[PATCH 04/11] drm/ttm: add resource iterator v2
Felix Kuehling
felix.kuehling at amd.com
Mon Feb 14 16:09:21 UTC 2022
Am 2022-02-14 um 04:34 schrieb Christian König:
> Instead of duplicating that at different places add an iterator over all
> the resources in a resource manager.
>
> v2: add lockdep annotation and kerneldoc
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Tested-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 41 ++++++++++---------------
> drivers/gpu/drm/ttm/ttm_device.c | 26 +++++++---------
> drivers/gpu/drm/ttm/ttm_resource.c | 49 ++++++++++++++++++++++++++++++
> include/drm/ttm/ttm_resource.h | 23 ++++++++++++++
> 4 files changed, 99 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index cb0fa932d495..599be3dda8a9 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -579,38 +579,29 @@ int ttm_mem_evict_first(struct ttm_device *bdev,
> struct ww_acquire_ctx *ticket)
> {
> struct ttm_buffer_object *bo = NULL, *busy_bo = NULL;
> + struct ttm_resource_cursor cursor;
> struct ttm_resource *res;
> bool locked = false;
> - unsigned i;
> int ret;
>
> spin_lock(&bdev->lru_lock);
> - for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> - list_for_each_entry(res, &man->lru[i], lru) {
> - bool busy;
> -
> - bo = res->bo;
> - if (!ttm_bo_evict_swapout_allowable(bo, ctx, place,
> - &locked, &busy)) {
> - if (busy && !busy_bo && ticket !=
> - dma_resv_locking_ctx(bo->base.resv))
> - busy_bo = bo;
> - continue;
> - }
> -
> - if (!ttm_bo_get_unless_zero(bo)) {
> - if (locked)
> - dma_resv_unlock(bo->base.resv);
> - continue;
> - }
> - break;
> + ttm_resource_manager_for_each_res(man, &cursor, res) {
> + bool busy;
> +
> + if (!ttm_bo_evict_swapout_allowable(res->bo, ctx, place,
> + &locked, &busy)) {
> + if (busy && !busy_bo && ticket !=
> + dma_resv_locking_ctx(bo->base.resv))
> + busy_bo = res->bo;
> + continue;
> }
>
> - /* If the inner loop terminated early, we have our candidate */
> - if (&res->lru != &man->lru[i])
> - break;
> -
> - bo = NULL;
> + if (!ttm_bo_get_unless_zero(res->bo)) {
> + if (locked)
> + dma_resv_unlock(res->bo->base.resv);
> + continue;
> + }
> + bo = res->bo;
> }
>
> if (!bo) {
> diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
> index ba35887147ba..a0562ab386f5 100644
> --- a/drivers/gpu/drm/ttm/ttm_device.c
> +++ b/drivers/gpu/drm/ttm/ttm_device.c
> @@ -142,10 +142,10 @@ EXPORT_SYMBOL(ttm_global_swapout);
> int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
> gfp_t gfp_flags)
> {
> + struct ttm_resource_cursor cursor;
> struct ttm_resource_manager *man;
> - struct ttm_buffer_object *bo;
> struct ttm_resource *res;
> - unsigned i, j;
> + unsigned i;
> int ret;
>
> spin_lock(&bdev->lru_lock);
> @@ -154,20 +154,16 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
> if (!man || !man->use_tt)
> continue;
>
> - for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
> - list_for_each_entry(res, &man->lru[j], lru) {
> - uint32_t num_pages;
> -
> - bo = res->bo;
> - num_pages = PFN_UP(bo->base.size);
> + ttm_resource_manager_for_each_res(man, &cursor, res) {
> + struct ttm_buffer_object *bo = res->bo;
> + uint32_t num_pages = PFN_UP(bo->base.size);
>
> - ret = ttm_bo_swapout(bo, ctx, gfp_flags);
> - /* ttm_bo_swapout has dropped the lru_lock */
> - if (!ret)
> - return num_pages;
> - if (ret != -EBUSY)
> - return ret;
> - }
> + ret = ttm_bo_swapout(bo, ctx, gfp_flags);
> + /* ttm_bo_swapout has dropped the lru_lock */
> + if (!ret)
> + return num_pages;
> + if (ret != -EBUSY)
> + return ret;
> }
> }
> spin_unlock(&bdev->lru_lock);
> diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c
> index 411b3f001eeb..1f9b8205b3a5 100644
> --- a/drivers/gpu/drm/ttm/ttm_resource.c
> +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> @@ -385,6 +385,55 @@ void ttm_resource_manager_debug(struct ttm_resource_manager *man,
> }
> EXPORT_SYMBOL(ttm_resource_manager_debug);
>
> +/**
> + * ttm_resource_manager_first
> + *
> + * @man: resource manager to iterate over
> + * @cursor: cursor to record the position
> + *
> + * Returns the first resource from the resource manager.
