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| | /*
* Copyright (C) 2018 mwrap hackers <mwrap-public@80x24.org>
* License: GPL-2.0+ <https://www.gnu.org/licenses/gpl-2.0.txt>
*/
#define _LGPL_SOURCE /* allows URCU to inline some stuff */
#include <ruby/ruby.h>
#include <ruby/thread.h>
#include <ruby/io.h>
#include <execinfo.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <pthread.h>
#include <urcu-bp.h>
#include <urcu/rculfhash.h>
#include <urcu/rculist.h>
#include "jhash.h"
static ID id_uminus;
const char *rb_source_location_cstr(int *line); /* requires 2.6.0dev */
extern int __attribute__((weak)) ruby_thread_has_gvl_p(void);
extern void * __attribute__((weak)) ruby_current_execution_context_ptr;
extern void * __attribute__((weak)) ruby_current_vm_ptr; /* for rb_gc_count */
extern size_t __attribute__((weak)) rb_gc_count(void);
extern VALUE __attribute__((weak)) rb_cObject;
extern VALUE __attribute__((weak)) rb_eTypeError;
extern VALUE __attribute__((weak)) rb_yield(VALUE);
static size_t total_bytes_inc, total_bytes_dec;
/* true for glibc/dlmalloc/ptmalloc, not sure about jemalloc */
#define ASSUMED_MALLOC_ALIGNMENT (sizeof(void *) * 2)
/* match values in Ruby gc.c */
#define HEAP_PAGE_ALIGN_LOG 14
enum {
HEAP_PAGE_ALIGN = (1UL << HEAP_PAGE_ALIGN_LOG),
REQUIRED_SIZE_BY_MALLOC = (sizeof(size_t) * 5),
HEAP_PAGE_SIZE = (HEAP_PAGE_ALIGN - REQUIRED_SIZE_BY_MALLOC)
};
#define IS_HEAP_PAGE_BODY ((struct src_loc *)-1)
int __attribute__((weak)) ruby_thread_has_gvl_p(void)
{
return 0;
}
#ifdef __FreeBSD__
void *__malloc(size_t);
void __free(void *);
# define real_malloc __malloc
# define real_free __free
#else
static void *(*real_malloc)(size_t);
static void (*real_free)(void *);
static int resolving_malloc;
#endif /* !FreeBSD */
/*
* we need to fake an OOM condition while dlsym is running,
* as that calls calloc under glibc, but we don't have the
* symbol for the jemalloc calloc, yet
*/
# define RETURN_IF_NOT_READY() do { \
if (!real_malloc) { \
errno = ENOMEM; \
return NULL; \
} \
} while (0)
static __thread size_t locating;
static size_t generation;
static size_t page_size;
static struct cds_lfht *totals;
union padded_mutex {
pthread_mutex_t mtx;
char pad[64];
};
/* a round-robin pool of mutexes */
#define MUTEX_NR (1 << 6)
#define MUTEX_MASK (MUTEX_NR - 1)
static size_t mutex_i;
static union padded_mutex mutexes[MUTEX_NR] = {
[0 ... (MUTEX_NR-1)].mtx = PTHREAD_MUTEX_INITIALIZER
};
static pthread_mutex_t *mutex_assign(void)
{
return &mutexes[uatomic_add_return(&mutex_i, 1) & MUTEX_MASK].mtx;
}
static struct cds_lfht *
lfht_new(void)
{
return cds_lfht_new(16384, 1, 0, CDS_LFHT_AUTO_RESIZE, 0);
}
__attribute__((constructor)) static void resolve_malloc(void)
{
int err;
++locating;
#ifdef __FreeBSD__
/*
* PTHREAD_MUTEX_INITIALIZER on FreeBSD means lazy initialization,
* which happens at pthread_mutex_lock, and that calls calloc
*/
{
size_t i;
for (i = 0; i < MUTEX_NR; i++) {
err = pthread_mutex_init(&mutexes[i].mtx, 0);
if (err) {
fprintf(stderr, "error: %s\n", strerror(err));
_exit(1);
}
}
/* initialize mutexes used by urcu-bp */
rcu_read_lock();
rcu_read_unlock();
}
#else /* !FreeBSD (tested on GNU/Linux) */
if (!real_malloc) {
resolving_malloc = 1;
real_malloc = dlsym(RTLD_NEXT, "malloc");
}
real_free = dlsym(RTLD_NEXT, "free");
if (!real_malloc || !real_free) {
fprintf(stderr, "missing malloc/aligned_alloc/free\n"
"\t%p %p\n", real_malloc, real_free);
_exit(1);
}
#endif /* !FreeBSD */
totals = lfht_new();
if (!totals)
fprintf(stderr, "failed to allocate totals table\n");
err = pthread_atfork(call_rcu_before_fork,
call_rcu_after_fork_parent,
call_rcu_after_fork_child);
if (err)
fprintf(stderr, "pthread_atfork failed: %s\n", strerror(err));
page_size = sysconf(_SC_PAGESIZE);
--locating;
}
static void
mutex_lock(pthread_mutex_t *m)
{
int err = pthread_mutex_lock(m);
assert(err == 0);
}
static void
mutex_unlock(pthread_mutex_t *m)
{
int err = pthread_mutex_unlock(m);
assert(err == 0);
}
#ifndef HAVE_MEMPCPY
static void *
my_mempcpy(void *dest, const void *src, size_t n)
{
return (char *)memcpy(dest, src, n) + n;
