[PATCH v4 00/16] treewide: Refactor heap related implementation

[PATCH v4 00/16] treewide: Refactor heap related implementation

[Kuan-Wei Chiu]

This patch series focuses on several adjustments related to heap
implementation. Firstly, a type-safe interface has been added to the
min_heap, along with the introduction of several new functions to
enhance its functionality. Additionally, the heap implementation for
bcache and bcachefs has been replaced with the generic min_heap
implementation from include/linux. Furthermore, several typos have been
corrected.

Previous discussion with Kent Overstreet:
https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu

Regards,
Kuan-Wei

---

You can preview this patch series on the 'refactor-heap-v4' branch of
the repository at the following link:

https://github.com/visitorckw/linux.git

Changes in v4:
- Change struct initializations to use designated initializers.
- Replace memcpy() with func->swp() in heap_del() due to issues with
  set_backpointer in bcachefs when setting idx.
- Fix an error in ec_stripes_heap_swap() where
  ec_stripes_heap_set_backpointer() should be called after swapping.

Changes in v3:
- Avoid heap->heap.nr to eliminate the nested types.
- Add MIN_HEAP_PREALLOCATED macro for preallocating some elements.
- Use min_heap_sift_up() in min_heap_push().
- Fix a bug in heap_del() where we should copy the last element to
  'data + idx * element_size' instead of 'data'.
- Add testcases for heap_del().
- Fix bugs in bcache/bcachefs patches where the parameter types in
  some compare functions should have been 'type **', but were
  mistakenly written as 'type *'.

Changes in v2:
- Add attribute __always_unused to the compare and swap functions
  that do not use the args parameter.
- Rename min_heapify() to min_heap_sift_down().
- Update lib/test_min_heap.c to use min_heap_init().
- Refine the commit message for bcache and bcachefs.
- Adjust the order of patches in the patch series.

Link to v3: https://lore.kernel.org/20240406164727.577914-1-visitorckw@gmail.com
Link to v2: https://lore.kernel.org/20240320145417.336208-1-visitorckw@gmail.com
Link to v1: https://lkml.kernel.org/20240319180005.246930-1-visitorckw@gmail.com

Kuan-Wei Chiu (16):
  perf/core: Fix several typos
  bcache: Fix typo
  bcachefs: Fix typo
  lib min_heap: Add type safe interface
  lib min_heap: Add min_heap_init()
  lib min_heap: Add min_heap_peek()
  lib min_heap: Add min_heap_full()
  lib min_heap: Add args for min_heap_callbacks
  lib min_heap: Add min_heap_sift_up()
  lib min_heap: Add min_heap_del()
  lib min_heap: Update min_heap_push() and min_heap_pop() to return bool
    values
  lib min_heap: Rename min_heapify() to min_heap_sift_down()
  lib min_heap: Update min_heap_push() to use min_heap_sift_up()
  lib/test_min_heap: Add test for heap_del()
  bcache: Remove heap-related macros and switch to generic min_heap
  bcachefs: Remove heap-related macros and switch to generic min_heap

 drivers/md/bcache/alloc.c      |  64 ++++++++---
 drivers/md/bcache/bcache.h     |   2 +-
 drivers/md/bcache/bset.c       |  84 ++++++++++-----
 drivers/md/bcache/bset.h       |  14 +--
 drivers/md/bcache/btree.c      |  17 ++-
 drivers/md/bcache/extents.c    |  53 ++++++----
 drivers/md/bcache/movinggc.c   |  41 +++++--
 drivers/md/bcache/sysfs.c      |   2 +
 drivers/md/bcache/util.c       |   2 +-
 drivers/md/bcache/util.h       |  67 +-----------
 drivers/md/bcache/writeback.c  |   3 +
 drivers/md/dm-vdo/repair.c     |  19 ++--
 drivers/md/dm-vdo/slab-depot.c |  14 +--
 fs/bcachefs/clock.c            |  43 ++++++--
 fs/bcachefs/clock_types.h      |   2 +-
 fs/bcachefs/ec.c               |  76 ++++++++-----
 fs/bcachefs/ec_types.h         |   2 +-
 fs/bcachefs/util.c             |   2 +-
 fs/bcachefs/util.h             | 118 +--------------------
 include/linux/min_heap.h       | 188 +++++++++++++++++++++++++--------
 kernel/events/core.c           |  29 ++---
 lib/test_min_heap.c            |  75 +++++++++----
 22 files changed, 522 insertions(+), 395 deletions(-)

-- 
2.34.1

[PATCH v4 01/16] perf/core: Fix several typos

[Kuan-Wei Chiu]

Replace 'artifically' with 'artificially'.
Replace 'irrespecive' with 'irrespective'.
Replace 'futher' with 'further'.
Replace 'sufficent' with 'sufficient'.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
---
 kernel/events/core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 724e6d7e128f..10ac2db83f14 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -534,7 +534,7 @@ void perf_sample_event_took(u64 sample_len_ns)
 	__this_cpu_write(running_sample_length, running_len);
 
 	/*
-	 * Note: this will be biased artifically low until we have
+	 * Note: this will be biased artificially low until we have
 	 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
 	 * from having to maintain a count.
 	 */
@@ -596,10 +596,10 @@ static inline u64 perf_event_clock(struct perf_event *event)
  *
  * Event groups make things a little more complicated, but not terribly so. The
  * rules for a group are that if the group leader is OFF the entire group is
- * OFF, irrespecive of what the group member states are. This results in
+ * OFF, irrespective of what the group member states are. This results in
  * __perf_effective_state().
  *
- * A futher ramification is that when a group leader flips between OFF and
+ * A further ramification is that when a group leader flips between OFF and
  * !OFF, we need to update all group member times.
  *
  *
@@ -891,7 +891,7 @@ static int perf_cgroup_ensure_storage(struct perf_event *event,
 	int cpu, heap_size, ret = 0;
 
 	/*
-	 * Allow storage to have sufficent space for an iterator for each
+	 * Allow storage to have sufficient space for an iterator for each
 	 * possibly nested cgroup plus an iterator for events with no cgroup.
 	 */
 	for (heap_size = 1; css; css = css->parent)
-- 
2.34.1

[PATCH v4 02/16] bcache: Fix typo

[Kuan-Wei Chiu]

Replace 'utiility' with 'utility'.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
---
 drivers/md/bcache/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index ae380bc3992e..410d8cb49e50 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * random utiility code, for bcache but in theory not specific to bcache
+ * random utility code, for bcache but in theory not specific to bcache
  *
  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
  * Copyright 2012 Google, Inc.
-- 
2.34.1

[PATCH v4 03/16] bcachefs: Fix typo

[Kuan-Wei Chiu]

Replace 'utiility' with 'utility'.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
---
 fs/bcachefs/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index 92c6ad75e702..05ac1b3b0604 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * random utiility code, for bcache but in theory not specific to bcache
+ * random utility code, for bcache but in theory not specific to bcache
  *
  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
  * Copyright 2012 Google, Inc.
-- 
2.34.1

[PATCH v4 04/16] lib min_heap: Add type safe interface

[Kuan-Wei Chiu]

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
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
Changes in v4:
- Change struct initializations to use designated initializers.

 drivers/md/dm-vdo/repair.c     |  9 ++--
 drivers/md/dm-vdo/slab-depot.c |  5 +--
 include/linux/min_heap.h       | 79 ++++++++++++++++++++++------------
 kernel/events/core.c           | 11 ++---
 lib/test_min_heap.c            | 13 +++---
 5 files changed, 70 insertions(+), 47 deletions(-)

diff --git a/drivers/md/dm-vdo/repair.c b/drivers/md/dm-vdo/repair.c
index defc9359f10e..48c266fa07b6 100644
--- a/drivers/md/dm-vdo/repair.c
+++ b/drivers/md/dm-vdo/repair.c
@@ -51,6 +51,8 @@ struct recovery_point {
 	bool increment_applied;
 };
 
+MIN_HEAP(struct numbered_block_mapping, replay_heap);
+
 struct repair_completion {
 	/* The completion header */
 	struct vdo_completion completion;
@@ -97,7 +99,7 @@ struct repair_completion {
 	 * order, then original journal order. This permits efficient iteration over the journal
 	 * entries in order.
 	 */
-	struct min_heap replay_heap;
+	struct replay_heap replay_heap;
 	/* Fields tracking progress through the journal entries. */
 	struct numbered_block_mapping *current_entry;
 	struct numbered_block_mapping *current_unfetched_entry;
@@ -163,14 +165,13 @@ static void swap_mappings(void *item1, void *item2)
 }
 
 static const struct min_heap_callbacks repair_min_heap = {
-	.elem_size = sizeof(struct numbered_block_mapping),
 	.less = mapping_is_less_than,
 	.swp = swap_mappings,
 };
 
 static struct numbered_block_mapping *sort_next_heap_element(struct repair_completion *repair)
 {
-	struct min_heap *heap = &repair->replay_heap;
+	struct replay_heap *heap = &repair->replay_heap;
 	struct numbered_block_mapping *last;
 
 	if (heap->nr == 0)
@@ -1117,7 +1118,7 @@ static void recover_block_map(struct vdo_completion *completion)
 	 * Organize the journal entries into a binary heap so we can iterate over them in sorted
 	 * order incrementally, avoiding an expensive sort call.
 	 */
-	repair->replay_heap = (struct min_heap) {
+	repair->replay_heap = (struct replay_heap) {
 		.data = repair->entries,
 		.nr = repair->block_map_entry_count,
 		.size = repair->block_map_entry_count,
diff --git a/drivers/md/dm-vdo/slab-depot.c b/drivers/md/dm-vdo/slab-depot.c
index 46e4721e5b4f..f6ae6956f321 100644
--- a/drivers/md/dm-vdo/slab-depot.c
+++ b/drivers/md/dm-vdo/slab-depot.c
@@ -3309,7 +3309,6 @@ static void swap_slab_statuses(void *item1, void *item2)
 }
 
 static const struct min_heap_callbacks slab_status_min_heap = {
-	.elem_size = sizeof(struct slab_status),
 	.less = slab_status_is_less_than,
 	.swp = swap_slab_statuses,
 };
@@ -3509,7 +3508,7 @@ static int get_slab_statuses(struct block_allocator *allocator,
 static int __must_check vdo_prepare_slabs_for_allocation(struct block_allocator *allocator)
 {
 	struct slab_status current_slab_status;
-	struct min_heap heap;
+	MIN_HEAP(struct slab_status, heap) heap;
 	int result;
 	struct slab_status *slab_statuses;
 	struct slab_depot *depot = allocator->depot;
@@ -3521,7 +3520,7 @@ static int __must_check vdo_prepare_slabs_for_allocation(struct block_allocator
 		return result;
 
 	/* Sort the slabs by cleanliness, then by emptiness hint. */
-	heap = (struct min_heap) {
+	heap = (struct heap) {
 		.data = slab_statuses,
 		.nr = allocator->slab_count,
 		.size = allocator->slab_count,
diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index d52daf45861b..87737cadb9a5 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -7,45 +7,53 @@
 #include <linux/types.h>
 
 /**
- * struct min_heap - Data structure to hold a min-heap.
- * @data: Start of array holding the heap elements.
+ * Data structure to hold a min-heap.
  * @nr: Number of elements currently in the heap.
  * @size: Maximum number of elements that can be held in current storage.
+ * @data: Pointer to the start of array holding the heap elements.
+ * @preallocated: Start of the static preallocated array holding the heap elements.
  */
-struct min_heap {
-	void *data;
-	int nr;
-	int size;
-};
+#define MIN_HEAP_PREALLOCATED(_type, _name, _nr)	\
+struct _name {	\
+	int nr;	\
+	int size;	\
+	_type *data;	\
+	_type preallocated[_nr];	\
+}
+
+#define MIN_HEAP(_type, _name) MIN_HEAP_PREALLOCATED(_type, _name, 0)
+
+typedef MIN_HEAP(char, min_heap_char) min_heap_char;
+
+#define __minheap_cast(_heap)		(typeof((_heap)->data[0]) *)
+#define __minheap_obj_size(_heap)	sizeof((_heap)->data[0])
 
 /**
  * struct min_heap_callbacks - Data/functions to customise the min_heap.
- * @elem_size: The nr of each element in bytes.
  * @less: Partial order function for this heap.
  * @swp: Swap elements function.
  */
 struct min_heap_callbacks {
-	int elem_size;
 	bool (*less)(const void *lhs, const void *rhs);
 	void (*swp)(void *lhs, void *rhs);
 };
 
 /* Sift the element at pos down the heap. */
 static __always_inline
-void min_heapify(struct min_heap *heap, int pos,
+void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
 		const struct min_heap_callbacks *func)
 {
 	void *left, *right;
 	void *data = heap->data;
-	void *root = data + pos * func->elem_size;
+	void *root = data + pos * elem_size;
 	int i = pos, j;
 
 	/* Find the sift-down path all the way to the leaves. */
 	for (;;) {
 		if (i * 2 + 2 >= heap->nr)
 			break;
-		left = data + (i * 2 + 1) * func->elem_size;
-		right = data + (i * 2 + 2) * func->elem_size;
+		left = data + (i * 2 + 1) * elem_size;
+		right = data + (i * 2 + 2) * elem_size;
 		i = func->less(left, right) ? i * 2 + 1 : i * 2 + 2;
 	}
 
@@ -54,31 +62,37 @@ void min_heapify(struct min_heap *heap, int pos,
 		i = i * 2 + 1;
 
 	/* Backtrack to the correct location. */
-	while (i != pos && func->less(root, data + i * func->elem_size))
+	while (i != pos && func->less(root, data + i * elem_size))
 		i = (i - 1) / 2;
 
 	/* Shift the element into its correct place. */
 	j = i;
 	while (i != pos) {
 		i = (i - 1) / 2;
-		func->swp(data + i * func->elem_size, data + j * func->elem_size);
+		func->swp(data + i * elem_size, data + j * elem_size);
 	}
 }
 
