| Message ID | 20210521153253.518037-10-thomas.hellstrom@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: Move LMEM (VRAM) management over to TTM | expand |
On Fri, 21 May 2021 at 16:33, Thomas Hellström <thomas.hellstrom@linux.intel.com> wrote: > > If the bo is idle when calling ttm_bo_pipeline_gutting(), we unnecessarily > create a ghost object and push it out to delayed destroy. > Fix this by adding a path for idle, and document the function. > > Also avoid having the bo end up in a bad state vulnerable to user-space > triggered kernel BUGs if the call to ttm_tt_create() fails. > > Finally reuse ttm_bo_pipeline_gutting() in ttm_bo_evict(). > > Cc: Christian König <christian.koenig@amd.com> > Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> > --- > drivers/gpu/drm/ttm/ttm_bo.c | 20 ++++++------ > drivers/gpu/drm/ttm/ttm_bo_util.c | 52 ++++++++++++++++++++++++++++--- > drivers/gpu/drm/ttm/ttm_tt.c | 5 +++ > include/drm/ttm/ttm_tt.h | 10 ++++++ > 4 files changed, 73 insertions(+), 14 deletions(-) > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c > index ca1b098b6a56..a8fa3375b8aa 100644 > --- a/drivers/gpu/drm/ttm/ttm_bo.c > +++ b/drivers/gpu/drm/ttm/ttm_bo.c > @@ -501,10 +501,15 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, > bdev->funcs->evict_flags(bo, &placement); > > if (!placement.num_placement && !placement.num_busy_placement) { > - ttm_bo_wait(bo, false, false); > + ret = ttm_bo_wait(bo, true, false); > + if (ret) > + return ret; > > - ttm_bo_cleanup_memtype_use(bo); > - return ttm_tt_create(bo, false); > + /* > + * Since we've already synced, this frees backing store > + * immediately. > + */ > + return ttm_bo_pipeline_gutting(bo); > } > > ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx); > @@ -974,13 +979,8 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, > /* > * Remove the backing store if no placement is given. > */ > - if (!placement->num_placement && !placement->num_busy_placement) { > - ret = ttm_bo_pipeline_gutting(bo); > - if (ret) > - return ret; > - > - return ttm_tt_create(bo, false); > - } > + if (!placement->num_placement && !placement->num_busy_placement) > + return ttm_bo_pipeline_gutting(bo); > > /* > * Check whether we need to move buffer. > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c > index 4a7d3d672f9a..7fa9b3a852eb 100644 > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c > @@ -585,26 +585,70 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo, > } > EXPORT_SYMBOL(ttm_bo_move_accel_cleanup); > > +/** > + * ttm_bo_pipeline_gutting - purge the contents of a bo > + * @bo: The buffer object > + * > + * Purge the contents of a bo, async if the bo is not idle. > + * After a successful call, the bo is left unpopulated in > + * system placement. The function may wait uninterruptible > + * for idle on OOM. > + * > + * Return: 0 if successful, negative error code on failure. > + */ > int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo) > { > static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM }; > struct ttm_buffer_object *ghost; > + struct ttm_tt *ttm; > int ret; > > - ret = ttm_buffer_object_transfer(bo, &ghost); > + /* If already idle, no need for ghost object dance. */ > + ret = ttm_bo_wait(bo, false, true); > + if (ret != -EBUSY) { > + if (!bo->ttm) { > + ret = ttm_tt_create(bo, true); Why do we now unconditionally add clearing? Below also. > + if (ret) > + return ret; > + } else { > + ttm_tt_unpopulate(bo->bdev, bo->ttm); > + if (bo->type == ttm_bo_type_device) > + ttm_tt_mark_for_clear(bo->ttm); > + } > + ttm_resource_free(bo, &bo->mem); > + ttm_resource_alloc(bo, &sys_mem, &bo->mem); > + > + return 0; > + } > + > + /* > + * We need an unpopulated ttm_tt