server-skynet-source-3rd-je.../include/jemalloc/internal/rtree.h

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/*
* This radix tree implementation is tailored to the singular purpose of
* associating metadata with chunks that are currently owned by jemalloc.
*
*******************************************************************************
*/
#ifdef JEMALLOC_H_TYPES
typedef struct rtree_node_elm_s rtree_node_elm_t;
typedef struct rtree_level_s rtree_level_t;
typedef struct rtree_s rtree_t;
/*
* RTREE_BITS_PER_LEVEL must be a power of two that is no larger than the
* machine address width.
*/
#define LG_RTREE_BITS_PER_LEVEL 4
#define RTREE_BITS_PER_LEVEL (ZU(1) << LG_RTREE_BITS_PER_LEVEL)
#define RTREE_HEIGHT_MAX \
((ZU(1) << (LG_SIZEOF_PTR+3)) / RTREE_BITS_PER_LEVEL)
/* Used for two-stage lock-free node initialization. */
#define RTREE_NODE_INITIALIZING ((rtree_node_elm_t *)0x1)
/*
* The node allocation callback function's argument is the number of contiguous
* rtree_node_elm_t structures to allocate, and the resulting memory must be
* zeroed.
*/
typedef rtree_node_elm_t *(rtree_node_alloc_t)(size_t);
typedef void (rtree_node_dalloc_t)(rtree_node_elm_t *);
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#endif /* JEMALLOC_H_TYPES */
/******************************************************************************/
#ifdef JEMALLOC_H_STRUCTS
struct rtree_node_elm_s {
union {
rtree_node_elm_t *child;
extent_node_t *val;
};
};
struct rtree_level_s {
/*
* A non-NULL subtree points to a subtree rooted along the hypothetical
* path to the leaf node corresponding to key 0. Depending on what keys
* have been used to store to the tree, an arbitrary combination of
* subtree pointers may remain NULL.
*
* Suppose keys comprise 48 bits, and LG_RTREE_BITS_PER_LEVEL is 4.
* This results in a 3-level tree, and the leftmost leaf can be directly
* accessed via subtrees[2], the subtree prefixed by 0x0000 (excluding
* 0x00000000) can be accessed via subtrees[1], and the remainder of the
* tree can be accessed via subtrees[0].
*
* levels[0] : [<unused> | 0x0001******** | 0x0002******** | ...]
*
* levels[1] : [<unused> | 0x00000001**** | 0x00000002**** | ... ]
*
* levels[2] : [val(0x000000000000) | val(0x000000000001) | ...]
*
* This has practical implications on x64, which currently uses only the
* lower 47 bits of virtual address space in userland, thus leaving
* subtrees[0] unused and avoiding a level of tree traversal.
*/
rtree_node_elm_t *subtree;
/* Number of key bits distinguished by this level. */
unsigned bits;
/*
* Cumulative number of key bits distinguished by traversing to
* corresponding tree level.
*/
unsigned cumbits;
};
struct rtree_s {
rtree_node_alloc_t *alloc;
rtree_node_dalloc_t *dalloc;
unsigned height;
/*
* Precomputed table used to convert from the number of leading 0 key
* bits to which subtree level to start at.
*/
unsigned start_level[RTREE_HEIGHT_MAX];
rtree_level_t levels[RTREE_HEIGHT_MAX];
};
#endif /* JEMALLOC_H_STRUCTS */
/******************************************************************************/
#ifdef JEMALLOC_H_EXTERNS
bool rtree_new(rtree_t *rtree, unsigned bits, rtree_node_alloc_t *alloc,
rtree_node_dalloc_t *dalloc);
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void rtree_delete(rtree_t *rtree);
rtree_node_elm_t *rtree_subtree_read_hard(rtree_t *rtree,
unsigned level);
rtree_node_elm_t *rtree_child_read_hard(rtree_t *rtree,
rtree_node_elm_t *elm, unsigned level);
#endif /* JEMALLOC_H_EXTERNS */
/******************************************************************************/
#ifdef JEMALLOC_H_INLINES
#ifndef JEMALLOC_ENABLE_INLINE
unsigned rtree_start_level(rtree_t *rtree, uintptr_t key);
uintptr_t rtree_subkey(rtree_t *rtree, uintptr_t key, unsigned level);
bool rtree_node_valid(rtree_node_elm_t *node);
rtree_node_elm_t *rtree_child_tryread(rtree_node_elm_t *elm);
rtree_node_elm_t *rtree_child_read(rtree_t *rtree, rtree_node_elm_t *elm,
