On Sun, Mar 25, 2012 at 07:47:34PM +0200, Daniel Vetter wrote: > This speeds up pwrite and pread from ~120 µs ro ~100 µs for > reading/writing 1mb on my snb (if the backing storage pages > are already pinned, of course). > > v2: Chris Wilson pointed out a claring page reference bug - I've s/claring/glaring, noticed by Chris.
Note to self: Fix this when applying. -Daniel > unconditionally dropped the reference. With that fixed (and the > associated reduction of dirt in dmesg) it's now even a notch faster. > > v3: Unconditionaly grab a page reference when dropping > dev->struct_mutex to simplify the code-flow. > > Signed-off-by: Daniel Vetter <[email protected]> > --- > drivers/gpu/drm/i915/i915_gem.c | 42 +++++++++++++++++++++++++++----------- > 1 files changed, 30 insertions(+), 12 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index c5b250c..117fda4 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -321,6 +321,7 @@ i915_gem_shmem_pread(struct drm_device *dev, > int obj_do_bit17_swizzling, page_do_bit17_swizzling; > int hit_slowpath = 0; > int needs_clflush = 0; > + int release_page; > > user_data = (char __user *) (uintptr_t) args->data_ptr; > remain = args->size; > @@ -355,10 +356,16 @@ i915_gem_shmem_pread(struct drm_device *dev, > if ((shmem_page_offset + page_length) > PAGE_SIZE) > page_length = PAGE_SIZE - shmem_page_offset; > > - page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT); > - if (IS_ERR(page)) { > - ret = PTR_ERR(page); > - goto out; > + if (obj->pages) { > + page = obj->pages[offset >> PAGE_SHIFT]; > + release_page = 0; > + } else { > + page = shmem_read_mapping_page(mapping, offset >> > PAGE_SHIFT); > + if (IS_ERR(page)) { > + ret = PTR_ERR(page); > + goto out; > + } > + release_page = 1; > } > > page_do_bit17_swizzling = obj_do_bit17_swizzling && > @@ -378,7 +385,7 @@ i915_gem_shmem_pread(struct drm_device *dev, > } > > hit_slowpath = 1; > - > + page_cache_get(page); > mutex_unlock(&dev->struct_mutex); > > vaddr = kmap(page); > @@ -397,9 +404,11 @@ i915_gem_shmem_pread(struct drm_device *dev, > kunmap(page); > > mutex_lock(&dev->struct_mutex); > + page_cache_release(page); > next_page: > mark_page_accessed(page); > - page_cache_release(page); > + if (release_page) > + page_cache_release(page); > > if (ret) { > ret = -EFAULT; > @@ -680,6 +689,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev, > int shmem_page_offset, page_length, ret = 0; > int obj_do_bit17_swizzling, page_do_bit17_swizzling; > int hit_slowpath = 0; > + int release_page; > > user_data = (char __user *) (uintptr_t) args->data_ptr; > remain = args->size; > @@ -704,10 +714,16 @@ i915_gem_shmem_pwrite(struct drm_device *dev, > if ((shmem_page_offset + page_length) > PAGE_SIZE) > page_length = PAGE_SIZE - shmem_page_offset; > > - page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT); > - if (IS_ERR(page)) { > - ret = PTR_ERR(page); > - goto out; > + if (obj->pages) { > + page = obj->pages[offset >> PAGE_SHIFT]; > + release_page = 0; > + } else { > + page = shmem_read_mapping_page(mapping, offset >> > PAGE_SHIFT); > + if (IS_ERR(page)) { > + ret = PTR_ERR(page); > + goto out; > + } > + release_page = 1; > } > > page_do_bit17_swizzling = obj_do_bit17_swizzling && > @@ -725,7 +741,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev, > } > > hit_slowpath = 1; > - > + page_cache_get(page); > mutex_unlock(&dev->struct_mutex); > > vaddr = kmap(page); > @@ -740,10 +756,12 @@ i915_gem_shmem_pwrite(struct drm_device *dev, > kunmap(page); > > mutex_lock(&dev->struct_mutex); > + page_cache_release(page); > next_page: > set_page_dirty(page); > mark_page_accessed(page); > - page_cache_release(page); > + if (release_page) > + page_cache_release(page); > > if (ret) { > ret = -EFAULT; > -- > 1.7.7.6 > -- Daniel Vetter Mail: [email protected] Mobile: +41 (0)79 365 57 48 _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
