497 lines
14 KiB
C
497 lines
14 KiB
C
/*
|
|
* 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_elm_s rtree_elm_t;
|
|
typedef struct rtree_elm_witness_s rtree_elm_witness_t;
|
|
typedef struct rtree_elm_witness_tsd_s rtree_elm_witness_tsd_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 (1U << LG_RTREE_BITS_PER_LEVEL)
|
|
/* Maximum rtree height. */
|
|
#define RTREE_HEIGHT_MAX \
|
|
((1U << (LG_SIZEOF_PTR+3)) / RTREE_BITS_PER_LEVEL)
|
|
|
|
/* Used for two-stage lock-free node initialization. */
|
|
#define RTREE_NODE_INITIALIZING ((rtree_elm_t *)0x1)
|
|
|
|
/*
|
|
* Maximum number of concurrently acquired elements per thread. This controls
|
|
* how many witness_t structures are embedded in tsd. Ideally rtree_elm_t would
|
|
* have a witness_t directly embedded, but that would dramatically bloat the
|
|
* tree. This must contain enough entries to e.g. coalesce two extents.
|
|
*/
|
|
#define RTREE_ELM_ACQUIRE_MAX 4
|
|
|
|
/* Initializers for rtree_elm_witness_tsd_t. */
|
|
#define RTREE_ELM_WITNESS_INITIALIZER { \
|
|
NULL, \
|
|
WITNESS_INITIALIZER("rtree_elm", WITNESS_RANK_RTREE_ELM) \
|
|
}
|
|
|
|
#define RTREE_ELM_WITNESS_TSD_INITIALIZER { \
|
|
{ \
|
|
RTREE_ELM_WITNESS_INITIALIZER, \
|
|
RTREE_ELM_WITNESS_INITIALIZER, \
|
|
RTREE_ELM_WITNESS_INITIALIZER, \
|
|
RTREE_ELM_WITNESS_INITIALIZER \
|
|
} \
|
|
}
|
|
|
|
#endif /* JEMALLOC_H_TYPES */
|
|
/******************************************************************************/
|
|
#ifdef JEMALLOC_H_STRUCTS
|
|
|
|
struct rtree_elm_s {
|
|
union {
|
|
void *pun;
|
|
rtree_elm_t *child;
|
|
extent_t *extent;
|
|
};
|
|
};
|
|
|
|
struct rtree_elm_witness_s {
|
|
const rtree_elm_t *elm;
|
|
witness_t witness;
|
|
};
|
|
|
|
struct rtree_elm_witness_tsd_s {
|
|
rtree_elm_witness_t witnesses[RTREE_ELM_ACQUIRE_MAX];
|
|
};
|
|
|
|
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] : [extent(0x000000000000) | extent(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.
|
|
*/
|
|
union {
|
|
void *subtree_pun;
|
|
rtree_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 {
|
|
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);
|
|
#ifdef JEMALLOC_JET
|
|
typedef rtree_elm_t *(rtree_node_alloc_t)(tsdn_t *, rtree_t *, size_t);
|
|
extern rtree_node_alloc_t *rtree_node_alloc;
|
|
typedef void (rtree_node_dalloc_t)(tsdn_t *, rtree_t *, rtree_elm_t *);
|
|
extern rtree_node_dalloc_t *rtree_node_dalloc;
|
|
void rtree_delete(tsdn_t *tsdn, rtree_t *rtree);
|
|
#endif
|
|
rtree_elm_t *rtree_subtree_read_hard(tsdn_t *tsdn, rtree_t *rtree,
|
|
unsigned level);
|
|
rtree_elm_t *rtree_child_read_hard(tsdn_t *tsdn, rtree_t *rtree,
|
|
rtree_elm_t *elm, unsigned level);
|
|
void rtree_elm_witness_acquire(tsdn_t *tsdn, const rtree_t *rtree,
|
|
uintptr_t key, const rtree_elm_t *elm);
|
|
void rtree_elm_witness_access(tsdn_t *tsdn, const rtree_t *rtree,
|
|
const rtree_elm_t *elm);
|
|
void rtree_elm_witness_release(tsdn_t *tsdn, const rtree_t *rtree,
|
|
const rtree_elm_t *elm);
|
|
void rtree_elm_witnesses_cleanup(tsd_t *tsd);
|
|
|
|
#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_elm_t *node);
|
|
