server-skynet-source-3rd-je.../include/jemalloc/internal/log.h
David Goldblatt a9f7732d45 Logging: allow logging with empty varargs.
Currently, the log macro requires at least one argument after the format string,
because of the way the preprocessor handles varargs macros.  We can hide some of
that irritation by pushing the extra arguments into a varargs function.
2017-07-22 09:38:19 -07:00

124 lines
4.1 KiB
C

#ifndef JEMALLOC_INTERNAL_LOG_H
#define JEMALLOC_INTERNAL_LOG_H
#include "jemalloc/internal/atomic.h"
#include "jemalloc/internal/malloc_io.h"
#include "jemalloc/internal/mutex.h"
#ifdef JEMALLOC_LOG
# define JEMALLOC_LOG_VAR_BUFSIZE 1000
#else
# define JEMALLOC_LOG_VAR_BUFSIZE 1
#endif
#define JEMALLOC_LOG_BUFSIZE 4096
/*
* The log_vars malloc_conf option is a '|'-delimited list of log_var name
* segments to log. The log_var names are themselves hierarchical, with '.' as
* the delimiter (a "segment" is just a prefix in the log namespace). So, if
* you have:
*
* static log_var_t log_arena = LOG_VAR_INIT("arena"); // 1
* static log_var_t log_arena_a = LOG_VAR_INIT("arena.a"); // 2
* static log_var_t log_arena_b = LOG_VAR_INIT("arena.b"); // 3
* static log_var_t log_arena_a_a = LOG_VAR_INIT("arena.a.a"); // 4
* static_log_var_t log_extent_a = LOG_VAR_INIT("extent.a"); // 5
* static_log_var_t log_extent_b = LOG_VAR_INIT("extent.b"); // 6
*
* And your malloc_conf option is "log_vars=arena.a|extent", then log_vars 2, 4,
* 5, and 6 will be enabled. You can enable logging from all log vars by
* writing "log_vars=.".
*
* You can then log by writing:
* log(log_var, "format string -- my int is %d", my_int);
*
* The namespaces currently in use:
* core.[malloc|free|posix_memalign|...].[entry|exit]:
* The entry/exit points of the functions publicly exposed by jemalloc.
* The "entry" variants try to log arguments to the functions, and the
* "exit" ones try to log return values.
*
* None of this should be regarded as a stable API for right now. It's intended
* as a debugging interface, to let us keep around some of our printf-debugging
* statements.
*/
extern char log_var_names[JEMALLOC_LOG_VAR_BUFSIZE];
extern atomic_b_t log_init_done;
typedef struct log_var_s log_var_t;
struct log_var_s {
/*
* Lowest bit is "inited", second lowest is "enabled". Putting them in
* a single word lets us avoid any fences on weak architectures.
*/
atomic_u_t state;
const char *name;
};
#define LOG_NOT_INITIALIZED 0U
#define LOG_INITIALIZED_NOT_ENABLED 1U
#define LOG_ENABLED 2U
#define LOG_VAR_INIT(name_str) {ATOMIC_INIT(LOG_NOT_INITIALIZED), name_str}
/*
* Returns the value we should assume for state (which is not necessarily
* accurate; if logging is done before logging has finished initializing, then
* we default to doing the safe thing by logging everything).
*/
unsigned log_var_update_state(log_var_t *log_var);
/* We factor out the metadata management to allow us to test more easily. */
#define log_do_begin(log_var) \
if (config_log) { \
unsigned log_state = atomic_load_u(&(log_var).state, \
ATOMIC_RELAXED); \
if (unlikely(log_state == LOG_NOT_INITIALIZED)) { \
log_state = log_var_update_state(&(log_var)); \
assert(log_state != LOG_NOT_INITIALIZED); \
} \
if (log_state == LOG_ENABLED) { \
{
/* User code executes here. */
#define log_do_end(log_var) \
} \
} \
}
/*
* MSVC has some preprocessor bugs in its expansion of __VA_ARGS__ during
* preprocessing. To work around this, we take all potential extra arguments in
* a var-args functions. Since a varargs macro needs at least one argument in
* the "...", we accept the format string there, and require that the first
* argument in this "..." is a const char *.
*/
static inline void
log_impl_varargs(const char *name, ...) {
char buf[JEMALLOC_LOG_BUFSIZE];
va_list ap;
va_start(ap, name);
const char *format = va_arg(ap, const char *);
size_t dst_offset = 0;
dst_offset += malloc_snprintf(buf, JEMALLOC_LOG_BUFSIZE, "%s: ", name);
dst_offset += malloc_vsnprintf(buf + dst_offset,
JEMALLOC_LOG_BUFSIZE - dst_offset, format, ap);
dst_offset += malloc_snprintf(buf + dst_offset,
JEMALLOC_LOG_BUFSIZE - dst_offset, "\n");
va_end(ap);
malloc_write(buf);
}
/* Call as log(log_var, "format_string %d", arg_for_format_string); */
#define log(log_var, ...) \
do { \
log_do_begin(log_var) \
log_impl_varargs((log_var).name, __VA_ARGS__); \
log_do_end(log_var) \
} while (0)
#endif /* JEMALLOC_INTERNAL_LOG_H */