server-skynet-source-3rd-je.../include/jemalloc/internal/prof.h
Jason Evans 6ef80d68f0 Fix profile dumping race.
Fix a race that caused a non-critical assertion failure.  To trigger the
race, a thread had to be part way through initializing a new sample,
such that it was discoverable by the dumping thread, but not yet linked
into its gctx by the time a later dump phase would normally have reset
its state to 'nominal'.

Additionally, lock access to the state field during modification to
transition to the dumping state.  It's not apparent that this oversight
could have caused an actual problem due to outer locking that protects
the dumping machinery, but the added locking pedantically follows the
stated locking protocol for the state field.
2014-09-24 22:23:43 -07:00

471 lines
13 KiB
C

/******************************************************************************/
#ifdef JEMALLOC_H_TYPES
typedef struct prof_bt_s prof_bt_t;
typedef struct prof_cnt_s prof_cnt_t;
typedef struct prof_tctx_s prof_tctx_t;
typedef struct prof_gctx_s prof_gctx_t;
typedef struct prof_tdata_s prof_tdata_t;
/* Option defaults. */
#ifdef JEMALLOC_PROF
# define PROF_PREFIX_DEFAULT "jeprof"
#else
# define PROF_PREFIX_DEFAULT ""
#endif
#define LG_PROF_SAMPLE_DEFAULT 19
#define LG_PROF_INTERVAL_DEFAULT -1
/*
* Hard limit on stack backtrace depth. The version of prof_backtrace() that
* is based on __builtin_return_address() necessarily has a hard-coded number
* of backtrace frame handlers, and should be kept in sync with this setting.
*/
#define PROF_BT_MAX 128
/* Initial hash table size. */
#define PROF_CKH_MINITEMS 64
/* Size of memory buffer to use when writing dump files. */
#define PROF_DUMP_BUFSIZE 65536
/* Size of stack-allocated buffer used by prof_printf(). */
#define PROF_PRINTF_BUFSIZE 128
/*
* Number of mutexes shared among all gctx's. No space is allocated for these
* unless profiling is enabled, so it's okay to over-provision.
*/
#define PROF_NCTX_LOCKS 1024
/*
* Number of mutexes shared among all tdata's. No space is allocated for these
* unless profiling is enabled, so it's okay to over-provision.
*/
#define PROF_NTDATA_LOCKS 256
/*
* prof_tdata pointers close to NULL are used to encode state information that
* is used for cleaning up during thread shutdown.
*/
#define PROF_TDATA_STATE_REINCARNATED ((prof_tdata_t *)(uintptr_t)1)
#define PROF_TDATA_STATE_PURGATORY ((prof_tdata_t *)(uintptr_t)2)
#define PROF_TDATA_STATE_MAX PROF_TDATA_STATE_PURGATORY
#endif /* JEMALLOC_H_TYPES */
/******************************************************************************/
#ifdef JEMALLOC_H_STRUCTS
struct prof_bt_s {
/* Backtrace, stored as len program counters. */
void **vec;
unsigned len;
};
#ifdef JEMALLOC_PROF_LIBGCC
/* Data structure passed to libgcc _Unwind_Backtrace() callback functions. */
typedef struct {
prof_bt_t *bt;
unsigned max;
} prof_unwind_data_t;
#endif
struct prof_cnt_s {
/* Profiling counters. */
uint64_t curobjs;
uint64_t curbytes;
uint64_t accumobjs;
uint64_t accumbytes;
};
typedef enum {
prof_tctx_state_initializing,
prof_tctx_state_nominal,
prof_tctx_state_dumping,
prof_tctx_state_purgatory /* Dumper must finish destroying. */
} prof_tctx_state_t;
struct prof_tctx_s {
/* Thread data for thread that performed the allocation. */
prof_tdata_t *tdata;
/* Profiling counters, protected by tdata->lock. */
prof_cnt_t cnts;
/* Associated global context. */
prof_gctx_t *gctx;
/* Linkage into gctx's tctxs. */
rb_node(prof_tctx_t) tctx_link;
/*
* True during prof_alloc_prep()..prof_malloc_sample_object(), prevents
* sample vs destroy race.
