> > > >    
> > > > +                       caching = pages;
> > > >                          do {
> > > >                                  r =
> > > > ttm_pool_page_allocated(pool,
> > > > order, p,
> > > >                                                             
> > > > &dma_addr,
> > > > @@ -426,14 +462,15 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > > > struct ttm_tt *tt,
> > > >                                  if (r)
> > > >                                          goto error_free_page;
> > > >    
> > > > +                               caching = pages;
> > > >                                  if (num_pages < (1 << order))
> > > >                                          break;
> > > >    
> > > >                                  p = ttm_pool_type_take(pt);
> > > >                          } while (p);
> > > > -                       caching = pages;
> > > >                  }
> > > >    
> > > > +               page_caching = ttm_cached;
> > > >                  while (num_pages >= (1 << order) &&
> > > >                         (p = ttm_pool_alloc_page(pool,
> > > > gfp_flags,
> > > > order))) {
> > > >    
> > > > @@ -442,6 +479,7 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > > > struct ttm_tt *tt,
> > > >                                                             tt-
> > > > > caching);
> > > >                                  if (r)
> > > >                                          goto error_free_page;
> > > > +                               caching = pages;
> > > >                          }
> > > >                          r = ttm_pool_page_allocated(pool,
> > > > order, p,
> > > > &dma_addr,
> > > >                                                     
> > > > &num_pages,
> > > > &pages);
> > > > @@ -468,15 +506,12 @@ int ttm_pool_alloc(struct ttm_pool *pool,
> > > > struct ttm_tt *tt,
> > > >          return 0;
> > > >    
> > > >    error_free_page:
> > > > -       ttm_pool_free_page(pool, tt->caching, order, p);
> > > > +       ttm_pool_free_page(pool, page_caching, order, p);
> > > >    
> > > >    error_free_all:
> > > >          num_pages = tt->num_pages - num_pages;
> > > > -       for (i = 0; i < num_pages; ) {
> > > > -               order = ttm_pool_page_order(pool, tt-
> > > > >pages[i]);
> > > > -               ttm_pool_free_page(pool, tt->caching, order,
> > > > tt-
> > > > > pages[i]);
> > > > -               i += 1 << order;
> > > > -       }
> > > > +       __ttm_pool_free(pool, tt, caching, tt->caching,
> > > > ttm_cached,
> > > > +                       num_pages);
> > > >    
> > > >          return r;
> > > >    }
> > > > @@ -492,27 +527,8 @@ EXPORT_SYMBOL(ttm_pool_alloc);
> > > >     */
> > > >    void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
> > > >    {
> > > > -       unsigned int i;
> > > > -
> > > > -       for (i = 0; i < tt->num_pages; ) {
> > > > -               struct page *p = tt->pages[i];
> > > > -               unsigned int order, num_pages;
> > > > -               struct ttm_pool_type *pt;
> > > > -
> > > > -               order = ttm_pool_page_order(pool, p);
> > > > -               num_pages = 1ULL << order;
> > > > -               if (tt->dma_address)
> > > > -                       ttm_pool_unmap(pool, tt-
> > > > >dma_address[i],
> > > > num_pages);
> > > > -
> > > > -               pt = ttm_pool_select_type(pool, tt->caching,
> > > > order);
> > > > -               if (pt)
> > > > -                       ttm_pool_type_give(pt, tt->pages[i]);
> > > > -               else
> > > > -                       ttm_pool_free_page(pool, tt->caching,
> > > > order,
> > > > -                                          tt->pages[i]);
> > > > -
> > > > -               i += num_pages;
> > > > -       }
> > > > +       __ttm_pool_free(pool, tt, NULL, tt->caching, tt-
> > > > >caching,
> > > > +                       tt->num_pages);
> > > >    
> > > >          while (atomic_long_read(&allocated_pages) >
> > > > page_pool_size)
> > > >                  ttm_pool_shrink();
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
index aa116a7bbae3..1cc7591a9542 100644
--- a/drivers/gpu/drm/ttm/ttm_pool.c
+++ b/drivers/gpu/drm/ttm/ttm_pool.c
@@ -367,6 +367,39 @@  static int ttm_pool_page_allocated(struct ttm_pool *pool, unsigned int order,
 	return 0;
 }
 