}
#define mempcpy(dst,src,n) my_mempcpy(dst,src,n)
#endif
/* stolen from glibc: */
#define RETURN_ADDRESS(nr) \
(uintptr_t)(__builtin_extract_return_addr(__builtin_return_address(nr)))
#define INT2STR_MAX (sizeof(int) == 4 ? 10 : 19)
static char *int2str(int num, char *dst, size_t * size)
{
if (num <= 9) {
*size -= 1;
*dst++ = (char)(num + '0');
return dst;
} else {
char buf[INT2STR_MAX];
char *end = buf + sizeof(buf);
char *p = end;
size_t adj;
do {
*size -= 1;
*--p = (char)((num % 10) + '0');
num /= 10;
} while (num && *size);
if (!num) {
adj = end - p;
return mempcpy(dst, p, adj);
}
}
return NULL;
}
/*
* rb_source_location_cstr relies on GET_EC(), and it's possible
* to have a native thread but no EC during the early and late
* (teardown) phases of the Ruby process
*/
static int has_ec_p(void)
{
return (ruby_thread_has_gvl_p() && ruby_current_vm_ptr &&
ruby_current_execution_context_ptr);
}
struct acc {
uint64_t nr;
int64_t min;
int64_t max;
double m2;
double mean;
};
#define ACC_INIT(name) { .nr=0, .min=INT64_MAX, .max=-1, .m2=0, .mean=0 }
/* for tracking 16K-aligned heap page bodies (protected by GVL) */
struct {
pthread_mutex_t lock;
struct cds_list_head bodies;
struct cds_list_head freed;
struct acc alive;
struct acc reborn;
} hpb_stats = {
.lock = PTHREAD_MUTEX_INITIALIZER,
.bodies = CDS_LIST_HEAD_INIT(hpb_stats.bodies),
.freed = CDS_LIST_HEAD_INIT(hpb_stats.freed),
.alive = ACC_INIT(hpb_stats.alive),
.reborn = ACC_INIT(hpb_stats.reborn)
};
/* allocated via real_malloc/real_free */
struct src_loc {
pthread_mutex_t *mtx;
size_t total;
size_t allocations;
size_t frees;
size_t age_total; /* (age_total / frees) => mean age at free */
size_t max_lifespan;
struct cds_lfht_node hnode;
struct cds_list_head allocs; /* <=> alloc_hdr.node */
uint32_t hval;
uint32_t capa;
char k[];
};
/* every allocation has this in the header, maintain alignment with malloc */
struct alloc_hdr {
struct cds_list_head anode; /* <=> src_loc.allocs */
union {
struct {
size_t gen; /* rb_gc_count() */
struct src_loc *loc;
} live;
struct rcu_head dead;
struct {
size_t at; /* rb_gc_count() */
} hpb_freed;
} as;
void *real; /* what to call real_free on */
size_t size;
};
static char kbuf[PATH_MAX + INT2STR_MAX + sizeof(struct alloc_hdr) + 2];
static struct alloc_hdr *ptr2hdr(void *p)
{
return (struct alloc_hdr *)((uintptr_t)p - sizeof(struct alloc_hdr));
}
static void *hdr2ptr(struct alloc_hdr *h)
{
return (void *)((uintptr_t)h + sizeof(struct alloc_hdr));
}
static int loc_is_addr(const struct src_loc *l)
{
return l->capa == 0;
}
static size_t loc_size(const struct src_loc *l)
{
return loc_is_addr(l) ? sizeof(uintptr_t) : l->capa;
}
static int loc_eq(struct cds_lfht_node *node, const void *key)
{
const struct src_loc *existing;
const struct src_loc *k = key;
existing = caa_container_of(node, struct src_loc, hnode);
return (k->hval == existing->hval &&
k->capa == existing->capa &&
memcmp(k->k, existing->k, loc_size(k)) == 0);
}
/* note: not atomic */
static void
acc_add(struct acc *acc, size_t val)
{
double delta = val - acc->mean;
uint64_t nr = ++acc->nr;
/* just don't divide-by-zero if we ever hit this (unlikely :P) */
if (nr)
acc->mean += delta / nr;
acc->m2 += delta * (val - acc->mean);
if ((int64_t)val < acc->min)
acc->min = (int64_t)val;
if ((int64_t)val > acc->max)
acc->max = (int64_t)val;
}
#if SIZEOF_LONG == 8
# define INT64toNUM(x) LONG2NUM((long)x)
#elif defined(HAVE_LONG_LONG) && SIZEOF_LONG_LONG == 8
# define INT64toNUM(x) LL2NUM((LONG_LONG)x)
#endif
static VALUE
acc_max(const struct acc *acc)
{
return INT64toNUM(acc->max);
}
static VALUE
acc_min(const struct acc *acc)
{
return acc->min == INT64_MAX ? INT2FIX(-1) : INT64toNUM(acc->min);
}
static VALUE
acc_mean(const struct acc *acc)
{
return DBL2NUM(acc->nr ? acc->mean : HUGE_VAL);
}
static double
acc_stddev_dbl(const struct acc *acc)
{
if (acc->nr > 1) {
double variance = acc->m2 / (acc->nr - 1);
return sqrt(variance);
}
return 0.0;
}
static VALUE
acc_stddev(const struct acc *acc)
{
return DBL2NUM(acc_stddev_dbl(acc));
}
static struct src_loc *totals_add_rcu(struct src_loc *k)
