[PATCH v9 2/3] drm/amdgpu: Enable clear page functionality
Paneer Selvam, Arunpravin
arunpravin.paneerselvam at amd.com
Tue Mar 19 13:57:11 UTC 2024
Hi Christian,
On 3/19/2024 7:17 PM, Christian König wrote:
> Am 19.03.24 um 12:41 schrieb Paneer Selvam, Arunpravin:
>> Hi Christian,
>>
>> On 3/19/2024 3:58 PM, Christian König wrote:
>>>
>>>
>>> Am 18.03.24 um 22:40 schrieb Arunpravin Paneer Selvam:
>>>> Add clear page support in vram memory region.
>>>>
>>>> v1(Christian):
>>>> - Dont handle clear page as TTM flag since when moving the BO back
>>>> in from GTT again we don't need that.
>>>> - Make a specialized version of amdgpu_fill_buffer() which only
>>>> clears the VRAM areas which are not already cleared
>>>> - Drop the TTM_PL_FLAG_WIPE_ON_RELEASE check in
>>>> amdgpu_object.c
>>>>
>>>> v2:
>>>> - Modify the function name amdgpu_ttm_* (Alex)
>>>> - Drop the delayed parameter (Christian)
>>>> - handle amdgpu_res_cleared(&cursor) just above the size
>>>> calculation (Christian)
>>>> - Use AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE for clearing the
>>>> buffers
>>>> in the free path to properly wait for fences etc.. (Christian)
>>>>
>>>> v3(Christian):
>>>> - Remove buffer clear code in VRAM manager instead change the
>>>> AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE handling to set
>>>> the DRM_BUDDY_CLEARED flag.
>>>> - Remove ! from amdgpu_res_cleared(&cursor) check.
>>>>
>>>> Signed-off-by: Arunpravin Paneer Selvam
>>>> <Arunpravin.PaneerSelvam at amd.com>
>>>> Suggested-by: Christian König <christian.koenig at amd.com>
>>>> Acked-by: Felix Kuehling <felix.kuehling at amd.com>
>>>
>>> Just a few nit picks below, but in general already looks good to me.
>>>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 22 ++++---
>>>> .../gpu/drm/amd/amdgpu/amdgpu_res_cursor.h | 25 ++++++++
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 61
>>>> ++++++++++++++++++-
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 5 +-
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 6 +-
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h | 5 ++
>>>> 6 files changed, 111 insertions(+), 13 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>> index 8bc79924d171..c92d92b28a57 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>> @@ -39,6 +39,7 @@
>>>> #include "amdgpu.h"
>>>> #include "amdgpu_trace.h"
>>>> #include "amdgpu_amdkfd.h"
>>>> +#include "amdgpu_vram_mgr.h"
>>>> /**
>>>> * DOC: amdgpu_object
>>>> @@ -601,8 +602,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
>>>> if (!amdgpu_bo_support_uswc(bo->flags))
>>>> bo->flags &= ~AMDGPU_GEM_CREATE_CPU_GTT_USWC;
>>>> - if (adev->ras_enabled)
>>>> - bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
>>>> + bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
>>>> bo->tbo.bdev = &adev->mman.bdev;
>>>> if (bp->domain & (AMDGPU_GEM_DOMAIN_GWS | AMDGPU_GEM_DOMAIN_OA |
>>>> @@ -632,15 +632,17 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
>>>> if (bp->flags & AMDGPU_GEM_CREATE_VRAM_CLEARED &&
>>>> bo->tbo.resource->mem_type == TTM_PL_VRAM) {
>>>> - struct dma_fence *fence;
>>>> + struct dma_fence *fence = NULL;
>>>> - r = amdgpu_fill_buffer(bo, 0, bo->tbo.base.resv, &fence,
>>>> true);
>>>> + r = amdgpu_ttm_clear_buffer(bo, bo->tbo.base.resv, &fence);
>>>> if (unlikely(r))
>>>> goto fail_unreserve;
>>>> - dma_resv_add_fence(bo->tbo.base.resv, fence,
>>>> - DMA_RESV_USAGE_KERNEL);
>>>> - dma_fence_put(fence);
>>>> + if (fence) {
>>>> + dma_resv_add_fence(bo->tbo.base.resv, fence,
>>>> + DMA_RESV_USAGE_KERNEL);
>>>> + dma_fence_put(fence);
>>>> + }
>>>> }
>>>> if (!bp->resv)
>>>> amdgpu_bo_unreserve(bo);
>>>> @@ -1365,8 +1367,12 @@ void amdgpu_bo_release_notify(struct
>>>> ttm_buffer_object *bo)
>>>> if (WARN_ON_ONCE(!dma_resv_trylock(bo->base.resv)))
>>>> return;
>>>> - r = amdgpu_fill_buffer(abo, AMDGPU_POISON, bo->base.resv,
>>>> &fence, true);
>>>> + r = amdgpu_fill_buffer(abo, 0, bo->base.resv, &fence, true);
>>>> if (!WARN_ON(r)) {
>>>> + struct amdgpu_vram_mgr_resource *vres;
>>>> +
>>>> + vres = to_amdgpu_vram_mgr_resource(bo->resource);
>>>> + vres->flags |= DRM_BUDDY_CLEARED;
>>>
>>> Those lines should probably be in the VRAM manager.
