server-skynet-source-3rd-je.../include/jemalloc/internal/ph.h
David Goldblatt 08a4cc0969 Pairing heap: inline functions instead of macros.
By force-inlining everything that would otherwise be a macro, we get the same
effect (it's not clear in the first place that this is actually a good idea, but
it avoids making any changes to the existing performance profile).

This makes the code more maintainable (in anticipation of subsequent changes),
as well as making performance profiles and debug info more readable (we get
"real" line numbers, instead of making everything point to the macro definition
of all associated functions).
2021-08-02 15:02:49 -07:00

450 lines
12 KiB
C

#ifndef JEMALLOC_INTERNAL_PH_H
#define JEMALLOC_INTERNAL_PH_H
/*
* A Pairing Heap implementation.
*
* "The Pairing Heap: A New Form of Self-Adjusting Heap"
* https://www.cs.cmu.edu/~sleator/papers/pairing-heaps.pdf
*
* With auxiliary twopass list, described in a follow on paper.
*
* "Pairing Heaps: Experiments and Analysis"
* http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.106.2988&rep=rep1&type=pdf
*
*******************************************************************************
*/
typedef int (*ph_cmp_t)(void *, void *);
/* Node structure. */
typedef struct phn_link_s phn_link_t;
struct phn_link_s {
void *prev;
void *next;
void *lchild;
};
typedef struct ph_s ph_t;
struct ph_s {
void *root;
};
JEMALLOC_ALWAYS_INLINE phn_link_t *
phn_link_get(void *phn, size_t offset) {
return (phn_link_t *)(((uintptr_t)phn) + offset);
}
JEMALLOC_ALWAYS_INLINE void
phn_link_init(void *phn, size_t offset) {
phn_link_get(phn, offset)->prev = NULL;
phn_link_get(phn, offset)->next = NULL;
phn_link_get(phn, offset)->lchild = NULL;
}
/* Internal utility helpers. */
JEMALLOC_ALWAYS_INLINE void *
phn_lchild_get(void *phn, size_t offset) {
return phn_link_get(phn, offset)->lchild;
}
JEMALLOC_ALWAYS_INLINE void
phn_lchild_set(void *phn, void *lchild, size_t offset) {
phn_link_get(phn, offset)->lchild = lchild;
}
JEMALLOC_ALWAYS_INLINE void *
phn_next_get(void *phn, size_t offset) {
return phn_link_get(phn, offset)->next;
}
JEMALLOC_ALWAYS_INLINE void
phn_next_set(void *phn, void *next, size_t offset) {
phn_link_get(phn, offset)->next = next;
}
JEMALLOC_ALWAYS_INLINE void *
phn_prev_get(void *phn, size_t offset) {
return phn_link_get(phn, offset)->prev;
}
JEMALLOC_ALWAYS_INLINE void
phn_prev_set(void *phn, void *prev, size_t offset) {
phn_link_get(phn, offset)->prev = prev;
}
JEMALLOC_ALWAYS_INLINE void
phn_merge_ordered(void *phn0, void *phn1, size_t offset,
ph_cmp_t cmp) {
void *phn0child;
assert(phn0 != NULL);
assert(phn1 != NULL);
assert(cmp(phn0, phn1) <= 0);
phn_prev_set(phn1, phn0, offset);
phn0child = phn_lchild_get(phn0, offset);
phn_next_set(phn1, phn0child, offset);
if (phn0child != NULL) {
phn_prev_set(phn0child, phn1, offset);
}
phn_lchild_set(phn0, phn1, offset);
}
JEMALLOC_ALWAYS_INLINE void *
phn_merge(void *phn0, void *phn1, size_t offset, ph_cmp_t cmp) {
void *result;
if (phn0 == NULL) {
result = phn1;
} else if (phn1 == NULL) {
result = phn0;
} else if (cmp(phn0, phn1) < 0) {
phn_merge_ordered(phn0, phn1, offset, cmp);
result = phn0;
} else {
phn_merge_ordered(phn1, phn0, offset, cmp);
result = phn1;
}
return result;
}
JEMALLOC_ALWAYS_INLINE void *
phn_merge_siblings(void *phn, size_t offset, ph_cmp_t cmp) {
void *head = NULL;
void *tail = NULL;
void *phn0 = phn;
void *phn1 = phn_next_get(phn0, offset);
/*
* Multipass merge, wherein the first two elements of a FIFO
* are repeatedly merged, and each result is appended to the
* singly linked FIFO, until the FIFO contains only a single
* element. We start with a sibling list but no reference to
* its tail, so we do a single pass over the sibling list to
* populate the FIFO.
