| Message ID | 20201120095445.1195585-5-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/ttm: don't set page->mapping | expand |
Am 20.11.20 um 10:54 schrieb Daniel Vetter: > Random observation while trying to review Christian's patch series to > stop looking at struct page for dma-buf imports. > > This was originally added in > > commit 58aa6622d32af7d2c08d45085f44c54554a16ed7 > Author: Thomas Hellstrom <thellstrom@vmware.com> > Date: Fri Jan 3 11:47:23 2014 +0100 > > drm/ttm: Correctly set page mapping and -index members > > Needed for some vm operations; most notably unmap_mapping_range() with > even_cows = 0. > > Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> > Reviewed-by: Brian Paul <brianp@vmware.com> > > but we do not have a single caller of unmap_mapping_range with > even_cows == 0. And all the gem drivers don't do this, so another > small thing we could standardize between drm and ttm drivers. > > Plus I don't really see a need for unamp_mapping_range where we don't > want to indiscriminately shoot down all ptes. > > Cc: Thomas Hellstrom <thellstrom@vmware.com> > Cc: Brian Paul <brianp@vmware.com> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> > Cc: Christian Koenig <christian.koenig@amd.com> > Cc: Huang Rui <ray.huang@amd.com> This is still a NAK as long as we can't come up with a better way to track TTMs page allocations. Additional to that page_mapping() is used quite extensively in the mm code and I'm not sure if that isn't needed for other stuff as well. Regards, Christian. > --- > drivers/gpu/drm/ttm/ttm_tt.c | 12 ------------ > 1 file changed, 12 deletions(-) > > diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c > index da9eeffe0c6d..5b2eb6d58bb7 100644 > --- a/drivers/gpu/drm/ttm/ttm_tt.c > +++ b/drivers/gpu/drm/ttm/ttm_tt.c > @@ -284,17 +284,6 @@ int ttm_tt_swapout(struct ttm_bo_device *bdev, struct ttm_tt *ttm) > return ret; > } > > -static void ttm_tt_add_mapping(struct ttm_bo_device *bdev, struct ttm_tt *ttm) > -{ > - pgoff_t i; > - > - if (ttm->page_flags & TTM_PAGE_FLAG_SG) > - return; > - > - for (i = 0; i < ttm->num_pages; ++i) > - ttm->pages[i]->mapping = bdev->dev_mapping; > -} > - > int ttm_tt_populate(struct ttm_bo_device *bdev, > struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) > { > @@ -313,7 +302,6 @@ int ttm_tt_populate(struct ttm_bo_device *bdev, > if (ret) > return ret; > > - ttm_tt_add_mapping(bdev, ttm); > ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED; > if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) { > ret = ttm_tt_swapin(ttm);
On Fri, Nov 20, 2020 at 11:04 AM Christian König <christian.koenig@amd.com> wrote: > > Am 20.11.20 um 10:54 schrieb Daniel Vetter: > > Random observation while trying to review Christian's patch series to > > stop looking at struct page for dma-buf imports. > > > > This was originally added in > > > > commit 58aa6622d32af7d2c08d45085f44c54554a16ed7 > > Author: Thomas Hellstrom <thellstrom@vmware.com> > > Date: Fri Jan 3 11:47:23 2014 +0100 > > > > drm/ttm: Correctly set page mapping and -index members > > > > Needed for some vm operations; most notably unmap_mapping_range() with > > even_cows = 0. > > > > Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> > > Reviewed-by: Brian Paul <brianp@vmware.com> > > > > but we do not have a single caller of unmap_mapping_range with > > even_cows == 0. And all the gem drivers don't do this, so another > > small thing we could standardize between drm and ttm drivers. > > > > Plus I don't really see a need for unamp_mapping_range where we don't > > want to indiscriminately shoot down all ptes. > > > > Cc: Thomas Hellstrom <thellstrom@vmware.com> > > Cc: Brian Paul <brianp@vmware.com> > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> > > Cc: Christian Koenig <christian.koenig@amd.com> > > Cc: Huang Rui <ray.huang@amd.com> > > This is still a NAK as long as we can't come up with a better way to > track TTMs page allocations. > > Additional to that page_mapping() is used quite extensively in the mm > code and I'm not sure if that isn't needed for other stuff as well. Apologies, I'm honestly not quite sure how this lone patch here ended up in this submission. I didn't want to send it out. -Daniel > > Regards, > Christian. > > > --- > > drivers/gpu/drm/ttm/ttm_tt.c | 12 ------------ > > 1 file changed, 12 deletions(-) > > > > diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c > > index da9eeffe0c6d..5b2eb6d58bb7 100644 > > --- a/drivers/gpu/drm/ttm/ttm_tt.c > > +++ b/drivers/gpu/drm/ttm/ttm_tt.c > > @@ -284,17 +284,6 @@ int ttm_tt_swapout(struct ttm_bo_device *bdev, struct ttm_tt *ttm) > > return ret; > > } > > > > -static void ttm_tt_add_mapping(struct ttm_bo_device *bdev, struct ttm_tt *ttm) > > -{ > > - pgoff_t i; > > - > > - if (ttm->page_flags & TTM_PAGE_FLAG_SG) > > - return; > > - > > - for (i = 0; i < ttm->num_pages; ++i) > > - ttm->pages[i]->mapping = bdev->dev_mapping; > > -} > > - > > int ttm_tt_populate(struct ttm_bo_device *bdev, > > struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) > > { > > @@ -313,7 +302,6 @@ int ttm_tt_populate(struct ttm_bo_device *bdev, > > if (ret) > > return ret; > > > > - ttm_tt_add_mapping(bdev, ttm); > > ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED; > > if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) { > > ret = ttm_tt_swapin(ttm); >
