[PATCHv2 2/3] drm/amdgpu: Set GTT size equal to TTM mem limit

[Mukul Joshi]

Use the helper function in TTM to get TTM mem limit and
set GTT size to be equal to TTL mem limit.

Signed-off-by: Mukul Joshi <mukul.joshi at amd.com>
Reviewed-by: Christian König <christian.koenig at amd.com>
---
v1->v2:
- Remove AMDGPU_DEFAULT_GTT_SIZE_MB as well as it is
  unused.

 drivers/gpu/drm/amd/amdgpu/amdgpu.h     |  1 -
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 25 ++++++-------------------
 2 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index d107d95e2e6f..5ded5a90dc68 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -245,7 +245,6 @@ extern int amdgpu_sg_display;
 
 #define AMDGPU_VM_MAX_NUM_CTX			4096
 #define AMDGPU_SG_THRESHOLD			(256*1024*1024)
-#define AMDGPU_DEFAULT_GTT_SIZE_MB		3072ULL /* 3GB by default */
 #define AMDGPU_WAIT_IDLE_TIMEOUT_IN_MS	        3000
 #define AMDGPU_MAX_USEC_TIMEOUT			100000	/* 100 ms */
 #define AMDGPU_FENCE_JIFFIES_TIMEOUT		(HZ / 2)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index ce34b73d05bc..ac220c779fc8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1807,26 +1807,13 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
 	DRM_INFO("amdgpu: %uM of VRAM memory ready\n",
 		 (unsigned) (adev->gmc.real_vram_size / (1024 * 1024)));
 
-	/* Compute GTT size, either based on 1/2 the size of RAM size
-	 * or whatever the user passed on module init */
-	if (amdgpu_gtt_size == -1) {
-		struct sysinfo si;
-
-		si_meminfo(&si);
-		/* Certain GL unit tests for large textures can cause problems
-		 * with the OOM killer since there is no way to link this memory
-		 * to a process.  This was originally mitigated (but not necessarily
-		 * eliminated) by limiting the GTT size.  The problem is this limit
-		 * is often too low for many modern games so just make the limit 1/2
-		 * of system memory which aligns with TTM. The OOM accounting needs
-		 * to be addressed, but we shouldn't prevent common 3D applications
-		 * from being usable just to potentially mitigate that corner case.
-		 */
-		gtt_size = max((AMDGPU_DEFAULT_GTT_SIZE_MB << 20),
-			       (u64)si.totalram * si.mem_unit / 2);
-	} else {
+	/* Compute GTT size, either based on TTM limit
+	 * or whatever the user passed on module init.
+	 */
+	if (amdgpu_gtt_size == -1)
+		gtt_size = ttm_tt_pages_limit() << PAGE_SHIFT;
+	else
 		gtt_size = (uint64_t)amdgpu_gtt_size << 20;
-	}
 
 	/* Initialize GTT memory pool */
 	r = amdgpu_gtt_mgr_init(adev, gtt_size);
-- 
2.35.1