server-skynet-source-3rd-je.../include/jemalloc/internal/rtree.h
Qi Wang 4be74d5112 Consolidate the two memory loads in rtree_szind_slab_read().
szind and slab bits are read on fast path, where compiler generated two memory
loads separately for them before this diff.  Manually operate on the bits to
avoid the extra memory load.
2018-04-10 10:18:46 -07:00

493 lines
16 KiB
C

#ifndef JEMALLOC_INTERNAL_RTREE_H
#define JEMALLOC_INTERNAL_RTREE_H
#include "jemalloc/internal/atomic.h"
#include "jemalloc/internal/mutex.h"
#include "jemalloc/internal/rtree_tsd.h"
#include "jemalloc/internal/size_classes.h"
#include "jemalloc/internal/tsd.h"
/*
* This radix tree implementation is tailored to the singular purpose of
* associating metadata with extents that are currently owned by jemalloc.
*
*******************************************************************************
*/
/* Number of high insignificant bits. */
#define RTREE_NHIB ((1U << (LG_SIZEOF_PTR+3)) - LG_VADDR)
/* Number of low insigificant bits. */
#define RTREE_NLIB LG_PAGE
/* Number of significant bits. */
#define RTREE_NSB (LG_VADDR - RTREE_NLIB)
/* Number of levels in radix tree. */
#if RTREE_NSB <= 10
# define RTREE_HEIGHT 1
#elif RTREE_NSB <= 36
# define RTREE_HEIGHT 2
#elif RTREE_NSB <= 52
# define RTREE_HEIGHT 3
#else
# error Unsupported number of significant virtual address bits
#endif
/* Use compact leaf representation if virtual address encoding allows. */
#if RTREE_NHIB >= LG_CEIL_NSIZES
# define RTREE_LEAF_COMPACT
#endif
/* Needed for initialization only. */
#define RTREE_LEAFKEY_INVALID ((uintptr_t)1)
typedef struct rtree_node_elm_s rtree_node_elm_t;
struct rtree_node_elm_s {
atomic_p_t child; /* (rtree_{node,leaf}_elm_t *) */
};
struct rtree_leaf_elm_s {
#ifdef RTREE_LEAF_COMPACT
/*
* Single pointer-width field containing all three leaf element fields.
* For example, on a 64-bit x64 system with 48 significant virtual
* memory address bits, the index, extent, and slab fields are packed as
* such:
*
* x: index
* e: extent
* b: slab
*
* 00000000 xxxxxxxx eeeeeeee [...] eeeeeeee eeee000b
*/
atomic_p_t le_bits;
#else
atomic_p_t le_extent; /* (extent_t *) */
atomic_u_t le_szind; /* (szind_t) */
atomic_b_t le_slab; /* (bool) */
#endif
};
typedef struct rtree_level_s rtree_level_t;
struct rtree_level_s {
/* Number of key bits distinguished by this level. */
unsigned bits;
/*
* Cumulative number of key bits distinguished by traversing to
* corresponding tree level.
*/
unsigned cumbits;
};
typedef struct rtree_s rtree_t;
struct rtree_s {
malloc_mutex_t init_lock;
/* Number of elements based on rtree_levels[0].bits. */
#if RTREE_HEIGHT > 1
rtree_node_elm_t root[1U << (RTREE_NSB/RTREE_HEIGHT)];
#else
rtree_leaf_elm_t root[1U << (RTREE_NSB/RTREE_HEIGHT)];
#endif
};
/*
* Split the bits into one to three partitions depending on number of
* significant bits. It the number of bits does not divide evenly into the
* number of levels, place one remainder bit per level starting at the leaf
* level.
