[PATCH 1/1] [RFC] drm/ttm: Don't init dma32_zone on 64-bit systems

[Kuehling, Felix]

This is an RFC. I'm not sure this is the right solution, but it
highlights the problem I'm trying to solve.

The dma32_zone limits the acc_size of all allocated BOs to 2GB. On a
64-bit system with hundreds of GB of system memory and GPU memory,
this can become a bottle neck. We're seeing TTM memory allocation
failures not because we're truly out of memory, but because we're
out of space in the dma32_zone for the acc_size needed for our BO
book-keeping.

Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
CC: thellstrom at vmware.com
CC: christian.koenig at amd.com
---
 drivers/gpu/drm/ttm/ttm_memory.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_memory.c b/drivers/gpu/drm/ttm/ttm_memory.c
index f1567c3..bb05365 100644
--- a/drivers/gpu/drm/ttm/ttm_memory.c
+++ b/drivers/gpu/drm/ttm/ttm_memory.c
@@ -363,7 +363,7 @@ static int ttm_mem_init_highmem_zone(struct ttm_mem_global *glob,
 	glob->zones[glob->num_zones++] = zone;
 	return 0;
 }
-#else
+#elifndef CONFIG_64BIT
 static int ttm_mem_init_dma32_zone(struct ttm_mem_global *glob,
 				   const struct sysinfo *si)
 {
@@ -441,7 +441,7 @@ int ttm_mem_global_init(struct ttm_mem_global *glob)
 	ret = ttm_mem_init_highmem_zone(glob, &si);
 	if (unlikely(ret != 0))
 		goto out_no_zone;
-#else
+#elifndef CONFIG_64BIT
 	ret = ttm_mem_init_dma32_zone(glob, &si);
 	if (unlikely(ret != 0))
 		goto out_no_zone;
-- 
2.7.4