after giving our current one, > + * if any, to the ghost object. And we can't afford to fail > + * creating one *after* the operation. > + */ > + > + ttm = bo->ttm; > + bo->ttm = NULL; > + ret = ttm_tt_create(bo, true); > + swap(bo->ttm, ttm); > if (ret) > return ret; > > + ret = ttm_buffer_object_transfer(bo, &ghost); > + if (ret) { > + ttm_tt_destroy(bo->bdev, ttm); > + return ret; > + } > + > ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv); > /* Last resort, wait for the BO to be idle when we are OOM */ > if (ret) > ttm_bo_wait(bo, false, false); > > - ttm_resource_alloc(bo, &sys_mem, &bo->mem); > - bo->ttm = NULL; > - > dma_resv_unlock(&ghost->base._resv); > ttm_bo_put(ghost); > + bo->ttm = ttm; > + ttm_resource_alloc(bo, &sys_mem, &bo->mem); > > return 0; > } > diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c > index 0e41227116b1..913b330a234b 100644 > --- a/drivers/gpu/drm/ttm/ttm_tt.c > +++ b/drivers/gpu/drm/ttm/ttm_tt.c > @@ -134,6 +134,11 @@ void ttm_tt_destroy_common(struct ttm_device *bdev, struct ttm_tt *ttm) > } > EXPORT_SYMBOL(ttm_tt_destroy_common); > > +void ttm_tt_mark_for_clear(struct ttm_tt *ttm) > +{ > + ttm->page_flags |= TTM_PAGE_FLAG_ZERO_ALLOC; > +} > + > void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm) > { > bdev->funcs->ttm_tt_destroy(bdev, ttm); > diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h > index 3102059db726..daa9c4cf48bb 100644 > --- a/include/drm/ttm/ttm_tt.h > +++ b/include/drm/ttm/ttm_tt.h > @@ -170,6 +170,16 @@ int ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm, struct ttm_oper > */ > void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm); > > +/** > + * ttm_tt_mark_for_clear - Mark pages for clearing on populate. > + * > + * @ttm: Pointer to the ttm_tt structure > + * > + * Marks pages for clearing so that the next time the page vector is > + * populated, the pages will be cleared. > + */ > +void ttm_tt_mark_for_clear(struct ttm_tt *ttm); > + > void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages); > > struct ttm_kmap_iter *ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt, > -- > 2.31.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
On Tue, 2021-05-25 at 12:00 +0100, Matthew Auld wrote: > On Fri, 21 May 2021 at 16:33, Thomas Hellström > <thomas.hellstrom@linux.intel.com> wrote: > > > > If the bo is idle when calling ttm_bo_pipeline_gutting(), we > > unnecessarily > > create a ghost object and push it out to delayed destroy. > > Fix this by adding a path for idle, and document the function. > > > > Also avoid having the bo end up in a bad state vulnerable to user- > > space > > triggered kernel BUGs if the call to ttm_tt_create() fails. > > > > Finally reuse ttm_bo_pipeline_gutting() in ttm_bo_evict(). > > > > Cc: Christian König <christian.koenig@amd.com> > > Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> > > --- > > drivers/gpu/drm/ttm/ttm_bo.c | 20 ++++++------ > > drivers/gpu/drm/ttm/ttm_bo_util.c | 52 > > ++++++++++++++++++++++++++++--- > > drivers/gpu/drm/ttm/ttm_tt.c | 5 +++ > > include/drm/ttm/ttm_tt.h | 10 ++++++ > > 4 files changed, 73 insertions(+), 14 deletions(-) > > > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c > > b/drivers/gpu/drm/ttm/ttm_bo.c > > index ca1b098b6a56..a8fa3375b8aa 100644 > > --- a/drivers/gpu/drm/ttm/ttm_bo.c > > +++ b/drivers/gpu/drm/ttm/ttm_bo.c > > @@ -501,10 +501,15 @@ static int ttm_bo_evict(struct > > ttm_buffer_object *bo, > > bdev->funcs->evict_flags(bo, &placement); > > > > if (!placement.num_placement && > > !placement.num_busy_placement) { > > - ttm_bo_wait(bo, false, false); > > + ret = ttm_bo_wait(bo, true, false); > > + if (ret) > > + return ret; > > > > - ttm_bo_cleanup_memtype_use(bo); > > - return