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path: root/include/drm/drm_buddy.h
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2023-09-11drm/buddy: Improve contiguous memory allocationArunpravin Paneer Selvam
Problem statement: The current method roundup_power_of_two() to allocate contiguous address triggers -ENOSPC in some cases even though we have enough free spaces and so to help with that we introduce a try harder mechanism. In case of -ENOSPC, the new try harder mechanism rounddown the original size to power of 2 and iterating over the round down sized freelist blocks to allocate the required size traversing RHS and LHS. As part of the above new method implementation we moved contiguous/alignment size computation part and trim function to the drm buddy file. v2: Modify the alloc_range() function to return total allocated size on -ENOSPC err and traverse RHS/LHS to allocate the required size (Matthew). Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230909160902.15644-1-Arunpravin.PaneerSelvam@amd.com Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Christian König <christian.koenig@amd.com>
2022-02-23drm/selftests: add drm buddy alloc range testcaseArunpravin
- add a test to check the range allocation - export get_buddy() function in drm_buddy.c - export drm_prandom_u32_max_state() in lib/drm_random.c - include helper functions - include prime number header file v2: - add drm_get_buddy() function description (Matthew Auld) - removed unnecessary test succeeded print Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Acked-by: Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220222174845.2175-3-Arunpravin.PaneerSelvam@amd.com Signed-off-by: Christian König <christian.koenig@amd.com>
2022-02-22drm: implement a method to free unused pagesArunpravin
On contiguous allocation, we round up the size to the *next* power of 2, implement a function to free the unused pages after the newly allocate block. v2(Matthew Auld): - replace function name 'drm_buddy_free_unused_pages' with drm_buddy_block_trim - replace input argument name 'actual_size' with 'new_size' - add more validation checks for input arguments - add overlaps check to avoid needless searching and splitting - merged the below patch to see the feature in action - add free unused pages support to i915 driver - lock drm_buddy_block_trim() function as it calls mark_free/mark_split are all globally visible v3(Matthew Auld): - remove trim method error handling as we address the failure case at drm_buddy_block_trim() function v4: - in case of trim, at __alloc_range() split_block failure path marks the block as free and removes it from the original list, potentially also freeing it, to overcome this problem, we turn the drm_buddy_block_trim() input node into a temporary node to prevent recursively freeing itself, but still retain the un-splitting/freeing of the other nodes(Matthew Auld) - modify the drm_buddy_block_trim() function return type v5(Matthew Auld): - revert drm_buddy_block_trim() function return type changes in v4 - modify drm_buddy_block_trim() passing argument n_pages to original_size as n_pages has already been rounded up to the next power-of-two and passing n_pages results noop v6: - fix warnings reported by kernel test robot <lkp@intel.com> v7: - modify drm_buddy_block_trim() function doc description - at drm_buddy_block_trim() handle non-allocated block as a serious programmer error - fix a typo Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220221164552.2434-3-Arunpravin.PaneerSelvam@amd.com Signed-off-by: Christian König <christian.koenig@amd.com>
2022-02-22drm: implement top-down allocation methodArunpravin
Implemented a function which walk through the order list, compares the offset and returns the maximum offset block, this method is unpredictable in obtaining the high range address blocks which depends on allocation and deallocation. for instance, if driver requests address at a low specific range, allocator traverses from the root block and splits the larger blocks until it reaches the specific block and in the process of splitting, lower orders in the freelist are occupied with low range address blocks and for the subsequent TOPDOWN memory request we may return the low range blocks.To overcome this issue, we may go with the below approach. The other approach, sorting each order list entries in ascending order and compares the last entry of each order list in the freelist and return the max block. This creates sorting overhead on every drm_buddy_free() request and split up of larger blocks for a single page request. v2: - Fix alignment issues(Matthew Auld) - Remove unnecessary list_empty check(Matthew Auld) - merged the below patch to see the feature in action - add top-down alloc support to i915 driver Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220221164552.2434-2-Arunpravin.PaneerSelvam@amd.com Signed-off-by: Christian König <christian.koenig@amd.com>
