The heap ID is used to index the heap context pool, and allocating
in the [1:MAX_HEAPS_PER_POOL] leads to an off-by-one. This was
originally to avoid returning a zero heap handle, but given the handle
is formed with (vm_id << 16) | heap_id, with vm_id > 0, we already can't
end up with a valid heap handle that's zero.
v4:
- s/XA_FLAGS_ALLOC1/XA_FLAGS_ALLOC/
v3:
- Allocate in the [0:MAX_HEAPS_PER_POOL-1] range
v2:
- New patch
Fixes: 9cca48fa4f ("drm/panthor: Add the heap logical block")
Reported-by: Eric Smith <eric.smith@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Tested-by: Eric Smith <eric.smith@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502165158.1458959-5-boris.brezillon@collabora.com
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.
v4:
- Actually fix the range in the kerneldoc
v3:
- Add R-bs
- Fix valid range in the kerneldoc
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: 9cca48fa4f ("drm/panthor: Add the heap logical block")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502165158.1458959-4-boris.brezillon@collabora.com
It doesn't make sense to have a maximum number of chunks smaller than
the initial number of chunks attached to the context.
Fix the uAPI header to reflect the new constraint, and mention the
undocumented "initial_chunk_count > 0" constraint while at it.
v3:
- Add R-b
v2:
- Fix the check
Fixes: 9cca48fa4f ("drm/panthor: Add the heap logical block")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502165158.1458959-3-boris.brezillon@collabora.com
If the kernel couldn't allocate memory because we reached the maximum
number of chunks but no render passes are in flight
(panthor_heap_grow() returning -ENOMEM), we should defer the OOM
handling to the FW by returning a NULL chunk. The FW will then call
the tiler OOM exception handler, which is supposed to implement
incremental rendering (execute an intermediate fragment job to flush
the pending primitives, release the tiler memory that was used to
store those primitives, and start over from where it stopped).
Instead of checking for both ENOMEM and EBUSY, make panthor_heap_grow()
return ENOMEM no matter the reason of this allocation failure, the FW
doesn't care anyway.
v3:
- Add R-bs
v2:
- Make panthor_heap_grow() return -ENOMEM for all kind of allocation
failures
- Document the panthor_heap_grow() semantics
Fixes: de85488138 ("drm/panthor: Add the scheduler logical block")
Signed-off-by: Antonino Maniscalco <antonino.maniscalco@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502165158.1458959-2-boris.brezillon@collabora.com
Tiler heap growing requires some kernel driver involvement: when the
tiler runs out of heap memory, it will raise an exception which is
either directly handled by the firmware if some free heap chunks are
available in the heap context, or passed back to the kernel otherwise.
The heap helpers will be used by the scheduler logic to allocate more
heap chunks to a heap context, when such a situation happens.
Heap context creation is explicitly requested by userspace (using
the TILER_HEAP_CREATE ioctl), and the returned context is attached to a
queue through some command stream instruction.
All the kernel does is keep the list of heap chunks allocated to a
context, so they can be freed when TILER_HEAP_DESTROY is called, or
extended when the FW requests a new chunk.
v6:
- Add Maxime's and Heiko's acks
v5:
- Fix FIXME comment
- Add Steve's R-b
v4:
- Rework locking to allow concurrent calls to panthor_heap_grow()
- Add a helper to return a heap chunk if we couldn't pass it to the
FW because the group was scheduled out
v3:
- Add a FIXME for the heap OOM deadlock
- Use the panthor_kernel_bo abstraction for the heap context and heap
chunks
- Drop the panthor_heap_gpu_ctx struct as it is opaque to the driver
- Ensure that the heap context is aligned to the GPU cache line size
- Minor code tidy ups
Co-developed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240229162230.2634044-10-boris.brezillon@collabora.com