>> This flag is set based on the amdgpu_fill_buffer() function return
>> value, can we move the amdgpu_fill_buffer() function call and
>> DRM_BUDDY_CLEARED flag set lines to amdgpu_vram_mgr_del() in VRAM
>> manager and does it require to wipe the VRAM buffers here as well
>> without setting the DRM_BUDDY_CLEARED.
>
> No that won't work. The call to amdgpu_fill_buffer() *must* be here
> because that here is called before the resource is actually freed.
>
> Only setting the vres->flags should probably be moved into
> amdgpu_vram_mgr.c.
>
> So instead of calling that manually here just make a function for it
> to keep the code related to the buddy allocator in one place.
I got it, Thanks.
Regards,
Arun.
>
> Regards,
> Christian.
>
>>>
>>>> amdgpu_bo_fence(abo, fence, false);
>>>> dma_fence_put(fence);
>>>> }
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
>>>> index 381101d2bf05..50fcd86e1033 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
>>>> @@ -164,4 +164,29 @@ static inline void amdgpu_res_next(struct
>>>> amdgpu_res_cursor *cur, uint64_t size)
>>>> }
>>>> }
>>>> +/**
>>>> + * amdgpu_res_cleared - check if blocks are cleared
>>>> + *
>>>> + * @cur: the cursor to extract the block
>>>> + *
>>>> + * Check if the @cur block is cleared
>>>> + */
>>>> +static inline bool amdgpu_res_cleared(struct amdgpu_res_cursor *cur)
>>>> +{
>>>> + struct drm_buddy_block *block;
>>>> +
>>>> + switch (cur->mem_type) {
>>>> + case TTM_PL_VRAM:
>>>> + block = cur->node;
>>>> +
>>>> + if (!amdgpu_vram_mgr_is_cleared(block))
>>>> + return false;
>>>> + break;
>>>> + default:
>>>> + return false;
>>>> + }
>>>> +
>>>> + return true;
>>>> +}
>>>> +
>>>> #endif
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> index 8722beba494e..bcbffe909b47 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> @@ -378,11 +378,15 @@ static int amdgpu_move_blit(struct
>>>> ttm_buffer_object *bo,
>>>> (abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) {
>>>> struct dma_fence *wipe_fence = NULL;
>>>> - r = amdgpu_fill_buffer(abo, AMDGPU_POISON, NULL,
>>>> &wipe_fence,
>>>> - false);
>>>> + r = amdgpu_fill_buffer(abo, 0, NULL, &wipe_fence,
>>>> + false);
>>>> if (r) {
>>>> goto error;
>>>> } else if (wipe_fence) {
>>>> + struct amdgpu_vram_mgr_resource *vres;
>>>> +
>>>> + vres = to_amdgpu_vram_mgr_resource(bo->resource);
>>>> + vres->flags |= DRM_BUDDY_CLEARED;
>> Does it require to set the DRM_BUDDY_CLEARED flag as we are not
>> freeing the VRAM buffers?
>>>> dma_fence_put(fence);
>>>> fence = wipe_fence;
>>>> }
>>>> @@ -2214,6 +2218,59 @@ static int amdgpu_ttm_fill_mem(struct
>>>> amdgpu_ring *ring, uint32_t src_data,
>>>> return 0;
>>>> }
>>>
>>> Some kerneldoc here what the function does would ne nice to have.
>>>
>>>> +int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
>>>> + struct dma_resv *resv,
>>>> + struct dma_fence **fence)
>>>> +{
>>>> + struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>>>> + struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
>>>> + struct amdgpu_res_cursor cursor;
>>>> + struct dma_fence *f = NULL;
>>>
>>> It might be cleaner to just use the stub fence here (see
>>> dma_fence_get_stub()).
>>>
>>> This would avoid to local variable init in the caller and the if
>>> which checks if the function returned a fence or not.