2022-02-22drm: improve drm_buddy_alloc functionArunpravin
- Make drm_buddy_alloc a single function to handle range allocation and non-range allocation demands - Implemented a new function alloc_range() which allocates the requested power-of-two block comply with range limitations - Moved order computation and memory alignment logic from i915 driver to drm buddy v2: merged below changes to keep the build unbroken - drm_buddy_alloc_range() becomes obsolete and may be removed - enable ttm range allocation (fpfn / lpfn) support in i915 driver - apply enhanced drm_buddy_alloc() function to i915 driver v3(Matthew Auld): - Fix alignment issues and remove unnecessary list_empty check - add more validation checks for input arguments - make alloc_range() block allocations as bottom-up - optimize order computation logic - replace uint64_t with u64, which is preferred in the kernel v4(Matthew Auld): - keep drm_buddy_alloc_range() function implementation for generic actual range allocations - keep alloc_range() implementation for end bias allocations v5(Matthew Auld): - modify drm_buddy_alloc() passing argument place->lpfn to lpfn as place->lpfn will currently always be zero for i915 v6(Matthew Auld): - fixup potential uaf - If we are unlucky and can't allocate enough memory when splitting blocks, where we temporarily end up with the given block and its buddy on the respective free list, then we need to ensure we delete both blocks, and no just the buddy, before potentially freeing them - fix warnings reported by kernel test robot <lkp@intel.com> v7(Matthew Auld): - revert fixup potential uaf - keep __alloc_range() add node to the list logic same as drm_buddy_alloc_blocks() by having a temporary list variable - at drm_buddy_alloc_blocks() keep i915 range_overflows macro and add a new check for end variable v8: - fix warnings reported by kernel test robot <lkp@intel.com> v9(Matthew Auld): - remove DRM_BUDDY_RANGE_ALLOCATION flag - remove unnecessary function description v10: - keep DRM_BUDDY_RANGE_ALLOCATION flag as removing the flag and replacing with (end < size) logic fails amdgpu driver load Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220221164552.2434-1-Arunpravin.PaneerSelvam@amd.com
2022-01-19drm: move the buddy allocator from i915 into common drmArunpravin
Move the base i915 buddy allocator code into drm - Move i915_buddy.h to include/drm - Move i915_buddy.c to drm root folder - Rename "i915" string with "drm" string wherever applicable - Rename "I915" string with "DRM" string wherever applicable - Fix header file dependencies - Fix alignment issues - add Makefile support for drm buddy - export functions and write kerneldoc description - Remove i915 selftest config check condition as buddy selftest will be moved to drm selftest folder cleanup i915 buddy references in i915 driver module and replace with drm buddy v2: - include header file in alphabetical order(Thomas) - merged changes listed in the body section into a single patch to keep the build intact(Christian, Jani) v3: - make drm buddy a separate module(Thomas, Christian) v4: - Fix build error reported by kernel test robot <lkp@intel.com> - removed i915 buddy selftest from i915_mock_selftests.h to avoid build error - removed selftests/i915_buddy.c file as we create a new set of buddy test cases in drm/selftests folder v5: - Fix merge conflict issue v6: - replace drm_buddy_mm structure name as drm_buddy(Thomas, Christian) - replace drm_buddy_alloc() function name as drm_buddy_alloc_blocks() (Thomas) - replace drm_buddy_free() function name as drm_buddy_free_block() (Thomas) - export drm_buddy_free_block() function - fix multiple instances of KMEM_CACHE() entry v7: - fix warnings reported by kernel test robot <lkp@intel.com> - modify the license(Christian) v8: - fix warnings reported by kernel test robot <lkp@intel.com> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com> Acked-by: Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220118104504.2349-1-Arunpravin.PaneerSelvam@amd.com Signed-off-by: Christian König <christian.koenig@amd.com>