[Intel-gfx] [PATCH] drm: Convert prime dma-buf <-> handle to rhashtable
Sean Paul
seanpaul at chromium.org
Fri Sep 23 10:27:34 UTC 2016
On Thu, Sep 22, 2016 at 7:43 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> 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 <chris at chris-wilson.co.uk>
Looks like a nice improvement
Reviewed-by: Sean Paul <seanpaul at chromium.org>
> ---
> 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
>
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