| Message ID | 1375779586-24918-1-git-send-email-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 06, 2013 at 09:59:46AM +0100, Chris Wilson wrote: > We can apply the same optimisation tricks as kref_put_mutex() in our > local equivalent function. However, we have a different locking semantic > (we unlock ourselves, in kref_put_mutex() the callee unlocks) so that we > can use the same callbacks for both locked and unlocked kref_put()s and > so can not simply convert to using kref_put_mutex() directly. > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> I think longterm we want to move to delayed free callbacks (similar to how fput works) since the locking with dma-buf and all will simply get too hairy. But for now this is a neat optimization imo, so Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> > --- > include/drm/drmP.h | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/include/drm/drmP.h b/include/drm/drmP.h > index 4b518e0..ee2ef27 100644 > --- a/include/drm/drmP.h > +++ b/include/drm/drmP.h > @@ -1626,10 +1626,12 @@ drm_gem_object_unreference(struct drm_gem_object *obj) > static inline void > drm_gem_object_unreference_unlocked(struct drm_gem_object *obj) > { > - if (obj != NULL) { > + if (obj && !atomic_add_unless(&obj->refcount.refcount, -1, 1)) { > struct drm_device *dev = obj->dev; > + > mutex_lock(&dev->struct_mutex); > - kref_put(&obj->refcount, drm_gem_object_free); > + if (likely(atomic_dec_and_test(&obj->refcount.refcount))) > + drm_gem_object_free(&obj->refcount); > mutex_unlock(&dev->struct_mutex); > } > } > -- > 1.8.4.rc1 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
On Tue, Aug 06, 2013 at 11:27:50PM +0200, Daniel Vetter wrote: > On Tue, Aug 06, 2013 at 09:59:46AM +0100, Chris Wilson wrote: > > We can apply the same optimisation tricks as kref_put_mutex() in our > > local equivalent function. However, we have a different locking semantic > > (we unlock ourselves, in kref_put_mutex() the callee unlocks) so that we > > can use the same callbacks for both locked and unlocked kref_put()s and > > so can not simply convert to using kref_put_mutex() directly. > > > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > > I think longterm we want to move to delayed free callbacks (similar to how > fput works) since the locking with dma-buf and all will simply get too > hairy. But for now this is a neat optimization imo, so I have bad memories of delayed free batching up several thousand small bo. *shudder* -Chris
diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 4b518e0..ee2ef27 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1626,10 +1626,12 @@ drm_gem_object_unreference(struct drm_gem_object *obj) static inline void drm_gem_object_unreference_unlocked(struct drm_gem_object *obj) { - if (obj != NULL) { + if (obj && !atomic_add_unless(&obj->refcount.refcount, -1, 1)) { struct drm_device *dev = obj->dev; + mutex_lock(&dev->struct_mutex); - kref_put(&obj->refcount, drm_gem_object_free); + if (likely(atomic_dec_and_test(&obj->refcount.refcount))) + drm_gem_object_free(&obj->refcount); mutex_unlock(&dev->struct_mutex); } }
We can apply the same optimisation tricks as kref_put_mutex() in our local equivalent function. However, we have a different locking semantic (we unlock ourselves, in kref_put_mutex() the callee unlocks) so that we can use the same callbacks for both locked and unlocked kref_put()s and so can not simply convert to using kref_put_mutex() directly. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- include/drm/drmP.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)