{
struct cds_lfht_iter iter;
struct cds_lfht_node *cur;
struct src_loc *l = 0;
struct cds_lfht *t;
again:
t = rcu_dereference(totals);
if (!t) goto out_unlock;
cds_lfht_lookup(t, k->hval, loc_eq, k, &iter);
cur = cds_lfht_iter_get_node(&iter);
if (cur) {
l = caa_container_of(cur, struct src_loc, hnode);
uatomic_add(&l->total, k->total);
uatomic_add(&l->allocations, 1);
} else {
size_t n = loc_size(k);
l = real_malloc(sizeof(*l) + n);
if (!l) goto out_unlock;
memcpy(l, k, sizeof(*l) + n);
l->mtx = mutex_assign();
l->age_total = 0;
l->max_lifespan = 0;
l->frees = 0;
l->allocations = 1;
CDS_INIT_LIST_HEAD(&l->allocs);
cur = cds_lfht_add_unique(t, k->hval, loc_eq, l, &l->hnode);
if (cur != &l->hnode) { /* lost race */
rcu_read_unlock();
real_free(l);
rcu_read_lock();
goto again;
}
}
out_unlock:
return l;
}
static void update_stats_rcu_unlock(const struct src_loc *l)
{
if (caa_likely(l)) rcu_read_unlock();
}
static struct src_loc *update_stats_rcu_lock(size_t size, uintptr_t caller)
{
struct src_loc *k, *ret = 0;
static const size_t xlen = sizeof(caller);
char *dst;
if (caa_unlikely(!totals)) return 0;
if (locating++) goto out; /* do not recurse into another *alloc */
uatomic_add(&total_bytes_inc, size);
rcu_read_lock();
if (has_ec_p()) {
int line;
const char *ptr = rb_source_location_cstr(&line);
size_t len;
size_t int_size = INT2STR_MAX;
generation = rb_gc_count();
if (!ptr) goto unknown;
/* avoid vsnprintf or anything which could call malloc here: */
len = strlen(ptr);
k = (void *)kbuf;
k->total = size;
dst = mempcpy(k->k, ptr, len);
*dst++ = ':';
dst = int2str(line, dst, &int_size);
if (dst) {
*dst = 0; /* terminate string */
k->capa = (uint32_t)(dst - k->k + 1);
k->hval = jhash(k->k, k->capa, 0xdeadbeef);
ret = totals_add_rcu(k);
} else {
rb_bug("bad math making key from location %s:%d\n",
ptr, line);
}
} else {
unknown:
k = alloca(sizeof(*k) + xlen);
k->total = size;
memcpy(k->k, &caller, xlen);
k->capa = 0;
k->hval = jhash(k->k, xlen, 0xdeadbeef);
ret = totals_add_rcu(k);
}
out:
--locating;
return ret;
}
size_t malloc_usable_size(void *p)
{
return ptr2hdr(p)->size;
}
static void
free_hdr_rcu(struct rcu_head *dead)
{
struct alloc_hdr *h = caa_container_of(dead, struct alloc_hdr, as.dead);
real_free(h->real);
}
void free(void *p)
{
if (p) {
struct alloc_hdr *h = ptr2hdr(p);
struct src_loc *l = h->as.live.loc;
if (!real_free) return; /* oh well, leak a little */
if (l && l != IS_HEAP_PAGE_BODY) {
size_t age = generation - h->as.live.gen;
uatomic_add(&total_bytes_dec, h->size);
uatomic_set(&h->size, 0);
uatomic_add(&l->frees, 1);
uatomic_add(&l->age_total, age);
mutex_lock(l->mtx);
cds_list_del_rcu(&h->anode);
if (age > l->max_lifespan)
l->max_lifespan = age;
mutex_unlock(l->mtx);
call_rcu(&h->as.dead, free_hdr_rcu);
} else if (l == IS_HEAP_PAGE_BODY) {
size_t gen = generation;
size_t age = gen - h->as.live.gen;
h->as.hpb_freed.at = gen;
mutex_lock(&hpb_stats.lock);
acc_add(&hpb_stats.alive, age);
/* hpb_stats.bodies => hpb_stats.freed */
cds_list_move(&h->anode, &hpb_stats.freed);
mutex_unlock(&hpb_stats.lock);
} else {
real_free(h->real);
}
}
}
static void
alloc_insert_rcu(struct src_loc *l, struct alloc_hdr *h, size_t size, void *real)
{
/* we need src_loc to remain alive for the duration of this call */
if (!h) return;
h->size = size;
h->real = real;
h->as.live.loc = l;
h->as.live.gen = generation;
if (l) {
mutex_lock(l->mtx);
cds_list_add_rcu(&h->anode, &l->allocs);
mutex_unlock(l->mtx);
}
}
static size_t size_align(size_t size, size_t alignment)
{
return ((size + (alignment - 1)) & ~(alignment - 1));
}
static bool ptr_is_aligned(const void *ptr, size_t alignment)
{
return ((uintptr_t)ptr & (alignment - 1)) == 0;
}
static void *ptr_align(void *ptr, size_t alignment)
{
return (void *)(((uintptr_t)ptr + (alignment - 1)) & ~(alignment - 1));
}
static bool is_power_of_two(size_t n) { return (n & (n - 1)) == 0; }
static int
internal_memalign(void **pp, size_t alignment, size_t size, uintptr_t caller)
{
struct src_loc *l;
struct alloc_hdr *h;
void *real;
size_t asize;
