347 lines
8.8 KiB
C
347 lines
8.8 KiB
C
#define JEMALLOC_CHUNK_DSS_C_
|
|
#include "jemalloc/internal/jemalloc_internal.h"
|
|
/******************************************************************************/
|
|
/* Data. */
|
|
|
|
/*
|
|
* Protects sbrk() calls. This avoids malloc races among threads, though it
|
|
* does not protect against races with threads that call sbrk() directly.
|
|
*/
|
|
static malloc_mutex_t dss_mtx;
|
|
|
|
/* Base address of the DSS. */
|
|
static void *dss_base;
|
|
/* Current end of the DSS, or ((void *)-1) if the DSS is exhausted. */
|
|
static void *dss_prev;
|
|
/* Current upper limit on DSS addresses. */
|
|
static void *dss_max;
|
|
|
|
/*
|
|
* Trees of chunks that were previously allocated (trees differ only in node
|
|
* ordering). These are used when allocating chunks, in an attempt to re-use
|
|
* address space. Depending on function, different tree orderings are needed,
|
|
* which is why there are two trees with the same contents.
|
|
*/
|
|
static extent_tree_t dss_chunks_szad;
|
|
static extent_tree_t dss_chunks_ad;
|
|
|
|
/******************************************************************************/
|
|
/* Function prototypes for non-inline static functions. */
|
|
|
|
static void *chunk_recycle_dss(size_t size, size_t alignment, bool *zero);
|
|
static extent_node_t *chunk_dealloc_dss_record(void *chunk, size_t size);
|
|
|
|
/******************************************************************************/
|
|
|
|
static void *
|
|
chunk_recycle_dss(size_t size, size_t alignment, bool *zero)
|
|
{
|
|
extent_node_t *node, key;
|
|
|
|
cassert(config_dss);
|
|
|
|
key.addr = NULL;
|
|
key.size = size + alignment - chunksize;
|
|
malloc_mutex_lock(&dss_mtx);
|
|
node = extent_tree_szad_nsearch(&dss_chunks_szad, &key);
|
|
if (node != NULL) {
|
|
size_t offset = (size_t)((uintptr_t)(node->addr) & (alignment -
|
|
1));
|
|
void *ret;
|
|
if (offset > 0)
|
|
offset = alignment - offset;
|
|
ret = (void *)((uintptr_t)(node->addr) + offset);
|
|
|
|
/* Remove node from the tree. */
|
|
extent_tree_szad_remove(&dss_chunks_szad, node);
|
|
extent_tree_ad_remove(&dss_chunks_ad, node);
|
|
if (offset > 0) {
|
|
/* Insert the leading space as a smaller chunk. */
|
|
node->size = offset;
|
|
extent_tree_szad_insert(&dss_chunks_szad, node);
|
|
extent_tree_ad_insert(&dss_chunks_ad, node);
|
|
}
|
|
if (alignment - chunksize > offset) {
|
|
if (offset > 0)
|
|
node = base_node_alloc();
|
|
/* Insert the trailing space as a smaller chunk. */
|
|
node->addr = (void *)((uintptr_t)(ret) + size);
|
|
node->size = alignment - chunksize - offset;
|
|
extent_tree_szad_insert(&dss_chunks_szad, node);
|
|
extent_tree_ad_insert(&dss_chunks_ad, node);
|
|
} else if (offset == 0)
|
|
base_node_dealloc(node);
|
|
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
|
|
if (*zero)
|
|
memset(ret, 0, size);
|
|
return (ret);
|
|
}
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
void *
|
|
chunk_alloc_dss(size_t size, size_t alignment, bool *zero)
|
|
{
|
|
void *ret;
|
|
|
|
cassert(config_dss);
|
|
assert(size > 0 && (size & chunksize_mask) == 0);
|
|
assert(alignment > 0 && (alignment & chunksize_mask) == 0);
|
|
|
|
ret = chunk_recycle_dss(size, alignment, zero);
|
|
if (ret != NULL)
|
|
return (ret);
|
|
|
|
/*
|
|
* sbrk() uses a signed increment argument, so take care not to
|
|
* interpret a huge allocation request as a negative increment.
