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f18719ef4b
This commit refactors the AMDGPU userqueue management subsystem to replace
IDR (ID Allocation) with XArray for improved performance, scalability, and
maintainability. The changes address several issues with the previous IDR
implementation and provide better locking semantics.
Key changes:
1. **Global XArray Introduction**:
- Added `userq_doorbell_xa` to `struct amdgpu_device` for global queue tracking
- Uses doorbell_index as key for efficient global lookup
- Replaces the previous `userq_mgr_list` linked list approach
2. **Per-process XArray Conversion**:
- Replaced `userq_idr` with `userq_mgr_xa` in `struct amdgpu_userq_mgr`
- Maintains per-process queue tracking with queue_id as key
- Uses XA_FLAGS_ALLOC for automatic ID allocation
3. **Locking Improvements**:
- Removed global `userq_mutex` from `struct amdgpu_device`
- Replaced with fine-grained XArray locking using XArray's internal spinlocks
4. **Runtime Idle Check Optimization**:
- Updated `amdgpu_runtime_idle_check_userq()` to use xa_empty
5. **Queue Management Functions**:
- Converted all IDR operations to equivalent XArray functions:
- `idr_alloc()` → `xa_alloc()`
- `idr_find()` → `xa_load()`
- `idr_remove()` → `xa_erase()`
- `idr_for_each()` → `xa_for_each()`
Benefits:
- **Performance**: XArray provides better scalability for large numbers of queues
- **Memory Efficiency**: Reduced memory overhead compared to IDR
- **Thread Safety**: Improved locking semantics with XArray's internal spinlocks
v2: rename userq_global_xa/userq_xa to userq_doorbell_xa/userq_mgr_xa
Remove xa_lock and use its own lock.
v3: Set queue->userq_mgr = uq_mgr in amdgpu_userq_create()
v4: use xa_store_irq (Christian)
hold the read side of the reset lock while creating/destroying queues and the manager data structure. (Chritian)
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.