size_t d = alignment / sizeof(void*);
size_t r = alignment % sizeof(void*);
if (!real_malloc) return ENOMEM;
if (r != 0 || d == 0 || !is_power_of_two(d))
return EINVAL;
if (alignment <= ASSUMED_MALLOC_ALIGNMENT) {
void *p = malloc(size);
if (!p) return ENOMEM;
*pp = p;
return 0;
}
for (; alignment < sizeof(struct alloc_hdr); alignment *= 2)
; /* double alignment until >= sizeof(struct alloc_hdr) */
if (__builtin_add_overflow(size, alignment, &asize) ||
__builtin_add_overflow(asize, sizeof(struct alloc_hdr), &asize))
return ENOMEM;
if (alignment == HEAP_PAGE_ALIGN && size == HEAP_PAGE_SIZE) {
if (has_ec_p()) generation = rb_gc_count();
l = IS_HEAP_PAGE_BODY;
} else {
l = update_stats_rcu_lock(size, caller);
}
if (l == IS_HEAP_PAGE_BODY) {
void *p;
size_t gen = generation;
mutex_lock(&hpb_stats.lock);
/* reuse existing entry */
if (!cds_list_empty(&hpb_stats.freed)) {
size_t deathspan;
h = cds_list_first_entry(&hpb_stats.freed,
struct alloc_hdr, anode);
/* hpb_stats.freed => hpb_stats.bodies */
cds_list_move(&h->anode, &hpb_stats.bodies);
assert(h->size == size);
assert(h->real);
real = h->real;
p = hdr2ptr(h);
assert(ptr_is_aligned(p, alignment));
deathspan = gen - h->as.hpb_freed.at;
acc_add(&hpb_stats.reborn, deathspan);
}
else {
real = real_malloc(asize);
if (!real) return ENOMEM;
p = hdr2ptr(real);
if (!ptr_is_aligned(p, alignment))
p = ptr_align(p, alignment);
h = ptr2hdr(p);
h->size = size;
h->real = real;
cds_list_add(&h->anode, &hpb_stats.bodies);
}
mutex_unlock(&hpb_stats.lock);
h->as.live.loc = l;
h->as.live.gen = gen;
*pp = p;
}
else {
real = real_malloc(asize);
if (real) {
void *p = hdr2ptr(real);
if (!ptr_is_aligned(p, alignment))
p = ptr_align(p, alignment);
h = ptr2hdr(p);
alloc_insert_rcu(l, h, size, real);
update_stats_rcu_unlock(l);
*pp = p;
}
}
return real ? 0 : ENOMEM;
}
static void *
memalign_result(int err, void *p)
{
if (caa_unlikely(err)) {
errno = err;
return 0;
}
return p;
}
void *memalign(size_t alignment, size_t size)
{
void *p;
int err = internal_memalign(&p, alignment, size, RETURN_ADDRESS(0));
return memalign_result(err, p);
}
int posix_memalign(void **p, size_t alignment, size_t size)
{
return internal_memalign(p, alignment, size, RETURN_ADDRESS(0));
}
void *aligned_alloc(size_t, size_t) __attribute__((alias("memalign")));
void cfree(void *) __attribute__((alias("free")));
void *valloc(size_t size)
{
void *p;
int err = internal_memalign(&p, page_size, size, RETURN_ADDRESS(0));
return memalign_result(err, p);
}
#if __GNUC__ < 7
# define add_overflow_p(a,b) __extension__({ \
__typeof__(a) _c; \
__builtin_add_overflow(a,b,&_c); \
})
#else
# define add_overflow_p(a,b) \
__builtin_add_overflow_p((a),(b),(__typeof__(a+b))0)
#endif
void *pvalloc(size_t size)
{
size_t alignment = page_size;
void *p;
int err;
if (add_overflow_p(size, alignment)) {
errno = ENOMEM;
return 0;
}
size = size_align(size, alignment);
err = internal_memalign(&p, alignment, size, RETURN_ADDRESS(0));
return memalign_result(err, p);
}
void *malloc(size_t size)
{
struct src_loc *l;
struct alloc_hdr *h;
size_t asize;
void *p;
if (__builtin_add_overflow(size, sizeof(struct alloc_hdr), &asize))
goto enomem;
/*
* Needed for C++ global declarations using "new",
* which happens before our constructor
*/
#ifndef __FreeBSD__
if (!real_malloc) {
if (resolving_malloc) goto enomem;
resolving_malloc = 1;
real_malloc = dlsym(RTLD_NEXT, "malloc");
}
#endif
l = update_stats_rcu_lock(size, RETURN_ADDRESS(0));
p = h = real_malloc(asize);
if (h) {
alloc_insert_rcu(l, h, size, h);
p = hdr2ptr(h);
}
update_stats_rcu_unlock(l);
if (caa_unlikely(!p)) errno = ENOMEM;
return p;
enomem:
errno = ENOMEM;
return 0;
}
void *calloc(size_t nmemb, size_t size)
{
void *p;
struct src_loc *l;
struct alloc_hdr *h;
size_t asize;
if (__builtin_mul_overflow(size, nmemb, &size)) {
errno = ENOMEM;
return 0;
}
if (__builtin_add_overflow(size, sizeof(struct alloc_hdr), &asize)) {
errno = ENOMEM;
return 0;
}
RETURN_IF_NOT_READY();
l = update_stats_rcu_lock(size, RETURN_ADDRESS(0));
p = h = real_malloc(asize);
if (p) {
alloc_insert_rcu(l, h, size, h);
p = hdr2ptr(h);