rtree_elm_t *rtree_child_tryread(rtree_elm_t *elm, bool dependent);
|
|
rtree_elm_t *rtree_child_read(tsdn_t *tsdn, rtree_t *rtree, rtree_elm_t *elm,
|
|
unsigned level, bool dependent);
|
|
extent_t *rtree_elm_read(rtree_elm_t *elm, bool dependent);
|
|
void rtree_elm_write(rtree_elm_t *elm, const extent_t *extent);
|
|
rtree_elm_t *rtree_subtree_tryread(rtree_t *rtree, unsigned level,
|
|
bool dependent);
|
|
rtree_elm_t *rtree_subtree_read(tsdn_t *tsdn, rtree_t *rtree,
|
|
unsigned level, bool dependent);
|
|
rtree_elm_t *rtree_elm_lookup(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key,
|
|
bool dependent, bool init_missing);
|
|
|
|
bool rtree_write(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key,
|
|
const extent_t *extent);
|
|
extent_t *rtree_read(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key,
|
|
bool dependent);
|
|
rtree_elm_t *rtree_elm_acquire(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key,
|
|
bool dependent, bool init_missing);
|
|
extent_t *rtree_elm_read_acquired(tsdn_t *tsdn, const rtree_t *rtree,
|
|
rtree_elm_t *elm);
|
|
void rtree_elm_write_acquired(tsdn_t *tsdn, const rtree_t *rtree,
|
|
rtree_elm_t *elm, const extent_t *extent);
|
|
void rtree_elm_release(tsdn_t *tsdn, const rtree_t *rtree, rtree_elm_t *elm);
|
|
void rtree_clear(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key);
|
|
#endif
|
|
|
|
#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_RTREE_C_))
|
|
JEMALLOC_ALWAYS_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_ALWAYS_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_ALWAYS_INLINE bool
|
|
rtree_node_valid(rtree_elm_t *node)
|
|
{
|
|
|
|
return ((uintptr_t)node > (uintptr_t)RTREE_NODE_INITIALIZING);
|
|
}
|
|
|
|
JEMALLOC_ALWAYS_INLINE rtree_elm_t *
|
|
rtree_child_tryread(rtree_elm_t *elm, bool dependent)
|
|
{
|
|
rtree_elm_t *child;
|
|
|
|
/* Double-checked read (first read may be stale). */
|
|
child = elm->child;
|
|
if (!dependent && !rtree_node_valid(child))
|
|
child = atomic_read_p(&elm->pun);
|
|
assert(!dependent || child != NULL);
|
|
return (child);
|
|
}
|
|
|
|
JEMALLOC_ALWAYS_INLINE rtree_elm_t *
|
|
rtree_child_read(tsdn_t *tsdn, rtree_t *rtree, rtree_elm_t *elm, unsigned level,
|
|
bool dependent)
|
|
{
|
|
rtree_elm_t *child;
|
|
|
|
child = rtree_child_tryread(elm, dependent);
|
|
if (!dependent && unlikely(!rtree_node_valid(child)))
|
|
child = rtree_child_read_hard(tsdn, rtree, elm, level);
|
|
assert(!dependent || child != NULL);
|
|
return (child);
|
|
}
|
|
|
|
JEMALLOC_ALWAYS_INLINE extent_t *
|
|
rtree_elm_read(rtree_elm_t *elm, bool dependent)
|
|
{
|
|
extent_t *extent;
|
|
|
|
if (dependent) {
|
|
/*
|
|
* Reading a value on behalf of a pointer to a valid allocation
|
|
* is guaranteed to be a clean read even without
|
|
* synchronization, because the rtree update became visible in
|
|
* memory before the pointer came into existence.
|
|
*/
|
|
extent = elm->extent;
|
|
} else {
|
|
/*
|
|
* An arbitrary read, e.g. on behalf of ivsalloc(), may not be
|
|
* dependent on a previous rtree write, which means a stale read
|
|
* could result if synchronization were omitted here.
