[AMD Official Use Only - AMD Internal Distribution Only]
Hi Christian,
Thank you for the feedback.
For “return ret < 0 ? ret : 0;”, it is equivalent to “return ret;” since ret is
always <= 0 after the loop.
For all other comments, I will revise the patch accordingly in v2.
Regards
Sam
From: Koenig, Christian <christian.koe...@amd.com>
Date: Monday, June 30, 2025 at 19:54
To: Zhang, GuoQing (Sam) <guoqing.zh...@amd.com>, raf...@kernel.org
<raf...@kernel.org>, len.br...@intel.com <len.br...@intel.com>,
pa...@kernel.org <pa...@kernel.org>, Deucher, Alexander
<alexander.deuc...@amd.com>, Limonciello, Mario <mario.limoncie...@amd.com>,
Lazar, Lijo <lijo.la...@amd.com>
Cc: Zhao, Victor <victor.z...@amd.com>, Chang, HaiJun <haijun.ch...@amd.com>,
Ma, Qing (Mark) <qing...@amd.com>, amd-gfx@lists.freedesktop.org
<amd-gfx@lists.freedesktop.org>, dri-de...@lists.freedesktop.org
<dri-de...@lists.freedesktop.org>, linux...@vger.kernel.org
<linux...@vger.kernel.org>, linux-ker...@vger.kernel.org
<linux-ker...@vger.kernel.org>
Subject: Re: [PATCH 1/3] drm/amdgpu: move GTT to SHM after eviction for
hibernation
On 30.06.25 12:41, Samuel Zhang wrote:
> When hibernate with data center dGPUs, huge number of VRAM BOs evicted
> to GTT and takes too much system memory. This will cause hibernation
> fail due to insufficient memory for creating the hibernation image.
>
> Move GTT BOs to shmem in KMD, then shmem to swap disk in kernel
> hibernation code to make room for hibernation image.
This should probably be two patches, one for TTM and then an amdgpu patch to
forward the event.
>
> Signed-off-by: Samuel Zhang <guoqing.zh...@amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 13 ++++++++++++-
> drivers/gpu/drm/ttm/ttm_resource.c | 18 ++++++++++++++++++
> include/drm/ttm/ttm_resource.h | 1 +
> 3 files changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 4d57269c9ca8..5aede907a591 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -2889,6 +2889,7 @@ int amdgpu_fill_buffer(struct amdgpu_bo *bo,
> int amdgpu_ttm_evict_resources(struct amdgpu_device *adev, int mem_type)
> {
> struct ttm_resource_manager *man;
> + int r;
>
> switch (mem_type) {
> case TTM_PL_VRAM:
> @@ -2903,7 +2904,17 @@ int amdgpu_ttm_evict_resources(struct amdgpu_device
> *adev, int mem_type)
> return -EINVAL;
> }
>
> - return ttm_resource_manager_evict_all(&adev->mman.bdev, man);
> + r = ttm_resource_manager_evict_all(&adev->mman.bdev, man);
> + if (r) {
> + DRM_ERROR("Failed to evict memory type %d\n", mem_type);
> + return r;
> + }
> + if (adev->in_s4 && mem_type == TTM_PL_VRAM) {
> + r = ttm_resource_manager_swapout();
> + if (r)
> + DRM_ERROR("Failed to swap out, %d\n", r);
> + }
> + return r;
> }
>
> #if defined(CONFIG_DEBUG_FS)
> diff --git a/drivers/gpu/drm/ttm/ttm_resource.c
> b/drivers/gpu/drm/ttm/ttm_resource.c
> index fd41b56e2c66..07b1f5a5afc2 100644
> --- a/drivers/gpu/drm/ttm/ttm_resource.c
> +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> @@ -534,6 +534,24 @@ void ttm_resource_manager_init(struct
> ttm_resource_manager *man,
> }
> EXPORT_SYMBOL(ttm_resource_manager_init);
>
> +int ttm_resource_manager_swapout(void)
This needs documentation, better placement and a better name.
First of all put it into ttm_device.c instead of the resource manager.
Then call it something like ttm_device_prepare_hibernation or similar.
> +{
> + struct ttm_operation_ctx ctx = {
> + .interruptible = false,
> + .no_wait_gpu = false,
> + .force_alloc = true
> + };
> + int ret;
> +
> + while (true) {
Make that:
do {
ret = ...
} while (ret > 0);
> + ret = ttm_global_swapout(&ctx, GFP_KERNEL);
> + if (ret <= 0)
> + break;
> + }
> + return ret;
It's rather pointless to return the number of swapped out pages.
Make that "return ret < 0 ? ret : 0;
Regards,
Christian.
> +}
> +EXPORT_SYMBOL(ttm_resource_manager_swapout);
> +
> /*
> * ttm_resource_manager_evict_all
> *
> diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
> index b873be9597e2..46181758068e 100644
> --- a/include/drm/ttm/ttm_resource.h
> +++ b/include/drm/ttm/ttm_resource.h
> @@ -463,6 +463,7 @@ void ttm_resource_manager_init(struct
> ttm_resource_manager *man,
>
> int ttm_resource_manager_evict_all(struct ttm_device *bdev,
> struct ttm_resource_manager *man);
> +int ttm_resource_manager_swapout(void);
>
> uint64_t ttm_resource_manager_usage(struct ttm_resource_manager *man);
> void ttm_resource_manager_debug(struct ttm_resource_manager *man,