+#define min_heapify(_heap, _pos, _func)	\
+	__min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func)
+
 /* Floyd's approach to heapification that is O(nr). */
 static __always_inline
-void min_heapify_all(struct min_heap *heap,
+void __min_heapify_all(min_heap_char *heap, size_t elem_size,
 		const struct min_heap_callbacks *func)
 {
 	int i;
 
 	for (i = heap->nr / 2 - 1; i >= 0; i--)
-		min_heapify(heap, i, func);
+		__min_heapify(heap, i, elem_size, func);
 }
 
+#define min_heapify_all(_heap, _func)	\
+	__min_heapify_all((min_heap_char *)_heap, __minheap_obj_size(_heap), _func)
+
 /* Remove minimum element from the heap, O(log2(nr)). */
 static __always_inline
-void min_heap_pop(struct min_heap *heap,
+void __min_heap_pop(min_heap_char *heap, size_t elem_size,
 		const struct min_heap_callbacks *func)
 {
 	void *data = heap->data;
@@ -88,27 +102,33 @@ void min_heap_pop(struct min_heap *heap,
 
 	/* Place last element at the root (position 0) and then sift down. */
 	heap->nr--;
-	memcpy(data, data + (heap->nr * func->elem_size), func->elem_size);
-	min_heapify(heap, 0, func);
+	memcpy(data, data + (heap->nr * elem_size), elem_size);
+	__min_heapify(heap, 0, elem_size, func);
 }
 
+#define min_heap_pop(_heap, _func)	\
+	__min_heap_pop((min_heap_char *)_heap, __minheap_obj_size(_heap), _func)
+
 /*
  * Remove the minimum element and then push the given element. The
  * implementation performs 1 sift (O(log2(nr))) and is therefore more
  * efficient than a pop followed by a push that does 2.
  */
 static __always_inline
-void min_heap_pop_push(struct min_heap *heap,
-		const void *element,
+void __min_heap_pop_push(min_heap_char *heap,
+		const void *element, size_t elem_size,
 		const struct min_heap_callbacks *func)
 {
-	memcpy(heap->data, element, func->elem_size);
-	min_heapify(heap, 0, func);
+	memcpy(heap->data, element, elem_size);
+	__min_heapify(heap, 0, elem_size, func);
 }
 
+#define min_heap_pop_push(_heap, _element, _func)	\
+	__min_heap_pop_push((min_heap_char *)_heap, _element, __minheap_obj_size(_heap), _func)
+
 /* Push an element on to the heap, O(log2(nr)). */
 static __always_inline
-void min_heap_push(struct min_heap *heap, const void *element,
+void __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 		const struct min_heap_callbacks *func)
 {
 	void *data = heap->data;
@@ -120,17 +140,20 @@ void min_heap_push(struct min_heap *heap, const void *element,
 
 	/* Place at the end of data. */
 	pos = heap->nr;
-	memcpy(data + (pos * func->elem_size), element, func->elem_size);
+	memcpy(data + (pos * elem_size), element, elem_size);
 	heap->nr++;
 
 	/* Sift child at pos up. */
 	for (; pos > 0; pos = (pos - 1) / 2) {
-		child = data + (pos * func->elem_size);
-		parent = data + ((pos - 1) / 2) * func->elem_size;
+		child = data + (pos * elem_size);
+		parent = data + ((pos - 1) / 2) * elem_size;
 		if (func->less(parent, child))
 			break;
 		func->swp(parent, child);
 	}
 }
 
+#define min_heap_push(_heap, _element, _func)	\
+	__min_heap_push((min_heap_char *)_heap, _element, __minheap_obj_size(_heap), _func)
+
 #endif /* _LINUX_MIN_HEAP_H */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 10ac2db83f14..55930479599b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3698,13 +3698,14 @@ static void swap_ptr(void *l, void *r)
 	swap(*lp, *rp);
 }
 
+MIN_HEAP(struct perf_event *, perf_event_min_heap);
+
 static const struct min_heap_callbacks perf_min_heap = {
-	.elem_size = sizeof(struct perf_event *),
 	.less = perf_less_group_idx,
 	.swp = swap_ptr,
 };
 
-static void __heap_add(struct min_heap *heap, struct perf_event *event)
+static void __heap_add(struct perf_event_min_heap *heap, struct perf_event *event)
 {
 	struct perf_event **itrs = heap->data;
 
@@ -3738,7 +3739,7 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx,
 	struct perf_cpu_context *cpuctx = NULL;
 	/* Space for per CPU and/or any CPU event iterators. */
 	struct perf_event *itrs[2];
-	struct min_heap event_heap;
+	struct perf_event_min_heap event_heap;
 	struct perf_event **evt;
 	int ret;
 
@@ -3747,7 +3748,7 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx,
 
 	if (!ctx->task) {
 		cpuctx = this_cpu_ptr(&perf_cpu_context);
-		event_heap = (struct min_heap){
+		event_heap = (struct perf_event_min_heap){
 			.data = cpuctx->heap,
 			.nr = 0,
 			.size = cpuctx->heap_size,
@@ -3760,7 +3761,7 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx,
 			css = &cpuctx->cgrp->css;
 #endif
 	} else {
-		event_heap = (struct min_heap){
+		event_heap = (struct perf_event_min_heap){
 			.data = itrs,
 			.nr = 0,
 			.size = ARRAY_SIZE(itrs),
diff --git a/lib/test_min_heap.c b/lib/test_min_heap.c
index 7b01b4387cfb..dd5c0fa862ab 100644
--- a/lib/test_min_heap.c
+++ b/lib/test_min_heap.c
@@ -11,6 +11,8 @@
 #include <linux/printk.h>
 #include <linux/random.h>
 
+MIN_HEAP(int, min_heap_test);
+
 static __init bool less_than(const void *lhs, const void *rhs)
 {
 	return *(int *)lhs < *(int *)rhs;
@@ -30,7 +32,7 @@ static __init void swap_ints(void *lhs, void *rhs)
 }
 
 static __init int pop_verify_heap(bool min_heap,
-				struct min_heap *heap,
+				struct min_heap_test *heap,
 				const struct min_heap_callbacks *funcs)
 {
 	int *values = heap->data;
@@ -63,13 +65,12 @@ static __init int test_heapify_all(bool min_heap)
 {
 	int values[] = { 3, 1, 2, 4, 0x8000000, 0x7FFFFFF, 0,
 			 -3, -1, -2, -4, 0x8000000, 0x7FFFFFF };
-	struct min_heap heap = {
+	struct min_heap_test heap = {
 		.data = values,
 		.nr = ARRAY_SIZE(values),
 		.size =  ARRAY_SIZE(values),
 	};
 	struct min_heap_callbacks funcs = {
-		.elem_size = sizeof(int),
 		.less = min_heap ? less_than : greater_than,
 		.swp = swap_ints,
 	};
@@ -96,13 +97,12 @@ static __init int test_heap_push(bool min_heap)
 	const int data[] = { 3, 1, 2, 4, 0x80000000, 0x7FFFFFFF, 0,
 			     -3, -1, -2, -4, 0x80000000, 0x7FFFFFFF };
 	int values[ARRAY_SIZE(data)];
-	struct min_heap heap = {
+	struct min_heap_test heap = {
 		.data = values,
 		.nr = 0,
 		.size =  ARRAY_SIZE(values),
 	};
 	struct min_heap_callbacks funcs = {
-		.elem_size = sizeof(int),
 		.less = min_heap ? less_than : greater_than,
 		.swp = swap_ints,
 	};
@@ -129,13 +129,12 @@ static __init int test_heap_pop_push(bool min_heap)
 	const int data[] = { 3, 1, 2, 4, 0x80000000, 0x7FFFFFFF, 0,
 			     -3, -1, -2, -4, 0x80000000, 0x7FFFFFFF };
 	int values[ARRAY_SIZE(data)];
-	struct min_heap heap = {
+	struct min_heap_test heap = {
 		.data = values,
 		.nr = 0,
 		.size =  ARRAY_SIZE(values),
 	};
 	struct min_heap_callbacks funcs = {
-		.elem_size = sizeof(int),
 		.less = min_heap ? less_than : greater_than,
 		.swp = swap_ints,
 	};
-- 
2.34.1

[PATCH v4 05/16] lib min_heap: Add min_heap_init()

[Kuan-Wei Chiu]

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

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 include/linux/min_heap.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index 87737cadb9a5..f6b07fb8b2d3 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -38,6 +38,21 @@ struct min_heap_callbacks {
 	void (*swp)(void *lhs, void *rhs);
 };
 
+/* Initialize a min-heap. */
+static __always_inline
+void __min_heap_init(min_heap_char *heap, void *data, int size)
+{
+	heap->nr = 0;
+	heap->size = size;
+	if (data)
+		heap->data = data;
+	else
+		heap->data = heap->preallocated;
+}
+
+#define min_heap_init(_heap, _data, _size)	\
+	__min_heap_init((min_heap_char *)_heap, _data, _size)
+
 /* Sift the element at pos down the heap. */
 static __always_inline
 void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
-- 
2.34.1

[PATCH v4 06/16] lib min_heap: Add min_heap_peek()

[Kuan-Wei Chiu]

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

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 include/linux/min_heap.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index f6b07fb8b2d3..043de539bf71 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -53,6 +53,16 @@ void __min_heap_init(min_heap_char *heap, void *data, int size)
 #define min_heap_init(_heap, _data, _size)	\
 	__min_heap_init((min_heap_char *)_heap, _data, _size)
 
+/* Get the minimum element from the heap. */
+static __always_inline
+void *__min_heap_peek(struct min_heap_char *heap)
+{
+	return heap->nr ? heap->data : NULL;
+}
+
+#define min_heap_peek(_heap)	\
+	(__minheap_cast(_heap) __min_heap_peek((min_heap_char *)_heap))
+
 /* Sift the element at pos down the heap. */
 static __always_inline
 void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
-- 
2.34.1

[PATCH v4 07/16] lib min_heap: Add min_heap_full()

[Kuan-Wei Chiu]

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

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 include/linux/min_heap.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index 043de539bf71..d4ec7e749280 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -63,6 +63,16 @@ void *__min_heap_peek(struct min_heap_char *heap)
 #define min_heap_peek(_heap)	\
 	(__minheap_cast(_heap) __min_heap_peek((min_heap_char *)_heap))
 
+/* Check if the heap is full. */
+static __always_inline
+bool __min_heap_full(min_heap_char *heap)
+{
+	return heap->nr == heap->size;
+}
+
+#define min_heap_full(_heap)	\
+	__min_heap_full((min_heap_char *)_heap)
+
 /* Sift the element at pos down the heap. */
 static __always_inline
 void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
-- 
2.34.1

[PATCH v4 08/16] lib min_heap: Add args for min_heap_callbacks

[Kuan-Wei Chiu]

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.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 drivers/md/dm-vdo/repair.c     | 10 +++----
 drivers/md/dm-vdo/slab-depot.c |  9 +++---
 include/linux/min_heap.h       | 51 +++++++++++++++++-----------------
 kernel/events/core.c           | 10 +++----
 lib/test_min_heap.c            | 26 ++++++++---------
 5 files changed, 54 insertions(+), 52 deletions(-)

diff --git a/drivers/md/dm-vdo/repair.c b/drivers/md/dm-vdo/repair.c
index 48c266fa07b6..c1ed3ae823bf 100644
--- a/drivers/md/dm-vdo/repair.c
+++ b/drivers/md/dm-vdo/repair.c
@@ -137,7 +137,7 @@ struct repair_completion {
  * to sort by slot while still ensuring we replay all entries with the same slot in the exact order
  * as they appeared in the journal.
  */
-static bool mapping_is_less_than(const void *item1, const void *item2)
+static bool mapping_is_less_than(const void *item1, const void *item2, void __always_unused *args)
 {
 	const struct numbered_block_mapping *mapping1 =
 		(const struct numbered_block_mapping *) item1;
@@ -156,7 +156,7 @@ static bool mapping_is_less_than(const void *item1, const void *item2)
 	return 0;
 }
 
-static void swap_mappings(void *item1, void *item2)
+static void swap_mappings(void *item1, void *item2, void __always_unused *args)
 {
 	struct numbered_block_mapping *mapping1 = item1;
 	struct numbered_block_mapping *mapping2 = item2;
@@ -182,8 +182,8 @@ static struct numbered_block_mapping *sort_next_heap_element(struct repair_compl
 	 * restore the heap invariant, and return a pointer to the popped element.
 	 */
 	last = &repair->entries[--heap->nr];
-	swap_mappings(heap->data, last);
-	min_heapify(heap, 0, &repair_min_heap);
+	swap_mappings(heap->data, last, NULL);
+	min_heapify(heap, 0, &repair_min_heap, NULL);
 	return last;
 }
 
@@ -1123,7 +1123,7 @@ static void recover_block_map(struct vdo_completion *completion)
 		.nr = repair->block_map_entry_count,
 		.size = repair->block_map_entry_count,
 	};
-	min_heapify_all(&repair->replay_heap, &repair_min_heap);
+	min_heapify_all(&repair->replay_heap, &repair_min_heap, NULL);
 
 	vdo_log_info("Replaying %zu recovery entries into block map",
 		     repair->block_map_entry_count);
diff --git a/drivers/md/dm-vdo/slab-depot.c b/drivers/md/dm-vdo/slab-depot.c
index f6ae6956f321..2739f5b1f8bd 100644
--- a/drivers/md/dm-vdo/slab-depot.c
+++ b/drivers/md/dm-vdo/slab-depot.c
@@ -3288,7 +3288,8 @@ int vdo_release_block_reference(struct block_allocator *allocator,
  * Thus, the ordering is reversed from the usual sense since min_heap returns smaller elements
  * before larger ones.
  */
-static bool slab_status_is_less_than(const void *item1, const void *item2)
+static bool slab_status_is_less_than(const void *item1, const void *item2,
+					void __always_unused *args)
 {
 	const struct slab_status *info1 = item1;
 	const struct slab_status *info2 = item2;
@@ -3300,7 +3301,7 @@ static bool slab_status_is_less_than(const void *item1, const void *item2)
 	return info1->slab_number < info2->slab_number;
 }
 
