server-skynet-source-3rd-je.../src/chunk.c

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#define JEMALLOC_CHUNK_C_
2010-02-12 06:45:59 +08:00
#include "jemalloc/internal/jemalloc_internal.h"
/******************************************************************************/
/* Data. */
const char *opt_dss = DSS_DEFAULT;
size_t opt_lg_chunk = LG_CHUNK_DEFAULT;
/* Used exclusively for gdump triggering. */
static size_t curchunks;
static size_t highchunks;
rtree_t chunks_rtree;
/* Various chunk-related settings. */
size_t chunksize;
size_t chunksize_mask; /* (chunksize - 1). */
size_t chunk_npages;
/******************************************************************************/
bool
chunk_register(const void *chunk, const extent_node_t *node)
{
assert(extent_node_addr_get(node) == chunk);
if (rtree_set(&chunks_rtree, (uintptr_t)chunk, node))
return (true);
if (config_prof && opt_prof) {
size_t size = extent_node_size_get(node);
size_t nadd = (size == 0) ? 1 : size / chunksize;
size_t cur = atomic_add_z(&curchunks, nadd);
size_t high = atomic_read_z(&highchunks);
while (cur > high && atomic_cas_z(&highchunks, high, cur)) {
/*
* Don't refresh cur, because it may have decreased
* since this thread lost the highchunks update race.
*/
high = atomic_read_z(&highchunks);
}
if (cur > high && prof_gdump_get_unlocked())
prof_gdump();
}
return (false);
}
void
chunk_deregister(const void *chunk, const extent_node_t *node)
{
bool err;
err = rtree_set(&chunks_rtree, (uintptr_t)chunk, NULL);
assert(!err);
if (config_prof && opt_prof) {
size_t size = extent_node_size_get(node);
size_t nsub = (size == 0) ? 1 : size / chunksize;
assert(atomic_read_z(&curchunks) >= nsub);
atomic_sub_z(&curchunks, nsub);
}
}
/* Do first-fit chunk selection. */
static extent_node_t *
chunk_first_fit(arena_t *arena, extent_tree_t *chunks_szad,
extent_tree_t *chunks_ad, size_t size)
{
extent_node_t *node;
index_t index;
assert(size == CHUNK_CEILING(size));
if (size == chunksize) {
/*
* Any chunk will suffice, so simply select the one lowest in
* memory.
*/
return (extent_tree_ad_first(chunks_ad));
}
/*
* Iterate over all size classes that are at least large enough to
* satisfy the request, search for the lowest chunk of each size class,
* and choose the lowest of the chunks found.
*/
node = NULL;
for (index = size2index(size); index < NSIZES;) {
extent_node_t *curnode;
extent_node_t key;
extent_node_init(&key, arena, NULL,
CHUNK_CEILING(index2size(index)), false);
curnode = extent_tree_szad_nsearch(chunks_szad, &key);
if (curnode == NULL)
break;
if (node == NULL || (uintptr_t)extent_node_addr_get(curnode) <
(uintptr_t)extent_node_addr_get(node))
node = curnode;
assert(size2index(extent_node_size_get(curnode)) + 1 > index);
index = size2index(extent_node_size_get(curnode)) + 1;
}
return (node);
}
static void *
chunk_recycle(arena_t *arena, extent_tree_t *chunks_szad,
extent_tree_t *chunks_ad, bool cache, void *new_addr, size_t size,
size_t alignment, bool *zero, bool dalloc_node)
{
void *ret;
extent_node_t *node;