|
|
*/
|
|
if ((intptr_t)size < 0)
|
|
return (NULL);
|
|
|
|
malloc_mutex_lock(&dss_mtx);
|
|
if (dss_prev != (void *)-1) {
|
|
size_t gap_size, cpad_size;
|
|
void *cpad, *dss_next;
|
|
intptr_t incr;
|
|
|
|
/*
|
|
* The loop is necessary to recover from races with other
|
|
* threads that are using the DSS for something other than
|
|
* malloc.
|
|
*/
|
|
do {
|
|
/* Get the current end of the DSS. */
|
|
dss_max = sbrk(0);
|
|
/*
|
|
* Calculate how much padding is necessary to
|
|
* chunk-align the end of the DSS.
|
|
*/
|
|
gap_size = (chunksize - CHUNK_ADDR2OFFSET(dss_max)) &
|
|
chunksize_mask;
|
|
/*
|
|
* Compute how much chunk-aligned pad space (if any) is
|
|
* necessary to satisfy alignment. This space can be
|
|
* recycled for later use.
|
|
*/
|
|
cpad = (void *)((uintptr_t)dss_max + gap_size);
|
|
ret = (void *)(((uintptr_t)dss_max + (alignment - 1)) &
|
|
~(alignment - 1));
|
|
cpad_size = (uintptr_t)ret - (uintptr_t)cpad;
|
|
dss_next = (void *)((uintptr_t)ret + size);
|
|
if ((uintptr_t)ret < (uintptr_t)dss_max ||
|
|
(uintptr_t)dss_next < (uintptr_t)dss_max) {
|
|
/* Wrap-around. */
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
return (NULL);
|
|
}
|
|
incr = gap_size + cpad_size + size;
|
|
dss_prev = sbrk(incr);
|
|
if (dss_prev == dss_max) {
|
|
/* Success. */
|
|
dss_max = dss_next;
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
if (cpad_size != 0)
|
|
chunk_dealloc_dss(cpad, cpad_size);
|
|
*zero = true;
|
|
return (ret);
|
|
}
|
|
} while (dss_prev != (void *)-1);
|
|
}
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
static extent_node_t *
|
|
chunk_dealloc_dss_record(void *chunk, size_t size)
|
|
{
|
|
extent_node_t *xnode, *node, *prev, key;
|
|
|
|
cassert(config_dss);
|
|
|
|
xnode = NULL;
|
|
while (true) {
|
|
key.addr = (void *)((uintptr_t)chunk + size);
|
|
node = extent_tree_ad_nsearch(&dss_chunks_ad, &key);
|
|
/* Try to coalesce forward. */
|
|
if (node != NULL && node->addr == key.addr) {
|
|
/*
|
|
* Coalesce chunk with the following address range.
|
|
* This does not change the position within
|
|
* dss_chunks_ad, so only remove/insert from/into
|
|
* dss_chunks_szad.
|
|
*/
|
|
extent_tree_szad_remove(&dss_chunks_szad, node);
|
|
node->addr = chunk;
|
|
node->size += size;
|
|
extent_tree_szad_insert(&dss_chunks_szad, node);
|
|
break;
|
|
} else if (xnode == NULL) {
|
|
/*
|
|
* It is possible that base_node_alloc() will cause a
|
|
* new base chunk to be allocated, so take care not to
|
|
* deadlock on dss_mtx, and recover if another thread
|
|
* deallocates an adjacent chunk while this one is busy
|
|
* allocating xnode.
|
|
*/
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
xnode = base_node_alloc();
|
|
malloc_mutex_lock(&dss_mtx);
|
|
if (xnode == NULL)
|
|
return (NULL);
|
|
} else {
|
|
/* Coalescing forward failed, so insert a new node. */
|
|
node = xnode;
|
|
xnode = NULL;
|
|
node->addr = chunk;
|
|
node->size = size;
|
|
extent_tree_ad_insert(&dss_chunks_ad, node);
|
|
extent_tree_szad_insert(&dss_chunks_szad, node);
|
|
break;
|
|
}
|
|
}
|
|
/* Discard xnode if it ended up unused do to a race. */
|
|
if (xnode != NULL)
|
|
base_node_dealloc(xnode);
|
|
|
|
/* Try to coalesce backward. */
|
|
prev = extent_tree_ad_prev(&dss_chunks_ad, node);
|
|
if (prev != NULL && (void *)((uintptr_t)prev->addr + prev->size) ==
|
|
chunk) {
|
|
/*
|
|
* Coalesce chunk with the previous address range. This does
|
|
* not change the position within dss_chunks_ad, so only
|
|
* remove/insert node from/into dss_chunks_szad.
