| Message ID | 20241003084533.871524-1-ubizjak@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/active: Use try_cmpxchg() in active_fence_cb() | expand |
On Thu, 03 Oct 2024, Uros Bizjak <ubizjak@gmail.com> wrote: > Replace this pattern in active_fence_cb(): > > cmpxchg(*ptr, old, new) == old > > ... with the simpler and faster: > > try_cmpxchg(*ptr, &old, new) > > The x86 CMPXCHG instruction returns success in the ZF flag, > so this change saves a compare after the CMPXCHG. > > Signed-off-by: Uros Bizjak <ubizjak@gmail.com> > Cc: Jani Nikula <jani.nikula@linux.intel.com> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> > Cc: Tvrtko Ursulin <tursulin@ursulin.net> > Cc: David Airlie <airlied@gmail.com> > Cc: Simona Vetter <simona@ffwll.ch> Pushed to drm-intel-next, thanks for the patch. BR, Jani. > --- > drivers/gpu/drm/i915/i915_active.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c > index 5ec293011d99..35319228bc51 100644 > --- a/drivers/gpu/drm/i915/i915_active.c > +++ b/drivers/gpu/drm/i915/i915_active.c > @@ -212,7 +212,7 @@ active_fence_cb(struct dma_fence *fence, struct dma_fence_cb *cb) > struct i915_active_fence *active = > container_of(cb, typeof(*active), cb); > > - return cmpxchg(__active_fence_slot(active), fence, NULL) == fence; > + return try_cmpxchg(__active_fence_slot(active), &fence, NULL); > } > > static void
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index 5ec293011d99..35319228bc51 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -212,7 +212,7 @@ active_fence_cb(struct dma_fence *fence, struct dma_fence_cb *cb) struct i915_active_fence *active = container_of(cb, typeof(*active), cb); - return cmpxchg(__active_fence_slot(active), fence, NULL) == fence; + return try_cmpxchg(__active_fence_slot(active), &fence, NULL); } static void
Replace this pattern in active_fence_cb(): cmpxchg(*ptr, old, new) == old ... with the simpler and faster: try_cmpxchg(*ptr, &old, new) The x86 CMPXCHG instruction returns success in the ZF flag, so this change saves a compare after the CMPXCHG. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tvrtko Ursulin <tursulin@ursulin.net> Cc: David Airlie <airlied@gmail.com> Cc: Simona Vetter <simona@ffwll.ch> --- drivers/gpu/drm/i915/i915_active.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)