-static void swap_slab_statuses(void *item1, void *item2)
+static void swap_slab_statuses(void *item1, void *item2, void __always_unused *args)
 {
 	struct slab_status *info1 = item1;
 	struct slab_status *info2 = item2;
@@ -3525,7 +3526,7 @@ static int __must_check vdo_prepare_slabs_for_allocation(struct block_allocator
 		.nr = allocator->slab_count,
 		.size = allocator->slab_count,
 	};
-	min_heapify_all(&heap, &slab_status_min_heap);
+	min_heapify_all(&heap, &slab_status_min_heap, NULL);
 
 	while (heap.nr > 0) {
 		bool high_priority;
@@ -3533,7 +3534,7 @@ static int __must_check vdo_prepare_slabs_for_allocation(struct block_allocator
 		struct slab_journal *journal;
 
 		current_slab_status = slab_statuses[0];
-		min_heap_pop(&heap, &slab_status_min_heap);
+		min_heap_pop(&heap, &slab_status_min_heap, NULL);
 		slab = depot->slabs[current_slab_status.slab_number];
 
 		if ((depot->load_type == VDO_SLAB_DEPOT_REBUILD_LOAD) ||
diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index d4ec7e749280..9391f7cc9da9 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -34,8 +34,8 @@ typedef MIN_HEAP(char, min_heap_char) min_heap_char;
  * @swp: Swap elements function.
  */
 struct min_heap_callbacks {
-	bool (*less)(const void *lhs, const void *rhs);
-	void (*swp)(void *lhs, void *rhs);
+	bool (*less)(const void *lhs, const void *rhs, void *args);
+	void (*swp)(void *lhs, void *rhs, void *args);
 };
 
 /* Initialize a min-heap. */
@@ -76,7 +76,7 @@ bool __min_heap_full(min_heap_char *heap)
 /* Sift the element at pos down the heap. */
 static __always_inline
 void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
-		const struct min_heap_callbacks *func)
+		const struct min_heap_callbacks *func, void *args)
 {
 	void *left, *right;
 	void *data = heap->data;
@@ -89,7 +89,7 @@ void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
 			break;
 		left = data + (i * 2 + 1) * elem_size;
 		right = data + (i * 2 + 2) * elem_size;
-		i = func->less(left, right) ? i * 2 + 1 : i * 2 + 2;
+		i = func->less(left, right, args) ? i * 2 + 1 : i * 2 + 2;
 	}
 
 	/* Special case for the last leaf with no sibling. */
@@ -97,38 +97,38 @@ void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
 		i = i * 2 + 1;
 
 	/* Backtrack to the correct location. */
-	while (i != pos && func->less(root, data + i * elem_size))
+	while (i != pos && func->less(root, data + i * elem_size, args))
 		i = (i - 1) / 2;
 
 	/* Shift the element into its correct place. */
 	j = i;
 	while (i != pos) {
 		i = (i - 1) / 2;
-		func->swp(data + i * elem_size, data + j * elem_size);
+		func->swp(data + i * elem_size, data + j * elem_size, args);
 	}
 }
 
-#define min_heapify(_heap, _pos, _func)	\
-	__min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func)
+#define min_heapify(_heap, _pos, _func, _args)	\
+	__min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func, _args)
 
 /* Floyd's approach to heapification that is O(nr). */
 static __always_inline
 void __min_heapify_all(min_heap_char *heap, size_t elem_size,
-		const struct min_heap_callbacks *func)
+		const struct min_heap_callbacks *func, void *args)
 {
 	int i;
 
 	for (i = heap->nr / 2 - 1; i >= 0; i--)
-		__min_heapify(heap, i, elem_size, func);
+		__min_heapify(heap, i, elem_size, func, args);
 }
 
-#define min_heapify_all(_heap, _func)	\
-	__min_heapify_all((min_heap_char *)_heap, __minheap_obj_size(_heap), _func)
+#define min_heapify_all(_heap, _func, _args)	\
+	__min_heapify_all((min_heap_char *)_heap, __minheap_obj_size(_heap), _func, _args)
 
 /* Remove minimum element from the heap, O(log2(nr)). */
 static __always_inline
 void __min_heap_pop(min_heap_char *heap, size_t elem_size,
-		const struct min_heap_callbacks *func)
+		const struct min_heap_callbacks *func, void *args)
 {
 	void *data = heap->data;
 
@@ -138,11 +138,11 @@ void __min_heap_pop(min_heap_char *heap, size_t elem_size,
 	/* Place last element at the root (position 0) and then sift down. */
 	heap->nr--;
 	memcpy(data, data + (heap->nr * elem_size), elem_size);
-	__min_heapify(heap, 0, elem_size, func);
+	__min_heapify(heap, 0, elem_size, func, args);
 }
 
-#define min_heap_pop(_heap, _func)	\
-	__min_heap_pop((min_heap_char *)_heap, __minheap_obj_size(_heap), _func)
+#define min_heap_pop(_heap, _func, _args)	\
+	__min_heap_pop((min_heap_char *)_heap, __minheap_obj_size(_heap), _func, _args)
 
 /*
  * Remove the minimum element and then push the given element. The
@@ -152,19 +152,20 @@ void __min_heap_pop(min_heap_char *heap, size_t elem_size,
 static __always_inline
 void __min_heap_pop_push(min_heap_char *heap,
 		const void *element, size_t elem_size,
-		const struct min_heap_callbacks *func)
+		const struct min_heap_callbacks *func,
+		void *args)
 {
 	memcpy(heap->data, element, elem_size);
-	__min_heapify(heap, 0, elem_size, func);
+	__min_heapify(heap, 0, elem_size, func, args);
 }
 
-#define min_heap_pop_push(_heap, _element, _func)	\
-	__min_heap_pop_push((min_heap_char *)_heap, _element, __minheap_obj_size(_heap), _func)
+#define min_heap_pop_push(_heap, _element, _func, _args)	\
+	__min_heap_pop_push((min_heap_char *)_heap, _element, __minheap_obj_size(_heap), _func, _args)
 
 /* Push an element on to the heap, O(log2(nr)). */
 static __always_inline
 void __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
-		const struct min_heap_callbacks *func)
+		const struct min_heap_callbacks *func, void *args)
 {
 	void *data = heap->data;
 	void *child, *parent;
@@ -182,13 +183,13 @@ void __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 	for (; pos > 0; pos = (pos - 1) / 2) {
 		child = data + (pos * elem_size);
 		parent = data + ((pos - 1) / 2) * elem_size;
-		if (func->less(parent, child))
+		if (func->less(parent, child, args))
 			break;
-		func->swp(parent, child);
+		func->swp(parent, child, args);
 	}
 }
 
-#define min_heap_push(_heap, _element, _func)	\
-	__min_heap_push((min_heap_char *)_heap, _element, __minheap_obj_size(_heap), _func)
+#define min_heap_push(_heap, _element, _func, _args)	\
+	__min_heap_push((min_heap_char *)_heap, _element, __minheap_obj_size(_heap), _func, _args)
 
 #endif /* _LINUX_MIN_HEAP_H */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 55930479599b..dfd7b5748cbb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3683,7 +3683,7 @@ void __perf_event_task_sched_out(struct task_struct *task,
 	perf_cgroup_switch(next);
 }
 
-static bool perf_less_group_idx(const void *l, const void *r)
+static bool perf_less_group_idx(const void *l, const void *r, void __always_unused *args)
 {
 	const struct perf_event *le = *(const struct perf_event **)l;
 	const struct perf_event *re = *(const struct perf_event **)r;
@@ -3691,7 +3691,7 @@ static bool perf_less_group_idx(const void *l, const void *r)
 	return le->group_index < re->group_index;
 }
 
-static void swap_ptr(void *l, void *r)
+static void swap_ptr(void *l, void *r, void __always_unused *args)
 {
 	void **lp = l, **rp = r;
 
@@ -3783,7 +3783,7 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx,
 		perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu);
 	}
 
-	min_heapify_all(&event_heap, &perf_min_heap);
+	min_heapify_all(&event_heap, &perf_min_heap, NULL);
 
 	while (event_heap.nr) {
 		ret = func(*evt, data);
@@ -3792,9 +3792,9 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx,
 
 		*evt = perf_event_groups_next(*evt, pmu);
 		if (*evt)
-			min_heapify(&event_heap, 0, &perf_min_heap);
+			min_heapify(&event_heap, 0, &perf_min_heap, NULL);
 		else
-			min_heap_pop(&event_heap, &perf_min_heap);
+			min_heap_pop(&event_heap, &perf_min_heap, NULL);
 	}
 
 	return 0;
diff --git a/lib/test_min_heap.c b/lib/test_min_heap.c
index dd5c0fa862ab..0b5037b4bd68 100644
--- a/lib/test_min_heap.c
+++ b/lib/test_min_heap.c
@@ -13,17 +13,17 @@
 
 MIN_HEAP(int, min_heap_test);
 
-static __init bool less_than(const void *lhs, const void *rhs)
+static __init bool less_than(const void *lhs, const void *rhs, void __always_unused *args)
 {
 	return *(int *)lhs < *(int *)rhs;
 }
 
-static __init bool greater_than(const void *lhs, const void *rhs)
+static __init bool greater_than(const void *lhs, const void *rhs, void __always_unused *args)
 {
 	return *(int *)lhs > *(int *)rhs;
 }
 
-static __init void swap_ints(void *lhs, void *rhs)
+static __init void swap_ints(void *lhs, void *rhs, void __always_unused *args)
 {
 	int temp = *(int *)lhs;
 
@@ -40,7 +40,7 @@ static __init int pop_verify_heap(bool min_heap,
 	int last;
 
 	last = values[0];
-	min_heap_pop(heap, funcs);
+	min_heap_pop(heap, funcs, NULL);
 	while (heap->nr > 0) {
 		if (min_heap) {
 			if (last > values[0]) {
@@ -56,7 +56,7 @@ static __init int pop_verify_heap(bool min_heap,
 			}
 		}
 		last = values[0];
-		min_heap_pop(heap, funcs);
+		min_heap_pop(heap, funcs, NULL);
 	}
 	return err;
 }
@@ -77,7 +77,7 @@ static __init int test_heapify_all(bool min_heap)
 	int i, err;
 
 	/* Test with known set of values. */
-	min_heapify_all(&heap, &funcs);
+	min_heapify_all(&heap, &funcs, NULL);
 	err = pop_verify_heap(min_heap, &heap, &funcs);
 
 
@@ -86,7 +86,7 @@ static __init int test_heapify_all(bool min_heap)
 	for (i = 0; i < heap.nr; i++)
 		values[i] = get_random_u32();
 
-	min_heapify_all(&heap, &funcs);
+	min_heapify_all(&heap, &funcs, NULL);
 	err += pop_verify_heap(min_heap, &heap, &funcs);
 
 	return err;
@@ -110,14 +110,14 @@ static __init int test_heap_push(bool min_heap)
 
 	/* Test with known set of values copied from data. */
 	for (i = 0; i < ARRAY_SIZE(data); i++)
-		min_heap_push(&heap, &data[i], &funcs);
+		min_heap_push(&heap, &data[i], &funcs, NULL);
 
 	err = pop_verify_heap(min_heap, &heap, &funcs);
 
 	/* Test with randomly generated values. */
 	while (heap.nr < heap.size) {
 		temp = get_random_u32();
-		min_heap_push(&heap, &temp, &funcs);
+		min_heap_push(&heap, &temp, &funcs, NULL);
 	}
 	err += pop_verify_heap(min_heap, &heap, &funcs);
 
@@ -143,22 +143,22 @@ static __init int test_heap_pop_push(bool min_heap)
 	/* Fill values with data to pop and replace. */
 	temp = min_heap ? 0x80000000 : 0x7FFFFFFF;
 	for (i = 0; i < ARRAY_SIZE(data); i++)
-		min_heap_push(&heap, &temp, &funcs);
+		min_heap_push(&heap, &temp, &funcs, NULL);
 
 	/* Test with known set of values copied from data. */
 	for (i = 0; i < ARRAY_SIZE(data); i++)
-		min_heap_pop_push(&heap, &data[i], &funcs);
+		min_heap_pop_push(&heap, &data[i], &funcs, NULL);
 
 	err = pop_verify_heap(min_heap, &heap, &funcs);
 
 	heap.nr = 0;
 	for (i = 0; i < ARRAY_SIZE(data); i++)
-		min_heap_push(&heap, &temp, &funcs);
+		min_heap_push(&heap, &temp, &funcs, NULL);
 
 	/* Test with randomly generated values. */
 	for (i = 0; i < ARRAY_SIZE(data); i++) {
 		temp = get_random_u32();
-		min_heap_pop_push(&heap, &temp, &funcs);
+		min_heap_pop_push(&heap, &temp, &funcs, NULL);
 	}
 	err += pop_verify_heap(min_heap, &heap, &funcs);
 
-- 
2.34.1

[PATCH v4 09/16] lib min_heap: Add min_heap_sift_up()

[Kuan-Wei Chiu]

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

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 include/linux/min_heap.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index 9391f7cc9da9..201f59cb3558 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -111,6 +111,26 @@ void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
 #define min_heapify(_heap, _pos, _func, _args)	\
 	__min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func, _args)
 
+/* Sift up ith element from the heap, O(log2(nr)). */
+static __always_inline
+void __min_heap_sift_up(min_heap_char *heap, size_t elem_size, size_t idx,
+		const struct min_heap_callbacks *func, void *args)
+{
+	void *data = heap->data;
+	size_t parent;
+
+	while (idx) {
+		parent = (idx - 1) / 2;
+		if (func->less(data + parent * elem_size, data + idx * elem_size, args))
+			break;
+		func->swp(data + parent * elem_size, data + idx * elem_size, args);
+		idx = parent;
+	}
+}
+
+#define min_heap_sift_up(_heap, _idx, _func, _args)	\
+	__min_heap_sift_up((min_heap_char *)_heap, __minheap_obj_size(_heap), _idx, _func, _args)
+
 /* Floyd's approach to heapification that is O(nr). */
 static __always_inline
 void __min_heapify_all(min_heap_char *heap, size_t elem_size,
-- 
2.34.1

[PATCH v4 10/16] lib min_heap: Add min_heap_del()

[Kuan-Wei Chiu]

