[Intel-gfx] [PATCH 07/17] drm/i915: request THP for shmem backed objects

[Matthew Auld]

Default to transparent-huge-pages for shmem backed objects through the
SHMEM_HUGE_WITHIN_SIZE huge option. Best effort only.

Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Dave Hansen <dave.hansen at intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Hugh Dickins <hughd at google.com>
Cc: linux-mm at kvack.org
---
 drivers/gpu/drm/i915/i915_gem.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6a5e864d7710..e4ee54f0f55f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4308,6 +4308,16 @@ i915_gem_object_create(struct drm_i915_private *dev_priv, u64 size)
 	mapping = obj->base.filp->f_mapping;
 	mapping_set_gfp_mask(mapping, mask);
 
+	/* If configured attempt to use THP through shmemfs. This will
+	 * effectively default to huge-pages for this mapping if it makes sense
+	 * given the object size and HPAGE_PMD_SIZE. This is best effort only.
+	 */
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+	if (has_transparent_hugepage() &&
+	    HAS_PAGE_SIZE(dev_priv, HPAGE_PMD_SIZE))
+		SHMEM_I(mapping->host)->huge = SHMEM_HUGE_WITHIN_SIZE;
+#endif
+
 	i915_gem_object_init(obj, &i915_gem_object_ops);
 
 	obj->base.write_domain = I915_GEM_DOMAIN_CPU;
-- 
2.9.4