|
|
*/
|
|
extent_tree_szad_remove(&dss_chunks_szad, prev);
|
|
extent_tree_ad_remove(&dss_chunks_ad, prev);
|
|
|
|
extent_tree_szad_remove(&dss_chunks_szad, node);
|
|
node->addr = prev->addr;
|
|
node->size += prev->size;
|
|
extent_tree_szad_insert(&dss_chunks_szad, node);
|
|
|
|
base_node_dealloc(prev);
|
|
}
|
|
|
|
return (node);
|
|
}
|
|
|
|
bool
|
|
chunk_in_dss(void *chunk)
|
|
{
|
|
bool ret;
|
|
|
|
cassert(config_dss);
|
|
|
|
malloc_mutex_lock(&dss_mtx);
|
|
if ((uintptr_t)chunk >= (uintptr_t)dss_base
|
|
&& (uintptr_t)chunk < (uintptr_t)dss_max)
|
|
ret = true;
|
|
else
|
|
ret = false;
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
bool
|
|
chunk_dealloc_dss(void *chunk, size_t size)
|
|
{
|
|
bool ret;
|
|
|
|
cassert(config_dss);
|
|
|
|
malloc_mutex_lock(&dss_mtx);
|
|
if ((uintptr_t)chunk >= (uintptr_t)dss_base
|
|
&& (uintptr_t)chunk < (uintptr_t)dss_max) {
|
|
extent_node_t *node;
|
|
|
|
/* Try to coalesce with other unused chunks. */
|
|
node = chunk_dealloc_dss_record(chunk, size);
|
|
if (node != NULL) {
|
|
chunk = node->addr;
|
|
size = node->size;
|
|
}
|
|
|
|
/* Get the current end of the DSS. */
|
|
dss_max = sbrk(0);
|
|
|
|
/*
|
|
* Try to shrink the DSS if this chunk is at the end of the
|
|
* DSS. The sbrk() call here is subject to a race condition
|
|
* with threads that use brk(2) or sbrk(2) directly, but the
|
|
* alternative would be to leak memory for the sake of poorly
|
|
* designed multi-threaded programs.
|
|
*/
|
|
if ((void *)((uintptr_t)chunk + size) == dss_max
|
|
&& (dss_prev = sbrk(-(intptr_t)size)) == dss_max) {
|
|
/* Success. */
|
|
dss_max = (void *)((intptr_t)dss_prev - (intptr_t)size);
|
|
|
|
if (node != NULL) {
|
|
extent_tree_szad_remove(&dss_chunks_szad, node);
|
|
extent_tree_ad_remove(&dss_chunks_ad, node);
|
|
base_node_dealloc(node);
|
|
}
|
|
} else
|
|
madvise(chunk, size, MADV_DONTNEED);
|
|
|
|
ret = false;
|
|
goto RETURN;
|
|
}
|
|
|
|
ret = true;
|
|
RETURN:
|
|
malloc_mutex_unlock(&dss_mtx);
|
|
return (ret);
|
|
}
|
|
|
|
bool
|
|
chunk_dss_boot(void)
|
|
{
|
|
|
|
cassert(config_dss);
|
|
|
|
if (malloc_mutex_init(&dss_mtx))
|
|
return (true);
|
|
dss_base = sbrk(0);
|
|
dss_prev = dss_base;
|
|
dss_max = dss_base;
|
|
extent_tree_szad_new(&dss_chunks_szad);
|
|
extent_tree_ad_new(&dss_chunks_ad);
|
|
|
|
return (false);
|
|
}
|
|
|
|
void
|
|
chunk_dss_prefork(void)
|
|
{
|
|
|
|
if (config_dss)
|
|
malloc_mutex_prefork(&dss_mtx);
|
|
}
|
|
|
|
void
|
|
chunk_dss_postfork_parent(void)
|
|
{
|
|
|
|
if (config_dss)
|
|
malloc_mutex_postfork_parent(&dss_mtx);
|
|
}
|
|
|
|
void
|
|
chunk_dss_postfork_child(void)
|
|
{
|
|
|
|
if (config_dss)
|
|
malloc_mutex_postfork_child(&dss_mtx);
|
|
}
|
|
|
|
/******************************************************************************/
|