On Thu, 03 Oct 2024, Uros Bizjak <[email protected]> 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 <[email protected]> > Cc: Jani Nikula <[email protected]> > Cc: Joonas Lahtinen <[email protected]> > Cc: Rodrigo Vivi <[email protected]> > Cc: Tvrtko Ursulin <[email protected]> > Cc: David Airlie <[email protected]> > Cc: Simona Vetter <[email protected]>
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 -- Jani Nikula, Intel