memset(p, 0, size);
}
update_stats_rcu_unlock(l);
if (caa_unlikely(!p)) errno = ENOMEM;
return p;
}
void *realloc(void *ptr, size_t size)
{
void *p;
struct src_loc *l;
struct alloc_hdr *h;
size_t asize;
if (!size) {
free(ptr);
return 0;
}
if (__builtin_add_overflow(size, sizeof(struct alloc_hdr), &asize)) {
errno = ENOMEM;
return 0;
}
RETURN_IF_NOT_READY();
l = update_stats_rcu_lock(size, RETURN_ADDRESS(0));
p = h = real_malloc(asize);
if (p) {
alloc_insert_rcu(l, h, size, h);
p = hdr2ptr(h);
}
update_stats_rcu_unlock(l);
if (ptr && p) {
struct alloc_hdr *old = ptr2hdr(ptr);
memcpy(p, ptr, old->size < size ? old->size : size);
free(ptr);
}
if (caa_unlikely(!p)) errno = ENOMEM;
return p;
}
struct dump_arg {
FILE *fp;
size_t min;
};
static void *dump_to_file(void *x)
{
struct dump_arg *a = x;
struct cds_lfht_iter iter;
struct src_loc *l;
struct cds_lfht *t;
++locating;
rcu_read_lock();
t = rcu_dereference(totals);
if (!t)
goto out_unlock;
cds_lfht_for_each_entry(t, &iter, l, hnode) {
const void *p = l->k;
char **s = 0;
if (l->total <= a->min) continue;
if (loc_is_addr(l)) {
s = backtrace_symbols(p, 1);
p = s[0];
}
fprintf(a->fp, "%16zu %12zu %s\n",
l->total, l->allocations, (const char *)p);
if (s) free(s);
}
out_unlock:
rcu_read_unlock();
--locating;
return 0;
}
/*
* call-seq:
*
* Mwrap.dump([[io] [, min]] -> nil
*
* Dumps the current totals to +io+ which must be an IO object
* (StringIO and similar are not supported). Total sizes smaller
* than or equal to +min+ are skipped.
*
* The output is space-delimited by 3 columns:
*
* total_size call_count location
*/
static VALUE mwrap_dump(int argc, VALUE * argv, VALUE mod)
{
VALUE io, min;
struct dump_arg a;
rb_io_t *fptr;
rb_scan_args(argc, argv, "02", &io, &min);
if (NIL_P(io))
/* library may be linked w/o Ruby */
io = *((VALUE *)dlsym(RTLD_DEFAULT, "rb_stderr"));
a.min = NIL_P(min) ? 0 : NUM2SIZET(min);
io = rb_io_get_io(io);
io = rb_io_get_write_io(io);
GetOpenFile(io, fptr);
a.fp = rb_io_stdio_file(fptr);
rb_thread_call_without_gvl(dump_to_file, &a, 0, 0);
RB_GC_GUARD(io);
return Qnil;
}
/* The whole operation is not remotely atomic... */
static void *totals_reset(void *ign)
{
struct cds_lfht *t;
struct cds_lfht_iter iter;
struct src_loc *l;
uatomic_set(&total_bytes_inc, 0);
uatomic_set(&total_bytes_dec, 0);
rcu_read_lock();
t = rcu_dereference(totals);
cds_lfht_for_each_entry(t, &iter, l, hnode) {
uatomic_set(&l->total, 0);
uatomic_set(&l->allocations, 0);
uatomic_set(&l->frees, 0);
uatomic_set(&l->age_total, 0);
uatomic_set(&l->max_lifespan, 0);
}
rcu_read_unlock();
return 0;
}
/*
* call-seq:
*
* Mwrap.reset -> nil
*
* Resets the the total tables by zero-ing all counters.
* This resets all statistics. This is not an atomic operation
* as other threads (outside of GVL) may increment counters.
*/
static VALUE mwrap_reset(VALUE mod)
{
rb_thread_call_without_gvl(totals_reset, 0, 0, 0);
return Qnil;
}
/* :nodoc: */
static VALUE mwrap_clear(VALUE mod)
{
return mwrap_reset(mod);
}
static VALUE rcu_unlock_ensure(VALUE ignored)
{
rcu_read_unlock();
--locating;
return Qfalse;
}
static VALUE location_string(struct src_loc *l)
{
VALUE ret, tmp;
if (loc_is_addr(l)) {
char **s = backtrace_symbols((void *)l->k, 1);
tmp = rb_str_new_cstr(s[0]);
free(s);
}
else {
tmp = rb_str_new(l->k, l->capa - 1);
}
/* deduplicate and try to free up some memory */
ret = rb_funcall(tmp, id_uminus, 0);
if (!OBJ_FROZEN_RAW(tmp))
rb_str_resize(tmp, 0);
return ret;
}
static VALUE dump_each_rcu(VALUE x)
{
struct dump_arg *a = (struct dump_arg *)x;
struct cds_lfht *t;
struct cds_lfht_iter iter;
struct src_loc *l;
t = rcu_dereference(totals);
cds_lfht_for_each_entry(t, &iter, l, hnode) {
VALUE v[6];
if (l->total <= a->min) continue;
v[0] = location_string(l);
v[1] = SIZET2NUM(l->total);
v[2] = SIZET2NUM(l->allocations);
v[3] = SIZET2NUM(l->frees);
v[4] = SIZET2NUM(l->age_total);
v[5] = SIZET2NUM(l->max_lifespan);
rb_yield_values2(6, v);
assert(rcu_read_ongoing());
}
return Qnil;
}
/*
* call-seq:
*
* Mwrap.each([min]) do |location,total,allocations,frees,age_total,max_lifespan|
* ...