*/
static const rtree_level_t rtree_levels[] = {
#if RTREE_HEIGHT == 1
{RTREE_NSB, RTREE_NHIB + RTREE_NSB}
#elif RTREE_HEIGHT == 2
{RTREE_NSB/2, RTREE_NHIB + RTREE_NSB/2},
{RTREE_NSB/2 + RTREE_NSB%2, RTREE_NHIB + RTREE_NSB}
#elif RTREE_HEIGHT == 3
{RTREE_NSB/3, RTREE_NHIB + RTREE_NSB/3},
{RTREE_NSB/3 + RTREE_NSB%3/2,
RTREE_NHIB + RTREE_NSB/3*2 + RTREE_NSB%3/2},
{RTREE_NSB/3 + RTREE_NSB%3 - RTREE_NSB%3/2, RTREE_NHIB + RTREE_NSB}
#else
# error Unsupported rtree height
#endif
};
bool rtree_new(rtree_t *rtree, bool zeroed);
typedef rtree_node_elm_t *(rtree_node_alloc_t)(tsdn_t *, rtree_t *, size_t);
extern rtree_node_alloc_t *JET_MUTABLE rtree_node_alloc;
typedef rtree_leaf_elm_t *(rtree_leaf_alloc_t)(tsdn_t *, rtree_t *, size_t);
extern rtree_leaf_alloc_t *JET_MUTABLE rtree_leaf_alloc;
typedef void (rtree_node_dalloc_t)(tsdn_t *, rtree_t *, rtree_node_elm_t *);
extern rtree_node_dalloc_t *JET_MUTABLE rtree_node_dalloc;
typedef void (rtree_leaf_dalloc_t)(tsdn_t *, rtree_t *, rtree_leaf_elm_t *);
extern rtree_leaf_dalloc_t *JET_MUTABLE rtree_leaf_dalloc;
#ifdef JEMALLOC_JET
void rtree_delete(tsdn_t *tsdn, rtree_t *rtree);
#endif
rtree_leaf_elm_t *rtree_leaf_elm_lookup_hard(tsdn_t *tsdn, rtree_t *rtree,
rtree_ctx_t *rtree_ctx, uintptr_t key, bool dependent, bool init_missing);
JEMALLOC_ALWAYS_INLINE uintptr_t
rtree_leafkey(uintptr_t key) {
unsigned ptrbits = ZU(1) << (LG_SIZEOF_PTR+3);
unsigned cumbits = (rtree_levels[RTREE_HEIGHT-1].cumbits -
rtree_levels[RTREE_HEIGHT-1].bits);
unsigned maskbits = ptrbits - cumbits;
uintptr_t mask = ~((ZU(1) << maskbits) - 1);
return (key & mask);
}
JEMALLOC_ALWAYS_INLINE size_t
rtree_cache_direct_map(uintptr_t key) {
unsigned ptrbits = ZU(1) << (LG_SIZEOF_PTR+3);
unsigned cumbits = (rtree_levels[RTREE_HEIGHT-1].cumbits -
rtree_levels[RTREE_HEIGHT-1].bits);
unsigned maskbits = ptrbits - cumbits;
return (size_t)((key >> maskbits) & (RTREE_CTX_NCACHE - 1));
}
JEMALLOC_ALWAYS_INLINE uintptr_t
rtree_subkey(uintptr_t key, unsigned level) {
unsigned ptrbits = ZU(1) << (LG_SIZEOF_PTR+3);
unsigned cumbits = rtree_levels[level].cumbits;
unsigned shiftbits = ptrbits - cumbits;
unsigned maskbits = rtree_levels[level].bits;
uintptr_t mask = (ZU(1) << maskbits) - 1;
return ((key >> shiftbits) & mask);
}
/*
* Atomic getters.
*
* 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.
* !dependent: 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.
*/
# ifdef RTREE_LEAF_COMPACT
JEMALLOC_ALWAYS_INLINE uintptr_t
rtree_leaf_elm_bits_read(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
bool dependent) {
return (uintptr_t)atomic_load_p(&elm->le_bits, dependent
? ATOMIC_RELAXED : ATOMIC_ACQUIRE);
}
JEMALLOC_ALWAYS_INLINE extent_t *
rtree_leaf_elm_bits_extent_get(uintptr_t bits) {
# ifdef __aarch64__
/*
* aarch64 doesn't sign extend the highest virtual address bit to set
* the higher ones. Instead, the high bits gets zeroed.