+static void __ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt,
+			    struct page **caching_divide,
+			    enum ttm_caching initial_caching,
+			    enum ttm_caching subseq_caching,
+			    pgoff_t num_pages)
+{
+	enum ttm_caching caching = subseq_caching;
+	struct page **pages = tt->pages;
+	unsigned int order;
+	pgoff_t i, nr;
+
+	if (pool && caching_divide)
+		caching = initial_caching;
+
+	for (i = 0; i < num_pages; i += nr, pages += nr) {
+		struct ttm_pool_type *pt = NULL;
+
+		if (unlikely(caching_divide == pages))
+			caching = subseq_caching;
+
+		order = ttm_pool_page_order(pool, *pages);
+		nr = (1UL << order);
+		if (tt->dma_address)
+			ttm_pool_unmap(pool, tt->dma_address[i], nr);
+
+		pt = ttm_pool_select_type(pool, caching, order);
+		if (pt)
+			ttm_pool_type_give(pt, *pages);
+		else
+			ttm_pool_free_page(pool, caching, order, *pages);
+	}
+}
+
 /**
  * ttm_pool_alloc - Fill a ttm_tt object
  *
@@ -386,8 +419,9 @@  int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 	dma_addr_t *dma_addr = tt->dma_address;
 	struct page **caching = tt->pages;
 	struct page **pages = tt->pages;
+	enum ttm_caching page_caching;
 	gfp_t gfp_flags = GFP_USER;
-	unsigned int i, order;
+	unsigned int order;
 	struct page *p;
 	int r;
 
@@ -410,6 +444,7 @@  int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 	     order = min_t(unsigned int, order, __fls(num_pages))) {
 		struct ttm_pool_type *pt;
 
+		page_caching = tt->caching;
 		pt = ttm_pool_select_type(pool, tt->caching, order);
 		p = pt ? ttm_pool_type_take(pt) : NULL;
 		if (p) {
@@ -418,6 +453,7 @@  int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 			if (r)
 				goto error_free_page;
 
+			caching = pages;
 			do {
 				r = ttm_pool_page_allocated(pool, order, p,
 							    &dma_addr,
@@ -426,14 +462,15 @@  int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 				if (r)
 					goto error_free_page;
 
+				caching = pages;
 				if (num_pages < (1 << order))
 					break;
 
 				p = ttm_pool_type_take(pt);
 			} while (p);
-			caching = pages;
 		}
 
+		page_caching = ttm_cached;
 		while (num_pages >= (1 << order) &&
 		       (p = ttm_pool_alloc_page(pool, gfp_flags, order))) {
 
@@ -442,6 +479,7 @@  int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 							   tt->caching);
 				if (r)
 					goto error_free_page;
+				caching = pages;
 			}
 			r = ttm_pool_page_allocated(pool, order, p, &dma_addr,
 						    &num_pages, &pages);
@@ -468,15 +506,12 @@  int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 	return 0;
 
 error_free_page:
-	ttm_pool_free_page(pool, tt->caching, order, p);
+	ttm_pool_free_page(pool, page_caching, order, p);
 
 error_free_all:
 	num_pages = tt->num_pages - num_pages;
-	for (i = 0; i < num_pages; ) {
-		order = ttm_pool_page_order(pool, tt->pages[i]);
-		ttm_pool_free_page(pool, tt->caching, order, tt->pages[i]);
-		i += 1 << order;
-	}
+	__ttm_pool_free(pool, tt, caching, tt->caching, ttm_cached,
+			num_pages);
 
 	return r;
 }
@@ -492,27 +527,8 @@  EXPORT_SYMBOL(ttm_pool_alloc);
  */
 void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
 {
-	unsigned int i;
-
-	for (i = 0; i < tt->num_pages; ) {
-		struct page *p = tt->pages[i];
-		unsigned int order, num_pages;
-		struct ttm_pool_type *pt;
-
-		order = ttm_pool_page_order(pool, p);
-		num_pages = 1ULL << order;
-		if (tt->dma_address)
-			ttm_pool_unmap(pool, tt->dma_address[i], num_pages);
-
-		pt = ttm_pool_select_type(pool, tt->caching, order);
-		if (pt)
-			ttm_pool_type_give(pt, tt->pages[i]);
-		else
-			ttm_pool_free_page(pool, tt->caching, order,
-					   tt->pages[i]);
-
-		i += num_pages;
-	}
+	__ttm_pool_free(pool, tt, NULL, tt->caching, tt->caching,
+			tt->num_pages);
 
 	while (atomic_long_read(&allocated_pages) > page_pool_size)
 		ttm_pool_shrink();