*/
bool prepared;
/* Current dump-related state, protected by gctx->lock. */
prof_tctx_state_t state;
/*
* Copy of cnts snapshotted during early dump phase, protected by
* dump_mtx.
*/
prof_cnt_t dump_cnts;
};
typedef rb_tree(prof_tctx_t) prof_tctx_tree_t;
struct prof_gctx_s {
/* Protects nlimbo, cnt_summed, and tctxs. */
malloc_mutex_t *lock;
/*
* Number of threads that currently cause this gctx to be in a state of
* limbo due to one of:
* - Initializing this gctx.
* - Initializing per thread counters associated with this gctx.
* - Preparing to destroy this gctx.
* - Dumping a heap profile that includes this gctx.
* nlimbo must be 1 (single destroyer) in order to safely destroy the
* gctx.
*/
unsigned nlimbo;
/*
* Tree of profile counters, one for each thread that has allocated in
* this context.
*/
prof_tctx_tree_t tctxs;
/* Linkage for tree of contexts to be dumped. */
rb_node(prof_gctx_t) dump_link;
/* Temporary storage for summation during dump. */
prof_cnt_t cnt_summed;
/* Associated backtrace. */
prof_bt_t bt;
/* Backtrace vector, variable size, referred to by bt. */
void *vec[1];
};
typedef rb_tree(prof_gctx_t) prof_gctx_tree_t;
typedef enum {
prof_tdata_state_attached, /* Active thread attached, data valid. */
prof_tdata_state_detached, /* Defunct thread, data remain valid. */
prof_tdata_state_expired /* Predates reset, omit data from dump. */
} prof_tdata_state_t;
struct prof_tdata_s {
malloc_mutex_t *lock;
/* Monotonically increasing unique thread identifier. */
uint64_t thr_uid;
/* Included in heap profile dumps if non-NULL. */
char *thread_name;
prof_tdata_state_t state;
rb_node(prof_tdata_t) tdata_link;
/*
* Hash of (prof_bt_t *)-->(prof_tctx_t *). Each thread tracks
* backtraces for which it has non-zero allocation/deallocation counters
* associated with thread-specific prof_tctx_t objects. Other threads
* may write to prof_tctx_t contents when freeing associated objects.
*/
ckh_t bt2tctx;
/* Sampling state. */
uint64_t prng_state;
uint64_t bytes_until_sample;
/* State used to avoid dumping while operating on prof internals. */
bool enq;
bool enq_idump;
bool enq_gdump;
/*
* Set to true during an early dump phase for tdata's which are
* currently being dumped. New threads' tdata's have this initialized
* to false so that they aren't accidentally included in later dump
* phases.
*/
bool dumping;
/*
* True if profiling is active for this tdata's thread
* (thread.prof.active mallctl).
*/
bool active;
/* Temporary storage for summation during dump. */
prof_cnt_t cnt_summed;
/* Backtrace vector, used for calls to prof_backtrace(). */
void *vec[PROF_BT_MAX];
};
typedef rb_tree(prof_tdata_t) prof_tdata_tree_t;
#endif /* JEMALLOC_H_STRUCTS */
/******************************************************************************/
#ifdef JEMALLOC_H_EXTERNS
extern bool opt_prof;
/*
* Even if opt_prof is true, sampling can be temporarily disabled by setting
* opt_prof_active to false. No locking is used when updating opt_prof_active,
* so there are no guarantees regarding how long it will take for all threads
* to notice state changes.
*/
extern bool opt_prof_active;
extern size_t opt_lg_prof_sample; /* Mean bytes between samples. */
extern ssize_t opt_lg_prof_interval; /* lg(prof_interval). */
extern bool opt_prof_gdump; /* High-water memory dumping. */
extern bool opt_prof_final; /* Final profile dumping. */
extern bool opt_prof_leak; /* Dump leak summary at exit. */
extern bool opt_prof_accum; /* Report cumulative bytes. */
extern char opt_prof_prefix[
/* Minimize memory bloat for non-prof builds. */
#ifdef JEMALLOC_PROF
PATH_MAX +
#endif
1];
/*
* Profile dump interval, measured in bytes allocated. Each arena triggers a
* profile dump when it reaches this threshold. The effect is that the
* interval between profile dumps averages prof_interval, though the actual
* interval between dumps will tend to be sporadic, and the interval will be a
* maximum of approximately (prof_interval * narenas).