*/
uintptr_t high_bit_mask = ((uintptr_t)1 << LG_VADDR) - 1;
/* Mask off the slab bit. */
uintptr_t low_bit_mask = ~(uintptr_t)1;
uintptr_t mask = high_bit_mask & low_bit_mask;
return (extent_t *)(bits & mask);
# else
/* Restore sign-extended high bits, mask slab bit. */
return (extent_t *)((uintptr_t)((intptr_t)(bits << RTREE_NHIB) >>
RTREE_NHIB) & ~((uintptr_t)0x1));
# endif
}
JEMALLOC_ALWAYS_INLINE szind_t
rtree_leaf_elm_bits_szind_get(uintptr_t bits) {
return (szind_t)(bits >> LG_VADDR);
}
JEMALLOC_ALWAYS_INLINE bool
rtree_leaf_elm_bits_slab_get(uintptr_t bits) {
return (bool)(bits & (uintptr_t)0x1);
}
# endif
JEMALLOC_ALWAYS_INLINE extent_t *
rtree_leaf_elm_extent_read(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
bool dependent) {
#ifdef RTREE_LEAF_COMPACT
uintptr_t bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm, dependent);
return rtree_leaf_elm_bits_extent_get(bits);
#else
extent_t *extent = (extent_t *)atomic_load_p(&elm->le_extent, dependent
? ATOMIC_RELAXED : ATOMIC_ACQUIRE);
return extent;
#endif
}
JEMALLOC_ALWAYS_INLINE szind_t
rtree_leaf_elm_szind_read(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
bool dependent) {
#ifdef RTREE_LEAF_COMPACT
uintptr_t bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm, dependent);
return rtree_leaf_elm_bits_szind_get(bits);
#else
return (szind_t)atomic_load_u(&elm->le_szind, dependent ? ATOMIC_RELAXED
: ATOMIC_ACQUIRE);
#endif
}
JEMALLOC_ALWAYS_INLINE bool
rtree_leaf_elm_slab_read(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
bool dependent) {
#ifdef RTREE_LEAF_COMPACT
uintptr_t bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm, dependent);
return rtree_leaf_elm_bits_slab_get(bits);
#else
return atomic_load_b(&elm->le_slab, dependent ? ATOMIC_RELAXED :
ATOMIC_ACQUIRE);
#endif
}
static inline void
rtree_leaf_elm_extent_write(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
extent_t *extent) {
#ifdef RTREE_LEAF_COMPACT
uintptr_t old_bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm, true);
uintptr_t bits = ((uintptr_t)rtree_leaf_elm_bits_szind_get(old_bits) <<
LG_VADDR) | ((uintptr_t)extent & (((uintptr_t)0x1 << LG_VADDR) - 1))
| ((uintptr_t)rtree_leaf_elm_bits_slab_get(old_bits));
atomic_store_p(&elm->le_bits, (void *)bits, ATOMIC_RELEASE);
#else
atomic_store_p(&elm->le_extent, extent, ATOMIC_RELEASE);
#endif
}
static inline void
rtree_leaf_elm_szind_write(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
szind_t szind) {
assert(szind <= NSIZES);
#ifdef RTREE_LEAF_COMPACT
uintptr_t old_bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm,
true);
uintptr_t bits = ((uintptr_t)szind << LG_VADDR) |