size_t alloc_size, leadsize, trailsize;
bool zeroed;
assert(new_addr == NULL || alignment == chunksize);
assert(dalloc_node || new_addr != NULL);
alloc_size = CHUNK_CEILING(s2u(size + alignment - chunksize));
/* Beware size_t wrap-around. */
if (alloc_size < size)
return (NULL);
malloc_mutex_lock(&arena->chunks_mtx);
if (new_addr != NULL) {
extent_node_t key;
extent_node_init(&key, arena, new_addr, alloc_size, false);
node = extent_tree_ad_search(chunks_ad, &key);
} else {
node = chunk_first_fit(arena, chunks_szad, chunks_ad,
alloc_size);
}
if (node == NULL || (new_addr != NULL && extent_node_size_get(node) <
size)) {
malloc_mutex_unlock(&arena->chunks_mtx);
return (NULL);
}
leadsize = ALIGNMENT_CEILING((uintptr_t)extent_node_addr_get(node),
alignment) - (uintptr_t)extent_node_addr_get(node);
assert(new_addr == NULL || leadsize == 0);
assert(extent_node_size_get(node) >= leadsize + size);
trailsize = extent_node_size_get(node) - leadsize - size;
ret = (void *)((uintptr_t)extent_node_addr_get(node) + leadsize);
zeroed = extent_node_zeroed_get(node);
if (zeroed)
*zero = true;
/* Remove node from the tree. */
extent_tree_szad_remove(chunks_szad, node);
extent_tree_ad_remove(chunks_ad, node);
arena_chunk_cache_maybe_remove(arena, node, cache);
if (leadsize != 0) {
/* Insert the leading space as a smaller chunk. */
extent_node_size_set(node, leadsize);
extent_tree_szad_insert(chunks_szad, node);
extent_tree_ad_insert(chunks_ad, node);
arena_chunk_cache_maybe_insert(arena, node, cache);
node = NULL;
}
if (trailsize != 0) {
/* Insert the trailing space as a smaller chunk. */
if (node == NULL) {
node = arena_node_alloc(arena);
if (node == NULL) {
malloc_mutex_unlock(&arena->chunks_mtx);
chunk_record(arena, chunks_szad, chunks_ad,
cache, ret, size, zeroed);
return (NULL);
}
}
extent_node_init(node, arena, (void *)((uintptr_t)(ret) + size),
trailsize, zeroed);
extent_tree_szad_insert(chunks_szad, node);
extent_tree_ad_insert(chunks_ad, node);
arena_chunk_cache_maybe_insert(arena, node, cache);
node = NULL;
}
malloc_mutex_unlock(&arena->chunks_mtx);
assert(dalloc_node || node != NULL);
if (dalloc_node && node != NULL)
arena_node_dalloc(arena, node);
if (*zero) {
if (!zeroed)
memset(ret, 0, size);
else if (config_debug) {
size_t i;
size_t *p = (size_t *)(uintptr_t)ret;
JEMALLOC_VALGRIND_MAKE_MEM_DEFINED(ret, size);
for (i = 0; i < size / sizeof(size_t); i++)
assert(p[i] == 0);
}
}
return (ret);
}
static void *
chunk_alloc_core_dss(arena_t *arena, void *new_addr, size_t size,
size_t alignment, bool *zero)
{
void *ret;
if ((ret = chunk_recycle(arena, &arena->chunks_szad_dss,
&arena->chunks_ad_dss, false, new_addr, size, alignment, zero,
true)) != NULL)
return (ret);
ret = chunk_alloc_dss(arena, new_addr, size, alignment, zero);
return (ret);
}
/*
* If the caller specifies (!*zero), it is still possible to receive zeroed
* memory, in which case *zero is toggled to true. arena_chunk_alloc() takes
* advantage of this to avoid demanding zeroed chunks, but taking advantage of
* them if they are returned.