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

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
Changes in v4:
- Replace memcpy() with func->swp() in heap_del() due to issues with
  set_backpointer in bcachefs when setting idx.

 include/linux/min_heap.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index 201f59cb3558..c94f9d303205 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -212,4 +212,28 @@ void __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 #define min_heap_push(_heap, _element, _func, _args)	\
 	__min_heap_push((min_heap_char *)_heap, _element, __minheap_obj_size(_heap), _func, _args)
 
+/* Remove ith element from the heap, O(log2(nr)). */
+static __always_inline
+bool __min_heap_del(min_heap_char *heap, size_t elem_size, size_t idx,
+		const struct min_heap_callbacks *func, void *args)
+{
+	void *data = heap->data;
+
+	if (WARN_ONCE(heap->nr <= 0, "Popping an empty heap"))
+		return false;
+
+	/* Place last element at the root (position 0) and then sift down. */
+	heap->nr--;
+	if (idx == heap->nr)
+		return true;
+	func->swp(data + (idx * elem_size), data + (heap->nr * elem_size), args);
+	__min_heap_sift_up(heap, elem_size, idx, func, args);
+	__min_heapify(heap, idx, elem_size, func, args);
+
+	return true;
+}
+
+#define min_heap_del(_heap, _idx, _func, _args)	\
+	__min_heap_del((min_heap_char *)_heap, __minheap_obj_size(_heap), _idx, _func, _args)
+
 #endif /* _LINUX_MIN_HEAP_H */
-- 
2.34.1

[PATCH v4 11/16] lib min_heap: Update min_heap_push() and min_heap_pop() to return bool values

[Kuan-Wei Chiu]

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.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 include/linux/min_heap.h | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index c94f9d303205..2d080f85ad0d 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -147,18 +147,20 @@ void __min_heapify_all(min_heap_char *heap, size_t elem_size,
 
 /* Remove minimum element from the heap, O(log2(nr)). */
 static __always_inline
-void __min_heap_pop(min_heap_char *heap, size_t elem_size,
+bool __min_heap_pop(min_heap_char *heap, size_t elem_size,
 		const struct min_heap_callbacks *func, void *args)
 {
 	void *data = heap->data;
 
 	if (WARN_ONCE(heap->nr <= 0, "Popping an empty heap"))
-		return;
+		return false;
 
 	/* Place last element at the root (position 0) and then sift down. */
 	heap->nr--;
 	memcpy(data, data + (heap->nr * elem_size), elem_size);
 	__min_heapify(heap, 0, elem_size, func, args);
+
+	return true;
 }
 
 #define min_heap_pop(_heap, _func, _args)	\
@@ -184,7 +186,7 @@ void __min_heap_pop_push(min_heap_char *heap,
 
 /* Push an element on to the heap, O(log2(nr)). */
 static __always_inline
-void __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
+bool __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 		const struct min_heap_callbacks *func, void *args)
 {
 	void *data = heap->data;
@@ -192,7 +194,7 @@ void __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 	int pos;
 
 	if (WARN_ONCE(heap->nr >= heap->size, "Pushing on a full heap"))
-		return;
+		return false;
 
 	/* Place at the end of data. */
 	pos = heap->nr;
@@ -207,6 +209,8 @@ void __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 			break;
 		func->swp(parent, child, args);
 	}
+
+	return true;
 }
 
 #define min_heap_push(_heap, _element, _func, _args)	\
-- 
2.34.1

[PATCH v4 12/16] lib min_heap: Rename min_heapify() to min_heap_sift_down()

[Kuan-Wei Chiu]

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
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 drivers/md/dm-vdo/repair.c |  2 +-
 include/linux/min_heap.h   | 14 +++++++-------
 kernel/events/core.c       |  2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/md/dm-vdo/repair.c b/drivers/md/dm-vdo/repair.c
index c1ed3ae823bf..941ac9eda8ca 100644
--- a/drivers/md/dm-vdo/repair.c
+++ b/drivers/md/dm-vdo/repair.c
@@ -183,7 +183,7 @@ static struct numbered_block_mapping *sort_next_heap_element(struct repair_compl
 	 */
 	last = &repair->entries[--heap->nr];
 	swap_mappings(heap->data, last, NULL);
-	min_heapify(heap, 0, &repair_min_heap, NULL);
+	min_heap_sift_down(heap, 0, &repair_min_heap, NULL);
 	return last;
 }
 
diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index 2d080f85ad0d..f907c694e852 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -75,7 +75,7 @@ bool __min_heap_full(min_heap_char *heap)
 
 /* Sift the element at pos down the heap. */
 static __always_inline
-void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
+void __min_heap_sift_down(min_heap_char *heap, int pos, size_t elem_size,
 		const struct min_heap_callbacks *func, void *args)
 {
 	void *left, *right;
@@ -108,8 +108,8 @@ void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
 	}
 }
 
-#define min_heapify(_heap, _pos, _func, _args)	\
-	__min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func, _args)
+#define min_heap_sift_down(_heap, _pos, _func, _args)	\
+	__min_heap_sift_down((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func, _args)
 
 /* Sift up ith element from the heap, O(log2(nr)). */
 static __always_inline
@@ -139,7 +139,7 @@ void __min_heapify_all(min_heap_char *heap, size_t elem_size,
 	int i;
 
 	for (i = heap->nr / 2 - 1; i >= 0; i--)
-		__min_heapify(heap, i, elem_size, func, args);
+		__min_heap_sift_down(heap, i, elem_size, func, args);
 }
 
 #define min_heapify_all(_heap, _func, _args)	\
@@ -158,7 +158,7 @@ bool __min_heap_pop(min_heap_char *heap, size_t elem_size,
 	/* Place last element at the root (position 0) and then sift down. */
 	heap->nr--;
 	memcpy(data, data + (heap->nr * elem_size), elem_size);
-	__min_heapify(heap, 0, elem_size, func, args);
+	__min_heap_sift_down(heap, 0, elem_size, func, args);
 
 	return true;
 }
@@ -178,7 +178,7 @@ void __min_heap_pop_push(min_heap_char *heap,
 		void *args)
 {
 	memcpy(heap->data, element, elem_size);
-	__min_heapify(heap, 0, elem_size, func, args);
+	__min_heap_sift_down(heap, 0, elem_size, func, args);
 }
 
 #define min_heap_pop_push(_heap, _element, _func, _args)	\
@@ -232,7 +232,7 @@ bool __min_heap_del(min_heap_char *heap, size_t elem_size, size_t idx,
 		return true;
 	func->swp(data + (idx * elem_size), data + (heap->nr * elem_size), args);
 	__min_heap_sift_up(heap, elem_size, idx, func, args);
-	__min_heapify(heap, idx, elem_size, func, args);
+	__min_heap_sift_down(heap, idx, elem_size, func, args);
 
 	return true;
 }
diff --git a/kernel/events/core.c b/kernel/events/core.c
index dfd7b5748cbb..82f329c8caea 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3792,7 +3792,7 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx,
 
 		*evt = perf_event_groups_next(*evt, pmu);
 		if (*evt)
-			min_heapify(&event_heap, 0, &perf_min_heap, NULL);
+			min_heap_sift_down(&event_heap, 0, &perf_min_heap, NULL);
 		else
 			min_heap_pop(&event_heap, &perf_min_heap, NULL);
 	}
-- 
2.34.1

[PATCH v4 13/16] lib min_heap: Update min_heap_push() to use min_heap_sift_up()

[Kuan-Wei Chiu]

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

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 include/linux/min_heap.h | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index f907c694e852..78de60f6ef1c 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -190,7 +190,6 @@ bool __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 		const struct min_heap_callbacks *func, void *args)
 {
 	void *data = heap->data;
-	void *child, *parent;
 	int pos;
 
 	if (WARN_ONCE(heap->nr >= heap->size, "Pushing on a full heap"))
@@ -202,13 +201,7 @@ bool __min_heap_push(min_heap_char *heap, const void *element, size_t elem_size,
 	heap->nr++;
 
 	/* Sift child at pos up. */
-	for (; pos > 0; pos = (pos - 1) / 2) {
-		child = data + (pos * elem_size);
-		parent = data + ((pos - 1) / 2) * elem_size;
-		if (func->less(parent, child, args))
-			break;
-		func->swp(parent, child, args);
-	}
+	__min_heap_sift_up(heap, elem_size, pos, func, args);
 
 	return true;
 }
-- 
2.34.1

[PATCH v4 14/16] lib/test_min_heap: Add test for heap_del()

[Kuan-Wei Chiu]

Add test cases for the min_heap_del() to ensure its functionality is
thoroughly tested.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 lib/test_min_heap.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/lib/test_min_heap.c b/lib/test_min_heap.c
index 0b5037b4bd68..d40851cfd824 100644
--- a/lib/test_min_heap.c
+++ b/lib/test_min_heap.c
@@ -165,6 +165,40 @@ static __init int test_heap_pop_push(bool min_heap)
 	return err;
 }
 
+static __init int test_heap_del(bool min_heap)
+{
+	int values[] = { 3, 1, 2, 4, 0x8000000, 0x7FFFFFF, 0,
+			 -3, -1, -2, -4, 0x8000000, 0x7FFFFFF };
+	struct min_heap_test heap;
+
+	min_heap_init(&heap, values, ARRAY_SIZE(values));
+	heap.nr = ARRAY_SIZE(values);
+	struct min_heap_callbacks funcs = {
+		.less = min_heap ? less_than : greater_than,
+		.swp = swap_ints,
+	};
+	int i, err;
+
+	/* Test with known set of values. */
+	min_heapify_all(&heap, &funcs, NULL);
+	for (i = 0; i < ARRAY_SIZE(values) / 2; i++)
+		min_heap_del(&heap, get_random_u32() % heap.nr, &funcs, NULL);
+	err = pop_verify_heap(min_heap, &heap, &funcs);
+
+
+	/* Test with randomly generated values. */
+	heap.nr = ARRAY_SIZE(values);
+	for (i = 0; i < heap.nr; i++)
+		values[i] = get_random_u32();
+	min_heapify_all(&heap, &funcs, NULL);
+
+	for (i = 0; i < ARRAY_SIZE(values) / 2; i++)
+		min_heap_del(&heap, get_random_u32() % heap.nr, &funcs, NULL);
+	err += pop_verify_heap(min_heap, &heap, &funcs);
+
+	return err;
+}
+
 static int __init test_min_heap_init(void)
 {
 	int err = 0;
@@ -175,6 +209,8 @@ static int __init test_min_heap_init(void)
 	err += test_heap_push(false);
 	err += test_heap_pop_push(true);
 	err += test_heap_pop_push(false);
+	err += test_heap_del(true);
+	err += test_heap_del(false);
 	if (err) {
 		pr_err("test failed with %d errors\n", err);
 		return -EINVAL;
-- 
2.34.1

[PATCH v4 15/16] bcache: Remove heap-related macros and switch to generic min_heap

[Kuan-Wei Chiu]

Drop the heap-related macros from bcache and replacing them with the
generic min_heap implementation from include/linux. By doing so, code
readability is improved by using functions instead of macros. Moreover,
the min_heap implementation in include/linux adopts a bottom-up
variation compared to the textbook version currently used in bcache.
This bottom-up variation allows for approximately 50% reduction in the
number of comparison operations during heap siftdown, without changing
the number of swaps, thus making it more efficient.

Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Coly Li <colyli@suse.de>
---
 drivers/md/bcache/alloc.c     | 64 +++++++++++++++++++-------
 drivers/md/bcache/bcache.h    |  2 +-
 drivers/md/bcache/bset.c      | 84 ++++++++++++++++++++++++-----------
 drivers/md/bcache/bset.h      | 14 +++---
 drivers/md/bcache/btree.c     | 17 ++++++-
 drivers/md/bcache/extents.c   | 53 ++++++++++++++--------
 drivers/md/bcache/movinggc.c  | 41 ++++++++++++-----
 drivers/md/bcache/sysfs.c     |  2 +
 drivers/md/bcache/util.h      | 67 +---------------------------
 drivers/md/bcache/writeback.c |  3 ++
 10 files changed, 202 insertions(+), 145 deletions(-)

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index ce13c272c387..8cfa15ea32b4 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -166,40 +166,68 @@ static void bch_invalidate_one_bucket(struct cache *ca, struct bucket *b)
  * prio is worth 1/8th of what INITIAL_PRIO is worth.
  */
 
-#define bucket_prio(b)							\
-({									\
-	unsigned int min_prio = (INITIAL_PRIO - ca->set->min_prio) / 8;	\
-									\
-	(b->prio - ca->set->min_prio + min_prio) * GC_SECTORS_USED(b);	\
-})
+static inline unsigned int new_bucket_prio(struct cache *ca, struct bucket *b)
+{
+	unsigned int min_prio = (INITIAL_PRIO - ca->set->min_prio) / 8;
+
+	return (b->prio - ca->set->min_prio + min_prio) * GC_SECTORS_USED(b);
+}
+
+static inline bool new_bucket_max_cmp(const void *l, const void *r, void *args)
+{
+	struct bucket **lhs = (struct bucket **)l;
+	struct bucket **rhs = (struct bucket **)r;
+	struct cache *ca = args;
+
+	return new_bucket_prio(ca, *lhs) > new_bucket_prio(ca, *rhs);
+}
 
-#define bucket_max_cmp(l, r)	(bucket_prio(l) < bucket_prio(r))
-#define bucket_min_cmp(l, r)	(bucket_prio(l) > bucket_prio(r))
+static inline bool new_bucket_min_cmp(const void *l, const void *r, void *args)
+{
+	struct bucket **lhs = (struct bucket **)l;
+	struct bucket **rhs = (struct bucket **)r;
+	struct cache *ca = args;
+
+	return new_bucket_prio(ca, *lhs) < new_bucket_prio(ca, *rhs);
+}
+
+static inline void new_bucket_swap(void *l, void *r, void __always_unused *args)
+{
+	struct bucket **lhs = l, **rhs = r;
+
+	swap(*lhs, *rhs);
+}
 
 static void invalidate_buckets_lru(struct cache *ca)
 {
 	struct bucket *b;
-	ssize_t i;
+	const struct min_heap_callbacks bucket_max_cmp_callback = {
+		.less = new_bucket_max_cmp,
+		.swp = new_bucket_swap,
+	};
+	const struct min_heap_callbacks bucket_min_cmp_callback = {
+		.less = new_bucket_min_cmp,
+		.swp = new_bucket_swap,
+	};
 
