diff options
| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2012-03-25 19:47:34 +0200 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2012-03-27 13:27:03 +0200 |
| commit | 692a576b9ddf8006f1559e14a5022c0a100440f1 (patch) | |
| tree | 61b63ce355ddbc87d26129bc58a08d9873957b6e /drivers/gpu/drm/i915/i915_gem.c | |
| parent | 3ae5378330f581466b05bcea2dd3bc8731a598cb (diff) | |
| download | op-kernel-dev-692a576b9ddf8006f1559e14a5022c0a100440f1.zip op-kernel-dev-692a576b9ddf8006f1559e14a5022c0a100440f1.tar.gz | |
drm/i915: don't call shmem_read_mapping unnecessarily
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 glaring page reference bug - I've
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.
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem.c')
| -rw-r--r-- | 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 75e3b84..b253257 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -301,6 +301,7 @@ 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; @@ -335,10 +336,16 @@ 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 && @@ -358,7 +365,7 @@ i915_gem_shmem_pread(struct drm_device *dev, } hit_slowpath = 1; - + page_cache_get(page); mutex_unlock(&dev->struct_mutex); vaddr = kmap(page); @@ -377,9 +384,11 @@ 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; @@ -660,6 +669,7 @@ 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; @@ -684,10 +694,16 @@ 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 && @@ -705,7 +721,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev, } hit_slowpath = 1; - + page_cache_get(page); mutex_unlock(&dev->struct_mutex); vaddr = kmap(page); @@ -720,10 +736,12 @@ 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; |