*/
if (phn1 != NULL) {
void *phnrest = phn_next_get(phn1, offset);
if (phnrest != NULL) {
phn_prev_set(phnrest, NULL, offset);
}
phn_prev_set(phn0, NULL, offset);
phn_next_set(phn0, NULL, offset);
phn_prev_set(phn1, NULL, offset);
phn_next_set(phn1, NULL, offset);
phn0 = phn_merge(phn0, phn1, offset, cmp);
head = tail = phn0;
phn0 = phnrest;
while (phn0 != NULL) {
phn1 = phn_next_get(phn0, offset);
if (phn1 != NULL) {
phnrest = phn_next_get(phn1, offset);
if (phnrest != NULL) {
phn_prev_set(phnrest, NULL, offset);
}
phn_prev_set(phn0, NULL, offset);
phn_next_set(phn0, NULL, offset);
phn_prev_set(phn1, NULL, offset);
phn_next_set(phn1, NULL, offset);
phn0 = phn_merge(phn0, phn1, offset, cmp);
phn_next_set(tail, phn0, offset);
tail = phn0;
phn0 = phnrest;
} else {
phn_next_set(tail, phn0, offset);
tail = phn0;
phn0 = NULL;
}
}
phn0 = head;
phn1 = phn_next_get(phn0, offset);
if (phn1 != NULL) {
while (true) {
head = phn_next_get(phn1, offset);
assert(phn_prev_get(phn0, offset) == NULL);
phn_next_set(phn0, NULL, offset);
assert(phn_prev_get(phn1, offset) == NULL);
phn_next_set(phn1, NULL, offset);
phn0 = phn_merge(phn0, phn1, offset, cmp);
if (head == NULL) {
break;
}
phn_next_set(tail, phn0, offset);
tail = phn0;
phn0 = head;
phn1 = phn_next_get(phn0, offset);
}
}
}
return phn0;
}
JEMALLOC_ALWAYS_INLINE void
ph_merge_aux(ph_t *ph, size_t offset, ph_cmp_t cmp) {
void *phn = phn_next_get(ph->root, offset);
if (phn != NULL) {
phn_prev_set(ph->root, NULL, offset);
phn_next_set(ph->root, NULL, offset);
phn_prev_set(phn, NULL, offset);
phn = phn_merge_siblings(phn, offset, cmp);
assert(phn_next_get(phn, offset) == NULL);
ph->root = phn_merge(ph->root, phn, offset, cmp);
}
}
JEMALLOC_ALWAYS_INLINE void *
ph_merge_children(void *phn, size_t offset, ph_cmp_t cmp) {
void *result;
void *lchild = phn_lchild_get(phn, offset);
if (lchild == NULL) {
result = NULL;
} else {
result = phn_merge_siblings(lchild, offset, cmp);
}
return result;
}
JEMALLOC_ALWAYS_INLINE void
ph_new(ph_t *ph) {
ph->root = NULL;
}
JEMALLOC_ALWAYS_INLINE bool
ph_empty(ph_t *ph) {
return ph->root == NULL;
}
JEMALLOC_ALWAYS_INLINE void *
ph_first(ph_t *ph, size_t offset, ph_cmp_t cmp) {
if (ph->root == NULL) {
return NULL;
}
ph_merge_aux(ph, offset, cmp);
return ph->root;
}
JEMALLOC_ALWAYS_INLINE void *
ph_any(ph_t *ph, size_t offset) {
if (ph->root == NULL) {
return NULL;
}
void *aux = phn_next_get(ph->root, offset);
if (aux != NULL) {
return aux;
}
return ph->root;
}
JEMALLOC_ALWAYS_INLINE void
ph_insert(ph_t *ph, void *phn, size_t offset) {
phn_link_init(phn, offset);
/*
* Treat the root as an aux list during insertion, and lazily merge
* during a_prefix##remove_first(). For elements that are inserted,
* then removed via a_prefix##remove() before the aux list is ever
* processed, this makes insert/remove constant-time, whereas eager
* merging would make insert O(log n).
*/
if (ph->root == NULL) {
ph->root = phn;
} else {
phn_next_set(phn, phn_next_get(ph->root, offset), offset);
if (phn_next_get(ph->root, offset) != NULL) {
phn_prev_set(phn_next_get(ph->root, offset), phn,
offset);
}
phn_prev_set(phn, ph->root, offset);
phn_next_set(ph->root, phn, offset);
}
}
JEMALLOC_ALWAYS_INLINE void *
ph_remove_first(ph_t *ph, size_t offset, ph_cmp_t cmp) {
void *ret;
if (ph->root == NULL) {
return NULL;
}
ph_merge_aux(ph, offset, cmp);
ret = ph->root;
ph->root = ph_merge_children(ph->root, offset, cmp);
return ret;
}
JEMALLOC_ALWAYS_INLINE void *
ph_remove_any(ph_t *ph, size_t offset, ph_cmp_t cmp) {
/*
* Remove the most recently inserted aux list element, or the root if
* the aux list is empty. This has the effect of behaving as a LIFO
* (and insertion/removal is therefore constant-time) if
* a_prefix##[remove_]first() are never called.
*/
if (ph->root == NULL) {
return NULL;
}
void *ret = phn_next_get(ph->root, offset);
if (ret != NULL) {
void *aux = phn_next_get(ret, offset);
phn_next_set(ph->root, aux, offset);
if (aux != NULL) {
phn_prev_set(aux, ph->root, offset);
}
return ret;
}
ret = ph->root;
ph->root = ph_merge_children(ph->root, offset, cmp);
return ret;
}
JEMALLOC_ALWAYS_INLINE void
ph_remove(ph_t *ph, void *phn, size_t offset, ph_cmp_t cmp) {
void *replace;
void *parent;
if (ph->root == phn) {
/*
* We can delete from aux list without merging it, but we need
* to merge if we are dealing with the root node and it has
* children.