ttm_tt_create(bo, false); > > + /* > > + * Since we've already synced, this frees backing > > store > > + * immediately. > > + */ > > + return ttm_bo_pipeline_gutting(bo); > > } > > > > ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx); > > @@ -974,13 +979,8 @@ int ttm_bo_validate(struct ttm_buffer_object > > *bo, > > /* > > * Remove the backing store if no placement is given. > > */ > > - if (!placement->num_placement && !placement- > > >num_busy_placement) { > > - ret = ttm_bo_pipeline_gutting(bo); > > - if (ret) > > - return ret; > > - > > - return ttm_tt_create(bo, false); > > - } > > + if (!placement->num_placement && !placement- > > >num_busy_placement) > > + return ttm_bo_pipeline_gutting(bo); > > > > /* > > * Check whether we need to move buffer. > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c > > b/drivers/gpu/drm/ttm/ttm_bo_util.c > > index 4a7d3d672f9a..7fa9b3a852eb 100644 > > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c > > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c > > @@ -585,26 +585,70 @@ int ttm_bo_move_accel_cleanup(struct > > ttm_buffer_object *bo, > > } > > EXPORT_SYMBOL(ttm_bo_move_accel_cleanup); > > > > +/** > > + * ttm_bo_pipeline_gutting - purge the contents of a bo > > + * @bo: The buffer object > > + * > > + * Purge the contents of a bo, async if the bo is not idle. > > + * After a successful call, the bo is left unpopulated in > > + * system placement. The function may wait uninterruptible > > + * for idle on OOM. > > + * > > + * Return: 0 if successful, negative error code on failure. > > + */ > > int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo) > > { > > static const struct ttm_place sys_mem = { .mem_type = > > TTM_PL_SYSTEM }; > > struct ttm_buffer_object *ghost; > > + struct ttm_tt *ttm; > > int ret; > > > > - ret = ttm_buffer_object_transfer(bo, &ghost); > > + /* If already idle, no need for ghost object dance. */ > > + ret = ttm_bo_wait(bo, false, true); > > + if (ret != -EBUSY) { > > + if (!bo->ttm) { > > + ret = ttm_tt_create(bo, true); > > Why do we now unconditionally add clearing? Below also. Here we've dropped the bo content and we add but do not populate a page vector. Now if someone resurrects this object we obtain new pages and those must be cleared, at least that's the intention. /Thomas
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index ca1b098b6a56..a8fa3375b8aa 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -501,10 +501,15 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bdev->funcs->evict_flags(bo, &placement); if (!placement.num_placement && !placement.num_busy_placement) { - ttm_bo_wait(bo, false, false); + ret = ttm_bo_wait(bo, true, false); + if (ret) + return ret; - ttm_bo_cleanup_memtype_use(bo); - return ttm_tt_create(bo, false); + /* + * Since we've already synced, this frees backing store + * immediately. + */ + return ttm_bo_pipeline_gutting(bo); } ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx); @@ -974,13 +979,8 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, /* * Remove the backing store if no placement is given. */ - if (!placement->num_placement && !placement->num_busy_placement) { - ret = ttm_bo_pipeline_gutting(bo); - if (ret) - return ret; - - return ttm_tt_create(bo, false); - } + if (!placement->num_placement && !placement->num_busy_placement) + return ttm_bo_pipeline_gutting(bo); /* * Check whether we need to move buffer. diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 4a7d3d672f9a..7fa9b3a852eb 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -585,26 +585,70 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo, } EXPORT_SYMBOL(ttm_bo_move_accel_cleanup); +/** + * ttm_bo_pipeline_gutting - purge the contents of a bo + * @bo: The buffer object + * + * Purge the contents of a bo, async if the bo is not idle. + * After a successful call, the bo is left unpopulated in + * system placement. The function may wait uninterruptible + * for idle on OOM. + * + * Return: 0 if successful, negative error code on failure. + */ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo) { static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM }; struct ttm_buffer_object *ghost; + struct ttm_tt *ttm; int ret; - ret = ttm_buffer_object_transfer(bo, &ghost); + /* If already idle, no need for ghost object dance. */ + ret = ttm_bo_wait(bo, false, true); + if (ret != -EBUSY) { + if (!bo->ttm) { + ret = ttm_tt_create(bo, true); + if (ret) + return ret; + } else { + ttm_tt_unpopulate(bo->bdev, bo->ttm); + if (bo->type == ttm_bo_type_device) + ttm_tt_mark_for_clear(bo->ttm); + } + ttm_resource_free(bo, &bo->mem); + ttm_resource_alloc(bo, &sys_mem, &bo->mem); + + return 0; + } + + /* + * We need an unpopulated ttm_tt after giving our current one, + * if any, to the ghost object. And we can't afford to fail + * creating one *after* the operation. + */ + + ttm = bo->ttm; + bo->ttm = NULL; + ret = ttm_tt_create(bo, true); + swap(bo->ttm, ttm); if (ret) return ret; + ret = ttm_buffer_object_transfer(bo, &ghost); + if (ret) { + ttm_tt_destroy(bo->bdev, ttm); + return ret; + } + ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv); /* Last resort, wait for the BO to be idle when we are OOM */ if (ret) ttm_bo_wait(bo, false, false); - ttm_resource_alloc(bo, &sys_mem, &bo->mem); - bo->ttm = NULL; - dma_resv_unlock(&ghost->base._resv); ttm_bo_put(ghost); + bo->ttm = ttm; + ttm_resource_alloc(bo, &sys_mem, &bo->mem); return 0; } diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index 0e41227116b1..913b330a234b 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -134,6 +134,11 @@ void ttm_tt_destroy_common(struct ttm_device *bdev, struct ttm_tt *ttm) } EXPORT_SYMBOL(ttm_tt_destroy_common); +void ttm_tt_mark_for_clear(struct ttm_tt *ttm) +{ + ttm->page_flags |= TTM_PAGE_FLAG_ZERO_ALLOC; +} + void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm) { bdev->funcs->ttm_tt_destroy(bdev, ttm); diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h index 3102059db726..daa9c4cf48bb 100644 --- a/include/drm/ttm/ttm_tt.h +++ b/include/drm/ttm/ttm_tt.h @@ -170,6 +170,16 @@ int ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm, struct ttm_oper */ void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm); +/** + * ttm_tt_mark_for_clear - Mark pages for clearing on populate. + * + * @ttm: Pointer to the ttm_tt structure + * + * Marks pages for clearing so that the next time the page vector is + * populated, the pages will be cleared. + */ +void ttm_tt_mark_for_clear(struct ttm_tt *ttm); + void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages); struct ttm_kmap_iter *ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
If the bo is idle when calling ttm_bo_pipeline_gutting(), we unnecessarily create a ghost object and push it out to delayed destroy. Fix this by adding a path for idle, and document the function. Also avoid having the bo end up in a bad state vulnerable to user-space triggered kernel BUGs if the call to ttm_tt_create() fails. Finally reuse ttm_bo_pipeline_gutting() in ttm_bo_evict(). Cc: Christian König <christian.koenig@amd.com> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> --- drivers/gpu/drm/ttm/ttm_bo.c | 20 ++++++------ drivers/gpu/drm/ttm/ttm_bo_util.c | 52 ++++++++++++++++++++++++++++--- drivers/gpu/drm/ttm/ttm_tt.c | 5 +++ include/drm/ttm/ttm_tt.h | 10 ++++++ 4 files changed, 73 insertions(+), 14 deletions(-)