|
|
*/
|
|
extent = (extent_t *)atomic_read_p(&elm->pun);
|
|
}
|
|
|
|
/* Mask the lock bit. */
|
|
extent = (extent_t *)((uintptr_t)extent & ~((uintptr_t)0x1));
|
|
|
|
return (extent);
|
|
}
|
|
|
|
JEMALLOC_INLINE void
|
|
rtree_elm_write(rtree_elm_t *elm, const extent_t *extent)
|
|
{
|
|
|
|
atomic_write_p(&elm->pun, extent);
|
|
}
|
|
|
|
JEMALLOC_ALWAYS_INLINE rtree_elm_t *
|
|
rtree_subtree_tryread(rtree_t *rtree, unsigned level, bool dependent)
|
|
{
|
|
rtree_elm_t *subtree;
|
|
|
|
/* Double-checked read (first read may be stale). */
|
|
subtree = rtree->levels[level].subtree;
|
|
if (!dependent && unlikely(!rtree_node_valid(subtree)))
|
|
subtree = atomic_read_p(&rtree->levels[level].subtree_pun);
|
|
assert(!dependent || subtree != NULL);
|
|
return (subtree);
|
|
}
|
|
|
|
JEMALLOC_ALWAYS_INLINE rtree_elm_t *
|
|
rtree_subtree_read(tsdn_t *tsdn, rtree_t *rtree, unsigned level, bool dependent)
|
|
{
|
|
rtree_elm_t *subtree;
|
|
|
|
subtree = rtree_subtree_tryread(rtree, level, dependent);
|
|
if (!dependent && unlikely(!rtree_node_valid(subtree)))
|
|
subtree = rtree_subtree_read_hard(tsdn, rtree, level);
|
|
assert(!dependent || subtree != NULL);
|
|
return (subtree);
|
|
}
|
|
|
|
JEMALLOC_ALWAYS_INLINE rtree_elm_t *
|
|
rtree_elm_lookup(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key, bool dependent,
|
|
bool init_missing)
|
|
{
|
|
uintptr_t subkey;
|
|
unsigned start_level;
|
|
rtree_elm_t *node;
|
|
|
|
assert(!dependent || !init_missing);
|
|
|
|
start_level = rtree_start_level(rtree, key);
|
|
|
|
node = init_missing ? rtree_subtree_read(tsdn, rtree, start_level,
|
|
dependent) : rtree_subtree_tryread(rtree, start_level, dependent);
|
|
#define RTREE_GET_BIAS (RTREE_HEIGHT_MAX - rtree->height)
|
|
switch (start_level + RTREE_GET_BIAS) {
|
|
#define RTREE_GET_SUBTREE(level) \
|
|
case level: \
|
|
assert(level < (RTREE_HEIGHT_MAX-1)); \
|
|
if (!dependent && unlikely(!rtree_node_valid(node))) \
|
|
return (NULL); \
|
|
subkey = rtree_subkey(rtree, key, level - \
|
|
RTREE_GET_BIAS); \
|
|
node = init_missing ? rtree_child_read(tsdn, rtree, \
|
|
&node[subkey], level - RTREE_GET_BIAS, dependent) : \
|
|
rtree_child_tryread(&node[subkey], dependent); \
|
|
/* Fall through. */
|
|
#define RTREE_GET_LEAF(level) \
|
|
case level: \
|
|
assert(level == (RTREE_HEIGHT_MAX-1)); \
|
|
if (!dependent && unlikely(!rtree_node_valid(node))) \
|
|
return (NULL); \
|
|
subkey = rtree_subkey(rtree, key, level - \
|
|
RTREE_GET_BIAS); \
|
|
/* \
|
|
* node is a leaf, so it contains values rather than \
|
|
* child pointers. \
|
|
*/ \
|
|
return (&node[subkey]);
|
|
#if RTREE_HEIGHT_MAX > 1
|
|
RTREE_GET_SUBTREE(0)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 2
|
|
RTREE_GET_SUBTREE(1)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 3
|
|
RTREE_GET_SUBTREE(2)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 4
|
|
RTREE_GET_SUBTREE(3)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 5
|
|
RTREE_GET_SUBTREE(4)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 6
|
|
RTREE_GET_SUBTREE(5)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 7
|
|
RTREE_GET_SUBTREE(6)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 8
|
|
RTREE_GET_SUBTREE(7)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 9
|
|
RTREE_GET_SUBTREE(8)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 10
|
|
RTREE_GET_SUBTREE(9)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 11
|
|
RTREE_GET_SUBTREE(10)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 12
|
|
RTREE_GET_SUBTREE(11)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 13
|
