Introduce a type-safe interface for min_heap by adding small macro wrappers around functions and using a 0-size array to store type information. This enables the use of __minheap_cast and __minheap_obj_size macros for type casting and obtaining element size. The implementation draws inspiration from generic-radix-tree.h, eliminating the need to pass element size in min_heap_callbacks.
Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu Signed-off-by: Kuan-Wei Chiu <[email protected]> Reviewed-by: Ian Rogers <[email protected]> --- drivers/md/dm-vdo/repair.c | 21 +++++----- drivers/md/dm-vdo/slab-depot.c | 13 +++--- include/linux/min_heap.h | 75 +++++++++++++++++++++++----------- kernel/events/core.c | 35 ++++++++-------- lib/test_min_heap.c | 49 +++++++++++----------- 5 files changed, 107 insertions(+), 86 deletions(-) diff --git a/drivers/md/dm-vdo/repair.c b/drivers/md/dm-vdo/repair.c index defc9359f10e..7663fa2098f4 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; @@ -163,25 +165,24 @@ 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) + if (heap->heap.nr == 0) return NULL; /* * Swap the next heap element with the last one on the heap, popping it off the heap, * restore the heap invariant, and return a pointer to the popped element. */ - last = &repair->entries[--heap->nr]; - swap_mappings(heap->data, last); + last = &repair->entries[--heap->heap.nr]; + swap_mappings(heap->heap.data, last); min_heapify(heap, 0, &repair_min_heap); return last; } @@ -1117,11 +1118,9 @@ 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) { - .data = repair->entries, - .nr = repair->block_map_entry_count, - .size = repair->block_map_entry_count, - }; + repair->replay_heap.heap.data = repair->entries; + repair->replay_heap.heap.nr = repair->block_map_entry_count; + repair->replay_heap.heap.size = repair->block_map_entry_count; min_heapify_all(&repair->replay_heap, &repair_min_heap); vdo_log_info("Replaying %zu recovery entries into block map", diff --git a/drivers/md/dm-vdo/slab-depot.c b/drivers/md/dm-vdo/slab-depot.c index 46e4721e5b4f..3309480170c3 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; @@ -3521,14 +3520,12 @@ 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) { - .data = slab_statuses, - .nr = allocator->slab_count, - .size = allocator->slab_count, - }; + heap.heap.data = slab_statuses; + heap.heap.nr = allocator->slab_count; + heap.heap.size = allocator->slab_count; min_heapify_all(&heap, &slab_status_min_heap); - while (heap.nr > 0) { + while (heap.heap.nr > 0) { bool high_priority; struct vdo_slab *slab; struct slab_journal *journal; diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h index d52daf45861b..c3635a7fdb88 100644 --- a/include/linux/min_heap.h +++ b/include/linux/min_heap.h @@ -7,45 +7,59 @@ #include <linux/types.h> /** - * struct min_heap - Data structure to hold a min-heap. + * struct __min_heap - Data structure to hold a min-heap. * @data: Start of array holding the heap elements. * @nr: Number of elements currently in the heap. * @size: Maximum number of elements that can be held in current storage. */ -struct min_heap { +struct __min_heap { void *data; int nr; int size; }; +/* + * We use a 0 size array to stash the type we're storing without taking any + * space at runtime - then the various accessor macros can use typeof() to get + * to it for casts/sizeof - we also force the alignment so that storing a type + * with a ridiculous alignment doesn't blow up the alignment or size of the + * min_heap. + */ +#define MIN_HEAP(_type, _name) \ +struct _name { \ + struct __min_heap heap; \ + _type type[0] __aligned(1); \ +} + +#define __minheap_cast(_heap) (typeof((_heap)->type[0]) *) +#define __minheap_obj_size(_heap) sizeof((_heap)->type[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(struct __min_heap *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 +68,37 @@ 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(&(_heap)->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(struct __min_heap *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(&(_heap)->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(struct __min_heap *heap, size_t elem_size, const struct min_heap_callbacks *func) { void *data = heap->data; @@ -88,27 +108,33 @@ 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(&(_heap)->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(struct __min_heap *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(&(_heap)->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(struct __min_heap *heap, const void *element, size_t elem_size, const struct min_heap_callbacks *func) { void *data = heap->data; @@ -120,17 +146,20 @@ 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(&(_heap)->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..065dfaa8b009 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3698,19 +3698,20 @@ 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; + struct perf_event **itrs = heap->heap.data; if (event) { - itrs[heap->nr] = event; - heap->nr++; + itrs[heap->heap.nr] = event; + heap->heap.nr++; } } @@ -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; @@ -3747,11 +3748,9 @@ 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){ - .data = cpuctx->heap, - .nr = 0, - .size = cpuctx->heap_size, - }; + event_heap.heap.data = cpuctx->heap; + event_heap.heap.nr = 0; + event_heap.heap.size = cpuctx->heap_size; lockdep_assert_held(&cpuctx->ctx.lock); @@ -3760,15 +3759,13 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx, css = &cpuctx->cgrp->css; #endif } else { - event_heap = (struct min_heap){ - .data = itrs, - .nr = 0, - .size = ARRAY_SIZE(itrs), - }; + event_heap.heap.data = itrs; + event_heap.heap.nr = 0; + event_heap.heap.size = ARRAY_SIZE(itrs); /* Events not within a CPU context may be on any CPU. */ __heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL)); } - evt = event_heap.data; + evt = event_heap.heap.data; __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL)); @@ -3777,14 +3774,14 @@ static noinline int visit_groups_merge(struct perf_event_context *ctx, __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup)); #endif - if (event_heap.nr) { + if (event_heap.heap.nr) { __link_epc((*evt)->pmu_ctx); perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu); } min_heapify_all(&event_heap, &perf_min_heap); - while (event_heap.nr) { + while (event_heap.heap.nr) { ret = func(*evt, data); if (ret) return ret; diff --git a/lib/test_min_heap.c b/lib/test_min_heap.c index 7b01b4387cfb..af2e446034d8 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; @@ -30,16 +32,16 @@ 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; + int *values = heap->heap.data; int err = 0; int last; last = values[0]; min_heap_pop(heap, funcs); - while (heap->nr > 0) { + while (heap->heap.nr > 0) { if (min_heap) { if (last > values[0]) { pr_err("error: expected %d <= %d\n", last, @@ -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 = { - .data = values, - .nr = ARRAY_SIZE(values), - .size = ARRAY_SIZE(values), - }; + struct min_heap_test heap; + + heap.heap.data = values; + heap.heap.nr = ARRAY_SIZE(values); + heap.heap.size = ARRAY_SIZE(values); struct min_heap_callbacks funcs = { - .elem_size = sizeof(int), .less = min_heap ? less_than : greater_than, .swp = swap_ints, }; @@ -81,8 +82,8 @@ static __init int test_heapify_all(bool min_heap) /* Test with randomly generated values. */ - heap.nr = ARRAY_SIZE(values); - for (i = 0; i < heap.nr; i++) + heap.heap.nr = ARRAY_SIZE(values); + for (i = 0; i < heap.heap.nr; i++) values[i] = get_random_u32(); min_heapify_all(&heap, &funcs); @@ -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 = { - .data = values, - .nr = 0, - .size = ARRAY_SIZE(values), - }; + struct min_heap_test heap; + + heap.heap.data = values; + heap.heap.nr = 0; + heap.heap.size = ARRAY_SIZE(values); struct min_heap_callbacks funcs = { - .elem_size = sizeof(int), .less = min_heap ? less_than : greater_than, .swp = swap_ints, }; @@ -115,7 +115,7 @@ static __init int test_heap_push(bool min_heap) err = pop_verify_heap(min_heap, &heap, &funcs); /* Test with randomly generated values. */ - while (heap.nr < heap.size) { + while (heap.heap.nr < heap.heap.size) { temp = get_random_u32(); min_heap_push(&heap, &temp, &funcs); } @@ -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 = { - .data = values, - .nr = 0, - .size = ARRAY_SIZE(values), - }; + struct min_heap_test heap; + + heap.heap.data = values; + heap.heap.nr = 0; + heap.heap.size = ARRAY_SIZE(values); struct min_heap_callbacks funcs = { - .elem_size = sizeof(int), .less = min_heap ? less_than : greater_than, .swp = swap_ints, }; @@ -152,7 +151,7 @@ static __init int test_heap_pop_push(bool min_heap) err = pop_verify_heap(min_heap, &heap, &funcs); - heap.nr = 0; + heap.heap.nr = 0; for (i = 0; i < ARRAY_SIZE(data); i++) min_heap_push(&heap, &temp, &funcs); -- 2.34.1