> + */
> +struct ttm_resource *
> +ttm_resource_manager_first(struct ttm_resource_manager *man,
> + struct ttm_resource_cursor *cursor)
> +{
> + struct ttm_resource *res;
> +
> + lockdep_assert_held(&man->bdev->lru_lock);
> +
> + for (cursor->priority = 0; cursor->priority < TTM_MAX_BO_PRIORITY;
> + ++cursor->priority)
> + list_for_each_entry(res, &man->lru[cursor->priority], lru)
> + return res;
> +
> + return NULL;
> +}
> +
> +/**
> + * ttm_resource_manager_next
> + *
> + * @man: resource manager to iterate over
> + * @cursor: cursor to record the position
Documentation of the "res" parameter is missing.
> + *
> + * Returns the next resource from the resource manager.
> + */
> +struct ttm_resource *
> +ttm_resource_manager_next(struct ttm_resource_manager *man,
> + struct ttm_resource_cursor *cursor,
> + struct ttm_resource *res)
> +{
> + lockdep_assert_held(&man->bdev->lru_lock);
> +
> + list_for_each_entry_continue(res, &man->lru[cursor->priority], lru)
> + return res;
> +
> + for (; cursor->priority < TTM_MAX_BO_PRIORITY; ++cursor->priority)
If you get here, the previous loop has finished iterating over the
current cursor->priority level. Therefore I think you need to increment
cursor->priority before the first loop iteration here. Otherwise you'll
just keep iterating over the same priority level over and over.
Regards,
Felix
> + list_for_each_entry(res, &man->lru[cursor->priority], lru)
> + return res;
> +
> + return NULL;
> +}
> +
> static void ttm_kmap_iter_iomap_map_local(struct ttm_kmap_iter *iter,
> struct dma_buf_map *dmap,
> pgoff_t i)
> diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
> index 181e82e3d806..ef0ec700e896 100644
> --- a/include/drm/ttm/ttm_resource.h
> +++ b/include/drm/ttm/ttm_resource.h
> @@ -184,6 +184,17 @@ struct ttm_resource {
> struct list_head lru;
> };
>
> +/**
> + * struct ttm_resource_cursor
> + *
> + * @priority: the current priority
> + *
> + * Cursor to iterate over the resources in a manager.
> + */
> +struct ttm_resource_cursor {
> + unsigned int priority;
> +};
> +
> /**
> * struct ttm_lru_bulk_move_pos
> *
> @@ -328,6 +339,18 @@ uint64_t ttm_resource_manager_usage(struct ttm_resource_manager *man);
> void ttm_resource_manager_debug(struct ttm_resource_manager *man,
> struct drm_printer *p);
>
> +struct ttm_resource *
> +ttm_resource_manager_first(struct ttm_resource_manager *man,
> + struct ttm_resource_cursor *cursor);
> +struct ttm_resource *
> +ttm_resource_manager_next(struct ttm_resource_manager *man,
> + struct ttm_resource_cursor *cursor,
> + struct ttm_resource *res);
> +
> +#define ttm_resource_manager_for_each_res(man, cursor, res) \
> + for (res = ttm_resource_manager_first(man, cursor); res; \
> + res = ttm_resource_manager_next(man, cursor, res))
> +
> struct ttm_kmap_iter *
> ttm_kmap_iter_iomap_init(struct ttm_kmap_iter_iomap *iter_io,
> struct io_mapping *iomap,
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