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d4cd665c98
Maintain two separate RB trees per order - one for clear (zeroed) blocks
and another for dirty (uncleared) blocks. This separation improves
code clarity and makes it more obvious which tree is being searched
during allocation. It also improves scalability and efficiency when
searching for a specific type of block, avoiding unnecessary checks
and making the allocator more predictable under fragmentation.
The changes have been validated using the existing drm_buddy_test
KUnit test cases, along with selected graphics workloads,
to ensure correctness and avoid regressions.
v2: Missed adding the suggested-by tag. Added it in v2.
v3(Matthew):
- Remove the double underscores from the internal functions.
- Rename the internal functions to have less generic names.
- Fix the error handling code.
- Pass tree argument for the tree macro.
- Use the existing dirty/free bit instead of new tree field.
- Make free_trees[] instead of clear_tree and dirty_tree for
more cleaner approach.
v4:
- A bug was reported by Intel CI and it is fixed by
Matthew Auld.
- Replace the get_root function with
&mm->free_trees[tree][order] (Matthew)
- Remove the unnecessary rbtree_is_empty() check (Matthew)
- Remove the unnecessary get_tree_for_flags() function.
- Rename get_tree_for_block() name with get_block_tree() for more
clarity.
v5(Jani Nikula):
- Don't use static inline in .c files.
- enum free_tree and enumerator names are quite generic for a header
and usage and the whole enum should be an implementation detail.
v6:
- Rewrite the __force_merge() function using the rb_last() and rb_prev().
v7(Matthew):
- Replace the open-coded tree iteration for loops with the
for_each_free_tree() macro throughout the code.
- Fixed out_free_roots to prevent double decrement of i,
addressing potential crash.
- Replaced enum drm_buddy_free_tree with unsigned int
in for_each_free_tree loops.
Cc: stable@vger.kernel.org
Fixes: a68c7eaa7a ("drm/amdgpu: Enable clear page functionality")
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4260
Link: https://lore.kernel.org/r/20251006095124.1663-2-Arunpravin.PaneerSelvam@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.