Am 20.11.20 um 11:05 schrieb Daniel Vetter: > On Fri, Nov 20, 2020 at 11:04 AM Christian König > <christian.koenig@amd.com> wrote: >> Am 20.11.20 um 10:54 schrieb Daniel Vetter: >>> Random observation while trying to review Christian's patch series to >>> stop looking at struct page for dma-buf imports. >>> >>> This was originally added in >>> >>> commit 58aa6622d32af7d2c08d45085f44c54554a16ed7 >>> Author: Thomas Hellstrom <thellstrom@vmware.com> >>> Date: Fri Jan 3 11:47:23 2014 +0100 >>> >>> drm/ttm: Correctly set page mapping and -index members >>> >>> Needed for some vm operations; most notably unmap_mapping_range() with >>> even_cows = 0. >>> >>> Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> >>> Reviewed-by: Brian Paul <brianp@vmware.com> >>> >>> but we do not have a single caller of unmap_mapping_range with >>> even_cows == 0. And all the gem drivers don't do this, so another >>> small thing we could standardize between drm and ttm drivers. >>> >>> Plus I don't really see a need for unamp_mapping_range where we don't >>> want to indiscriminately shoot down all ptes. >>> >>> Cc: Thomas Hellstrom <thellstrom@vmware.com> >>> Cc: Brian Paul <brianp@vmware.com> >>> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> >>> Cc: Christian Koenig <christian.koenig@amd.com> >>> Cc: Huang Rui <ray.huang@amd.com> >> This is still a NAK as long as we can't come up with a better way to >> track TTMs page allocations. >> >> Additional to that page_mapping() is used quite extensively in the mm >> code and I'm not sure if that isn't needed for other stuff as well. > Apologies, I'm honestly not quite sure how this lone patch here ended > up in this submission. I didn't want to send it out. No problem. But looking a bit deeper into the mm code that other drm drivers don't set this correctly and still use unmap_mapping_range() sounds like quite a bug to me. Going to track down what exactly that is used for. Christian. > -Daniel > >> Regards, >> Christian. >> >>> --- >>> drivers/gpu/drm/ttm/ttm_tt.c | 12 ------------ >>> 1 file changed, 12 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c >>> index da9eeffe0c6d..5b2eb6d58bb7 100644 >>> --- a/drivers/gpu/drm/ttm/ttm_tt.c >>> +++ b/drivers/gpu/drm/ttm/ttm_tt.c >>> @@ -284,17 +284,6 @@ int ttm_tt_swapout(struct ttm_bo_device *bdev, struct ttm_tt *ttm) >>> return ret; >>> } >>> >>> -static void ttm_tt_add_mapping(struct ttm_bo_device *bdev, struct ttm_tt *ttm) >>> -{ >>> - pgoff_t i; >>> - >>> - if (ttm->page_flags & TTM_PAGE_FLAG_SG) >>> - return; >>> - >>> - for (i = 0; i < ttm->num_pages; ++i) >>> - ttm->pages[i]->mapping = bdev->dev_mapping; >>> -} >>> - >>> int ttm_tt_populate(struct ttm_bo_device *bdev, >>> struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) >>> { >>> @@ -313,7 +302,6 @@ int ttm_tt_populate(struct ttm_bo_device *bdev, >>> if (ret) >>> return ret; >>> >>> - ttm_tt_add_mapping(bdev, ttm); >>> ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED; >>> if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) { >>> ret = ttm_tt_swapin(ttm); >
On Fri, Nov 20, 2020 at 11:08:31AM +0100, Christian König wrote: > Am 20.11.20 um 11:05 schrieb Daniel Vetter: > > On Fri, Nov 20, 2020 at 11:04 AM Christian König > > <christian.koenig@amd.com> wrote: > > > Am 20.11.20 um 10:54 schrieb Daniel Vetter: > > > > Random observation while trying to review Christian's patch series to > > > > stop looking at struct page for dma-buf imports. > > > > > > > > This was originally added in > > > > > > > > commit 58aa6622d32af7d2c08d45085f44c54554a16ed7 > > > > Author: Thomas Hellstrom <thellstrom@vmware.com> > > > > Date: Fri Jan 3 11:47:23 2014 +0100 > > > > > > > > drm/ttm: Correctly set page mapping and -index members > > > > > > > > Needed for some vm operations; most notably unmap_mapping_range() with > > > > even_cows = 0. > > > > > > > > Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> > > > > Reviewed-by: Brian Paul <brianp@vmware.com> > > > > > > > > but