*/
extern uint64_t prof_interval;
/*
* Initialized as opt_lg_prof_sample, and potentially modified during profiling
* resets.
*/
extern size_t lg_prof_sample;
void prof_alloc_rollback(tsd_t *tsd, prof_tctx_t *tctx, bool updated);
void prof_malloc_sample_object(const void *ptr, size_t usize,
prof_tctx_t *tctx);
void prof_free_sampled_object(tsd_t *tsd, size_t usize, prof_tctx_t *tctx);
void bt_init(prof_bt_t *bt, void **vec);
void prof_backtrace(prof_bt_t *bt);
prof_tctx_t *prof_lookup(tsd_t *tsd, prof_bt_t *bt);
#ifdef JEMALLOC_JET
size_t prof_bt_count(void);
typedef int (prof_dump_open_t)(bool, const char *);
extern prof_dump_open_t *prof_dump_open;
#endif
void prof_idump(void);
bool prof_mdump(const char *filename);
void prof_gdump(void);
prof_tdata_t *prof_tdata_init(tsd_t *tsd);
prof_tdata_t *prof_tdata_reinit(tsd_t *tsd, prof_tdata_t *tdata);
void prof_reset(tsd_t *tsd, size_t lg_sample);
void prof_tdata_cleanup(tsd_t *tsd);
const char *prof_thread_name_get(void);
bool prof_thread_name_set(tsd_t *tsd, const char *thread_name);
bool prof_thread_active_get(void);
bool prof_thread_active_set(bool active);
void prof_boot0(void);
void prof_boot1(void);
bool prof_boot2(void);
void prof_prefork(void);
void prof_postfork_parent(void);
void prof_postfork_child(void);
void prof_sample_threshold_update(prof_tdata_t *tdata);
#endif /* JEMALLOC_H_EXTERNS */
/******************************************************************************/
#ifdef JEMALLOC_H_INLINES
#ifndef JEMALLOC_ENABLE_INLINE
prof_tdata_t *prof_tdata_get(tsd_t *tsd, bool create);
bool prof_sample_accum_update(tsd_t *tsd, size_t usize, bool commit,
prof_tdata_t **tdata_out);
prof_tctx_t *prof_alloc_prep(tsd_t *tsd, size_t usize, bool update);
prof_tctx_t *prof_tctx_get(const void *ptr);
void prof_tctx_set(const void *ptr, prof_tctx_t *tctx);
void prof_malloc_sample_object(const void *ptr, size_t usize,
prof_tctx_t *tctx);
void prof_malloc(const void *ptr, size_t usize, prof_tctx_t *tctx);
void prof_realloc(tsd_t *tsd, const void *ptr, size_t usize,
prof_tctx_t *tctx, bool updated, size_t old_usize, prof_tctx_t *old_tctx);
void prof_free(tsd_t *tsd, const void *ptr, size_t usize);
#endif
#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_PROF_C_))
JEMALLOC_INLINE prof_tdata_t *
prof_tdata_get(tsd_t *tsd, bool create)
{
prof_tdata_t *tdata;
cassert(config_prof);
tdata = tsd_prof_tdata_get(tsd);
if (create) {
if (unlikely(tdata == NULL)) {
tdata = prof_tdata_init(tsd);
tsd_prof_tdata_set(tsd, tdata);
} else if (unlikely(tdata->state == prof_tdata_state_expired)) {
tdata = prof_tdata_reinit(tsd, tdata);
tsd_prof_tdata_set(tsd, tdata);
}
assert(tdata == NULL ||
tdata->state == prof_tdata_state_attached);
}
return (tdata);
}
JEMALLOC_INLINE prof_tctx_t *
prof_tctx_get(const void *ptr)
{
prof_tctx_t *ret;
arena_chunk_t *chunk;
cassert(config_prof);
assert(ptr != NULL);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
