drm/msm: don't allocate pages from the MOVABLE zone

The pages backing the GEM objects are kept pinned in place as
long as they are alive, so they must not be allocated from the
MOVABLE zone. Blocking page migration for too long will cause
the VM subsystem headaches and will outright break CMA, as a
few pinned pages in CMA will lead to failure to find the
required large contiguous regions.

Change-Id: I5eba32fc8a2730eac29668dbd96aaf8f04ac155f
Signed-off-by: Lucas Stach <[email protected]>
Signed-off-by: Rob Clark <[email protected]>
Signed-off-by: Rob Clark <[email protected]>
Git-commit: 0abdba47dc1df708c365421d481734d3f7fecb01
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Patrick Daly <[email protected]>
Signed-off-by: Narendra Muppalla <[email protected]>

msm/msm_gem.c

@@ -1092,6 +1092,14 @@ static struct drm_gem_object *_msm_gem_new(struct drm_device *dev,
 		ret = drm_gem_object_init(dev, obj, size);
 		if (ret)
 			goto fail;
+
+		/*
+		 * Our buffers are kept pinned, so allocating them from the
+		 * MOVABLE zone is a really bad idea, and conflicts with CMA.
+		 * See comments above new_inode() why this is required _and_
+		 * expected if you're going to pin these pages.
+		 */
+		mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER);
 	}
 
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 15, 0))