@@ -407,7 +407,6 @@ i915_gem_shmem_pread(struct drm_device *dev,
loff_t offset;
int shmem_page_offset, page_length, ret = 0;
int obj_do_bit17_swizzling, page_do_bit17_swizzling;
- int hit_slowpath = 0;
int prefaulted = 0;
int needs_clflush = 0;
struct scatterlist *sg;
@@ -469,7 +468,6 @@ i915_gem_shmem_pread(struct drm_device *dev,
if (ret == 0)
goto next_page;
- hit_slowpath = 1;
mutex_unlock(&dev->struct_mutex);
if (!prefaulted) {
@@ -502,12 +500,6 @@ next_page:
out:
i915_gem_object_unpin_pages(obj);
- if (hit_slowpath) {
- /* Fixup: Kill any reinstated backing storage pages */
- if (obj->madv == __I915_MADV_PURGED)
- i915_gem_object_truncate(obj);
- }
-
return ret;
}
@@ -838,11 +830,8 @@ out:
i915_gem_object_unpin_pages(obj);
if (hit_slowpath) {
- /* Fixup: Kill any reinstated backing storage pages */
- if (obj->madv == __I915_MADV_PURGED)
- i915_gem_object_truncate(obj);
- /* and flush dirty cachelines in case the object isn't in the cpu write
- * domain anymore. */
+ /* 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) {
i915_gem_clflush_object(obj);
i915_gem_chipset_flush(dev);
The shmem paths for pwrite/pread used a clever trick to hold onto a single page when dropping the big dev->struct_mutex for the slowpath. But this ran the risk of reinstating (or not completely purging) the backing storage when dropping purgeable objects. Hence the code needed to keep track of whether it ever dropped the lock, and if it did, manually check whether it needs to re-purge the backing storage. But thanks to the pages pin count introduced in commit a5570178c059cec59e9835be20bc8546377fa7b5 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Tue Sep 4 21:02:54 2012 +0100 drm/i915: Pin backing pages whilst exporting through a dmabuf vmap which allowed us to pin the backing storage and remove that page reference trick from shmem_pwrite/read in commit f60d7f0c1d55a935475ab394955cafddefaa6533 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Tue Sep 4 21:02:56 2012 +0100 drm/i915: Pin backing pages for pread and commit 755d22184f1e5015b040acee794542d9cf8a16c5 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Tue Sep 4 21:02:55 2012 +0100 drm/i915: Pin backing pages for pwrite we can now abolish this check. The slowpath cleanup completely disappears from pread, and for pwrite we're only left with the domain fixup in case someone moved the object out of the cpu domain from under us. A follow-on patch will optimize that a notch more. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> --- drivers/gpu/drm/i915/i915_gem.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-)