-	ca->heap.used = 0;
+	ca->heap.nr = 0;
 
 	for_each_bucket(b, ca) {
 		if (!bch_can_invalidate_bucket(ca, b))
 			continue;
 
-		if (!heap_full(&ca->heap))
-			heap_add(&ca->heap, b, bucket_max_cmp);
-		else if (bucket_max_cmp(b, heap_peek(&ca->heap))) {
+		if (!min_heap_full(&ca->heap))
+			min_heap_push(&ca->heap, &b, &bucket_max_cmp_callback, ca);
+		else if (!new_bucket_max_cmp(&b, min_heap_peek(&ca->heap), ca)) {
 			ca->heap.data[0] = b;
-			heap_sift(&ca->heap, 0, bucket_max_cmp);
+			min_heap_sift_down(&ca->heap, 0, &bucket_max_cmp_callback, ca);
 		}
 	}
 
-	for (i = ca->heap.used / 2 - 1; i >= 0; --i)
-		heap_sift(&ca->heap, i, bucket_min_cmp);
+	min_heapify_all(&ca->heap, &bucket_min_cmp_callback, ca);
 
 	while (!fifo_full(&ca->free_inc)) {
-		if (!heap_pop(&ca->heap, b, bucket_min_cmp)) {
+		if (!ca->heap.nr) {
 			/*
 			 * We don't want to be calling invalidate_buckets()
 			 * multiple times when it can't do anything
@@ -208,6 +236,8 @@ static void invalidate_buckets_lru(struct cache *ca)
 			wake_up_gc(ca->set);
 			return;
 		}
+		b = min_heap_peek(&ca->heap)[0];
+		min_heap_pop(&ca->heap, &bucket_min_cmp_callback, ca);
 
 		bch_invalidate_one_bucket(ca, b);
 	}
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 4e6afa89921f..575d1e3a5217 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -457,7 +457,7 @@ struct cache {
 	/* Allocation stuff: */
 	struct bucket		*buckets;
 
-	DECLARE_HEAP(struct bucket *, heap);
+	MIN_HEAP(struct bucket *, cache_heap) heap;
 
 	/*
 	 * If nonzero, we know we aren't going to find any buckets to invalidate
diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 2bba4d6aaaa2..bd97d8626887 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c
@@ -57,6 +57,8 @@ int __bch_count_data(struct btree_keys *b)
 	struct btree_iter iter;
 	struct bkey *k;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	if (b->ops->is_extents)
 		for_each_key(b, k, &iter)
 			ret += KEY_SIZE(k);
@@ -70,6 +72,8 @@ void __bch_check_keys(struct btree_keys *b, const char *fmt, ...)
 	struct btree_iter iter;
 	const char *err;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	for_each_key(b, k, &iter) {
 		if (b->ops->is_extents) {
 			err = "Keys out of order";
@@ -110,9 +114,9 @@ void __bch_check_keys(struct btree_keys *b, const char *fmt, ...)
 
 static void bch_btree_iter_next_check(struct btree_iter *iter)
 {
-	struct bkey *k = iter->data->k, *next = bkey_next(k);
+	struct bkey *k = iter->heap.data->k, *next = bkey_next(k);
 
-	if (next < iter->data->end &&
+	if (next < iter->heap.data->end &&
 	    bkey_cmp(k, iter->b->ops->is_extents ?
 		     &START_KEY(next) : next) > 0) {
 		bch_dump_bucket(iter->b);
@@ -885,6 +889,8 @@ unsigned int bch_btree_insert_key(struct btree_keys *b, struct bkey *k,
 
 	BUG_ON(b->ops->is_extents && !KEY_SIZE(k));
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	/*
 	 * If k has preceding key, preceding_key_p will be set to address
 	 *  of k's preceding key; otherwise preceding_key_p will be set
@@ -1077,27 +1083,42 @@ struct bkey *__bch_bset_search(struct btree_keys *b, struct bset_tree *t,
 
 /* Btree iterator */
 
-typedef bool (btree_iter_cmp_fn)(struct btree_iter_set,
-				 struct btree_iter_set);
+typedef bool (new_btree_iter_cmp_fn)(const void *, const void *, void *);
+
+static inline bool new_btree_iter_cmp(const void *l, const void *r, void __always_unused *args)
+{
+	const struct btree_iter_set *_l = l;
+	const struct btree_iter_set *_r = r;
+
+	return bkey_cmp(_l->k, _r->k) <= 0;
+}
 
-static inline bool btree_iter_cmp(struct btree_iter_set l,
-				  struct btree_iter_set r)
+static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args)
 {
-	return bkey_cmp(l.k, r.k) > 0;
+	struct btree_iter_set *_iter1 = iter1;
+	struct btree_iter_set *_iter2 = iter2;
+
+	swap(*_iter1, *_iter2);
 }
 
 static inline bool btree_iter_end(struct btree_iter *iter)
 {
-	return !iter->used;
+	return !iter->heap.nr;
 }
 
 void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
 			 struct bkey *end)
 {
+	const struct min_heap_callbacks callbacks = {
+		.less = new_btree_iter_cmp,
+		.swp = new_btree_iter_swap,
+	};
+
 	if (k != end)
-		BUG_ON(!heap_add(iter,
-				 ((struct btree_iter_set) { k, end }),
-				 btree_iter_cmp));
+		BUG_ON(!min_heap_push(&iter->heap,
+				 &((struct btree_iter_set) { k, end }),
+				 &callbacks,
+				 NULL));
 }
 
 static struct bkey *__bch_btree_iter_init(struct btree_keys *b,
@@ -1107,8 +1128,8 @@ static struct bkey *__bch_btree_iter_init(struct btree_keys *b,
 {
 	struct bkey *ret = NULL;
 
-	iter->size = ARRAY_SIZE(iter->data);
-	iter->used = 0;
+	iter->heap.size = ARRAY_SIZE(iter->heap.preallocated);
+	iter->heap.nr = 0;
 
 #ifdef CONFIG_BCACHE_DEBUG
 	iter->b = b;
@@ -1130,26 +1151,34 @@ struct bkey *bch_btree_iter_init(struct btree_keys *b,
 }
 
 static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter,
-						 btree_iter_cmp_fn *cmp)
+						 new_btree_iter_cmp_fn *cmp)
 {
 	struct btree_iter_set b __maybe_unused;
 	struct bkey *ret = NULL;
+	const struct min_heap_callbacks callbacks = {
+		.less = cmp,
+		.swp = new_btree_iter_swap,
+	};
 
 	if (!btree_iter_end(iter)) {
 		bch_btree_iter_next_check(iter);
 
-		ret = iter->data->k;
-		iter->data->k = bkey_next(iter->data->k);
+		ret = iter->heap.data->k;
+		iter->heap.data->k = bkey_next(iter->heap.data->k);
 
-		if (iter->data->k > iter->data->end) {
+		if (iter->heap.data->k > iter->heap.data->end) {
 			WARN_ONCE(1, "bset was corrupt!\n");
-			iter->data->k = iter->data->end;
+			iter->heap.data->k = iter->heap.data->end;
 		}
 
-		if (iter->data->k == iter->data->end)
-			heap_pop(iter, b, cmp);
+		if (iter->heap.data->k == iter->heap.data->end) {
+			if (iter->heap.nr) {
+				b = min_heap_peek(&iter->heap)[0];
+				min_heap_pop(&iter->heap, &callbacks, NULL);
+			}
+		}
 		else
-			heap_sift(iter, 0, cmp);
+			min_heap_sift_down(&iter->heap, 0, &callbacks, NULL);
 	}
 
 	return ret;
@@ -1157,7 +1186,7 @@ static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter,
 
 struct bkey *bch_btree_iter_next(struct btree_iter *iter)
 {
-	return __bch_btree_iter_next(iter, btree_iter_cmp);
+	return __bch_btree_iter_next(iter, new_btree_iter_cmp);
 
 }
 
@@ -1195,16 +1224,18 @@ static void btree_mergesort(struct btree_keys *b, struct bset *out,
 			    struct btree_iter *iter,
 			    bool fixup, bool remove_stale)
 {
-	int i;
 	struct bkey *k, *last = NULL;
 	BKEY_PADDED(k) tmp;
 	bool (*bad)(struct btree_keys *, const struct bkey *) = remove_stale
 		? bch_ptr_bad
 		: bch_ptr_invalid;
+	const struct min_heap_callbacks callbacks = {
+		.less = b->ops->sort_cmp,
+		.swp = new_btree_iter_swap,
+	};
 
 	/* Heapify the iterator, using our comparison function */
-	for (i = iter->used / 2 - 1; i >= 0; --i)
-		heap_sift(iter, i, b->ops->sort_cmp);
+	min_heapify_all(&iter->heap, &callbacks, NULL);
 
 	while (!btree_iter_end(iter)) {
 		if (b->ops->sort_fixup && fixup)
@@ -1296,6 +1327,7 @@ void bch_btree_sort_partial(struct btree_keys *b, unsigned int start,
 	struct btree_iter iter;
 	int oldsize = bch_count_data(b);
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
 	__bch_btree_iter_init(b, &iter, NULL, &b->set[start]);
 
 	if (start) {
@@ -1325,6 +1357,8 @@ void bch_btree_sort_into(struct btree_keys *b, struct btree_keys *new,
 	uint64_t start_time = local_clock();
 	struct btree_iter iter;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	bch_btree_iter_init(b, &iter, NULL);
 
 	btree_mergesort(b, new->set->data, &iter, false, true);
diff --git a/drivers/md/bcache/bset.h b/drivers/md/bcache/bset.h
index d795c84246b0..f79441acd4c1 100644
--- a/drivers/md/bcache/bset.h
+++ b/drivers/md/bcache/bset.h
@@ -187,8 +187,9 @@ struct bset_tree {
 };
 
 struct btree_keys_ops {
-	bool		(*sort_cmp)(struct btree_iter_set l,
-				    struct btree_iter_set r);
+	bool		(*sort_cmp)(const void *l,
+				    const void *r,
+					void *args);
 	struct bkey	*(*sort_fixup)(struct btree_iter *iter,
 				       struct bkey *tmp);
 	bool		(*insert_fixup)(struct btree_keys *b,
@@ -312,16 +313,17 @@ enum {
 	BTREE_INSERT_STATUS_FRONT_MERGE,
 };
 
+struct btree_iter_set {
+	struct bkey *k, *end;
+};
+
 /* Btree key iteration */
 
 struct btree_iter {
-	size_t size, used;
 #ifdef CONFIG_BCACHE_DEBUG
 	struct btree_keys *b;
 #endif
-	struct btree_iter_set {
-		struct bkey *k, *end;
-	} data[MAX_BSETS];
+	MIN_HEAP_PREALLOCATED(struct btree_iter_set, btree_iter_heap, MAX_BSETS) heap;
 };
 
 typedef bool (*ptr_filter_fn)(struct btree_keys *b, const struct bkey *k);
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 196cdacce38f..a2bb86d52ad4 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -157,8 +157,8 @@ void bch_btree_node_read_done(struct btree *b)
 	 * See the comment arount cache_set->fill_iter.
 	 */
 	iter = mempool_alloc(&b->c->fill_iter, GFP_NOIO);
-	iter->size = b->c->cache->sb.bucket_size / b->c->cache->sb.block_size;
-	iter->used = 0;
+	iter->heap.size = b->c->cache->sb.bucket_size / b->c->cache->sb.block_size;
+	iter->heap.nr = 0;
 
 #ifdef CONFIG_BCACHE_DEBUG
 	iter->b = &b->keys;
@@ -1312,6 +1312,8 @@ static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc)
 	struct btree_iter iter;
 	struct bset_tree *t;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	gc->nodes++;
 
 	for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid) {
@@ -1573,6 +1575,8 @@ static unsigned int btree_gc_count_keys(struct btree *b)
 	struct btree_iter iter;
 	unsigned int ret = 0;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
 		ret += bkey_u64s(k);
 
@@ -1615,6 +1619,7 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op,
 	struct gc_merge_info r[GC_MERGE_NODES];
 	struct gc_merge_info *i, *last = r + ARRAY_SIZE(r) - 1;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
 	bch_btree_iter_init(&b->keys, &iter, &b->c->gc_done);
 
 	for (i = r; i < r + ARRAY_SIZE(r); i++)
@@ -1913,6 +1918,8 @@ static int bch_btree_check_recurse(struct btree *b, struct btree_op *op)
 	struct bkey *k, *p = NULL;
 	struct btree_iter iter;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid)
 		bch_initial_mark_key(b->c, b->level, k);
 
@@ -1958,6 +1965,8 @@ static int bch_btree_check_thread(void *arg)
 	cur_idx = prev_idx = 0;
 	ret = 0;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	/* root node keys are checked before thread created */
 	bch_btree_iter_init(&c->root->keys, &iter, NULL);
 	k = bch_btree_iter_next_filter(&iter, &c->root->keys, bch_ptr_bad);
@@ -2054,6 +2063,8 @@ int bch_btree_check(struct cache_set *c)
 	struct btree_iter iter;
 	struct btree_check_state check_state;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	/* check and mark root node keys */
 	for_each_key_filter(&c->root->keys, k, &iter, bch_ptr_invalid)
 		bch_initial_mark_key(c, c->root->level, k);
@@ -2549,6 +2560,7 @@ static int bch_btree_map_nodes_recurse(struct btree *b, struct btree_op *op,
 		struct bkey *k;
 		struct btree_iter iter;
 