((uintptr_t)rtree_leaf_elm_bits_extent_get(old_bits) &
(((uintptr_t)0x1 << LG_VADDR) - 1)) |
((uintptr_t)rtree_leaf_elm_bits_slab_get(old_bits));
atomic_store_p(&elm->le_bits, (void *)bits, ATOMIC_RELEASE);
#else
atomic_store_u(&elm->le_szind, szind, ATOMIC_RELEASE);
#endif
}
static inline void
rtree_leaf_elm_slab_write(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
bool slab) {
#ifdef RTREE_LEAF_COMPACT
uintptr_t old_bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm,
true);
uintptr_t bits = ((uintptr_t)rtree_leaf_elm_bits_szind_get(old_bits) <<
LG_VADDR) | ((uintptr_t)rtree_leaf_elm_bits_extent_get(old_bits) &
(((uintptr_t)0x1 << LG_VADDR) - 1)) | ((uintptr_t)slab);
atomic_store_p(&elm->le_bits, (void *)bits, ATOMIC_RELEASE);
#else
atomic_store_b(&elm->le_slab, slab, ATOMIC_RELEASE);
#endif
}
static inline void
rtree_leaf_elm_write(tsdn_t *tsdn, rtree_t *rtree, rtree_leaf_elm_t *elm,
extent_t *extent, szind_t szind, bool slab) {
#ifdef RTREE_LEAF_COMPACT
uintptr_t bits = ((uintptr_t)szind << LG_VADDR) |
((uintptr_t)extent & (((uintptr_t)0x1 << LG_VADDR) - 1)) |
((uintptr_t)slab);
atomic_store_p(&elm->le_bits, (void *)bits, ATOMIC_RELEASE);
#else
rtree_leaf_elm_slab_write(tsdn, rtree, elm, slab);
rtree_leaf_elm_szind_write(tsdn, rtree, elm, szind);
/*
* Write extent last, since the element is atomically considered valid
* as soon as the extent field is non-NULL.
*/
rtree_leaf_elm_extent_write(tsdn, rtree, elm, extent);
#endif
}
static inline void
rtree_leaf_elm_szind_slab_update(tsdn_t *tsdn, rtree_t *rtree,
rtree_leaf_elm_t *elm, szind_t szind, bool slab) {
assert(!slab || szind < NBINS);
/*
* The caller implicitly assures that it is the only writer to the szind
* and slab fields, and that the extent field cannot currently change.
*/
rtree_leaf_elm_slab_write(tsdn, rtree, elm, slab);
rtree_leaf_elm_szind_write(tsdn, rtree, elm, szind);
}
JEMALLOC_ALWAYS_INLINE rtree_leaf_elm_t *
rtree_leaf_elm_lookup(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, bool dependent, bool init_missing) {
assert(key != 0);
assert(!dependent || !init_missing);
size_t slot = rtree_cache_direct_map(key);
uintptr_t leafkey = rtree_leafkey(key);
assert(leafkey != RTREE_LEAFKEY_INVALID);
/* Fast path: L1 direct mapped cache. */
if (likely(rtree_ctx->cache[slot].leafkey == leafkey)) {
rtree_leaf_elm_t *leaf = rtree_ctx->cache[slot].leaf;
assert(leaf != NULL);
uintptr_t subkey = rtree_subkey(key, RTREE_HEIGHT-1);
return &leaf[subkey];
}
/*
* Search the L2 LRU cache. On hit, swap the matching element into the
* slot in L1 cache, and move the position in L2 up by 1.
