Re: [PATCH] drm/amdgpu: take back kvmalloc_array for entries alloc because of kzalloc memory limit

[Christian König <christian.koenig@xxxxxxx>]

Am 02.06.21 um 10:54 schrieb Das, Nirmoy:
> On 6/2/2021 10:30 AM, Changfeng wrote:
> > From: changzhu <Changfeng.Zhu@xxxxxxx>
> >
> > From: Changfeng <Changfeng.Zhu@xxxxxxx>
> >
> > It will cause error when alloc memory larger than 128KB in
> > amdgpu_bo_create->kzalloc.
>
>
> I wonder why I didn't see the error on my machine. Is there any config 
> I might be missing ?

VM page table layout depends on hardware generation, APU vs dGPU and 
kernel command line settings.

I think we just need to switch amdgpu_bo_create() from kzalloc to 
kvmalloc (and kfree to kvfree in amdgpu_bo_destroy of course).

Shouldn't be more than a two line patch.

Regards,
Christian.

> Thanks,
>
> Nirmoy
>
> > Call Trace:
> >     alloc_pages_current+0x6a/0xe0
> >     kmalloc_order+0x32/0xb0
> >     kmalloc_order_trace+0x1e/0x80
> >     __kmalloc+0x249/0x2d0
> >     amdgpu_bo_create+0x102/0x500 [amdgpu]
> >     ? xas_create+0x264/0x3e0
> >     amdgpu_bo_create_vm+0x32/0x60 [amdgpu]
> >     amdgpu_vm_pt_create+0xf5/0x260 [amdgpu]
> >     amdgpu_vm_init+0x1fd/0x4d0 [amdgpu]
> >
> > Change-Id: I29e479db45ead37c39449e856599fd4f6a0e34ce
> > Signed-off-by: Changfeng <Changfeng.Zhu@xxxxxxx>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 27 +++++++++++++++-----------
> >   1 file changed, 16 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > index 1923f035713a..714d613d020b 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > @@ -894,6 +894,10 @@ static int amdgpu_vm_pt_create(struct 
> > amdgpu_device *adev,
> >           num_entries = 0;
> >         bp.bo_ptr_size = struct_size((*vmbo), entries, num_entries);
> > +    if (bp.bo_ptr_size > 32*AMDGPU_GPU_PAGE_SIZE) {
> > +        DRM_INFO("Can't alloc memory larger than 128KB by using 
> > kzalloc in amdgpu_bo_create\n");
> > +        bp.bo_ptr_size = sizeof(struct amdgpu_bo_vm);
> > +    }
> >         if (vm->use_cpu_for_update)
> >           bp.flags |= AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
> > @@ -965,15 +969,19 @@ static int amdgpu_vm_alloc_pts(struct 
> > amdgpu_device *adev,
> >       struct amdgpu_bo_vm *pt;
> >       int r;
> >   -    if (entry->base.bo) {
> > -        if (cursor->level < AMDGPU_VM_PTB)
> > -            entry->entries =
> > -                to_amdgpu_bo_vm(entry->base.bo)->entries;
> > -        else
> > -            entry->entries = NULL;
> > -        return 0;
> > +    if (cursor->level < AMDGPU_VM_PTB && !entry->entries) {
> > +        unsigned num_entries;
> > +        num_entries = amdgpu_vm_num_entries(adev, cursor->level);
> > +        entry->entries = kvmalloc_array(num_entries,
> > +                        sizeof(*entry->entries),
> > +                        GFP_KERNEL | __GFP_ZERO);
> > +        if (!entry->entries)
> > +            return -ENOMEM;
> >       }
> >   +    if (entry->base.bo)
> > +        return 0;
> > +
> >       r = amdgpu_vm_pt_create(adev, vm, cursor->level, immediate, &pt);
> >       if (r)
> >           return r;
> > @@ -984,10 +992,6 @@ static int amdgpu_vm_alloc_pts(struct 
> > amdgpu_device *adev,
> >       pt_bo = &pt->bo;
> >       pt_bo->parent = amdgpu_bo_ref(cursor->parent->base.bo);
> >       amdgpu_vm_bo_base_init(&entry->base, vm, pt_bo);
> > -    if (cursor->level < AMDGPU_VM_PTB)
> > -        entry->entries = pt->entries;
> > -    else
> > -        entry->entries = NULL;
> >         r = amdgpu_vm_clear_bo(adev, vm, pt, immediate);
> >       if (r)
> > @@ -1017,6 +1021,7 @@ static void amdgpu_vm_free_table(struct 
> > amdgpu_vm_pt *entry)
> >           amdgpu_bo_unref(&shadow);
> >           amdgpu_bo_unref(&entry->base.bo);
> >       }
> > +    kvfree(entry->entries);
> >       entry->entries = NULL;
> >   }

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