server-skynet-source-3rd-je.../include/jemalloc/internal/chunk.h
Jason Evans 20f1fc95ad Fix fork(2)-related deadlocks.
Add a library constructor for jemalloc that initializes the allocator.
This fixes a race that could occur if threads were created by the main
thread prior to any memory allocation, followed by fork(2), and then
memory allocation in the child process.

Fix the prefork/postfork functions to acquire/release the ctl, prof, and
rtree mutexes.  This fixes various fork() child process deadlocks, but
one possible deadlock remains (intentionally) unaddressed: prof
backtracing can acquire runtime library mutexes, so deadlock is still
possible if heap profiling is enabled during fork().  This deadlock is
known to be a real issue in at least the case of libgcc-based
backtracing.

Reported by tfengjun.
2012-10-09 15:21:46 -07:00

61 lines
1.9 KiB
C

/******************************************************************************/
#ifdef JEMALLOC_H_TYPES
/*
* Size and alignment of memory chunks that are allocated by the OS's virtual
* memory system.
*/
#define LG_CHUNK_DEFAULT 22
/* Return the chunk address for allocation address a. */
#define CHUNK_ADDR2BASE(a) \
((void *)((uintptr_t)(a) & ~chunksize_mask))
/* Return the chunk offset of address a. */
#define CHUNK_ADDR2OFFSET(a) \
((size_t)((uintptr_t)(a) & chunksize_mask))
/* Return the smallest chunk multiple that is >= s. */
#define CHUNK_CEILING(s) \
(((s) + chunksize_mask) & ~chunksize_mask)
#endif /* JEMALLOC_H_TYPES */
/******************************************************************************/
#ifdef JEMALLOC_H_STRUCTS
#endif /* JEMALLOC_H_STRUCTS */
/******************************************************************************/
#ifdef JEMALLOC_H_EXTERNS
extern size_t opt_lg_chunk;
/* Protects stats_chunks; currently not used for any other purpose. */
extern malloc_mutex_t chunks_mtx;
/* Chunk statistics. */
extern chunk_stats_t stats_chunks;
extern rtree_t *chunks_rtree;
extern size_t chunksize;
extern size_t chunksize_mask; /* (chunksize - 1). */
extern size_t chunk_npages;
extern size_t map_bias; /* Number of arena chunk header pages. */
extern size_t arena_maxclass; /* Max size class for arenas. */
void *chunk_alloc(size_t size, size_t alignment, bool base, bool *zero);
void chunk_dealloc(void *chunk, size_t size, bool unmap);
bool chunk_boot(void);
void chunk_prefork(void);
void chunk_postfork_parent(void);
void chunk_postfork_child(void);
#endif /* JEMALLOC_H_EXTERNS */
/******************************************************************************/
#ifdef JEMALLOC_H_INLINES
#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/
#include "jemalloc/internal/chunk_dss.h"
#include "jemalloc/internal/chunk_mmap.h"