*/
#define RTREE_CACHE_CHECK_L2(i) do { \
if (likely(rtree_ctx->l2_cache[i].leafkey == leafkey)) { \
rtree_leaf_elm_t *leaf = rtree_ctx->l2_cache[i].leaf; \
assert(leaf != NULL); \
if (i > 0) { \
/* Bubble up by one. */ \
rtree_ctx->l2_cache[i].leafkey = \
rtree_ctx->l2_cache[i - 1].leafkey; \
rtree_ctx->l2_cache[i].leaf = \
rtree_ctx->l2_cache[i - 1].leaf; \
rtree_ctx->l2_cache[i - 1].leafkey = \
rtree_ctx->cache[slot].leafkey; \
rtree_ctx->l2_cache[i - 1].leaf = \
rtree_ctx->cache[slot].leaf; \
} else { \
rtree_ctx->l2_cache[0].leafkey = \
rtree_ctx->cache[slot].leafkey; \
rtree_ctx->l2_cache[0].leaf = \
rtree_ctx->cache[slot].leaf; \
} \
rtree_ctx->cache[slot].leafkey = leafkey; \
rtree_ctx->cache[slot].leaf = leaf; \
uintptr_t subkey = rtree_subkey(key, RTREE_HEIGHT-1); \
return &leaf[subkey]; \
} \
} while (0)
/* Check the first cache entry. */
RTREE_CACHE_CHECK_L2(0);
/* Search the remaining cache elements. */
for (unsigned i = 1; i < RTREE_CTX_NCACHE_L2; i++) {
RTREE_CACHE_CHECK_L2(i);
}
#undef RTREE_CACHE_CHECK_L2
return rtree_leaf_elm_lookup_hard(tsdn, rtree, rtree_ctx, key,
dependent, init_missing);
}
static inline bool
rtree_write(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx, uintptr_t key,
extent_t *extent, szind_t szind, bool slab) {
/* Use rtree_clear() to set the extent to NULL. */
assert(extent != NULL);
rtree_leaf_elm_t *elm = rtree_leaf_elm_lookup(tsdn, rtree, rtree_ctx,
key, false, true);
if (elm == NULL) {
return true;
}
assert(rtree_leaf_elm_extent_read(tsdn, rtree, elm, false) == NULL);
rtree_leaf_elm_write(tsdn, rtree, elm, extent, szind, slab);
return false;
}
JEMALLOC_ALWAYS_INLINE rtree_leaf_elm_t *
rtree_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx, uintptr_t key,
bool dependent) {
rtree_leaf_elm_t *elm = rtree_leaf_elm_lookup(tsdn, rtree, rtree_ctx,
key, dependent, false);
if (!dependent && elm == NULL) {
return NULL;
}
assert(elm != NULL);
return elm;
}
JEMALLOC_ALWAYS_INLINE extent_t *
rtree_extent_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, bool dependent) {
rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key,
dependent);
if (!dependent && elm == NULL) {
return NULL;
}
return rtree_leaf_elm_extent_read(tsdn, rtree, elm, dependent);
}
JEMALLOC_ALWAYS_INLINE szind_t
rtree_szind_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, bool dependent) {
rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key,
dependent);
if (!dependent && elm == NULL) {
return NSIZES;
}
return rtree_leaf_elm_szind_read(tsdn, rtree, elm, dependent);
}
/*
* rtree_slab_read() is intentionally omitted because slab is always read in
* conjunction with szind, which makes rtree_szind_slab_read() a better choice.
*/
JEMALLOC_ALWAYS_INLINE bool
rtree_extent_szind_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, bool dependent, extent_t **r_extent, szind_t *r_szind) {
rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key,
dependent);
if (!dependent && elm == NULL) {
return true;
}
*r_extent = rtree_leaf_elm_extent_read(tsdn, rtree, elm, dependent);
*r_szind = rtree_leaf_elm_szind_read(tsdn, rtree, elm, dependent);
return false;
}
JEMALLOC_ALWAYS_INLINE bool
rtree_szind_slab_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, bool dependent, szind_t *r_szind, bool *r_slab) {
rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key,
dependent);
if (!dependent && elm == NULL) {
return true;
}
#ifdef RTREE_LEAF_COMPACT
uintptr_t bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm, dependent);
*r_szind = rtree_leaf_elm_bits_szind_get(bits);
*r_slab = rtree_leaf_elm_bits_slab_get(bits);
#else
*r_szind = rtree_leaf_elm_szind_read(tsdn, rtree, elm, dependent);
*r_slab = rtree_leaf_elm_slab_read(tsdn, rtree, elm, dependent);
#endif
return false;
}
static inline void
rtree_szind_slab_update(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, szind_t szind, bool slab) {
assert(!slab || szind < NBINS);
rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key, true);
rtree_leaf_elm_szind_slab_update(tsdn, rtree, elm, szind, slab);
}
static inline void
rtree_clear(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key) {
rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key, true);
assert(rtree_leaf_elm_extent_read(tsdn, rtree, elm, false) !=
NULL);
rtree_leaf_elm_write(tsdn, rtree, elm, NULL, NSIZES, false);
}
#endif /* JEMALLOC_INTERNAL_RTREE_H */