From: Steven Price <steven.price@arm.com>
To: "Adrián Larumbe" <adrian.larumbe@collabora.com>,
"Boris Brezillon" <boris.brezillon@collabora.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>,
dri-devel@lists.freedesktop.org, kernel@collabora.com
Subject: Re: [PATCH v2 3/4] drm/panthor: Relax the constraints on the tiler chunk size
Date: Thu, 2 May 2024 15:03:49 +0100 [thread overview]
Message-ID: <71be7135-992d-422e-bda8-4b51b6af54c0@arm.com> (raw)
In-Reply-To: <arfscr3mzmxezf7icupfr7urjfnujp5yogxfzrkmetuyhdztrg@zem4tqbphyab>
On 30/04/2024 14:08, Adrián Larumbe wrote:
> Hi Boris,
>
> On 30.04.2024 13:28, Boris Brezillon wrote:
>> The field used to store the chunk size if 12 bits wide, and the encoding
>> is chunk_size = chunk_header.chunk_size << 12, which gives us a
>> theoretical [4k:8M] range. This range is further limited by
>> implementation constraints, and all known implementations seem to
>> impose a [128k:8M] range, so do the same here.
>>
>> We also relax the power-of-two constraint, which doesn't seem to
>> exist on v10. This will allow userspace to fine-tune initial/max
>> tiler memory on memory-constrained devices.
>>
>> v2:
>> - Turn the power-of-two constraint into a page-aligned constraint to allow
>> fine-tune of the initial/max heap memory size
>> - Fix the panthor_heap_create() kerneldoc
>>
>> Fixes: 9cca48fa4f89 ("drm/panthor: Add the heap logical block")
>> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Other than the typo Adrián pointed out below...
Reviewed-by: Steven Price <steven.price@arm.com>
>> ---
>> drivers/gpu/drm/panthor/panthor_heap.c | 8 ++++----
>> include/uapi/drm/panthor_drm.h | 6 +++++-
>> 2 files changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c
>> index 3be86ec383d6..683bb94761bc 100644
>> --- a/drivers/gpu/drm/panthor/panthor_heap.c
>> +++ b/drivers/gpu/drm/panthor/panthor_heap.c
>> @@ -253,8 +253,8 @@ int panthor_heap_destroy(struct panthor_heap_pool *pool, u32 handle)
>> * @pool: Pool to instantiate the heap context from.
>> * @initial_chunk_count: Number of chunk allocated at initialization time.
>> * Must be at least 1.
>> - * @chunk_size: The size of each chunk. Must be a power of two between 256k
>> - * and 2M.
>> + * @chunk_size: The size of each chunk. Must be page-aligned and lie in the
>> + * [128k:2M] range.
>
> Probably a typo, but I guess this should be [128k:8M] ?
>
>> * @max_chunks: Maximum number of chunks that can be allocated.
>> * @target_in_flight: Maximum number of in-flight render passes.
>> * @heap_ctx_gpu_va: Pointer holding the GPU address of the allocated heap
>> @@ -284,8 +284,8 @@ int panthor_heap_create(struct panthor_heap_pool *pool,
>> if (initial_chunk_count > max_chunks)
>> return -EINVAL;
>>
>> - if (hweight32(chunk_size) != 1 ||
>> - chunk_size < SZ_256K || chunk_size > SZ_2M)
>> + if (!IS_ALIGNED(chunk_size, PAGE_SIZE) ||
>> + chunk_size < SZ_128K || chunk_size > SZ_8M)
>> return -EINVAL;
>>
>> down_read(&pool->lock);
>> diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
>> index 5db80a0682d5..b8220d2e698f 100644
>> --- a/include/uapi/drm/panthor_drm.h
>> +++ b/include/uapi/drm/panthor_drm.h
>> @@ -898,7 +898,11 @@ struct drm_panthor_tiler_heap_create {
>> /** @initial_chunk_count: Initial number of chunks to allocate. Must be at least one. */
>> __u32 initial_chunk_count;
>>
>> - /** @chunk_size: Chunk size. Must be a power of two at least 256KB large. */
>> + /**
>> + * @chunk_size: Chunk size.
>> + *
>> + * Must be page-aligned and lie in the [128k:8M] range.
>> + */
>> __u32 chunk_size;
>>
>> /**
>> --
>> 2.44.0
>
>
> Adrian Larumbe
next prev parent reply other threads:[~2024-05-02 14:03 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-30 11:28 [PATCH v2 0/4] drm/panthor: Collection of tiler heap related fixes Boris Brezillon
2024-04-30 11:28 ` [PATCH v2 1/4] drm/panthor: Fix tiler OOM handling to allow incremental rendering Boris Brezillon
2024-04-30 15:27 ` Liviu Dudau
2024-05-02 14:03 ` Steven Price
2024-04-30 11:28 ` [PATCH v2 2/4] drm/panthor: Make sure the tiler initial/max chunks are consistent Boris Brezillon
2024-04-30 15:31 ` Liviu Dudau
2024-05-02 14:03 ` Steven Price
2024-04-30 11:28 ` [PATCH v2 3/4] drm/panthor: Relax the constraints on the tiler chunk size Boris Brezillon
2024-04-30 13:08 ` Adrián Larumbe
2024-05-02 14:03 ` Steven Price [this message]
2024-04-30 16:10 ` Liviu Dudau
2024-04-30 11:28 ` [PATCH v2 4/4] drm/panthor: Fix an off-by-one in the heap context retrieval logic Boris Brezillon
2024-04-30 16:40 ` Liviu Dudau
2024-04-30 17:07 ` Boris Brezillon
2024-05-02 14:03 ` Steven Price
2024-05-02 14:15 ` Boris Brezillon
2024-05-02 14:26 ` Steven Price
2024-05-02 14:36 ` Boris Brezillon
2024-05-02 14:47 ` Boris Brezillon
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