On Wed, Mar 20, 2024 at 10:54:06PM +0800, Kuan-Wei Chiu wrote: > 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. let's avoid the heap->heap.nr - darray (fs/bcachefs/darray.h) has a trick for that. All heaps have the same memory layout, so we can just cast to a void pointer heap to get something the C code can use. > > Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu > Signed-off-by: Kuan-Wei Chiu <visitorckw@xxxxxxxxx> > Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx> > --- > 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 >
