kernel/linux.git/include/linux/min_heap.h, branch v6.19.11

lib min_heap: use size_t for array size and index variables

2025-03-17T06:24:14+00:00

Replace the int type with size_t for variables representing array sizes and indices in the min-heap implementation. Using size_t aligns with standard practices for size-related variables and avoids potential issues on platforms where int may be insufficient to represent all valid sizes or indices. Link: https://lkml.kernel.org/r/20250215165618.1757219-1-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Cc: Ching-Chun (Jim) Huang Cc: Yu-Chun Lin Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-01-27T01:50:53+00:00

Pull non-MM updates from Andrew Morton: "Mainly individually changelogged singleton patches. The patch series in this pull are: - "lib min_heap: Improve min_heap safety, testing, and documentation" from Kuan-Wei Chiu provides various tightenings to the min_heap library code - "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms some cleanup and Rust preparation in the xarray library code - "Update reference to include/asm-" from Geert Uytterhoeven fixes pathnames in some code comments - "Converge on using secs_to_jiffies()" from Easwar Hariharan uses the new secs_to_jiffies() in various places where that is appropriate - "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen switches two filesystems to the new mount API - "Convert ocfs2 to use folios" from Matthew Wilcox does that - "Remove get_task_comm() and print task comm directly" from Yafang Shao removes now-unneeded calls to get_task_comm() in various places - "squashfs: reduce memory usage and update docs" from Phillip Lougher implements some memory savings in squashfs and performs some maintainability work - "lib: clarify comparison function requirements" from Kuan-Wei Chiu tightens the sort code's behaviour and adds some maintenance work - "nilfs2: protect busy buffer heads from being force-cleared" from Ryusuke Konishi fixes an issues in nlifs when the fs is presented with a corrupted image - "nilfs2: fix kernel-doc comments for function return values" from Ryusuke Konishi fixes some nilfs kerneldoc - "nilfs2: fix issues with rename operations" from Ryusuke Konishi addresses some nilfs BUG_ONs which syzbot was able to trigger - "minmax.h: Cleanups and minor optimisations" from David Laight does some maintenance work on the min/max library code - "Fixes and cleanups to xarray" from Kemeng Shi does maintenance work on the xarray library code" * tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (131 commits) ocfs2: use str_yes_no() and str_no_yes() helper functions include/linux/lz4.h: add some missing macros Xarray: use xa_mark_t in xas_squash_marks() to keep code consistent Xarray: remove repeat check in xas_squash_marks() Xarray: distinguish large entries correctly in xas_split_alloc() Xarray: move forward index correctly in xas_pause() Xarray: do not return sibling entries from xas_find_marked() ipc/util.c: complete the kernel-doc function descriptions gcov: clang: use correct function param names latencytop: use correct kernel-doc format for func params minmax.h: remove some #defines that are only expanded once minmax.h: simplify the variants of clamp() minmax.h: move all the clamp() definitions after the min/max() ones minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp() minmax.h: reduce the #define expansion of min(), max() and clamp() minmax.h: update some comments minmax.h: add whitespace around operators and after commas nilfs2: do not update mtime of renamed directory that is not moved nilfs2: handle errors that nilfs_prepare_chunk() may return CREDITS: fix spelling mistake ...

lib min_heap: add brief introduction to Min Heap API

2025-01-13T04:20:57+00:00

A short description of the Min Heap API is added to the min_heap.h, explaining its purpose for managing min-heaps and emphasizing the use of macro wrappers instead of direct function calls. For more details, users are directed to the documentation at Documentation/core-api/min_heap.rst. Link: https://lkml.kernel.org/r/20241129181222.646855-4-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Cc: Ching-Chun (Jim) Huang Cc: Geert Uytterhoeven Cc: Jonathan Corbet Signed-off-by: Andrew Morton

lib min_heap: improve type safety in min_heap macros by using container_of

2025-01-13T04:20:57+00:00

Patch series "lib min_heap: Improve min_heap safety, testing, and documentation". Improve the min heap implementation by enhancing type safety with container_of, reducing the attack vector by replacing test function calls with inline variants, and adding a brief API introduction in min_heap.h. It also includes author information in Documentation/core-api/min_heap.rst. This patch (of 4): The current implementation of min_heap macros uses explicit casting to min_heap_char *, which prevents the compiler from detecting incorrect pointer types. This can lead to errors if non-min_heap pointers are passed inadvertently. To enhance safety, replace all explicit casts to min_heap_char * with the use of container_of(&(_heap)->nr, min_heap_char, nr). This approach ensures that the _heap parameter is indeed a min_heap_char-compatible structure, allowing the compiler to catch improper usages. Link: https://lkml.kernel.org/r/20241129181222.646855-1-visitorckw@gmail.com Link: https://lore.kernel.org/lkml/CAMuHMdVO5DPuD9HYWBFqKDHphx7+0BEhreUxtVC40A=8p6VAhQ@mail.gmail.com Link: https://lkml.kernel.org/r/20241129181222.646855-2-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Suggested-by: Geert Uytterhoeven Cc: Ching-Chun (Jim) Huang Cc: Jonathan Corbet Signed-off-by: Andrew Morton

