From f6c370976a25736b04f951b1857d76dbb1177ae2 Mon Sep 17 00:00:00 2001
From: David Heidelberg <david@ixit.cz>
Date: Wed, 1 Nov 2023 10:59:44 +0100
Subject: [PATCH] Revert "drm/amdgpu: Set GTT size equal to TTM mem limit"
We need `amdgpu.gttsize=3072` for the testing on machines with =< 4G RAM.
This reverts commit f1f6f48a338cdab96efef712dbef6b1e279583e2.
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 25 +++++++++++++++++++------
2 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 4653a8d2823a..91a9d9107d23 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -270,6 +270,7 @@ extern int amdgpu_wbrf;
#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 c8180cad0abd..df399651724e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1956,13 +1956,26 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
DRM_INFO("amdgpu: %uM of VRAM memory ready\n",
(unsigned int)(adev->gmc.real_vram_size / (1024 * 1024)));
- /* 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
+ /* 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 {
gtt_size = (uint64_t)amdgpu_gtt_size << 20;
+ }
/* Initialize GTT memory pool */
r = amdgpu_gtt_mgr_init(adev, gtt_size);
--
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