* end
*
* Yields each entry of the of the table to a caller-supplied block.
* +min+ may be specified to filter out lines with +total+ bytes
* equal-to-or-smaller-than the supplied minimum.
*/
static VALUE mwrap_each(int argc, VALUE * argv, VALUE mod)
{
VALUE min;
struct dump_arg a;
rb_scan_args(argc, argv, "01", &min);
a.min = NIL_P(min) ? 0 : NUM2SIZET(min);
++locating;
rcu_read_lock();
return rb_ensure(dump_each_rcu, (VALUE)&a, rcu_unlock_ensure, 0);
}
static size_t
src_loc_memsize(const void *p)
{
return sizeof(struct src_loc);
}
static const rb_data_type_t src_loc_type = {
"source_location",
/* no marking, no freeing */
{ 0, 0, src_loc_memsize, /* reserved */ },
/* parent, data, [ flags ] */
};
static VALUE cSrcLoc;
static int
extract_addr(const char *str, size_t len, void **p)
{
const char *c;
#if defined(__GLIBC__)
return ((c = memrchr(str, '[', len)) && sscanf(c, "[%p]", p));
#else /* tested FreeBSD */
return ((c = strstr(str, "0x")) && sscanf(c, "%p", p));
#endif
}
/*
* call-seq:
* Mwrap[location] -> Mwrap::SourceLocation
*
* Returns the associated Mwrap::SourceLocation given the +location+
* String. +location+ is either a Ruby source location path:line
* (e.g. "/path/to/foo.rb:5") or a hexadecimal memory address with
* square-braces part yielded by Mwrap.dump (e.g. "[0xdeadbeef]")
*/
static VALUE mwrap_aref(VALUE mod, VALUE loc)
{
const char *str = StringValueCStr(loc);
int len = RSTRING_LENINT(loc);
struct src_loc *k = 0;
uintptr_t p;
struct cds_lfht_iter iter;
struct cds_lfht_node *cur;
struct cds_lfht *t;
struct src_loc *l;
VALUE val = Qnil;
if (extract_addr(str, len, (void **)&p)) {
k = (void *)kbuf;
memcpy(k->k, &p, sizeof(p));
k->capa = 0;
k->hval = jhash(k->k, sizeof(p), 0xdeadbeef);
} else {
k = (void *)kbuf;
memcpy(k->k, str, len + 1);
k->capa = len + 1;
k->hval = jhash(k->k, k->capa, 0xdeadbeef);
}
if (!k) return val;
rcu_read_lock();
t = rcu_dereference(totals);
if (!t) goto out_unlock;
cds_lfht_lookup(t, k->hval, loc_eq, k, &iter);
cur = cds_lfht_iter_get_node(&iter);
if (cur) {
l = caa_container_of(cur, struct src_loc, hnode);
val = TypedData_Wrap_Struct(cSrcLoc, &src_loc_type, l);
}
out_unlock:
rcu_read_unlock();
return val;
}
static VALUE src_loc_each_i(VALUE p)
{
struct alloc_hdr *h;
struct src_loc *l = (struct src_loc *)p;
cds_list_for_each_entry_rcu(h, &l->allocs, anode) {
size_t gen = uatomic_read(&h->as.live.gen);
size_t size = uatomic_read(&h->size);
if (size) {
VALUE v[2];
v[0] = SIZET2NUM(size);
v[1] = SIZET2NUM(gen);
rb_yield_values2(2, v);
}
}
return Qfalse;
}
static struct src_loc *src_loc_get(VALUE self)
{
struct src_loc *l;
TypedData_Get_Struct(self, struct src_loc, &src_loc_type, l);
assert(l);
return l;
}
/*
* call-seq:
* loc = Mwrap[location]
* loc.each { |size,generation| ... }
*
* Iterates through live allocations for a given Mwrap::SourceLocation,
* yielding the +size+ (in bytes) and +generation+ of each allocation.
* The +generation+ is the value of the GC.count method at the time
* the allocation was made.
*
* This functionality is only available in mwrap 2.0.0+
*/
static VALUE src_loc_each(VALUE self)
{
struct src_loc *l = src_loc_get(self);
assert(locating == 0 && "forgot to clear locating");
++locating;
rcu_read_lock();
rb_ensure(src_loc_each_i, (VALUE)l, rcu_unlock_ensure, 0);
return self;
}
/*
* The the mean lifespan (in GC generations) of allocations made from this
* location. This does not account for live allocations.
*/
static VALUE src_loc_mean_lifespan(VALUE self)
{
struct src_loc *l = src_loc_get(self);
size_t tot, frees;
frees = uatomic_read(&l->frees);
tot = uatomic_read(&l->age_total);
return DBL2NUM(frees ? ((double)tot/(double)frees) : HUGE_VAL);
}
/* The number of frees made from this location */
static VALUE src_loc_frees(VALUE self)
{
return SIZET2NUM(uatomic_read(&src_loc_get(self)->frees));
}
/* The number of allocations made from this location */
static VALUE src_loc_allocations(VALUE self)
{
return SIZET2NUM(uatomic_read(&src_loc_get(self)->allocations));
}
/* The total number of bytes allocated from this location */
static VALUE src_loc_total(VALUE self)
{
return SIZET2NUM(uatomic_read(&src_loc_get(self)->total));
}
/*
* The maximum age (in GC generations) of an allocation before it was freed.
* This does not account for live allocations.
*/
static VALUE src_loc_max_lifespan(VALUE self)
{
return SIZET2NUM(uatomic_read(&src_loc_get(self)->max_lifespan));
}
/*
* Returns a frozen String location of the given SourceLocation object.
