On Thu, Sep 22, 2016 at 7:43 AM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx> Looks like a nice improvement Reviewed-by: Sean Paul <seanpaul@xxxxxxxxxxxx> > --- > 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@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
