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Convert rtree from (void *) to (uint8_t) storage.

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Reduce rtree memory usage by storing booleans (1 byte each) rather than
pointers.  The rtree code is only used to record whether jemalloc manages
a chunk of memory, so there's no need to store pointers in the rtree.

Increase rtree node size to 64 KiB in order to reduce tree depth from 13
to 3 on 64-bit systems.  The conversion to more compact leaf nodes was
enough by itself to make the rtree depth 1 on 32-bit systems; due to the
fact that root nodes are smaller than the specified node size if
possible, the node size change has no impact on 32-bit systems (assuming
default chunk size).
This commit is contained in:
Jason Evans
2014-01-02 17:36:38 -08:00
parent b980cc774a
commit b954bc5d3a
5 changed files with 64 additions and 55 deletions
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2
include/jemalloc/internal/jemalloc_internal.h.in
View File

@@ -853,7 +853,7 @@ ivsalloc(const void *ptr, bool demote)
{
/* Return 0 if ptr is not within a chunk managed by jemalloc. */
if (rtree_get(chunks_rtree, (uintptr_t)CHUNK_ADDR2BASE(ptr)) == NULL)
if (rtree_get(chunks_rtree, (uintptr_t)CHUNK_ADDR2BASE(ptr)) == 0)
return (0);
return (isalloc(ptr, demote));

38
include/jemalloc/internal/rtree.h
View File

@@ -14,11 +14,7 @@ typedef struct rtree_s rtree_t;
* Size of each radix tree node (must be a power of 2). This impacts tree
* depth.
*/
#if (LG_SIZEOF_PTR == 2)
# define RTREE_NODESIZE (1U << 14)
#else
# define RTREE_NODESIZE CACHELINE
#endif
#define RTREE_NODESIZE (1U << 16)
typedef void *(rtree_alloc_t)(size_t);
typedef void (rtree_dalloc_t)(void *);
@@ -52,19 +48,19 @@ void rtree_postfork_child(rtree_t *rtree);
#ifndef JEMALLOC_ENABLE_INLINE
#ifdef JEMALLOC_DEBUG
void *rtree_get_locked(rtree_t *rtree, uintptr_t key);
uint8_t rtree_get_locked(rtree_t *rtree, uintptr_t key);
#endif
void *rtree_get(rtree_t *rtree, uintptr_t key);
bool rtree_set(rtree_t *rtree, uintptr_t key, void *val);
uint8_t rtree_get(rtree_t *rtree, uintptr_t key);
bool rtree_set(rtree_t *rtree, uintptr_t key, uint8_t val);
#endif
#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_RTREE_C_))
#define RTREE_GET_GENERATE(f) \
/* The least significant bits of the key are ignored. */ \
JEMALLOC_INLINE void * \
JEMALLOC_INLINE uint8_t \
f(rtree_t *rtree, uintptr_t key) \
{ \
void *ret; \
uint8_t ret; \
uintptr_t subkey; \
unsigned i, lshift, height, bits; \
void **node, **child; \
@@ -79,7 +75,7 @@ f(rtree_t *rtree, uintptr_t key) \
child = (void**)node[subkey]; \
if (child == NULL) { \
RTREE_UNLOCK(&rtree->mutex); \
return (NULL); \
return (0); \
} \
} \
\
@@ -90,7 +86,10 @@ f(rtree_t *rtree, uintptr_t key) \
bits = rtree->level2bits[i]; \
subkey = (key << lshift) >> ((ZU(1) << (LG_SIZEOF_PTR+3)) - \
bits); \
ret = node[subkey]; \
{ \
uint8_t *leaf = (uint8_t *)node; \
ret = leaf[subkey]; \
} \
RTREE_UNLOCK(&rtree->mutex); \
\
RTREE_GET_VALIDATE \
@@ -129,7 +128,7 @@ RTREE_GET_GENERATE(rtree_get)
#undef RTREE_GET_VALIDATE
JEMALLOC_INLINE bool
rtree_set(rtree_t *rtree, uintptr_t key, void *val)
rtree_set(rtree_t *rtree, uintptr_t key, uint8_t val)
{
uintptr_t subkey;
unsigned i, lshift, height, bits;
@@ -144,14 +143,14 @@ rtree_set(rtree_t *rtree, uintptr_t key, void *val)
bits);
child = (void**)node[subkey];
if (child == NULL) {
child = (void**)rtree->alloc(sizeof(void *) <<
rtree->level2bits[i+1]);
size_t size = ((i + 1 < height - 1) ? sizeof(void *)
: (sizeof(uint8_t))) << rtree->level2bits[i+1];
child = (void**)rtree->alloc(size);
if (child == NULL) {
malloc_mutex_unlock(&rtree->mutex);
return (true);
}
memset(child, 0, sizeof(void *) <<
rtree->level2bits[i+1]);
memset(child, 0, size);
node[subkey] = child;
}
}
@@ -159,7 +158,10 @@ rtree_set(rtree_t *rtree, uintptr_t key, void *val)
/* node is a leaf, so it contains values rather than node pointers. */
bits = rtree->level2bits[i];
subkey = (key << lshift) >> ((ZU(1) << (LG_SIZEOF_PTR+3)) - bits);
node[subkey] = val;
{
uint8_t *leaf = (uint8_t *)node;
leaf[subkey] = val;
}
malloc_mutex_unlock(&rtree->mutex);
return (false);