*/
static VALUE src_loc_name(VALUE self)
{
struct src_loc *l = src_loc_get(self);
VALUE ret;
++locating;
ret = location_string(l);
--locating;
return ret;
}
static VALUE reset_locating(VALUE ign) { --locating; return Qfalse; }
/*
* call-seq:
*
* Mwrap.quiet do |depth|
* # expensive sort/calculate/emitting results of Mwrap.each
* # affecting statistics of the rest of the app
* end
*
* Stops allocation tracking inside the block. This is useful for
* monitoring code which calls other Mwrap (or ObjectSpace/GC)
* functions which unavoidably allocate memory.
*
* This feature was added in mwrap 2.0.0+
*/
static VALUE mwrap_quiet(VALUE mod)
{
size_t cur = ++locating;
return rb_ensure(rb_yield, SIZET2NUM(cur), reset_locating, 0);
}
/*
* total bytes allocated as tracked by mwrap
*/
static VALUE total_inc(VALUE mod)
{
return SIZET2NUM(total_bytes_inc);
}
/*
* total bytes freed as tracked by mwrap
*/
static VALUE total_dec(VALUE mod)
{
return SIZET2NUM(total_bytes_dec);
}
static VALUE hpb_each_yield(VALUE ignore)
{
struct alloc_hdr *h, *next;
cds_list_for_each_entry_safe(h, next, &hpb_stats.bodies, anode) {
VALUE v[2]; /* [ generation, address ] */
void *addr = hdr2ptr(h);
assert(ptr_is_aligned(addr, HEAP_PAGE_ALIGN));
v[0] = LONG2NUM((long)addr);
v[1] = SIZET2NUM(h->as.live.gen);
rb_yield_values2(2, v);
}
return Qnil;
}
/*
* call-seq:
*
* Mwrap::HeapPageBody.each { |gen, addr| } -> Integer
*
* Yields the generation (GC.count) the heap page body was created
* and address of the heap page body as an Integer. Returns the
* number of allocated pages as an Integer. This return value should
* match the result of GC.stat(:heap_allocated_pages)
*/
static VALUE hpb_each(VALUE mod)
{
++locating;
return rb_ensure(hpb_each_yield, Qfalse, reset_locating, 0);
}
/*
* call-seq:
*
* Mwrap::HeapPageBody.stat -> Hash
* Mwrap::HeapPageBody.stat(hash) -> hash
*
* The maximum lifespan of a heap page body in the Ruby VM.
* This may be Infinity if no heap page bodies were ever freed.
*/
static VALUE hpb_stat(int argc, VALUE *argv, VALUE hpb)
{
VALUE h;
rb_scan_args(argc, argv, "01", &h);
if (NIL_P(h))
h = rb_hash_new();
else if (!RB_TYPE_P(h, T_HASH))
rb_raise(rb_eTypeError, "not a hash %+"PRIsVALUE, h);
++locating;
#define S(x) ID2SYM(rb_intern(#x))
rb_hash_aset(h, S(lifespan_max), acc_max(&hpb_stats.alive));
rb_hash_aset(h, S(lifespan_min), acc_min(&hpb_stats.alive));
rb_hash_aset(h, S(lifespan_mean), acc_mean(&hpb_stats.alive));
rb_hash_aset(h, S(lifespan_stddev), acc_stddev(&hpb_stats.alive));
rb_hash_aset(h, S(deathspan_max), acc_max(&hpb_stats.reborn));
rb_hash_aset(h, S(deathspan_min), acc_min(&hpb_stats.reborn));
rb_hash_aset(h, S(deathspan_mean), acc_mean(&hpb_stats.reborn));
rb_hash_aset(h, S(deathspan_stddev), acc_stddev(&hpb_stats.reborn));
rb_hash_aset(h, S(resurrects), SIZET2NUM(hpb_stats.reborn.nr));
#undef S
--locating;
return h;
}
/*
* Document-module: Mwrap
*
* require 'mwrap'
*
* Mwrap has a dual function as both a Ruby C extension and LD_PRELOAD
* wrapper. As a Ruby C extension, it exposes a limited Ruby API.
* To be effective at gathering status, mwrap must be loaded as a
* LD_PRELOAD (using the mwrap(1) executable makes it easy)
*
* ENVIRONMENT
*
* The "MWRAP" environment variable contains a comma-delimited list
* of key:value options for automatically dumping at program exit.
*
* * dump_fd: a writable FD to dump to
* * dump_path: a path to dump to, the file is opened in O_APPEND mode
* * dump_min: the minimum allocation size (total) to dump
* * dump_heap: mask of heap_page_body statistics to dump
*
* If both `dump_fd' and `dump_path' are specified, dump_path takes
* precedence.
*
* dump_heap bitmask
* * 0x01 - summary stats (same info as HeapPageBody.stat)
* * 0x02 - all live heaps (similar to HeapPageBody.each)
* * 0x04 - skip non-heap_page_body-related output
*/
void Init_mwrap(void)
{
VALUE mod, hpb;
++locating;
mod = rb_define_module("Mwrap");
id_uminus = rb_intern("-@");
/*
* Represents a location in source code or library
* address which calls a memory allocation. It is
* updated automatically as allocations are made, so
* there is no need to reload or reread it from Mwrap#[].
* This class is only available since mwrap 2.0.0+.