>>>
>>>> + u64 addr;
>>>> + int r;
>>>> +
>>>> + if (!adev->mman.buffer_funcs_enabled)
>>>> + return -EINVAL;
>>>> +
>>>> + amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo),
>>>> &cursor);
>>>> +
>>>> + mutex_lock(&adev->mman.gtt_window_lock);
>>>> + while (cursor.remaining) {
>>>> + struct dma_fence *next = NULL;
>>>> + u64 size;
>>>> +
>>>> + if (amdgpu_res_cleared(&cursor)) {
>>>> + amdgpu_res_next(&cursor, cursor.size);
>>>> + continue;
>>>> + }
>>>> +
>>>> + /* Never clear more than 256MiB at once to avoid timeouts */
>>>> + size = min(cursor.size, 256ULL << 20);
>>>> +
>>>> + r = amdgpu_ttm_map_buffer(&bo->tbo, bo->tbo.resource,
>>>> &cursor,
>>>> + 1, ring, false, &size, &addr);
>>>> + if (r)
>>>> + goto err;
>>>> +
>>>> + r = amdgpu_ttm_fill_mem(ring, 0, addr, size, resv,
>>>> + &next, true, true);
>>>> + if (r)
>>>> + goto err;
>>>> +
>>>> + dma_fence_put(f);
>>>> + f = next;
>>>> +
>>>> + amdgpu_res_next(&cursor, size);
>>>> + }
>>>> +err:
>>>> + mutex_unlock(&adev->mman.gtt_window_lock);
>>>> + if (fence)
>>>
>>> Just make fence a mandatory parameter and drop the if and the
>>> get/put dance.
>>>
>>>> + *fence = dma_fence_get(f);
>>>> + dma_fence_put(f);
>>>> +
>>>> + return r;
>>>> +}
>>>> +
>>>> int amdgpu_fill_buffer(struct amdgpu_bo *bo,
>>>> uint32_t src_data,
>>>> struct dma_resv *resv,
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>> index 65ec82141a8e..b404d89d52e5 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>>> @@ -38,8 +38,6 @@
>>>> #define AMDGPU_GTT_MAX_TRANSFER_SIZE 512
>>>> #define AMDGPU_GTT_NUM_TRANSFER_WINDOWS 2
>>>> -#define AMDGPU_POISON 0xd0bed0be
>>>> -
>>>> extern const struct attribute_group amdgpu_vram_mgr_attr_group;
>>>> extern const struct attribute_group amdgpu_gtt_mgr_attr_group;
>>>> @@ -155,6 +153,9 @@ int amdgpu_ttm_copy_mem_to_mem(struct
>>>> amdgpu_device *adev,
>>>> uint64_t size, bool tmz,
>>>> struct dma_resv *resv,
>>>> struct dma_fence **f);
>>>> +int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
>>>> + struct dma_resv *resv,
>>>> + struct dma_fence **fence);
>>>> int amdgpu_fill_buffer(struct amdgpu_bo *bo,
>>>> uint32_t src_data,
>>>> struct dma_resv *resv,
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>>> index c0c851409241..e494f5bf136a 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>>> @@ -450,6 +450,7 @@ static int amdgpu_vram_mgr_new(struct
>>>> ttm_resource_manager *man,
>>>> {
>>>> struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
>>>> struct amdgpu_device *adev = to_amdgpu_device(mgr);
>>>> + struct amdgpu_bo *bo = ttm_to_amdgpu_bo(tbo);
>>>> u64 vis_usage = 0, max_bytes, min_block_size;
>>>> struct amdgpu_vram_mgr_resource *vres;
>>>> u64 size, remaining_size, lpfn, fpfn;
>>>> @@ -501,6 +502,9 @@ static int amdgpu_vram_mgr_new(struct
>>>> ttm_resource_manager *man,
>>>> if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
>>>> vres->flags |= DRM_BUDDY_CONTIGUOUS_ALLOCATION;
>>>> + if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CLEARED)
>>>> + vres->flags |= DRM_BUDDY_CLEAR_ALLOCATION;
>>>> +
>>>
>>> Mhm, you should probably *not* store this flags in the vres structure.
>>>
>>> As soon as the BO is used the VRAM wouldn't be cleared any more.
>>>
>>> Regards,
>>> Christian.
>>>
>>>> if (fpfn || lpfn != mgr->mm.size)
>>>> /* Allocate blocks in desired range */
>>>> vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
>>>> @@ -604,7 +608,7 @@ static void amdgpu_vram_mgr_del(struct
>>>> ttm_resource_manager *man,
>>>> amdgpu_vram_mgr_do_reserve(man);
>>>> - drm_buddy_free_list(mm, &vres->blocks, 0);
>>>> + drm_buddy_free_list(mm, &vres->blocks, vres->flags);
>>>> mutex_unlock(&mgr->lock);
>>>> atomic64_sub(vis_usage, &mgr->vis_usage);
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
>>>> index 0e04e42cf809..8478522d7366 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
>>>> @@ -53,6 +53,11 @@ static inline u64
>>>> amdgpu_vram_mgr_block_size(struct drm_buddy_block *block)
>>>> return (u64)PAGE_SIZE << drm_buddy_block_order(block);
>>>> }
>>>> +static inline bool amdgpu_vram_mgr_is_cleared(struct
>>>> drm_buddy_block *block)
>>>> +{
>>>> + return drm_buddy_block_is_clear(block);
>>>> +}
>>>> +
>>>> static inline struct amdgpu_vram_mgr_resource *
>>>> to_amdgpu_vram_mgr_resource(struct ttm_resource *res)
>>>> {
>>>
>>
>
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