we do not have a single caller of unmap_mapping_range with > > > > even_cows == 0. And all the gem drivers don't do this, so another > > > > small thing we could standardize between drm and ttm drivers. > > > > > > > > Plus I don't really see a need for unamp_mapping_range where we don't > > > > want to indiscriminately shoot down all ptes. > > > > > > > > Cc: Thomas Hellstrom <thellstrom@vmware.com> > > > > Cc: Brian Paul <brianp@vmware.com> > > > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> > > > > Cc: Christian Koenig <christian.koenig@amd.com> > > > > Cc: Huang Rui <ray.huang@amd.com> > > > This is still a NAK as long as we can't come up with a better way to > > > track TTMs page allocations. > > > > > > Additional to that page_mapping() is used quite extensively in the mm > > > code and I'm not sure if that isn't needed for other stuff as well. > > Apologies, I'm honestly not quite sure how this lone patch here ended > > up in this submission. I didn't want to send it out. > > No problem. > > But looking a bit deeper into the mm code that other drm drivers don't set > this correctly and still use unmap_mapping_range() sounds like quite a bug > to me. > > Going to track down what exactly that is used for. Pagecache shootdown. unmap_mapping_range only shoots down from the virtual side. Since that's all we care about, we don't need to set up the address_space in the page. -Daniel > > Christian. > > > -Daniel > > > > > Regards, > > > Christian. > > > > > > > --- > > > > drivers/gpu/drm/ttm/ttm_tt.c | 12 ------------ > > > > 1 file changed, 12 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c > > > > index da9eeffe0c6d..5b2eb6d58bb7 100644 > > > > --- a/drivers/gpu/drm/ttm/ttm_tt.c > > > > +++ b/drivers/gpu/drm/ttm/ttm_tt.c > > > > @@ -284,17 +284,6 @@ int ttm_tt_swapout(struct ttm_bo_device *bdev, struct ttm_tt *ttm) > > > > return ret; > > > > } > > > > > > > > -static void ttm_tt_add_mapping(struct ttm_bo_device *bdev, struct ttm_tt *ttm) > > > > -{ > > > > - pgoff_t i; > > > > - > > > > - if (ttm->page_flags & TTM_PAGE_FLAG_SG) > > > > - return; > > > > - > > > > - for (i = 0; i < ttm->num_pages; ++i) > > > > - ttm->pages[i]->mapping = bdev->dev_mapping; > > > > -} > > > > - > > > > int ttm_tt_populate(struct ttm_bo_device *bdev, > > > > struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) > > > > { > > > > @@ -313,7 +302,6 @@ int ttm_tt_populate(struct ttm_bo_device *bdev, > > > > if (ret) > > > > return ret; > > > > > > > > - ttm_tt_add_mapping(bdev, ttm); > > > > ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED; > > > > if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) { > > > > ret = ttm_tt_swapin(ttm); > > >
diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index da9eeffe0c6d..5b2eb6d58bb7 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -284,17 +284,6 @@ int ttm_tt_swapout(struct ttm_bo_device *bdev, struct ttm_tt *ttm) return ret; } -static void ttm_tt_add_mapping(struct ttm_bo_device *bdev, struct ttm_tt *ttm) -{ - pgoff_t i; - - if (ttm->page_flags & TTM_PAGE_FLAG_SG) - return; - - for (i = 0; i < ttm->num_pages; ++i) - ttm->pages[i]->mapping = bdev->dev_mapping; -} - int ttm_tt_populate(struct ttm_bo_device *bdev, struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) { @@ -313,7 +302,6 @@ int ttm_tt_populate(struct ttm_bo_device *bdev, if (ret) return ret; - ttm_tt_add_mapping(bdev, ttm); ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED; if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) { ret = ttm_tt_swapin(ttm);
Random observation while trying to review Christian's patch series to stop looking at struct page for dma-buf imports. This was originally added in commit 58aa6622d32af7d2c08d45085f44c54554a16ed7 Author: Thomas Hellstrom <thellstrom@vmware.com> Date: Fri Jan 3 11:47:23 2014 +0100 drm/ttm: Correctly set page mapping and -index members Needed for some vm operations; most notably unmap_mapping_range() with even_cows = 0. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Reviewed-by: Brian Paul <brianp@vmware.com> but we do not have a single caller of unmap_mapping_range with even_cows == 0. And all the gem drivers don't do this, so another small thing we could standardize between drm and ttm drivers. Plus I don't really see a need for unamp_mapping_range where we don't want to indiscriminately shoot down all ptes. Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Brian Paul <brianp@vmware.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Christian Koenig <christian.koenig@amd.com> Cc: Huang Rui <ray.huang@amd.com> --- drivers/gpu/drm/ttm/ttm_tt.c | 12 ------------ 1 file changed, 12 deletions(-)