From: Daniel Vetter Date: Thu, 15 Nov 2012 15:53:58 +0000 (+0100) Subject: drm/i915: optimize the shmem_pwrite slowpath handling X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=8dcf015eb967c718962c0690330d9a94d56f2c5d;p=linux-beck.git drm/i915: optimize the shmem_pwrite slowpath handling Since we drop dev->struct_mutex when going through the slowpath, the object might have been moved out of the cpu domain. Hence we need to clflush the entire object to ensure that after the ioctl returns, everything is coherent again (interwoven writes are ill-defined anyway). But we only need to do this if we start in the cpu domain and the object requires flushing for coherency. So don't do the flushing if the object is coherent anyway or if we've done in-line clfushing already. v2: i915_gem_clflush_object already checks whether the object is coherent and if so, drops the flushing. Hence we don't need to check that ourselves, simplifying the condition. v3: Reorder the checks for better clarity (and adjust the comment accordingly), suggested by Chris Wilson. Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 36f629a79d88..5c8df572cd17 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -830,9 +830,13 @@ out: i915_gem_object_unpin_pages(obj); if (hit_slowpath) { - /* Fixup: Flush dirty cachelines in case the object isn't in the - * cpu write domain anymore. */ - if (obj->base.write_domain != I915_GEM_DOMAIN_CPU) { + /* + * Fixup: Flush cpu caches in case we didn't flush the dirty + * cachelines in-line while writing and the object moved + * out of the cpu write domain while we've dropped the lock. + */ + if (!needs_clflush_after && + obj->base.write_domain != I915_GEM_DOMAIN_CPU) { i915_gem_clflush_object(obj); i915_gem_chipset_flush(dev); }