Currently we use a linear walk to lookup a handle and return a dma-buf, and vice versa. A long overdue TODO task is to convert that to a hashtable. Since the initial implementation of dma-buf/prime, we now have resizeable hashtables we can use (and now a future task is to RCU enable the lookup!).
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94631 Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> --- drivers/gpu/drm/drm_prime.c | 94 +++++++++++++++++++++++++++++++++++---------- include/drm/drmP.h | 5 ++- 2 files changed, 77 insertions(+), 22 deletions(-) diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 780589b420a4..ad077def660d 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -28,6 +28,7 @@ #include <linux/export.h> #include <linux/dma-buf.h> +#include <linux/rhashtable.h> #include <drm/drmP.h> #include <drm/drm_gem.h> @@ -61,9 +62,11 @@ */ struct drm_prime_member { - struct list_head entry; struct dma_buf *dma_buf; uint32_t handle; + + struct rhash_head dma_buf_rht; + struct rhash_head handle_rht; }; struct drm_prime_attachment { @@ -71,10 +74,31 @@ struct drm_prime_attachment { enum dma_data_direction dir; }; +static const struct rhashtable_params dma_buf_params = { + .head_offset = offsetof(struct drm_prime_member, dma_buf_rht), + .key_len = sizeof(struct dma_buf *), + .key_offset = offsetof(struct drm_prime_member, dma_buf), + .hashfn = jhash, + .nulls_base = 1u << RHT_BASE_SHIFT, + .automatic_shrinking = true, + .nelem_hint = 2, +}; + +static const struct rhashtable_params handle_params = { + .head_offset = offsetof(struct drm_prime_member, handle_rht), + .key_len = sizeof(uint32_t), + .key_offset = offsetof(struct drm_prime_member, handle), + .hashfn = jhash, + .nulls_base = 1u << RHT_BASE_SHIFT, + .automatic_shrinking = true, + .nelem_hint = 2, +}; + static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) { struct drm_prime_member *member; + int err; member = kmalloc(sizeof(*member), GFP_KERNEL); if (!member) @@ -83,8 +107,28 @@ static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, get_dma_buf(dma_buf); member->dma_buf = dma_buf; member->handle = handle; - list_add(&member->entry, &prime_fpriv->head); + + err = rhashtable_insert_fast(&prime_fpriv->dma_bufs, + &member->dma_buf_rht, + dma_buf_params); + if (err) + goto err_dma_buf; + + err = rhashtable_insert_fast(&prime_fpriv->handles, + &member->handle_rht, + handle_params); + if (err) + goto err_dma_rht; + return 0; + +err_dma_rht: + rhashtable_remove_fast(&prime_fpriv->dma_bufs, + &member->dma_buf_rht, + dma_buf_params); +err_dma_buf: + dma_buf_put(dma_buf); + return err; } static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv, @@ -92,10 +136,10 @@ static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_priv { struct drm_prime_member *member; - list_for_each_entry(member, &prime_fpriv->head, entry) { - if (member->handle == handle) - return member->dma_buf; - } + member = rhashtable_lookup_fast(&prime_fpriv->handles, + &handle, handle_params); + if (member) + return member->dma_buf; return NULL; } @@ -106,12 +150,13 @@ static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpri { struct drm_prime_member *member; - list_for_each_entry(member, &prime_fpriv->head, entry) { - if (member->dma_buf == dma_buf) { - *handle = member->handle; - return 0; - } + member = rhashtable_lookup_fast(&prime_fpriv->dma_bufs, + &dma_buf, dma_buf_params); + if (member) { + *handle = member->handle; + return 0; } + return -ENOENT; } @@ -166,14 +211,21 @@ static void drm_gem_map_detach(struct dma_buf *dma_buf, void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) { - struct drm_prime_member *member, *safe; + struct drm_prime_member *member; - list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { - if (member->dma_buf == dma_buf) { - dma_buf_put(dma_buf); - list_del(&member->entry); - kfree(member); - } + member = rhashtable_lookup_fast(&prime_fpriv->dma_bufs, + &dma_buf, dma_buf_params); + if (member) { + rhashtable_remove_fast(&prime_fpriv->dma_bufs, + &member->dma_buf_rht, + dma_buf_params); + + rhashtable_remove_fast(&prime_fpriv->handles, + &member->handle_rht, + handle_params); + + dma_buf_put(dma_buf); + kfree(member); } } @@ -759,12 +811,14 @@ EXPORT_SYMBOL(drm_prime_gem_destroy); void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv) { - INIT_LIST_HEAD(&prime_fpriv->head); mutex_init(&prime_fpriv->lock); + rhashtable_init(&prime_fpriv->dma_bufs, &dma_buf_params); + rhashtable_init(&prime_fpriv->handles, &handle_params); } void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv) { /* by now drm_gem_release should've made sure the list is empty */ - WARN_ON(!list_empty(&prime_fpriv->head)); + rhashtable_destroy(&prime_fpriv->dma_bufs); + rhashtable_destroy(&prime_fpriv->handles); } diff --git a/include/drm/drmP.h b/include/drm/drmP.h index c53dc90942e0..6966fb030d0f 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -51,6 +51,7 @@ #include <linux/platform_device.h> #include <linux/poll.h> #include <linux/ratelimit.h> +#include <linux/rhashtable.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/types.h> @@ -371,10 +372,10 @@ struct drm_pending_event { we deliver the event, for tracing only */ }; -/* initial implementaton using a linked list - todo hashtab */ struct drm_prime_file_private { - struct list_head head; struct mutex lock; + struct rhashtable dma_bufs; + struct rhashtable handles; }; /** File private data */ -- 2.9.3 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