*/
static void *
chunk_alloc_core(arena_t *arena, void *new_addr, size_t size, size_t alignment,
Attempt to expand huge allocations in-place. This adds support for expanding huge allocations in-place by requesting memory at a specific address from the chunk allocator. It's currently only implemented for the chunk recycling path, although in theory it could also be done by optimistically allocating new chunks. On Linux, it could attempt an in-place mremap. However, that won't work in practice since the heap is grown downwards and memory is not unmapped (in a normal build, at least). Repeated vector reallocation micro-benchmark: #include <string.h> #include <stdlib.h> int main(void) { for (size_t i = 0; i < 100; i++) { void *ptr = NULL; size_t old_size = 0; for (size_t size = 4; size < (1 << 30); size *= 2) { ptr = realloc(ptr, size); if (!ptr) return 1; memset(ptr + old_size, 0xff, size - old_size); old_size = size; } free(ptr); } } The glibc allocator fails to do any in-place reallocations on this benchmark once it passes the M_MMAP_THRESHOLD (default 128k) but it elides the cost of copies via mremap, which is currently not something that jemalloc can use. With this improvement, jemalloc still fails to do any in-place huge reallocations for the first outer loop, but then succeeds 100% of the time for the remaining 99 iterations. The time spent doing allocations and copies drops down to under 5%, with nearly all of it spent doing purging + faulting (when huge pages are disabled) and the array memset. An improved mremap API (MREMAP_RETAIN - #138) would be far more general but this is a portable optimization and would still be useful on Linux for xallocx. Numbers with transparent huge pages enabled: glibc (copies elided via MREMAP_MAYMOVE): 8.471s jemalloc: 17.816s jemalloc + no-op madvise: 13.236s jemalloc + this commit: 6.787s jemalloc + this commit + no-op madvise: 6.144s Numbers with transparent huge pages disabled: glibc (copies elided via MREMAP_MAYMOVE): 15.403s jemalloc: 39.456s jemalloc + no-op madvise: 12.768s jemalloc + this commit: 15.534s jemalloc + this commit + no-op madvise: 6.354s Closes #137
2014-10-04 13:39:32 +08:00
bool *zero, dss_prec_t dss_prec)
{
void *ret;
assert(size != 0);
assert((size & chunksize_mask) == 0);
assert(alignment != 0);
assert((alignment & chunksize_mask) == 0);
/* "primary" dss. */
if (have_dss && dss_prec == dss_prec_primary && (ret =
chunk_alloc_core_dss(arena, new_addr, size, alignment, zero)) !=
NULL)
return (ret);
/* mmap. */
if (!config_munmap && (ret = chunk_recycle(arena,
&arena->chunks_szad_mmap, &arena->chunks_ad_mmap, false, new_addr,
size, alignment, zero, true)) != NULL)
return (ret);
/*
* Requesting an address is not implemented for chunk_alloc_mmap(), so
* only call it if (new_addr == NULL).
*/
if (new_addr == NULL && (ret = chunk_alloc_mmap(size, alignment, zero))
!= NULL)
return (ret);
/* "secondary" dss. */
if (have_dss && dss_prec == dss_prec_secondary && (ret =
chunk_alloc_core_dss(arena, new_addr, size, alignment, zero)) !=
NULL)
return (ret);
/* All strategies for allocation failed. */
return (NULL);
}
void *
chunk_alloc_base(size_t size)
{
void *ret;
bool zero;
/*
* Directly call chunk_alloc_mmap() rather than chunk_alloc_core()
* because it's critical that chunk_alloc_base() return untouched
* demand-zeroed virtual memory.
*/
zero = true;
ret = chunk_alloc_mmap(size, chunksize, &zero);
if (ret == NULL)
return (NULL);
if (config_valgrind)
JEMALLOC_VALGRIND_MAKE_MEM_UNDEFINED(ret, size);
return (ret);
}
void *
chunk_alloc_cache(arena_t *arena, void *new_addr, size_t size, size_t alignment,
bool *zero, bool dalloc_node)
{
assert(size != 0);
assert((size & chunksize_mask) == 0);
assert(alignment != 0);
assert((alignment & chunksize_mask) == 0);
return (chunk_recycle(arena, &arena->chunks_szad_cache,
&arena->chunks_ad_cache, true, new_addr, size, alignment, zero,
dalloc_node));
}
static arena_t *
chunk_arena_get(unsigned arena_ind)
{
arena_t *arena;
/* Dodge tsd for a0 in order to avoid bootstrapping issues. */
arena = (arena_ind == 0) ? a0get() : arena_get(tsd_fetch(), arena_ind,
false, true);
/*
* The arena we're allocating on behalf of must have been initialized
* already.