|
RTREE_GET_SUBTREE(12)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 14
|
|
RTREE_GET_SUBTREE(13)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 15
|
|
RTREE_GET_SUBTREE(14)
|
|
#endif
|
|
#if RTREE_HEIGHT_MAX > 16
|
|
# error Unsupported RTREE_HEIGHT_MAX
|
|
#endif
|
|
RTREE_GET_LEAF(RTREE_HEIGHT_MAX-1)
|
|
#undef RTREE_GET_SUBTREE
|
|
#undef RTREE_GET_LEAF
|
|
default: not_reached();
|
|
}
|
|
#undef RTREE_GET_BIAS
|
|
not_reached();
|
|
}
|
|
|
|
JEMALLOC_INLINE bool
|
|
rtree_write(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key, const extent_t *extent)
|
|
{
|
|
rtree_elm_t *elm;
|
|
|
|
assert(extent != NULL); /* Use rtree_clear() for this case. */
|
|
assert(((uintptr_t)extent & (uintptr_t)0x1) == (uintptr_t)0x0);
|
|
|
|
elm = rtree_elm_lookup(tsdn, rtree, key, false, true);
|
|
if (elm == NULL)
|
|
return (true);
|
|
assert(rtree_elm_read(elm, false) == NULL);
|
|
rtree_elm_write(elm, extent);
|
|
|
|
return (false);
|
|
}
|
|
|
|
JEMALLOC_ALWAYS_INLINE extent_t *
|
|
rtree_read(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key, bool dependent)
|
|
{
|
|
rtree_elm_t *elm;
|
|
|
|
elm = rtree_elm_lookup(tsdn, rtree, key, dependent, false);
|
|
if (elm == NULL)
|
|
return (NULL);
|
|
|
|
return (rtree_elm_read(elm, dependent));
|
|
}
|
|
|
|
JEMALLOC_INLINE rtree_elm_t *
|
|
rtree_elm_acquire(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key, bool dependent,
|
|
bool init_missing)
|
|
{
|
|
rtree_elm_t *elm;
|
|
|
|
elm = rtree_elm_lookup(tsdn, rtree, key, dependent, init_missing);
|
|
if (!dependent && elm == NULL)
|
|
return (NULL);
|
|
{
|
|
extent_t *extent;
|
|
void *s;
|
|
|
|
do {
|
|
extent = rtree_elm_read(elm, false);
|
|
/* The least significant bit serves as a lock. */
|
|
s = (void *)((uintptr_t)extent | (uintptr_t)0x1);
|
|
} while (atomic_cas_p(&elm->pun, (void *)extent, s));
|
|
}
|
|
|
|
if (config_debug)
|
|
rtree_elm_witness_acquire(tsdn, rtree, key, elm);
|
|
|
|
return (elm);
|
|
}
|
|
|
|
JEMALLOC_INLINE extent_t *
|
|
rtree_elm_read_acquired(tsdn_t *tsdn, const rtree_t *rtree, rtree_elm_t *elm)
|
|
{
|
|
extent_t *extent;
|
|
|
|
assert(((uintptr_t)elm->pun & (uintptr_t)0x1) == (uintptr_t)0x1);
|
|
extent = (extent_t *)((uintptr_t)elm->pun & ~((uintptr_t)0x1));
|
|
assert(((uintptr_t)extent & (uintptr_t)0x1) == (uintptr_t)0x0);
|
|
|
|
if (config_debug)
|
|
rtree_elm_witness_access(tsdn, rtree, elm);
|
|
|
|
return (extent);
|
|
}
|
|
|
|
JEMALLOC_INLINE void
|
|
rtree_elm_write_acquired(tsdn_t *tsdn, const rtree_t *rtree, rtree_elm_t *elm,
|
|
const extent_t *extent)
|
|
{
|
|
|
|
assert(((uintptr_t)extent & (uintptr_t)0x1) == (uintptr_t)0x0);
|
|
assert(((uintptr_t)elm->pun & (uintptr_t)0x1) == (uintptr_t)0x1);
|
|
|
|
if (config_debug)
|
|
rtree_elm_witness_access(tsdn, rtree, elm);
|
|
|
|
elm->pun = (void *)((uintptr_t)extent | (uintptr_t)0x1);
|
|
assert(rtree_elm_read_acquired(tsdn, rtree, elm) == extent);
|
|
}
|
|
|
|
JEMALLOC_INLINE void
|
|
rtree_elm_release(tsdn_t *tsdn, const rtree_t *rtree, rtree_elm_t *elm)
|
|
{
|
|
|
|
rtree_elm_write(elm, rtree_elm_read_acquired(tsdn, rtree, elm));
|
|
if (config_debug)
|
|
rtree_elm_witness_release(tsdn, rtree, elm);
|
|
}
|
|
|
|
JEMALLOC_INLINE void
|
|
rtree_clear(tsdn_t *tsdn, rtree_t *rtree, uintptr_t key)
|
|
{
|
|
rtree_elm_t *elm;
|
|
|
|
elm = rtree_elm_acquire(tsdn, rtree, key, true, false);
|
|
rtree_elm_write_acquired(tsdn, rtree, elm, NULL);
|
|
rtree_elm_release(tsdn, rtree, elm);
|
|
}
|
|
#endif
|
|
|
|
#endif /* JEMALLOC_H_INLINES */
|
|
/******************************************************************************/
|