[PATCH] drm/amdkfd: Allocate doorbells only when needed

Bhardwaj, Rajneesh Rajneesh.Bhardwaj at amd.com
Thu Sep 1 17:58:33 UTC 2022


[AMD Official Use Only - General]

This seems to have broken CRIU restore. After I revert this, I can get CRIU restore working.

From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Russell, Kent
Sent: Tuesday, August 23, 2022 8:07 AM
To: Kuehling, Felix <Felix.Kuehling at amd.com>; amd-gfx at lists.freedesktop.org
Subject: Re: [PATCH] drm/amdkfd: Allocate doorbells only when needed

No one else seems to have any thoughts on it, so Reviewed-by: Kent Russell <kent.Russell at amd.com<mailto:kent.Russell at amd.com>>

 Kent

________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org<mailto:amd-gfx-bounces at lists.freedesktop.org>> on behalf of Russell, Kent <Kent.Russell at amd.com<mailto:Kent.Russell at amd.com>>
Sent: Monday, August 22, 2022 10:10 AM
To: Kuehling, Felix <Felix.Kuehling at amd.com<mailto:Felix.Kuehling at amd.com>>; amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org> <amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>>
Subject: RE: [PATCH] drm/amdkfd: Allocate doorbells only when needed

[AMD Official Use Only - General]

I can throw an Acked-by: Kent Russell <kent.russell at amd.com<mailto:kent.russell at amd.com>> since we don't have an RB yet.

 Kent

> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org<mailto:amd-gfx-bounces at lists.freedesktop.org>> On Behalf Of Felix
> Kuehling
> Sent: Wednesday, August 3, 2022 2:56 PM
> To: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>
> Subject: [PATCH] drm/amdkfd: Allocate doorbells only when needed
>
> Only allocate doorbells when the first queue is created on a GPU or the
> doorbells need to be mapped into CPU or GPU virtual address space. This
> avoids allocating doorbells unnecessarily and can allow more processes
> to use KFD on multi-GPU systems.
>
> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com<mailto:Felix.Kuehling at amd.com>>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c  | 13 +++++++++++++
>  drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c |  9 +++++++++
>  drivers/gpu/drm/amd/amdkfd/kfd_process.c  |  5 -----
>  3 files changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index 2b3d8bc8f0aa..907f4711abce 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -327,6 +327,12 @@ static int kfd_ioctl_create_queue(struct file *filep,
> struct kfd_process *p,
>                goto err_bind_process;
>        }
>
> +     if (!pdd->doorbell_index &&
> +         kfd_alloc_process_doorbells(dev, &pdd->doorbell_index) < 0) {
> +             err = -ENOMEM;
> +             goto err_alloc_doorbells;
> +     }
> +
>        /* Starting with GFX11, wptr BOs must be mapped to GART for MES to
> determine work
>         * on unmapped queues for usermode queue oversubscription (no
> aggregated doorbell)
>         */
> @@ -404,6 +410,7 @@ static int kfd_ioctl_create_queue(struct file *filep, struct
> kfd_process *p,
>        if (wptr_bo)
>                amdgpu_amdkfd_free_gtt_mem(dev->adev, wptr_bo);
>  err_wptr_map_gart:
> +err_alloc_doorbells:
>  err_bind_process:
>  err_pdd:
>        mutex_unlock(&p->mutex);
> @@ -1092,6 +1099,10 @@ static int kfd_ioctl_alloc_memory_of_gpu(struct file
> *filep,
>                        goto err_unlock;
>                }
>                offset = kfd_get_process_doorbells(pdd);
> +             if (!offset) {
> +                     err = -ENOMEM;
> +                     goto err_unlock;
> +             }
>        } else if (flags & KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP) {
>                if (args->size != PAGE_SIZE) {
>                        err = -EINVAL;
> @@ -2173,6 +2184,8 @@ static int criu_restore_memory_of_gpu(struct
> kfd_process_device *pdd,
>                        return -EINVAL;
>
>                offset = kfd_get_process_doorbells(pdd);
> +             if (!offset)
> +                     return -ENOMEM;

Looks like this is causing CRIU restore failure.

>        } else if (bo_bucket->alloc_flags &
> KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP) {
>                /* MMIO BOs need remapped bus address */
>                if (bo_bucket->size != PAGE_SIZE) {
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c
> index cb3d2ccc5100..b33798f89ef0 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c
> @@ -157,6 +157,8 @@ int kfd_doorbell_mmap(struct kfd_dev *dev, struct
> kfd_process *process,
>
>        /* Calculate physical address of doorbell */
>        address = kfd_get_process_doorbells(pdd);
> +     if (!address)
> +             return -ENOMEM;
>        vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND |
> VM_NORESERVE |
>                                VM_DONTDUMP | VM_PFNMAP;
>
> @@ -275,6 +277,13 @@ uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
>
>  phys_addr_t kfd_get_process_doorbells(struct kfd_process_device *pdd)
>  {
> +     if (!pdd->doorbell_index) {
> +             int r = kfd_alloc_process_doorbells(pdd->dev,
> +                                                 &pdd->doorbell_index);
> +             if (r)
> +                     return 0;
> +     }
> +
>        return pdd->dev->doorbell_base +
>                pdd->doorbell_index * kfd_doorbell_process_slice(pdd->dev);
>  }
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index 6c83a519b3a1..951b63677248 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -1499,11 +1499,6 @@ struct kfd_process_device
> *kfd_create_process_device_data(struct kfd_dev *dev,
>        if (!pdd)
>                return NULL;
>
> -     if (kfd_alloc_process_doorbells(dev, &pdd->doorbell_index) < 0) {
> -             pr_err("Failed to alloc doorbell for pdd\n");
> -             goto err_free_pdd;
> -     }
> -
>        if (init_doorbell_bitmap(&pdd->qpd, dev)) {
>                pr_err("Failed to init doorbell for process\n");
>                goto err_free_pdd;
> --
> 2.32.0
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