project-base/server-skynet-source-3rd-jemalloc
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Implement in-place huge allocation shrinking.

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Trivial example:

    #include <stdlib.h>

    int main(void) {
        void *ptr = malloc(1024 * 1024 * 8);
        if (!ptr) return 1;
        ptr = realloc(ptr, 1024 * 1024 * 4);
        if (!ptr) return 1;
    }

Before:

    mmap(NULL, 8388608, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fcfff000000
    mmap(NULL, 4194304, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fcffec00000
    madvise(0x7fcfff000000, 8388608, MADV_DONTNEED) = 0

After:

    mmap(NULL, 8388608, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1934800000
    madvise(0x7f1934c00000, 4194304, MADV_DONTNEED) = 0

Closes #134
This commit is contained in:
Daniel Micay 2014-09-30 10:33:46 -04:00 committed by Jason Evans
parent 4dcf04bfc0
commit f8034540a1
1 changed files with 62 additions and 27 deletions
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89
src/huge.c
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@ -72,21 +72,79 @@ huge_palloc(tsd_t *tsd, arena_t *arena, size_t size, size_t alignment,
return (ret);
}
#ifdef JEMALLOC_JET
#undef huge_dalloc_junk
#define huge_dalloc_junk JEMALLOC_N(huge_dalloc_junk_impl)
#endif
static void
huge_dalloc_junk(void *ptr, size_t usize)
{
if (config_fill && have_dss && unlikely(opt_junk)) {
/*
* Only bother junk filling if the chunk isn't about to be
* unmapped.
*/
if (config_munmap == false || (have_dss && chunk_in_dss(ptr)))
memset(ptr, 0x5a, usize);
}
}
#ifdef JEMALLOC_JET
#undef huge_dalloc_junk
#define huge_dalloc_junk JEMALLOC_N(huge_dalloc_junk)
huge_dalloc_junk_t *huge_dalloc_junk = JEMALLOC_N(huge_dalloc_junk_impl);
#endif
bool
huge_ralloc_no_move(void *ptr, size_t oldsize, size_t size, size_t extra)
{
/* Both allocations must be huge to avoid a move. */
if (oldsize <= arena_maxclass)
return (true);
assert(CHUNK_CEILING(oldsize) == oldsize);
/*
* Avoid moving the allocation if the size class can be left the same.
*/
if (oldsize > arena_maxclass
&& CHUNK_CEILING(oldsize) >= CHUNK_CEILING(size)
if (CHUNK_CEILING(oldsize) >= CHUNK_CEILING(size)
&& CHUNK_CEILING(oldsize) <= CHUNK_CEILING(size+extra)) {
assert(CHUNK_CEILING(oldsize) == oldsize);
return (false);
}
/* Reallocation would require a move. */
/* Overflow. */
if (CHUNK_CEILING(size) == 0)
return (true);
/* Shrink the allocation in-place. */
if (CHUNK_CEILING(oldsize) > CHUNK_CEILING(size)) {
extent_node_t *node, key;
void *excess_addr;
size_t excess_size;
malloc_mutex_lock(&huge_mtx);
key.addr = ptr;
node = extent_tree_ad_search(&huge, &key);
assert(node != NULL);
assert(node->addr == ptr);
/* Update the size of the huge allocation. */
node->size = CHUNK_CEILING(size);
malloc_mutex_unlock(&huge_mtx);
excess_addr = node->addr + CHUNK_CEILING(size);
excess_size = CHUNK_CEILING(oldsize) - CHUNK_CEILING(size);
/* Zap the excess chunks. */
huge_dalloc_junk(excess_addr, excess_size);
arena_chunk_dalloc_huge(node->arena, excess_addr, excess_size);
return (false);
}
return (true);
}
@ -134,29 +192,6 @@ huge_ralloc(tsd_t *tsd, arena_t *arena, void *ptr, size_t oldsize, size_t size,
return (ret);
}
#ifdef JEMALLOC_JET
#undef huge_dalloc_junk
#define huge_dalloc_junk JEMALLOC_N(huge_dalloc_junk_impl)
#endif
static void
huge_dalloc_junk(void *ptr, size_t usize)
{
if (config_fill && have_dss && unlikely(opt_junk)) {
/*
* Only bother junk filling if the chunk isn't about to be
* unmapped.
*/
if (config_munmap == false || (have_dss && chunk_in_dss(ptr)))
memset(ptr, 0x5a, usize);
}
}
#ifdef JEMALLOC_JET
#undef huge_dalloc_junk
#define huge_dalloc_junk JEMALLOC_N(huge_dalloc_junk)
huge_dalloc_junk_t *huge_dalloc_junk = JEMALLOC_N(huge_dalloc_junk_impl);
#endif
void
huge_dalloc(void *ptr)
{