lib min_heap: use size_t for array size and index variables

Replace the int type with size_t for variables representing array sizes
and indices in the min-heap implementation. Using size_t aligns w

lib min_heap: use size_t for array size and index variables

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/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Yu-Chun Lin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add brief introduction to Min Heap API

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
macr

lib min_heap: add brief introduction to Min Heap API

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/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

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

Patch series "lib min_heap: Improve min_heap safety, testing, and
documentation".

Improve the min heap implementation by e

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

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/[email protected]
Link: https://lore.kernel.org/lkml/CAMuHMdVO5DPuD9HYWBFqKDHphx7+0BEhreUxtVC40A=8p6VAhQ@mail.gmail.com
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Suggested-by: Geert Uytterhoeven <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: Switch to size_t

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

lib min_heap: Switch to size_t

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 <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Kent Overstreet <[email protected]>

show more ...

lib min_heap: avoid indirect function call by providing default swap

The non-inline min heap API can result in an indirect function call to the
custom swap function. This becomes particularly costl

lib min_heap: avoid indirect function call by providing default swap

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/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: "Liang, Kan" <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

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

Improve the efficiency of the min heap by prescaling counters, eliminating
the need to repeatedly compute 'index * eleme

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

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/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: "Liang, Kan" <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

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

Patch series "Enhance min heap API with non-inline functions and
optimizations", v2.

Add non-inline versions of the min heap AP

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

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/[email protected]
Link: https://lore.kernel.org/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Suggested-by: Andrew Morton <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Kuan-Wei Chiu <[email protected]>
Cc: "Liang, Kan" <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

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

Update min_heap_push() to use min_heap_sift_up() rather than its origin
inline version.

Link: https://lkml.kernel.org/r/20240524152958

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

Update min_heap_push() to use min_heap_sift_up() rather than its origin
inline version.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: rename min_heapify() to min_heap_sift_down()

After adding min_heap_sift_up(), the naming convention has been adjusted
to maintain consistency with the min_heap_sift_up(). Consequently

lib min_heap: rename min_heapify() to min_heap_sift_down()

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/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: update min_heap_push() and min_heap_pop() to return bool values

Modify the min_heap_push() and min_heap_pop() to return a boolean value.
They now return false when the operation fails

lib min_heap: update min_heap_push() and min_heap_pop() to return bool values

Modify the min_heap_push() and min_heap_pop() to return a boolean value.
They now return false when the operation fails and true when it succeeds.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add min_heap_del()

Add min_heap_del() to delete the element at index 'idx' in the heap.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ku

lib min_heap: add min_heap_del()

Add min_heap_del() to delete the element at index 'idx' in the heap.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add min_heap_sift_up()

Add min_heap_sift_up() to sift up the element at index 'idx' in the
heap.

Link: https://lkml.kernel.org/r/[email protected]
Signed-o

lib min_heap: add min_heap_sift_up()

Add min_heap_sift_up() to sift up the element at index 'idx' in the
heap.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add args for min_heap_callbacks

Add a third parameter 'args' for the 'less' and 'swp' functions in the
'struct min_heap_callbacks'. This additional parameter allows these
comparison a

lib min_heap: add args for min_heap_callbacks

Add a third parameter 'args' for the 'less' and 'swp' functions in the
'struct min_heap_callbacks'. This additional parameter allows these
comparison and swap functions to handle extra arguments when necessary.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add min_heap_full()

Add min_heap_full() which returns a boolean value indicating whether the
heap has reached its maximum capacity.

Link: https://lkml.kernel.org/r/20240524152958.9193

lib min_heap: add min_heap_full()

Add min_heap_full() which returns a boolean value indicating whether the
heap has reached its maximum capacity.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add min_heap_peek()

Add min_heap_peek() to retrieve a pointer to the smallest element. The
pointer is cast to the appropriate type of heap elements.

Link: https://lkml.kernel.org/r/2

lib min_heap: add min_heap_peek()

Add min_heap_peek() to retrieve a pointer to the smallest element. The
pointer is cast to the appropriate type of heap elements.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add min_heap_init()

Add min_heap_init() for initializing heap with data, nr, and size.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan

lib min_heap: add min_heap_init()

Add min_heap_init() for initializing heap with data, nr, and size.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: add type safe interface

Implement a type-safe interface for min_heap using strong type pointers
instead of void * in the data field. This change includes adding small
macro wrappers a

lib min_heap: add type safe interface

Implement a type-safe interface for min_heap using strong type pointers
instead of void * in the data field. This change includes adding small
macro wrappers around functions, enabling the use of __minheap_cast and
__minheap_obj_size macros for type casting and obtaining element size.
This implementation removes the necessity of passing element size in
min_heap_callbacks. Additionally, introduce the MIN_HEAP_PREALLOCATED
macro for preallocating some elements.

Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Brian Foster <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: optimize number of comparisons in min_heapify()

Optimize the min_heapify() function, resulting in a significant reduction
of approximately 50% in the number of comparisons for large ra

lib min_heap: optimize number of comparisons in min_heapify()

Optimize the min_heapify() function, resulting in a significant reduction
of approximately 50% in the number of comparisons for large random inputs,
while maintaining identical results.

The current implementation performs two comparisons per level to identify
the minimum among three elements. In contrast, the proposed bottom-up
variation uses only one comparison per level to assess two children until
reaching the leaves. Then, it sifts up until the correct position is
determined.

Typically, the process of sifting down proceeds to the leaf level,
resulting in O(1) secondary comparisons instead of log2(n). This
optimization significantly reduces the number of costly indirect function
calls and improves overall performance.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib min_heap: optimize number of calls to min_heapify()

Patch series "lib min_heap: Min heap optimizations".

The purpose of this patch series is to enhance the existing min heap
implementation. Th

lib min_heap: optimize number of calls to min_heapify()

Patch series "lib min_heap: Min heap optimizations".

The purpose of this patch series is to enhance the existing min heap
implementation. The optimization focuses on both the heap construction
process and the number of comparisons made during the heapify operation.


This patch (of 2):

Improve the heap construction process by reducing unnecessary heapify
operations. Specifically, adjust the starting condition from n / 2 to n /
2 - 1 in the loop that iterates over all non-leaf elements.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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lib: Introduce generic min-heap

Supports push, pop and converting an array into a heap. If the sense of
the compare function is inverted then it can provide a max-heap.

Based-on-work-by: Peter Zijl

lib: Introduce generic min-heap

Supports push, pop and converting an array into a heap. If the sense of
the compare function is inverted then it can provide a max-heap.

Based-on-work-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ian Rogers <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

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