[PATCH] drm/amdkfd: Simplify the mmap offset related bit operations
Zhao, Yong
Yong.Zhao at amd.com
Fri Nov 1 23:03:56 UTC 2019
> + /* only leave the offset segment */
> + vma->vm_pgoff &= (1ULL << (KFD_MMAP_GPU_ID_SHIFT - PAGE_SHIFT)) - 1;
You're now open-coding what used to be done by the
KFD_MMAP_OFFSET_VALUE_GET macro. I don't see how this is an improvement.
Maybe better to update the macro to do this.
I can definitely do that, but I think we'd better delete this line completely as it seems odd to change vm_pgoff. Moreover this vm_pgoff is not used at all in the following function calls. What do you think?
Regards,
Yong
________________________________
From: Kuehling, Felix <Felix.Kuehling at amd.com>
Sent: Friday, November 1, 2019 6:48 PM
To: Zhao, Yong <Yong.Zhao at amd.com>; amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
Subject: Re: [PATCH] drm/amdkfd: Simplify the mmap offset related bit operations
On 2019-11-01 4:48 p.m., Zhao, Yong wrote:
> The new code is much cleaner and results in better readability.
>
> Change-Id: I0c1f7cca7e24ddb7b4ffe1cb0fa71943828ae373
> Signed-off-by: Yong Zhao <Yong.Zhao at amd.com>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 13 +++++++------
> drivers/gpu/drm/amd/amdkfd/kfd_events.c | 1 -
> drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 9 +++------
> drivers/gpu/drm/amd/amdkfd/kfd_process.c | 3 +--
> 4 files changed, 11 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index b91993753b82..590138727ca9 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -298,7 +298,6 @@ static int kfd_ioctl_create_queue(struct file *filep, struct kfd_process *p,
> /* Return gpu_id as doorbell offset for mmap usage */
> args->doorbell_offset = KFD_MMAP_TYPE_DOORBELL;
> args->doorbell_offset |= KFD_MMAP_GPU_ID(args->gpu_id);
> - args->doorbell_offset <<= PAGE_SHIFT;
> if (KFD_IS_SOC15(dev->device_info->asic_family))
> /* On SOC15 ASICs, include the doorbell offset within the
> * process doorbell frame, which could be 1 page or 2 pages.
> @@ -1938,20 +1937,22 @@ static int kfd_mmap(struct file *filp, struct vm_area_struct *vma)
> {
> struct kfd_process *process;
> struct kfd_dev *dev = NULL;
> - unsigned long vm_pgoff;
> + unsigned long mmap_offset;
> unsigned int gpu_id;
>
> process = kfd_get_process(current);
> if (IS_ERR(process))
> return PTR_ERR(process);
>
> - vm_pgoff = vma->vm_pgoff;
> - vma->vm_pgoff = KFD_MMAP_OFFSET_VALUE_GET(vm_pgoff);
> - gpu_id = KFD_MMAP_GPU_ID_GET(vm_pgoff);
> + mmap_offset = vma->vm_pgoff << PAGE_SHIFT;
> + gpu_id = KFD_MMAP_GET_GPU_ID(mmap_offset);
> if (gpu_id)
> dev = kfd_device_by_id(gpu_id);
>
> - switch (vm_pgoff & KFD_MMAP_TYPE_MASK) {
> + /* only leave the offset segment */
> + vma->vm_pgoff &= (1ULL << (KFD_MMAP_GPU_ID_SHIFT - PAGE_SHIFT)) - 1;
You're now open-coding what used to be done by the
KFD_MMAP_OFFSET_VALUE_GET macro. I don't see how this is an improvement.
Maybe better to update the macro to do this.
> +
> + switch (mmap_offset & KFD_MMAP_TYPE_MASK) {
> case KFD_MMAP_TYPE_DOORBELL:
> if (!dev)
> return -ENODEV;
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> index 908081c85de1..1f8365575b12 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> @@ -346,7 +346,6 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p,
> ret = create_signal_event(devkfd, p, ev);
> if (!ret) {
> *event_page_offset = KFD_MMAP_TYPE_EVENTS;
> - *event_page_offset <<= PAGE_SHIFT;
> *event_slot_index = ev->event_id;
> }
> break;
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> index 66bae8f2dad1..8eecd2cd1fd2 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> @@ -59,24 +59,21 @@
> * NOTE: struct vm_area_struct.vm_pgoff uses offset in pages. Hence, these
> * defines are w.r.t to PAGE_SIZE
> */
> -#define KFD_MMAP_TYPE_SHIFT (62 - PAGE_SHIFT)
> +#define KFD_MMAP_TYPE_SHIFT (62)
> #define KFD_MMAP_TYPE_MASK (0x3ULL << KFD_MMAP_TYPE_SHIFT)
> #define KFD_MMAP_TYPE_DOORBELL (0x3ULL << KFD_MMAP_TYPE_SHIFT)
> #define KFD_MMAP_TYPE_EVENTS (0x2ULL << KFD_MMAP_TYPE_SHIFT)
> #define KFD_MMAP_TYPE_RESERVED_MEM (0x1ULL << KFD_MMAP_TYPE_SHIFT)
> #define KFD_MMAP_TYPE_MMIO (0x0ULL << KFD_MMAP_TYPE_SHIFT)
>
> -#define KFD_MMAP_GPU_ID_SHIFT (46 - PAGE_SHIFT)
> +#define KFD_MMAP_GPU_ID_SHIFT (46)
> #define KFD_MMAP_GPU_ID_MASK (((1ULL << KFD_GPU_ID_HASH_WIDTH) - 1) \
> << KFD_MMAP_GPU_ID_SHIFT)
> #define KFD_MMAP_GPU_ID(gpu_id) ((((uint64_t)gpu_id) << KFD_MMAP_GPU_ID_SHIFT)\
> & KFD_MMAP_GPU_ID_MASK)
> -#define KFD_MMAP_GPU_ID_GET(offset) ((offset & KFD_MMAP_GPU_ID_MASK) \
> +#define KFD_MMAP_GET_GPU_ID(offset) ((offset & KFD_MMAP_GPU_ID_MASK) \
> >> KFD_MMAP_GPU_ID_SHIFT)
>
> -#define KFD_MMAP_OFFSET_VALUE_MASK (0x3FFFFFFFFFFFULL >> PAGE_SHIFT)
> -#define KFD_MMAP_OFFSET_VALUE_GET(offset) (offset & KFD_MMAP_OFFSET_VALUE_MASK)
This macro is still useful. See above. I think you should just update
the mask and continue using it for clarity.
Regards,
Felix
> -
> /*
> * When working with cp scheduler we should assign the HIQ manually or via
> * the amdgpu driver to a fixed hqd slot, here are the fixed HIQ hqd slot
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index 6abfb77ae540..39dc49b8fd85 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -554,8 +554,7 @@ static int kfd_process_init_cwsr_apu(struct kfd_process *p, struct file *filep)
> if (!dev->cwsr_enabled || qpd->cwsr_kaddr || qpd->cwsr_base)
> continue;
>
> - offset = (KFD_MMAP_TYPE_RESERVED_MEM | KFD_MMAP_GPU_ID(dev->id))
> - << PAGE_SHIFT;
> + offset = KFD_MMAP_TYPE_RESERVED_MEM | KFD_MMAP_GPU_ID(dev->id);
> qpd->tba_addr = (int64_t)vm_mmap(filep, 0,
> KFD_CWSR_TBA_TMA_SIZE, PROT_READ | PROT_EXEC,
> MAP_SHARED, offset);
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