*/
cSrcLoc = rb_define_class_under(mod, "SourceLocation", rb_cObject);
rb_define_singleton_method(mod, "dump", mwrap_dump, -1);
rb_define_singleton_method(mod, "reset", mwrap_reset, 0);
rb_define_singleton_method(mod, "clear", mwrap_clear, 0);
rb_define_singleton_method(mod, "each", mwrap_each, -1);
rb_define_singleton_method(mod, "[]", mwrap_aref, 1);
rb_define_singleton_method(mod, "quiet", mwrap_quiet, 0);
rb_define_singleton_method(mod, "total_bytes_allocated", total_inc, 0);
rb_define_singleton_method(mod, "total_bytes_freed", total_dec, 0);
rb_define_method(cSrcLoc, "each", src_loc_each, 0);
rb_define_method(cSrcLoc, "frees", src_loc_frees, 0);
rb_define_method(cSrcLoc, "allocations", src_loc_allocations, 0);
rb_define_method(cSrcLoc, "total", src_loc_total, 0);
rb_define_method(cSrcLoc, "mean_lifespan", src_loc_mean_lifespan, 0);
rb_define_method(cSrcLoc, "max_lifespan", src_loc_max_lifespan, 0);
rb_define_method(cSrcLoc, "name", src_loc_name, 0);
/*
* Information about "struct heap_page_body" allocations from
* Ruby gc.c. This can be useful for tracking fragmentation
* from posix_memalign(3) use in mainline Ruby:
*
* https://sourceware.org/bugzilla/show_bug.cgi?id=14581
*
* These statistics are never reset by Mwrap.reset or
* any other method. They only make sense in the context
* of an entire program lifetime.
*/
hpb = rb_define_class_under(mod, "HeapPageBody", rb_cObject);
rb_define_singleton_method(hpb, "stat", hpb_stat, -1);
rb_define_singleton_method(hpb, "each", hpb_each, 0);
--locating;
}
enum {
DUMP_HPB_STATS = 0x1,
DUMP_HPB_EACH = 0x2,
DUMP_HPB_EXCL = 0x4,
};
static void dump_hpb(FILE *fp, unsigned flags)
{
if (flags & DUMP_HPB_STATS) {
fprintf(fp,
"lifespan_max: %"PRId64"\n"
"lifespan_min:%s%"PRId64"\n"
"lifespan_mean: %0.3f\n"
"lifespan_stddev: %0.3f\n"
"deathspan_max: %"PRId64"\n"
"deathspan_min:%s%"PRId64"\n"
"deathspan_mean: %0.3f\n"
"deathspan_stddev: %0.3f\n"
"gc_count: %zu\n",
hpb_stats.alive.max,
hpb_stats.alive.min == INT64_MAX ? " -" : " ",
hpb_stats.alive.min,
hpb_stats.alive.mean,
acc_stddev_dbl(&hpb_stats.alive),
hpb_stats.reborn.max,
hpb_stats.reborn.min == INT64_MAX ? " -" : " ",
hpb_stats.reborn.min,
hpb_stats.reborn.mean,
acc_stddev_dbl(&hpb_stats.reborn),
/* n.b.: unsafe to call rb_gc_count() in destructor */
generation);
}
if (flags & DUMP_HPB_EACH) {
struct alloc_hdr *h;
cds_list_for_each_entry(h, &hpb_stats.bodies, anode) {
void *addr = hdr2ptr(h);
fprintf(fp, "%p\t%zu\n", addr, h->as.live.gen);
}
}
}
/* rb_cloexec_open isn't usable by non-Ruby processes */
#ifndef O_CLOEXEC
# define O_CLOEXEC 0
#endif
__attribute__ ((destructor))
static void mwrap_dump_destructor(void)
{
const char *opt = getenv("MWRAP");
const char *modes[] = { "a", "a+", "w", "w+", "r+" };
struct dump_arg a = { .min = 0 };
size_t i;
int dump_fd;
unsigned dump_heap = 0;
char *dump_path;
char *s;
if (!opt)
return;
++locating;
if ((dump_path = strstr(opt, "dump_path:")) &&
(dump_path += sizeof("dump_path")) &&
*dump_path) {
char *end = strchr(dump_path, ',');
if (end) {
char *tmp = alloca(end - dump_path + 1);
end = mempcpy(tmp, dump_path, end - dump_path);
*end = 0;
dump_path = tmp;
}
dump_fd = open(dump_path, O_CLOEXEC|O_WRONLY|O_APPEND|O_CREAT,
0666);
if (dump_fd < 0) {
fprintf(stderr, "open %s failed: %s\n", dump_path,
strerror(errno));
goto out;
}
}
else if (!sscanf(opt, "dump_fd:%d", &dump_fd))
goto out;
if ((s = strstr(opt, "dump_min:")))
sscanf(s, "dump_min:%zu", &a.min);
if ((s = strstr(opt, "dump_heap:")))
sscanf(s, "dump_heap:%u", &dump_heap);
switch (dump_fd) {
case 0: goto out;
case 1: a.fp = stdout; break;
case 2: a.fp = stderr; break;
default:
if (dump_fd < 0)
goto out;
a.fp = 0;
for (i = 0; !a.fp && i < 5; i++)
a.fp = fdopen(dump_fd, modes[i]);
if (!a.fp) {
fprintf(stderr, "failed to open fd=%d: %s\n",
dump_fd, strerror(errno));
goto out;
}
/* we'll leak some memory here, but this is a destructor */
}
if ((dump_heap & DUMP_HPB_EXCL) == 0)
dump_to_file(&a);
dump_hpb(a.fp, dump_heap);
out:
--locating;
}
|