unsigned level);
extent_node_t *rtree_val_read(rtree_t *rtree, rtree_node_elm_t *elm);
void rtree_val_write(rtree_t *rtree, rtree_node_elm_t *elm,
const extent_node_t *val);
rtree_node_elm_t *rtree_subtree_tryread(rtree_t *rtree, unsigned level);
rtree_node_elm_t *rtree_subtree_read(rtree_t *rtree, unsigned level);
extent_node_t *rtree_get(rtree_t *rtree, uintptr_t key);
bool rtree_set(rtree_t *rtree, uintptr_t key, const extent_node_t *val);
#endif
#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_RTREE_C_))
JEMALLOC_INLINE unsigned
rtree_start_level(rtree_t *rtree, uintptr_t key)
{
unsigned start_level;
if (unlikely(key == 0))
return (rtree->height - 1);
start_level = rtree->start_level[lg_floor(key) >>
LG_RTREE_BITS_PER_LEVEL];
assert(start_level < rtree->height);
return (start_level);
}
JEMALLOC_INLINE uintptr_t
rtree_subkey(rtree_t *rtree, uintptr_t key, unsigned level)
{
return ((key >> ((ZU(1) << (LG_SIZEOF_PTR+3)) -
rtree->levels[level].cumbits)) & ((ZU(1) <<
rtree->levels[level].bits) - 1));
}
JEMALLOC_INLINE bool
rtree_node_valid(rtree_node_elm_t *node)
{
return ((uintptr_t)node > (uintptr_t)RTREE_NODE_INITIALIZING);
}
JEMALLOC_INLINE rtree_node_elm_t *
rtree_child_tryread(rtree_node_elm_t *elm)
{
rtree_node_elm_t *child;
/* Double-checked read (first read may be stale. */
child = elm->child;
if (!rtree_node_valid(child))
child = atomic_read_p((void **)&elm->child);
return (child);
}
JEMALLOC_INLINE rtree_node_elm_t *
rtree_child_read(rtree_t *rtree, rtree_node_elm_t *elm, unsigned level)
{
rtree_node_elm_t *child;
child = rtree_child_tryread(elm);
if (unlikely(!rtree_node_valid(child)))
child = rtree_child_read_hard(rtree, elm, level);
return (child);
}
JEMALLOC_INLINE extent_node_t *
rtree_val_read(rtree_t *rtree, rtree_node_elm_t *elm)
{
return (atomic_read_p((void **)&elm->val));
}
JEMALLOC_INLINE void
rtree_val_write(rtree_t *rtree, rtree_node_elm_t *elm, const extent_node_t *val)
{
atomic_write_p((void **)&elm->val, val);
}
JEMALLOC_INLINE rtree_node_elm_t *
rtree_subtree_tryread(rtree_t *rtree, unsigned level)
{
rtree_node_elm_t *subtree;
/* Double-checked read (first read may be stale. */
subtree = rtree->levels[level].subtree;
if (!rtree_node_valid(subtree))
subtree = atomic_read_p((void **)&rtree->levels[level].subtree);
return (subtree);
}
JEMALLOC_INLINE rtree_node_elm_t *
rtree_subtree_read(rtree_t *rtree, unsigned level)
{
rtree_node_elm_t *subtree;
subtree = rtree_subtree_tryread(rtree, level);
if (unlikely(!rtree_node_valid(subtree)))
subtree = rtree_subtree_read_hard(rtree, level);
return (subtree);
}
JEMALLOC_INLINE extent_node_t *
rtree_get(rtree_t *rtree, uintptr_t key)
{
uintptr_t subkey;
unsigned i, start_level;
rtree_node_elm_t *node, *child;
start_level = rtree_start_level(rtree, key);
for (i = start_level, node = rtree_subtree_tryread(rtree, start_level);
/**/; i++, node = child) {
if (unlikely(!rtree_node_valid(node)))
return (NULL);
subkey = rtree_subkey(rtree, key, i);
if (i == rtree->height - 1) {
/*
* node is a leaf, so it contains values rather than
* child pointers.
*/
return (rtree_val_read(rtree, &node[subkey]));
}
assert(i < rtree->height - 1);
child = rtree_child_tryread(&node[subkey]);
}
not_reached();
}
JEMALLOC_INLINE bool
rtree_set(rtree_t *rtree, uintptr_t key, const extent_node_t *val)
{
uintptr_t subkey;
unsigned i, start_level;
rtree_node_elm_t *node, *child;
start_level = rtree_start_level(rtree, key);
node = rtree_subtree_read(rtree, start_level);
if (node == NULL)
return (true);
for (i = start_level; /**/; i++, node = child) {
subkey = rtree_subkey(rtree, key, i);
if (i == rtree->height - 1) {
/*
* node is a leaf, so it contains values rather than
* child pointers.
*/
rtree_val_write(rtree, &node[subkey], val);
return (false);
}
assert(i < rtree->height - 1);
child = rtree_child_read(rtree, &node[subkey], i);
if (child == NULL)
return (true);
}
not_reached();
}
#endif
#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/