/* Region. */
ret = arena_prof_tctx_get(ptr);
} else
ret = huge_prof_tctx_get(ptr);
return (ret);
}
JEMALLOC_INLINE void
prof_tctx_set(const void *ptr, prof_tctx_t *tctx)
{
arena_chunk_t *chunk;
cassert(config_prof);
assert(ptr != NULL);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
/* Region. */
arena_prof_tctx_set(ptr, tctx);
} else
huge_prof_tctx_set(ptr, tctx);
}
JEMALLOC_INLINE bool
prof_sample_accum_update(tsd_t *tsd, size_t usize, bool update,
prof_tdata_t **tdata_out)
{
prof_tdata_t *tdata;
cassert(config_prof);
tdata = prof_tdata_get(tsd, true);
if ((uintptr_t)tdata <= (uintptr_t)PROF_TDATA_STATE_MAX)
tdata = NULL;
if (tdata_out != NULL)
*tdata_out = tdata;
if (tdata == NULL)
return (true);
if (tdata->bytes_until_sample >= usize) {
if (update)
tdata->bytes_until_sample -= usize;
return (true);
} else {
/* Compute new sample threshold. */
if (update)
prof_sample_threshold_update(tdata);
return (tdata->active == false);
}
}
JEMALLOC_INLINE prof_tctx_t *
prof_alloc_prep(tsd_t *tsd, size_t usize, bool update)
{
prof_tctx_t *ret;
prof_tdata_t *tdata;
prof_bt_t bt;
assert(usize == s2u(usize));
if (!opt_prof_active || likely(prof_sample_accum_update(tsd, usize,
update, &tdata)))
ret = (prof_tctx_t *)(uintptr_t)1U;
else {
bt_init(&bt, tdata->vec);
prof_backtrace(&bt);
ret = prof_lookup(tsd, &bt);
}
return (ret);
}
JEMALLOC_INLINE void
prof_malloc(const void *ptr, size_t usize, prof_tctx_t *tctx)
{
cassert(config_prof);
assert(ptr != NULL);
assert(usize == isalloc(ptr, true));
if (unlikely((uintptr_t)tctx > (uintptr_t)1U))
prof_malloc_sample_object(ptr, usize, tctx);
else
prof_tctx_set(ptr, (prof_tctx_t *)(uintptr_t)1U);
}
JEMALLOC_INLINE void
prof_realloc(tsd_t *tsd, const void *ptr, size_t usize, prof_tctx_t *tctx,
bool updated, size_t old_usize, prof_tctx_t *old_tctx)
{
cassert(config_prof);
assert(ptr != NULL || (uintptr_t)tctx <= (uintptr_t)1U);
if (!updated && ptr != NULL) {
assert(usize == isalloc(ptr, true));
if (prof_sample_accum_update(tsd, usize, true, NULL)) {
/*
* Don't sample. The usize passed to PROF_ALLOC_PREP()
* was larger than what actually got allocated, so a
* backtrace was captured for this allocation, even
* though its actual usize was insufficient to cross the
* sample threshold.
*/
tctx = (prof_tctx_t *)(uintptr_t)1U;
}
}
if (unlikely((uintptr_t)old_tctx > (uintptr_t)1U))
prof_free_sampled_object(tsd, old_usize, old_tctx);
if (unlikely((uintptr_t)tctx > (uintptr_t)1U))
prof_malloc_sample_object(ptr, usize, tctx);
else
prof_tctx_set(ptr, (prof_tctx_t *)(uintptr_t)1U);
}
JEMALLOC_INLINE void
prof_free(tsd_t *tsd, const void *ptr, size_t usize)
{
prof_tctx_t *tctx = prof_tctx_get(ptr);
cassert(config_prof);
assert(usize == isalloc(ptr, true));
if (unlikely((uintptr_t)tctx > (uintptr_t)1U))
prof_free_sampled_object(tsd, usize, tctx);
}
#endif
#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/