*/
if (phn_lchild_get(phn, offset) == NULL) {
ph->root = phn_next_get(phn, offset);
if (ph->root != NULL) {
phn_prev_set(ph->root, NULL, offset);
}
return;
}
ph_merge_aux(ph, offset, cmp);
if (ph->root == phn) {
ph->root = ph_merge_children(ph->root, offset, cmp);
return;
}
}
/* Get parent (if phn is leftmost child) before mutating. */
if ((parent = phn_prev_get(phn, offset)) != NULL) {
if (phn_lchild_get(parent, offset) != phn) {
parent = NULL;
}
}
/* Find a possible replacement node, and link to parent. */
replace = ph_merge_children(phn, offset, cmp);
/* Set next/prev for sibling linked list. */
if (replace != NULL) {
if (parent != NULL) {
phn_prev_set(replace, parent, offset);
phn_lchild_set(parent, replace, offset);
} else {
phn_prev_set(replace, phn_prev_get(phn, offset),
offset);
if (phn_prev_get(phn, offset) != NULL) {
phn_next_set(phn_prev_get(phn, offset), replace,
offset);
}
}
phn_next_set(replace, phn_next_get(phn, offset), offset);
if (phn_next_get(phn, offset) != NULL) {
phn_prev_set(phn_next_get(phn, offset), replace,
offset);
}
} else {
if (parent != NULL) {
void *next = phn_next_get(phn, offset);
phn_lchild_set(parent, next, offset);
if (next != NULL) {
phn_prev_set(next, parent, offset);
}
} else {
assert(phn_prev_get(phn, offset) != NULL);
phn_next_set(
phn_prev_get(phn, offset),
phn_next_get(phn, offset), offset);
}
if (phn_next_get(phn, offset) != NULL) {
phn_prev_set(
phn_next_get(phn, offset),
phn_prev_get(phn, offset), offset);
}
}
}
#define ph_structs(a_prefix, a_type) \
typedef struct { \
phn_link_t link; \
} a_prefix##_link_t; \
\
typedef struct { \
ph_t ph; \
} a_prefix##_t;
/*
* The ph_proto() macro generates function prototypes that correspond to the
* functions generated by an equivalently parameterized call to ph_gen().
*/
#define ph_proto(a_attr, a_prefix, a_type) \
\
a_attr void a_prefix##_new(a_prefix##_t *ph); \
a_attr bool a_prefix##_empty(a_prefix##_t *ph); \
a_attr a_type *a_prefix##_first(a_prefix##_t *ph); \
a_attr a_type *a_prefix##_any(a_prefix##_t *ph); \
a_attr void a_prefix##_insert(a_prefix##_t *ph, a_type *phn); \
a_attr a_type *a_prefix##_remove_first(a_prefix##_t *ph); \
a_attr a_type *a_prefix##_remove_any(a_prefix##_t *ph); \
a_attr void a_prefix##_remove(a_prefix##_t *ph, a_type *phn);
/* The ph_gen() macro generates a type-specific pairing heap implementation. */
#define ph_gen(a_attr, a_prefix, a_type, a_field, a_cmp) \
JEMALLOC_ALWAYS_INLINE int \
a_prefix##_ph_cmp(void *a, void *b) { \
return a_cmp((a_type *)a, (a_type *)b); \
} \
\
a_attr void \
a_prefix##_new(a_prefix##_t *ph) { \
ph_new(&ph->ph); \
} \
\
a_attr bool \
a_prefix##_empty(a_prefix##_t *ph) { \
return ph_empty(&ph->ph); \
} \
\
a_attr a_type * \
a_prefix##_first(a_prefix##_t *ph) { \
return ph_first(&ph->ph, offsetof(a_type, a_field), \
&a_prefix##_ph_cmp); \
} \
\
a_attr a_type * \
a_prefix##_any(a_prefix##_t *ph) { \
return ph_any(&ph->ph, offsetof(a_type, a_field)); \
} \
\
a_attr void \
a_prefix##_insert(a_prefix##_t *ph, a_type *phn) { \
ph_insert(&ph->ph, phn, offsetof(a_type, a_field)); \
} \
\
a_attr a_type * \
a_prefix##_remove_first(a_prefix##_t *ph) { \
return ph_remove_first(&ph->ph, offsetof(a_type, a_field), \
a_prefix##_ph_cmp); \
} \
\
a_attr a_type * \
a_prefix##_remove_any(a_prefix##_t *ph) { \
return ph_remove_any(&ph->ph, offsetof(a_type, a_field), \
a_prefix##_ph_cmp); \
} \
\
a_attr void \
a_prefix##_remove(a_prefix##_t *ph, a_type *phn) { \
ph_remove(&ph->ph, phn, offsetof(a_type, a_field), \
a_prefix##_ph_cmp); \
}
#endif /* JEMALLOC_INTERNAL_PH_H */