*/
assert(arena != NULL);
return (arena);
}
static void *
chunk_alloc_arena(arena_t *arena, void *new_addr, size_t size, size_t alignment,
bool *zero)
{
void *ret;
ret = chunk_alloc_core(arena, new_addr, size, alignment, zero,
arena->dss_prec);
if (ret == NULL)
return (NULL);
if (config_valgrind)
JEMALLOC_VALGRIND_MAKE_MEM_UNDEFINED(ret, size);
return (ret);
}
/*
* Default arena chunk allocation routine in the absence of user override. This
* function isn't actually used by jemalloc, but it does the right thing if the
* application passes calls through to it during chunk allocation.
*/
void *
chunk_alloc_default(void *new_addr, size_t size, size_t alignment, bool *zero,
unsigned arena_ind)
{
arena_t *arena;
arena = chunk_arena_get(arena_ind);
return (chunk_alloc_arena(arena, new_addr, size, alignment, zero));
}
void *
chunk_alloc_wrapper(arena_t *arena, chunk_alloc_t *chunk_alloc, void *new_addr,
size_t size, size_t alignment, bool *zero)
{
void *ret;
ret = chunk_alloc(new_addr, size, alignment, zero, arena->ind);
if (ret == NULL)
return (NULL);
if (config_valgrind && chunk_alloc != chunk_alloc_default)
JEMALLOC_VALGRIND_MAKE_MEM_UNDEFINED(ret, chunksize);
return (ret);
}
void
chunk_record(arena_t *arena, extent_tree_t *chunks_szad,
extent_tree_t *chunks_ad, bool cache, void *chunk, size_t size, bool zeroed)
{
bool unzeroed;
extent_node_t *node, *prev;
extent_node_t key;
assert(!cache || !zeroed);
unzeroed = cache || !zeroed;
JEMALLOC_VALGRIND_MAKE_MEM_NOACCESS(chunk, size);
malloc_mutex_lock(&arena->chunks_mtx);
extent_node_init(&key, arena, (void *)((uintptr_t)chunk + size), 0,
false);
node = extent_tree_ad_nsearch(chunks_ad, &key);
/* Try to coalesce forward. */
if (node != NULL && extent_node_addr_get(node) ==
extent_node_addr_get(&key)) {
/*
* Coalesce chunk with the following address range. This does
* not change the position within chunks_ad, so only
* remove/insert from/into chunks_szad.
*/
extent_tree_szad_remove(chunks_szad, node);
arena_chunk_cache_maybe_remove(arena, node, cache);
extent_node_addr_set(node, chunk);
extent_node_size_set(node, size + extent_node_size_get(node));
extent_node_zeroed_set(node, extent_node_zeroed_get(node) &&
!unzeroed);
extent_tree_szad_insert(chunks_szad, node);
arena_chunk_cache_maybe_insert(arena, node, cache);
} else {
/* Coalescing forward failed, so insert a new node. */
node = arena_node_alloc(arena);
if (node == NULL) {
/*
* Node allocation failed, which is an exceedingly
* unlikely failure. Leak chunk after making sure its
* pages have already been purged, so that this is only
* a virtual memory leak.
*/
if (cache)
pages_purge(chunk, size);
goto label_return;
}
extent_node_init(node, arena, chunk, size, !unzeroed);
extent_tree_ad_insert(chunks_ad, node);
extent_tree_szad_insert(chunks_szad, node);
arena_chunk_cache_maybe_insert(arena, node, cache);
}
/* Try to coalesce backward. */
prev = extent_tree_ad_prev(chunks_ad, node);
if (prev != NULL && (void *)((uintptr_t)extent_node_addr_get(prev) +
extent_node_size_get(prev)) == chunk) {
/*
* Coalesce chunk with the previous address range. This does
* not change the position within chunks_ad, so only
* remove/insert node from/into chunks_szad.