+		min_heap_init(&iter.heap, NULL, MAX_BSETS);
 		bch_btree_iter_init(&b->keys, &iter, from);
 
 		while ((k = bch_btree_iter_next_filter(&iter, &b->keys,
@@ -2582,6 +2594,7 @@ int bch_btree_map_keys_recurse(struct btree *b, struct btree_op *op,
 	struct bkey *k;
 	struct btree_iter iter;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
 	bch_btree_iter_init(&b->keys, &iter, from);
 
 	while ((k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad))) {
diff --git a/drivers/md/bcache/extents.c b/drivers/md/bcache/extents.c
index d626ffcbecb9..a7221e5dbe81 100644
--- a/drivers/md/bcache/extents.c
+++ b/drivers/md/bcache/extents.c
@@ -33,15 +33,16 @@ static void sort_key_next(struct btree_iter *iter,
 	i->k = bkey_next(i->k);
 
 	if (i->k == i->end)
-		*i = iter->data[--iter->used];
+		*i = iter->heap.data[--iter->heap.nr];
 }
 
-static bool bch_key_sort_cmp(struct btree_iter_set l,
-			     struct btree_iter_set r)
+static bool new_bch_key_sort_cmp(const void *l, const void *r, void *args)
 {
-	int64_t c = bkey_cmp(l.k, r.k);
+	struct btree_iter_set *_l = (struct btree_iter_set *)l;
+	struct btree_iter_set *_r = (struct btree_iter_set *)r;
+	int64_t c = bkey_cmp(_l->k, _r->k);
 
-	return c ? c > 0 : l.k < r.k;
+	return !(c ? c > 0 : _l->k < _r->k);
 }
 
 static bool __ptr_invalid(struct cache_set *c, const struct bkey *k)
@@ -238,7 +239,7 @@ static bool bch_btree_ptr_insert_fixup(struct btree_keys *bk,
 }
 
 const struct btree_keys_ops bch_btree_keys_ops = {
-	.sort_cmp	= bch_key_sort_cmp,
+	.sort_cmp	= new_bch_key_sort_cmp,
 	.insert_fixup	= bch_btree_ptr_insert_fixup,
 	.key_invalid	= bch_btree_ptr_invalid,
 	.key_bad	= bch_btree_ptr_bad,
@@ -255,22 +256,36 @@ const struct btree_keys_ops bch_btree_keys_ops = {
  * Necessary for btree_sort_fixup() - if there are multiple keys that compare
  * equal in different sets, we have to process them newest to oldest.
  */
-static bool bch_extent_sort_cmp(struct btree_iter_set l,
-				struct btree_iter_set r)
+
+static bool new_bch_extent_sort_cmp(const void *l, const void *r, void __always_unused *args)
+{
+	struct btree_iter_set *_l = (struct btree_iter_set *)l;
+	struct btree_iter_set *_r = (struct btree_iter_set *)r;
+	int64_t c = bkey_cmp(&START_KEY(_l->k), &START_KEY(_r->k));
+
+	return !(c ? c > 0 : _l->k < _r->k);
+}
+
+static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args)
 {
-	int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k));
+	struct btree_iter_set *_iter1 = iter1;
+	struct btree_iter_set *_iter2 = iter2;
 
-	return c ? c > 0 : l.k < r.k;
+	swap(*_iter1, *_iter2);
 }
 
 static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter,
 					  struct bkey *tmp)
 {
-	while (iter->used > 1) {
-		struct btree_iter_set *top = iter->data, *i = top + 1;
-
-		if (iter->used > 2 &&
-		    bch_extent_sort_cmp(i[0], i[1]))
+	const struct min_heap_callbacks callbacks = {
+		.less = new_bch_extent_sort_cmp,
+		.swp = new_btree_iter_swap,
+	};
+	while (iter->heap.nr > 1) {
+		struct btree_iter_set *top = iter->heap.data, *i = top + 1;
+
+		if (iter->heap.nr > 2 &&
+		    !new_bch_extent_sort_cmp(&i[0], &i[1], NULL))
 			i++;
 
 		if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0)
@@ -278,7 +293,7 @@ static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter,
 
 		if (!KEY_SIZE(i->k)) {
 			sort_key_next(iter, i);
-			heap_sift(iter, i - top, bch_extent_sort_cmp);
+			min_heap_sift_down(&iter->heap, i - top, &callbacks, NULL);
 			continue;
 		}
 
@@ -288,7 +303,7 @@ static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter,
 			else
 				bch_cut_front(top->k, i->k);
 
-			heap_sift(iter, i - top, bch_extent_sort_cmp);
+			min_heap_sift_down(&iter->heap, i - top, &callbacks, NULL);
 		} else {
 			/* can't happen because of comparison func */
 			BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k)));
@@ -298,7 +313,7 @@ static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter,
 
 				bch_cut_back(&START_KEY(i->k), tmp);
 				bch_cut_front(i->k, top->k);
-				heap_sift(iter, 0, bch_extent_sort_cmp);
+				min_heap_sift_down(&iter->heap, 0, &callbacks, NULL);
 
 				return tmp;
 			} else {
@@ -618,7 +633,7 @@ static bool bch_extent_merge(struct btree_keys *bk,
 }
 
 const struct btree_keys_ops bch_extent_keys_ops = {
-	.sort_cmp	= bch_extent_sort_cmp,
+	.sort_cmp	= new_bch_extent_sort_cmp,
 	.sort_fixup	= bch_extent_sort_fixup,
 	.insert_fixup	= bch_extent_insert_fixup,
 	.key_invalid	= bch_extent_invalid,
diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c
index ebd500bdf0b2..7f482729c56d 100644
--- a/drivers/md/bcache/movinggc.c
+++ b/drivers/md/bcache/movinggc.c
@@ -182,16 +182,27 @@ err:		if (!IS_ERR_OR_NULL(w->private))
 	closure_sync(&cl);
 }
 
-static bool bucket_cmp(struct bucket *l, struct bucket *r)
+static bool new_bucket_cmp(const void *l, const void *r, void __always_unused *args)
 {
-	return GC_SECTORS_USED(l) < GC_SECTORS_USED(r);
+	struct bucket **_l = (struct bucket **)l;
+	struct bucket **_r = (struct bucket **)r;
+
+	return GC_SECTORS_USED(*_l) >= GC_SECTORS_USED(*_r);
+}
+
+static void new_bucket_swap(void *l, void *r, void __always_unused *args)
+{
+	struct bucket **_l = l;
+	struct bucket **_r = r;
+
+	swap(*_l, *_r);
 }
 
 static unsigned int bucket_heap_top(struct cache *ca)
 {
 	struct bucket *b;
 
-	return (b = heap_peek(&ca->heap)) ? GC_SECTORS_USED(b) : 0;
+	return (b = min_heap_peek(&ca->heap)[0]) ? GC_SECTORS_USED(b) : 0;
 }
 
 void bch_moving_gc(struct cache_set *c)
@@ -199,6 +210,10 @@ void bch_moving_gc(struct cache_set *c)
 	struct cache *ca = c->cache;
 	struct bucket *b;
 	unsigned long sectors_to_move, reserve_sectors;
+	const struct min_heap_callbacks callbacks = {
+		.less = new_bucket_cmp,
+		.swp = new_bucket_swap,
+	};
 
 	if (!c->copy_gc_enabled)
 		return;
@@ -209,7 +224,7 @@ void bch_moving_gc(struct cache_set *c)
 	reserve_sectors = ca->sb.bucket_size *
 			     fifo_used(&ca->free[RESERVE_MOVINGGC]);
 
-	ca->heap.used = 0;
+	ca->heap.nr = 0;
 
 	for_each_bucket(b, ca) {
 		if (GC_MARK(b) == GC_MARK_METADATA ||
@@ -218,25 +233,31 @@ void bch_moving_gc(struct cache_set *c)
 		    atomic_read(&b->pin))
 			continue;
 
-		if (!heap_full(&ca->heap)) {
+		if (!min_heap_full(&ca->heap)) {
 			sectors_to_move += GC_SECTORS_USED(b);
-			heap_add(&ca->heap, b, bucket_cmp);
-		} else if (bucket_cmp(b, heap_peek(&ca->heap))) {
+			min_heap_push(&ca->heap, &b, &callbacks, NULL);
+		} else if (!new_bucket_cmp(&b, min_heap_peek(&ca->heap), ca)) {
 			sectors_to_move -= bucket_heap_top(ca);
 			sectors_to_move += GC_SECTORS_USED(b);
 
 			ca->heap.data[0] = b;
-			heap_sift(&ca->heap, 0, bucket_cmp);
+			min_heap_sift_down(&ca->heap, 0, &callbacks, NULL);
 		}
 	}
 
 	while (sectors_to_move > reserve_sectors) {
-		heap_pop(&ca->heap, b, bucket_cmp);
+		if (ca->heap.nr) {
+			b = min_heap_peek(&ca->heap)[0];
+			min_heap_pop(&ca->heap, &callbacks, NULL);
+		}
 		sectors_to_move -= GC_SECTORS_USED(b);
 	}
 
-	while (heap_pop(&ca->heap, b, bucket_cmp))
+	while (ca->heap.nr) {
+		b = min_heap_peek(&ca->heap)[0];
+		min_heap_pop(&ca->heap, &callbacks, NULL);
 		SET_GC_MOVE(b, 1);
+	}
 
 	mutex_unlock(&c->bucket_lock);
 
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 6956beb55326..e8f696cb58c0 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -662,6 +662,8 @@ static unsigned int bch_root_usage(struct cache_set *c)
 	struct btree *b;
 	struct btree_iter iter;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 	goto lock_root;
 
 	do {
diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
index f61ab1bada6c..539454d8e2d0 100644
--- a/drivers/md/bcache/util.h
+++ b/drivers/md/bcache/util.h
@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/sched/clock.h>
 #include <linux/llist.h>
+#include <linux/min_heap.h>
 #include <linux/ratelimit.h>
 #include <linux/vmalloc.h>
 #include <linux/workqueue.h>
@@ -30,16 +31,10 @@ struct closure;
 
 #endif
 
-#define DECLARE_HEAP(type, name)					\
-	struct {							\
-		size_t size, used;					\
-		type *data;						\
-	} name
-
 #define init_heap(heap, _size, gfp)					\
 ({									\
 	size_t _bytes;							\
-	(heap)->used = 0;						\
+	(heap)->nr = 0;						\
 	(heap)->size = (_size);						\
 	_bytes = (heap)->size * sizeof(*(heap)->data);			\
 	(heap)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL);		\
@@ -52,64 +47,6 @@ do {									\
 	(heap)->data = NULL;						\
 } while (0)
 
-#define heap_swap(h, i, j)	swap((h)->data[i], (h)->data[j])
-
-#define heap_sift(h, i, cmp)						\
-do {									\
-	size_t _r, _j = i;						\
-									\
-	for (; _j * 2 + 1 < (h)->used; _j = _r) {			\
-		_r = _j * 2 + 1;					\
-		if (_r + 1 < (h)->used &&				\
-		    cmp((h)->data[_r], (h)->data[_r + 1]))		\
-			_r++;						\
-									\
-		if (cmp((h)->data[_r], (h)->data[_j]))			\
-			break;						\
-		heap_swap(h, _r, _j);					\
-	}								\
-} while (0)
-
-#define heap_sift_down(h, i, cmp)					\
-do {									\
-	while (i) {							\
-		size_t p = (i - 1) / 2;					\
-		if (cmp((h)->data[i], (h)->data[p]))			\
-			break;						\
-		heap_swap(h, i, p);					\
-		i = p;							\
-	}								\
-} while (0)
-
-#define heap_add(h, d, cmp)						\
-({									\
-	bool _r = !heap_full(h);					\
-	if (_r) {							\
-		size_t _i = (h)->used++;				\
-		(h)->data[_i] = d;					\
-									\
-		heap_sift_down(h, _i, cmp);				\
-		heap_sift(h, _i, cmp);					\
-	}								\
-	_r;								\
-})
-
-#define heap_pop(h, d, cmp)						\
-({									\
-	bool _r = (h)->used;						\
-	if (_r) {							\
-		(d) = (h)->data[0];					\
-		(h)->used--;						\
-		heap_swap(h, 0, (h)->used);				\
-		heap_sift(h, 0, cmp);					\
-	}								\
-	_r;								\
-})
-
-#define heap_peek(h)	((h)->used ? (h)->data[0] : NULL)
-
-#define heap_full(h)	((h)->used == (h)->size)
-
 #define DECLARE_FIFO(type, name)					\
 	struct {							\
 		size_t front, back, size, mask;				\
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 8827a6f130ad..c1d28e365910 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -915,6 +915,7 @@ static int bch_dirty_init_thread(void *arg)
 	k = p = NULL;
 	prev_idx = 0;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
 	bch_btree_iter_init(&c->root->keys, &iter, NULL);
 	k = bch_btree_iter_next_filter(&iter, &c->root->keys, bch_ptr_bad);
 	BUG_ON(!k);
@@ -984,6 +985,8 @@ void bch_sectors_dirty_init(struct bcache_device *d)
 	struct cache_set *c = d->c;
 	struct bch_dirty_init_state state;
 
+	min_heap_init(&iter.heap, NULL, MAX_BSETS);
+
 retry_lock:
 	b = c->root;
 	rw_lock(0, b, b->level);
-- 
2.34.1

[PATCH v4 16/16] bcachefs: Remove heap-related macros and switch to generic min_heap

[Kuan-Wei Chiu]

Drop the heap-related macros from bcachefs and replacing them with the
generic min_heap implementation from include/linux. By doing so, code
readability is improved by using functions instead of macros. Moreover,
the min_heap implementation in include/linux adopts a bottom-up
variation compared to the textbook version currently used in bcachefs.
This bottom-up variation allows for approximately 50% reduction in the
number of comparison operations during heap siftdown, without changing
the number of swaps, thus making it more efficient.

Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
Changes in v4:
- Fix an error in ec_stripes_heap_swap() where
  ec_stripes_heap_set_backpointer() should be called after swapping.

 fs/bcachefs/clock.c       |  43 ++++++++++----
 fs/bcachefs/clock_types.h |   2 +-
 fs/bcachefs/ec.c          |  76 ++++++++++++++++--------
 fs/bcachefs/ec_types.h    |   2 +-
 fs/bcachefs/util.h        | 118 +-------------------------------------
 5 files changed, 87 insertions(+), 154 deletions(-)

diff --git a/fs/bcachefs/clock.c b/fs/bcachefs/clock.c
index 363644451106..3ec64fe6a064 100644
--- a/fs/bcachefs/clock.c
+++ b/fs/bcachefs/clock.c
@@ -6,16 +6,29 @@
 #include <linux/kthread.h>
 #include <linux/preempt.h>
 
-static inline long io_timer_cmp(io_timer_heap *h,
-				struct io_timer *l,
-				struct io_timer *r)
+static inline bool io_timer_cmp(const void *l, const void *r, void __always_unused *args)
 {
-	return l->expire - r->expire;
+	struct io_timer **_l = (struct io_timer **)l;
+	struct io_timer **_r = (struct io_timer **)r;
+
+	return (*_l)->expire < (*_r)->expire;
+}
+
+static inline void io_timer_swp(void *l, void *r, void __always_unused *args)
+{
+	struct io_timer **_l = (struct io_timer **)l;
+	struct io_timer **_r = (struct io_timer **)r;
+
+	swap(*_l, *_r);
 }
 
 void bch2_io_timer_add(struct io_clock *clock, struct io_timer *timer)
 {
 	size_t i;
+	const struct min_heap_callbacks callbacks = {
+		.less = io_timer_cmp,
+		.swp = io_timer_swp,
+	};
 
 	spin_lock(&clock->timer_lock);
 
@@ -26,11 +39,11 @@ void bch2_io_timer_add(struct io_clock *clock, struct io_timer *timer)
 		return;
 	}
 
-	for (i = 0; i < clock->timers.used; i++)
+	for (i = 0; i < clock->timers.nr; i++)
 		if (clock->timers.data[i] == timer)
 			goto out;
 
-	BUG_ON(!heap_add(&clock->timers, timer, io_timer_cmp, NULL));
+	BUG_ON(!min_heap_push(&clock->timers, &timer, &callbacks, NULL));
 out:
 	spin_unlock(&clock->timer_lock);
 }
@@ -38,12 +51,16 @@ void bch2_io_timer_add(struct io_clock *clock, struct io_timer *timer)
 void bch2_io_timer_del(struct io_clock *clock, struct io_timer *timer)
 {
 	size_t i;
+	const struct min_heap_callbacks callbacks = {
+		.less = io_timer_cmp,
+		.swp = io_timer_swp,
+	};
 
 	spin_lock(&clock->timer_lock);
 
-	for (i = 0; i < clock->timers.used; i++)
+	for (i = 0; i < clock->timers.nr; i++)
 		if (clock->timers.data[i] == timer) {
-			heap_del(&clock->timers, i, io_timer_cmp, NULL);
+			min_heap_del(&clock->timers, i, &callbacks, NULL);
 			break;
 		}
 
@@ -131,12 +148,16 @@ static struct io_timer *get_expired_timer(struct io_clock *clock,
 					  unsigned long now)
 {
 	struct io_timer *ret = NULL;
+	const struct min_heap_callbacks callbacks = {
+		.less = io_timer_cmp,
+		.swp = io_timer_swp,
+	};
 
 	spin_lock(&clock->timer_lock);
 
-	if (clock->timers.used &&
+	if (clock->timers.nr &&
 	    time_after_eq(now, clock->timers.data[0]->expire))
-		heap_pop(&clock->timers, ret, io_timer_cmp, NULL);
+		min_heap_pop(&clock->timers, &callbacks, NULL);
 
 	spin_unlock(&clock->timer_lock);
 
@@ -161,7 +182,7 @@ void bch2_io_timers_to_text(struct printbuf *out, struct io_clock *clock)
 	spin_lock(&clock->timer_lock);
 	now = atomic64_read(&clock->now);
 
-	for (i = 0; i < clock->timers.used; i++)
+	for (i = 0; i < clock->timers.nr; i++)
 		prt_printf(out, "%ps:\t%li\n",
 		       clock->timers.data[i]->fn,
 		       clock->timers.data[i]->expire - now);
diff --git a/fs/bcachefs/clock_types.h b/fs/bcachefs/clock_types.h
index 5fae0012d808..59716e148645 100644
--- a/fs/bcachefs/clock_types.h
+++ b/fs/bcachefs/clock_types.h
@@ -23,7 +23,7 @@ struct io_timer {
 /* Amount to buffer up on a percpu counter */
 #define IO_CLOCK_PCPU_SECTORS	128
 
-typedef HEAP(struct io_timer *)	io_timer_heap;
+typedef MIN_HEAP(struct io_timer *, io_timer_heap)	io_timer_heap;
 
 struct io_clock {
 	atomic64_t		now;
diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 556a217108d3..0831e745dd12 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -868,8 +868,8 @@ static int __ec_stripe_mem_alloc(struct bch_fs *c, size_t idx, gfp_t gfp)
 
 		mutex_lock(&c->ec_stripes_heap_lock);
 		if (n.size > h->size) {
-			memcpy(n.data, h->data, h->used * sizeof(h->data[0]));
-			n.used = h->used;
+			memcpy(n.data, h->data, h->nr * sizeof(h->data[0]));
+			n.nr = h->nr;
 			swap(*h, n);
 		}
 		mutex_unlock(&c->ec_stripes_heap_lock);
@@ -960,7 +960,7 @@ static u64 stripe_idx_to_delete(struct bch_fs *c)
 
 	lockdep_assert_held(&c->ec_stripes_heap_lock);
 
-	if (h->used &&
+	if (h->nr &&
 	    h->data[0].blocks_nonempty == 0 &&
 	    !bch2_stripe_is_open(c, h->data[0].idx))
 		return h->data[0].idx;
@@ -968,14 +968,6 @@ static u64 stripe_idx_to_delete(struct bch_fs *c)
 	return 0;
 }
 
-static inline int ec_stripes_heap_cmp(ec_stripes_heap *h,
-				      struct ec_stripe_heap_entry l,
-				      struct ec_stripe_heap_entry r)
-{
-	return ((l.blocks_nonempty > r.blocks_nonempty) -
-		(l.blocks_nonempty < r.blocks_nonempty));
-}
-
 static inline void ec_stripes_heap_set_backpointer(ec_stripes_heap *h,
 						   size_t i)
 {
@@ -984,39 +976,71 @@ static inline void ec_stripes_heap_set_backpointer(ec_stripes_heap *h,
 	genradix_ptr(&c->stripes, h->data[i].idx)->heap_idx = i;
 }
 
+static inline bool ec_stripes_heap_cmp(const void *l, const void *r, void __always_unused *args)
+{
+	struct ec_stripe_heap_entry *_l = (struct ec_stripe_heap_entry *)l;
+	struct ec_stripe_heap_entry *_r = (struct ec_stripe_heap_entry *)r;
+
+	return ((_l->blocks_nonempty > _r->blocks_nonempty) <
+		(_l->blocks_nonempty < _r->blocks_nonempty));
+}
+
+static inline void ec_stripes_heap_swap(void *l, void *r, void *h)
+{
+	struct ec_stripe_heap_entry *_l = (struct ec_stripe_heap_entry *)l;
+	struct ec_stripe_heap_entry *_r = (struct ec_stripe_heap_entry *)r;
+	ec_stripes_heap *_h = (ec_stripes_heap *)h;
+	size_t i = _l - _h->data;
+	size_t j = _r - _h->data;
+
+	swap(*_l, *_r);
+
+	ec_stripes_heap_set_backpointer(_h, i);
+	ec_stripes_heap_set_backpointer(_h, j);
+}
+
 static void heap_verify_backpointer(struct bch_fs *c, size_t idx)
 {
 	ec_stripes_heap *h = &c->ec_stripes_heap;
 	struct stripe *m = genradix_ptr(&c->stripes, idx);
 
-	BUG_ON(m->heap_idx >= h->used);
+	BUG_ON(m->heap_idx >= h->nr);
 	BUG_ON(h->data[m->heap_idx].idx != idx);
 }
 
 void bch2_stripes_heap_del(struct bch_fs *c,
 			   struct stripe *m, size_t idx)
 {
+	const struct min_heap_callbacks callbacks = {
+		.less = ec_stripes_heap_cmp,
+		.swp = ec_stripes_heap_swap,
+	};
+
 	mutex_lock(&c->ec_stripes_heap_lock);
 	heap_verify_backpointer(c, idx);
 
-	heap_del(&c->ec_stripes_heap, m->heap_idx,
-		 ec_stripes_heap_cmp,
-		 ec_stripes_heap_set_backpointer);
+	min_heap_del(&c->ec_stripes_heap, m->heap_idx, &callbacks, &c->ec_stripes_heap);
 	mutex_unlock(&c->ec_stripes_heap_lock);
 }
 
 void bch2_stripes_heap_insert(struct bch_fs *c,
 			      struct stripe *m, size_t idx)
 {
+	const struct min_heap_callbacks callbacks = {
+		.less = ec_stripes_heap_cmp,
+		.swp = ec_stripes_heap_swap,
+	};
+
 	mutex_lock(&c->ec_stripes_heap_lock);
-	BUG_ON(heap_full(&c->ec_stripes_heap));
+	BUG_ON(min_heap_full(&c->ec_stripes_heap));
 
-	heap_add(&c->ec_stripes_heap, ((struct ec_stripe_heap_entry) {
+	genradix_ptr(&c->stripes, idx)->heap_idx = c->ec_stripes_heap.nr;
+	min_heap_push(&c->ec_stripes_heap, &((struct ec_stripe_heap_entry) {
 			.idx = idx,
 			.blocks_nonempty = m->blocks_nonempty,
 		}),
-		 ec_stripes_heap_cmp,
-		 ec_stripes_heap_set_backpointer);
+		&callbacks,
+		&c->ec_stripes_heap);
 
 	heap_verify_backpointer(c, idx);
 	mutex_unlock(&c->ec_stripes_heap_lock);
@@ -1025,6 +1049,10 @@ void bch2_stripes_heap_insert(struct bch_fs *c,
 void bch2_stripes_heap_update(struct bch_fs *c,
 			      struct stripe *m, size_t idx)
 {
+	const struct min_heap_callbacks callbacks = {
+		.less = ec_stripes_heap_cmp,
+		.swp = ec_stripes_heap_swap,
+	};
 	ec_stripes_heap *h = &c->ec_stripes_heap;
 	bool do_deletes;
 	size_t i;
@@ -1035,10 +1063,8 @@ void bch2_stripes_heap_update(struct bch_fs *c,
 	h->data[m->heap_idx].blocks_nonempty = m->blocks_nonempty;
 
 	i = m->heap_idx;
-	heap_sift_up(h,	  i, ec_stripes_heap_cmp,
-		     ec_stripes_heap_set_backpointer);
-	heap_sift_down(h, i, ec_stripes_heap_cmp,
-		       ec_stripes_heap_set_backpointer);
+	min_heap_sift_up(h,	i, &callbacks, &c->ec_stripes_heap);
+	min_heap_sift_down(h, i, &callbacks, &c->ec_stripes_heap);
 
 	heap_verify_backpointer(c, idx);
 
@@ -1830,7 +1856,7 @@ static s64 get_existing_stripe(struct bch_fs *c,
 		return -1;
 
 	mutex_lock(&c->ec_stripes_heap_lock);
-	for (heap_idx = 0; heap_idx < h->used; heap_idx++) {
+	for (heap_idx = 0; heap_idx < h->nr; heap_idx++) {
 		/* No blocks worth reusing, stripe will just be deleted: */
 		if (!h->data[heap_idx].blocks_nonempty)
 			continue;
@@ -2161,7 +2187,7 @@ void bch2_stripes_heap_to_text(struct printbuf *out, struct bch_fs *c)
 	size_t i;
 
 	mutex_lock(&c->ec_stripes_heap_lock);
-	for (i = 0; i < min_t(size_t, h->used, 50); i++) {
+	for (i = 0; i < min_t(size_t, h->nr, 50); i++) {
 		m = genradix_ptr(&c->stripes, h->data[i].idx);
 
 		prt_printf(out, "%zu %u/%u+%u", h->data[i].idx,
diff --git a/fs/bcachefs/ec_types.h b/fs/bcachefs/ec_types.h
index 976426da3a12..2ed67431a81c 100644
--- a/fs/bcachefs/ec_types.h
+++ b/fs/bcachefs/ec_types.h
@@ -36,6 +36,6 @@ struct ec_stripe_heap_entry {
 	unsigned		blocks_nonempty;
 };
 
-typedef HEAP(struct ec_stripe_heap_entry) ec_stripes_heap;
+typedef MIN_HEAP(struct ec_stripe_heap_entry, ec_stripes_heap) ec_stripes_heap;
 
 #endif /* _BCACHEFS_EC_TYPES_H */
diff --git a/fs/bcachefs/util.h b/fs/bcachefs/util.h
index 5cf885b09986..d5a1f1e29013 100644
--- a/fs/bcachefs/util.h
+++ b/fs/bcachefs/util.h
@@ -8,6 +8,7 @@
 #include <linux/errno.h>
 #include <linux/freezer.h>
 #include <linux/kernel.h>
+#include <linux/min_heap.h>
 #include <linux/sched/clock.h>
 #include <linux/llist.h>
 #include <linux/log2.h>
@@ -54,17 +55,9 @@ static inline size_t buf_pages(void *p, size_t len)
 			    PAGE_SIZE);
 }
 
-#define HEAP(type)							\
-struct {								\
-	size_t size, used;						\
-	type *data;							\
-}
-
-#define DECLARE_HEAP(type, name) HEAP(type) name
-
 #define init_heap(heap, _size, gfp)					\
 ({									\
-	(heap)->used = 0;						\
+	(heap)->nr = 0;						\
 	(heap)->size = (_size);						\
 	(heap)->data = kvmalloc((heap)->size * sizeof((heap)->data[0]),\
 				 (gfp));				\
@@ -76,113 +69,6 @@ do {									\
 	(heap)->data = NULL;						\
 } while (0)
 