lib min_heap: Switch to size_t

2024-12-21T06:36:22+00:00

size_t is the correct type for a count of objects that can fit in memory: this also means heaps now have the same memory layout as darrays (fs/bcachefs/darray.h), and darrays can be used as heaps. Cc: Kuan-Wei Chiu Cc: Ian Rogers Cc: Andrew Morton Cc: Coly Li Cc: Peter Zijlstra Signed-off-by: Kent Overstreet

lib min_heap: avoid indirect function call by providing default swap

2024-11-06T01:12:35+00:00

The non-inline min heap API can result in an indirect function call to the custom swap function. This becomes particularly costly when CONFIG_MITIGATION_RETPOLINE is enabled, as indirect function calls are expensive in this case. To address this, copy the code from lib/sort.c and provide a default builtin swap implementation that performs element swaps based on the element size. This change allows most users to avoid the overhead of indirect function calls, improving efficiency. Link: https://lkml.kernel.org/r/20241020040200.939973-4-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Cc: Adrian Hunter Cc: Arnaldo Carvalho de Melo Cc: Ching-Chun (Jim) Huang Cc: Coly Li Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Jonathan Corbet Cc: Kent Overstreet Cc: "Liang, Kan" Cc: Mark Rutland Cc: Matthew Sakai Cc: Matthew Wilcox (Oracle) Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Andrew Morton

lib min_heap: optimize min heap by prescaling counters for better performance

2024-11-06T01:12:35+00:00

Improve the efficiency of the min heap by prescaling counters, eliminating the need to repeatedly compute 'index * element_size' when accessing elements. By doing so, we avoid the overhead associated with recalculating the byte offset for each heap operation. However, with prescaling, the calculation for the parent element's location is no longer as simple as '(i - 1) / 2'. To address this, we copy the parent function from 'lib/sort.c', which calculates the parent offset in a branchless manner without using any division instructions. This optimization should result in a more efficient heap implementation by reducing the computational overhead of finding parent and child offsets. Link: https://lkml.kernel.org/r/20241020040200.939973-3-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Cc: Adrian Hunter Cc: Arnaldo Carvalho de Melo Cc: Ching-Chun (Jim) Huang Cc: Coly Li Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Jonathan Corbet Cc: Kent Overstreet Cc: "Liang, Kan" Cc: Mark Rutland Cc: Matthew Sakai Cc: Matthew Wilcox (Oracle) Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Andrew Morton

lib/min_heap: introduce non-inline versions of min heap API functions

2024-11-06T01:12:34+00:00

Patch series "Enhance min heap API with non-inline functions and optimizations", v2. Add non-inline versions of the min heap API functions in lib/min_heap.c and updates all users outside of kernel/events/core.c to use these non-inline versions. To mitigate the performance impact of indirect function calls caused by the non-inline versions of the swap and compare functions, a builtin swap has been introduced that swaps elements based on their size. Additionally, it micro-optimizes the efficiency of the min heap by pre-scaling the counter, following the same approach as in lib/sort.c. Documentation for the min heap API has also been added to the core-api section. This patch (of 10): All current min heap API functions are marked with '__always_inline'. However, as the number of users increases, inlining these functions everywhere leads to a increase in kernel size. In performance-critical paths, such as when perf events are enabled and min heap functions are called on every context switch, it is important to retain the inline versions for optimal performance. To balance this, the original inline functions are kept, and additional non-inline versions of the functions have been added in lib/min_heap.c. Link: https://lkml.kernel.org/r/20241020040200.939973-1-visitorckw@gmail.com Link: https://lore.kernel.org/20240522161048.8d8bbc7b153b4ecd92c50666@linux-foundation.org Link: https://lkml.kernel.org/r/20241020040200.939973-2-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Suggested-by: Andrew Morton Cc: Adrian Hunter Cc: Arnaldo Carvalho de Melo Cc: Ching-Chun (Jim) Huang Cc: Coly Li Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Jonathan Corbet Cc: Kent Overstreet Cc: Kuan-Wei Chiu Cc: "Liang, Kan" Cc: Mark Rutland Cc: Matthew Sakai Cc: Matthew Wilcox (Oracle) Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Andrew Morton

lib min_heap: update min_heap_push() to use min_heap_sift_up()

2024-06-25T05:24:59+00:00

Update min_heap_push() to use min_heap_sift_up() rather than its origin inline version. Link: https://lkml.kernel.org/r/20240524152958.919343-14-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Reviewed-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Bagas Sanjaya Cc: Brian Foster Cc: Ching-Chun (Jim) Huang Cc: Coly Li Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kent Overstreet Cc: Mark Rutland Cc: Matthew Sakai Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Randy Dunlap Signed-off-by: Andrew Morton

lib min_heap: rename min_heapify() to min_heap_sift_down()

2024-06-25T05:24:59+00:00

After adding min_heap_sift_up(), the naming convention has been adjusted to maintain consistency with the min_heap_sift_up(). Consequently, min_heapify() has been renamed to min_heap_sift_down(). Link: https://lkml.kernel.org/CAP-5=fVcBAxt8Mw72=NCJPRJfjDaJcqk4rjbadgouAEAHz_q1A@mail.gmail.com Link: https://lkml.kernel.org/r/20240524152958.919343-13-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Reviewed-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Bagas Sanjaya Cc: Brian Foster Cc: Ching-Chun (Jim) Huang Cc: Coly Li Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kent Overstreet Cc: Mark Rutland Cc: Matthew Sakai Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Randy Dunlap Signed-off-by: Andrew Morton