*/
extent_tree_szad_remove(chunks_szad, prev);
extent_tree_ad_remove(chunks_ad, prev);
arena_chunk_cache_maybe_remove(arena, prev, cache);
extent_tree_szad_remove(chunks_szad, node);
arena_chunk_cache_maybe_remove(arena, node, cache);
extent_node_addr_set(node, extent_node_addr_get(prev));
extent_node_size_set(node, extent_node_size_get(prev) +
extent_node_size_get(node));
extent_node_zeroed_set(node, extent_node_zeroed_get(prev) &&
extent_node_zeroed_get(node));
extent_tree_szad_insert(chunks_szad, node);
arena_chunk_cache_maybe_insert(arena, node, cache);
arena_node_dalloc(arena, prev);
}
label_return:
malloc_mutex_unlock(&arena->chunks_mtx);
}
void
chunk_dalloc_cache(arena_t *arena, void *chunk, size_t size)
{
assert(chunk != NULL);
assert(CHUNK_ADDR2BASE(chunk) == chunk);
assert(size != 0);
assert((size & chunksize_mask) == 0);
chunk_record(arena, &arena->chunks_szad_cache, &arena->chunks_ad_cache,
true, chunk, size, false);
arena_maybe_purge(arena);
}
void
chunk_dalloc_arena(arena_t *arena, void *chunk, size_t size, bool zeroed)
{
assert(chunk != NULL);
assert(CHUNK_ADDR2BASE(chunk) == chunk);
assert(size != 0);
assert((size & chunksize_mask) == 0);
if (have_dss && chunk_in_dss(chunk)) {
chunk_record(arena, &arena->chunks_szad_dss,
&arena->chunks_ad_dss, false, chunk, size, zeroed);
} else if (chunk_dalloc_mmap(chunk, size)) {
chunk_record(arena, &arena->chunks_szad_mmap,
&arena->chunks_ad_mmap, false, chunk, size, zeroed);
}
}
/*
* Default arena chunk deallocation routine in the absence of user override.
* This function isn't actually used by jemalloc, but it does the right thing if
* the application passes calls through to it during chunk deallocation.
*/
bool
chunk_dalloc_default(void *chunk, size_t size, unsigned arena_ind)
{
chunk_dalloc_arena(chunk_arena_get(arena_ind), chunk, size, false);
return (false);
}
void
chunk_dalloc_wrapper(arena_t *arena, chunk_dalloc_t *chunk_dalloc, void *chunk,
size_t size)
{
chunk_dalloc(chunk, size, arena->ind);
if (config_valgrind && chunk_dalloc != chunk_dalloc_default)
JEMALLOC_VALGRIND_MAKE_MEM_NOACCESS(chunk, size);
}
static rtree_node_elm_t *
chunks_rtree_node_alloc(size_t nelms)
{
return ((rtree_node_elm_t *)base_alloc(nelms *
sizeof(rtree_node_elm_t)));
}
bool
chunk_boot(void)
{
/* Set variables according to the value of opt_lg_chunk. */
chunksize = (ZU(1) << opt_lg_chunk);
assert(chunksize >= PAGE);
chunksize_mask = chunksize - 1;
chunk_npages = (chunksize >> LG_PAGE);
if (have_dss && chunk_dss_boot())
return (true);
if (rtree_new(&chunks_rtree, (ZU(1) << (LG_SIZEOF_PTR+3)) -
opt_lg_chunk, chunks_rtree_node_alloc, NULL))
return (true);
return (false);
}
void
chunk_prefork(void)
{
chunk_dss_prefork();
}
void
chunk_postfork_parent(void)
{
chunk_dss_postfork_parent();
}
void
chunk_postfork_child(void)
{
chunk_dss_postfork_child();
}