[PATCH 2/3] drm/ttm: reapply increase ttm pre-fault value to PMD size"

[Christian König]

Now that we have improved the handling faulting in a full PMD only
increases the overhead on my test system from 21us to 29us if only a
single page is requested, but massively improves the performance for
all other use cases.

So re-apply that change again to improve the fault handling for large
allocations bringing us close to improving it by a factor of 10.

This reverts commit c358a809cb58af944d496944391a240e02f5837a.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 include/drm/ttm/ttm_bo.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
index 903cd1030110..e96477606207 100644
--- a/include/drm/ttm/ttm_bo.h
+++ b/include/drm/ttm/ttm_bo.h
@@ -39,7 +39,11 @@
 #include "ttm_device.h"
 
 /* Default number of pre-faulted pages in the TTM fault handler */
+#if CONFIG_PGTABLE_LEVELS > 2
+#define TTM_BO_VM_NUM_PREFAULT (1 << (PMD_SHIFT - PAGE_SHIFT))
+#else
 #define TTM_BO_VM_NUM_PREFAULT 16
+#endif
 
 struct iosys_map;
 
-- 
2.43.0