-#define heap_set_backpointer(h, i, _fn)					\
-do {									\
-	void (*fn)(typeof(h), size_t) = _fn;				\
-	if (fn)								\
-		fn(h, i);						\
-} while (0)
-
-#define heap_swap(h, i, j, set_backpointer)				\
-do {									\
-	swap((h)->data[i], (h)->data[j]);				\
-	heap_set_backpointer(h, i, set_backpointer);			\
-	heap_set_backpointer(h, j, set_backpointer);			\
-} while (0)
-
-#define heap_peek(h)							\
-({									\
-	EBUG_ON(!(h)->used);						\
-	(h)->data[0];							\
-})
-
-#define heap_full(h)	((h)->used == (h)->size)
-
-#define heap_sift_down(h, i, cmp, set_backpointer)			\
-do {									\
-	size_t _c, _j = i;						\
-									\
-	for (; _j * 2 + 1 < (h)->used; _j = _c) {			\
-		_c = _j * 2 + 1;					\
-		if (_c + 1 < (h)->used &&				\
-		    cmp(h, (h)->data[_c], (h)->data[_c + 1]) >= 0)	\
-			_c++;						\
-									\
-		if (cmp(h, (h)->data[_c], (h)->data[_j]) >= 0)		\
-			break;						\
-		heap_swap(h, _c, _j, set_backpointer);			\
-	}								\
-} while (0)
-
-#define heap_sift_up(h, i, cmp, set_backpointer)			\
-do {									\
-	while (i) {							\
-		size_t p = (i - 1) / 2;					\
-		if (cmp(h, (h)->data[i], (h)->data[p]) >= 0)		\
-			break;						\
-		heap_swap(h, i, p, set_backpointer);			\
-		i = p;							\
-	}								\
-} while (0)
-
-#define __heap_add(h, d, cmp, set_backpointer)				\
-({									\
-	size_t _i = (h)->used++;					\
-	(h)->data[_i] = d;						\
-	heap_set_backpointer(h, _i, set_backpointer);			\
-									\
-	heap_sift_up(h, _i, cmp, set_backpointer);			\
-	_i;								\
-})
-
-#define heap_add(h, d, cmp, set_backpointer)				\
-({									\
-	bool _r = !heap_full(h);					\
-	if (_r)								\
-		__heap_add(h, d, cmp, set_backpointer);			\
-	_r;								\
-})
-
-#define heap_add_or_replace(h, new, cmp, set_backpointer)		\
-do {									\
-	if (!heap_add(h, new, cmp, set_backpointer) &&			\
-	    cmp(h, new, heap_peek(h)) >= 0) {				\
-		(h)->data[0] = new;					\
-		heap_set_backpointer(h, 0, set_backpointer);		\
-		heap_sift_down(h, 0, cmp, set_backpointer);		\
-	}								\
-} while (0)
-
-#define heap_del(h, i, cmp, set_backpointer)				\
-do {									\
-	size_t _i = (i);						\
-									\
-	BUG_ON(_i >= (h)->used);					\
-	(h)->used--;							\
-	if ((_i) < (h)->used) {						\
-		heap_swap(h, _i, (h)->used, set_backpointer);		\
-		heap_sift_up(h, _i, cmp, set_backpointer);		\
-		heap_sift_down(h, _i, cmp, set_backpointer);		\
-	}								\
-} while (0)
-
-#define heap_pop(h, d, cmp, set_backpointer)				\
-({									\
-	bool _r = (h)->used;						\
-	if (_r) {							\
-		(d) = (h)->data[0];					\
-		heap_del(h, 0, cmp, set_backpointer);			\
-	}								\
-	_r;								\
-})
-
-#define heap_resort(heap, cmp, set_backpointer)				\
-do {									\
-	ssize_t _i;							\
-	for (_i = (ssize_t) (heap)->used / 2 -  1; _i >= 0; --_i)	\
-		heap_sift_down(heap, _i, cmp, set_backpointer);		\
-} while (0)
-
 #define ANYSINT_MAX(t)							\
 	((((t) 1 << (sizeof(t) * 8 - 2)) - (t) 1) * (t) 2 + (t) 1)
 
-- 
2.34.1

Re: [PATCH v4 00/16] treewide: Refactor heap related implementation

[Kent Overstreet]

Hey Stephen, I think this is ready for -next.

https://github.com/visitorckw/linux.git refactor-heap-v4

Kuan, please add my acked-by to the bcachefs patch as well.

Cheers,
Kent

On Thu, Apr 25, 2024 at 10:18:10PM +0800, Kuan-Wei Chiu wrote:
> This patch series focuses on several adjustments related to heap
> implementation. Firstly, a type-safe interface has been added to the
> min_heap, along with the introduction of several new functions to
> enhance its functionality. Additionally, the heap implementation for
> bcache and bcachefs has been replaced with the generic min_heap
> implementation from include/linux. Furthermore, several typos have been
> corrected.
> 
> Previous discussion with Kent Overstreet:
> https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu
> 
> Regards,
> Kuan-Wei
> 
> ---
> 
> You can preview this patch series on the 'refactor-heap-v4' branch of
> the repository at the following link:
> 
> https://github.com/visitorckw/linux.git
> 
> Changes in v4:
> - Change struct initializations to use designated initializers.
> - Replace memcpy() with func->swp() in heap_del() due to issues with
>   set_backpointer in bcachefs when setting idx.
> - Fix an error in ec_stripes_heap_swap() where
>   ec_stripes_heap_set_backpointer() should be called after swapping.
> 
> Changes in v3:
> - Avoid heap->heap.nr to eliminate the nested types.
> - Add MIN_HEAP_PREALLOCATED macro for preallocating some elements.
> - Use min_heap_sift_up() in min_heap_push().
> - Fix a bug in heap_del() where we should copy the last element to
>   'data + idx * element_size' instead of 'data'.
> - Add testcases for heap_del().
> - Fix bugs in bcache/bcachefs patches where the parameter types in
>   some compare functions should have been 'type **', but were
>   mistakenly written as 'type *'.
> 
> Changes in v2:
> - Add attribute __always_unused to the compare and swap functions
>   that do not use the args parameter.
> - Rename min_heapify() to min_heap_sift_down().
> - Update lib/test_min_heap.c to use min_heap_init().
> - Refine the commit message for bcache and bcachefs.
> - Adjust the order of patches in the patch series.
> 
> Link to v3: https://lore.kernel.org/20240406164727.577914-1-visitorckw@gmail.com
> Link to v2: https://lore.kernel.org/20240320145417.336208-1-visitorckw@gmail.com
> Link to v1: https://lkml.kernel.org/20240319180005.246930-1-visitorckw@gmail.com
> 
> Kuan-Wei Chiu (16):
>   perf/core: Fix several typos
>   bcache: Fix typo
>   bcachefs: Fix typo
>   lib min_heap: Add type safe interface
>   lib min_heap: Add min_heap_init()
>   lib min_heap: Add min_heap_peek()
>   lib min_heap: Add min_heap_full()
>   lib min_heap: Add args for min_heap_callbacks
>   lib min_heap: Add min_heap_sift_up()
>   lib min_heap: Add min_heap_del()
>   lib min_heap: Update min_heap_push() and min_heap_pop() to return bool
>     values
>   lib min_heap: Rename min_heapify() to min_heap_sift_down()
>   lib min_heap: Update min_heap_push() to use min_heap_sift_up()
>   lib/test_min_heap: Add test for heap_del()
>   bcache: Remove heap-related macros and switch to generic min_heap
>   bcachefs: Remove heap-related macros and switch to generic min_heap
> 
>  drivers/md/bcache/alloc.c      |  64 ++++++++---
>  drivers/md/bcache/bcache.h     |   2 +-
>  drivers/md/bcache/bset.c       |  84 ++++++++++-----
>  drivers/md/bcache/bset.h       |  14 +--
>  drivers/md/bcache/btree.c      |  17 ++-
>  drivers/md/bcache/extents.c    |  53 ++++++----
>  drivers/md/bcache/movinggc.c   |  41 +++++--
>  drivers/md/bcache/sysfs.c      |   2 +
>  drivers/md/bcache/util.c       |   2 +-
>  drivers/md/bcache/util.h       |  67 +-----------
>  drivers/md/bcache/writeback.c  |   3 +
>  drivers/md/dm-vdo/repair.c     |  19 ++--
>  drivers/md/dm-vdo/slab-depot.c |  14 +--
>  fs/bcachefs/clock.c            |  43 ++++++--
>  fs/bcachefs/clock_types.h      |   2 +-
>  fs/bcachefs/ec.c               |  76 ++++++++-----
>  fs/bcachefs/ec_types.h         |   2 +-
>  fs/bcachefs/util.c             |   2 +-
>  fs/bcachefs/util.h             | 118 +--------------------
>  include/linux/min_heap.h       | 188 +++++++++++++++++++++++++--------
>  kernel/events/core.c           |  29 ++---
>  lib/test_min_heap.c            |  75 +++++++++----
>  22 files changed, 522 insertions(+), 395 deletions(-)
> 
> -- 
> 2.34.1
> 

Re: [PATCH v4 00/16] treewide: Refactor heap related implementation

[Kuan-Wei Chiu]

On Thu, Apr 25, 2024 at 04:54:54PM -0400, Kent Overstreet wrote:
> Hey Stephen, I think this is ready for -next.
> 
> https://github.com/visitorckw/linux.git refactor-heap-v4
> 
> Kuan, please add my acked-by to the bcachefs patch as well.
> 
Acked-by tag has been added to the repository mentioned above and
pushed out.

Regards,
Kuan-Wei
> 
> On Thu, Apr 25, 2024 at 10:18:10PM +0800, Kuan-Wei Chiu wrote:
> > This patch series focuses on several adjustments related to heap
> > implementation. Firstly, a type-safe interface has been added to the
> > min_heap, along with the introduction of several new functions to
> > enhance its functionality. Additionally, the heap implementation for
> > bcache and bcachefs has been replaced with the generic min_heap
> > implementation from include/linux. Furthermore, several typos have been
> > corrected.
> > 
> > Previous discussion with Kent Overstreet:
> > https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu
> > 
> > Regards,
> > Kuan-Wei
> > 
> > ---
> > 
> > You can preview this patch series on the 'refactor-heap-v4' branch of
> > the repository at the following link:
> > 
> > https://github.com/visitorckw/linux.git
> > 
> > Changes in v4:
> > - Change struct initializations to use designated initializers.
> > - Replace memcpy() with func->swp() in heap_del() due to issues with
> >   set_backpointer in bcachefs when setting idx.
> > - Fix an error in ec_stripes_heap_swap() where
> >   ec_stripes_heap_set_backpointer() should be called after swapping.
> > 
> > Changes in v3:
> > - Avoid heap->heap.nr to eliminate the nested types.
> > - Add MIN_HEAP_PREALLOCATED macro for preallocating some elements.
> > - Use min_heap_sift_up() in min_heap_push().
> > - Fix a bug in heap_del() where we should copy the last element to
> >   'data + idx * element_size' instead of 'data'.
> > - Add testcases for heap_del().
> > - Fix bugs in bcache/bcachefs patches where the parameter types in
> >   some compare functions should have been 'type **', but were
> >   mistakenly written as 'type *'.
> > 
> > Changes in v2:
> > - Add attribute __always_unused to the compare and swap functions
> >   that do not use the args parameter.
> > - Rename min_heapify() to min_heap_sift_down().
> > - Update lib/test_min_heap.c to use min_heap_init().
> > - Refine the commit message for bcache and bcachefs.
> > - Adjust the order of patches in the patch series.
> > 
> > Link to v3: https://lore.kernel.org/20240406164727.577914-1-visitorckw@gmail.com
> > Link to v2: https://lore.kernel.org/20240320145417.336208-1-visitorckw@gmail.com
> > Link to v1: https://lkml.kernel.org/20240319180005.246930-1-visitorckw@gmail.com
> > 
> > Kuan-Wei Chiu (16):
> >   perf/core: Fix several typos
> >   bcache: Fix typo
> >   bcachefs: Fix typo
> >   lib min_heap: Add type safe interface
> >   lib min_heap: Add min_heap_init()
> >   lib min_heap: Add min_heap_peek()
> >   lib min_heap: Add min_heap_full()
> >   lib min_heap: Add args for min_heap_callbacks
> >   lib min_heap: Add min_heap_sift_up()
> >   lib min_heap: Add min_heap_del()
> >   lib min_heap: Update min_heap_push() and min_heap_pop() to return bool
> >     values
> >   lib min_heap: Rename min_heapify() to min_heap_sift_down()
> >   lib min_heap: Update min_heap_push() to use min_heap_sift_up()
> >   lib/test_min_heap: Add test for heap_del()
> >   bcache: Remove heap-related macros and switch to generic min_heap
> >   bcachefs: Remove heap-related macros and switch to generic min_heap
> > 
> >  drivers/md/bcache/alloc.c      |  64 ++++++++---
> >  drivers/md/bcache/bcache.h     |   2 +-
> >  drivers/md/bcache/bset.c       |  84 ++++++++++-----
> >  drivers/md/bcache/bset.h       |  14 +--
> >  drivers/md/bcache/btree.c      |  17 ++-
> >  drivers/md/bcache/extents.c    |  53 ++++++----
> >  drivers/md/bcache/movinggc.c   |  41 +++++--
> >  drivers/md/bcache/sysfs.c      |   2 +
> >  drivers/md/bcache/util.c       |   2 +-
> >  drivers/md/bcache/util.h       |  67 +-----------
> >  drivers/md/bcache/writeback.c  |   3 +
> >  drivers/md/dm-vdo/repair.c     |  19 ++--
> >  drivers/md/dm-vdo/slab-depot.c |  14 +--
> >  fs/bcachefs/clock.c            |  43 ++++++--
> >  fs/bcachefs/clock_types.h      |   2 +-
> >  fs/bcachefs/ec.c               |  76 ++++++++-----
> >  fs/bcachefs/ec_types.h         |   2 +-
> >  fs/bcachefs/util.c             |   2 +-
> >  fs/bcachefs/util.h             | 118 +--------------------
> >  include/linux/min_heap.h       | 188 +++++++++++++++++++++++++--------
> >  kernel/events/core.c           |  29 ++---
> >  lib/test_min_heap.c            |  75 +++++++++----
> >  22 files changed, 522 insertions(+), 395 deletions(-)
> > 
> > -- 
> > 2.34.1
> >