Test prof.reset mallctl and fix numerous discovered bugs.

2014-10-02 23:01:10 -07:00
parent cc9e626ea9
commit 20c31deaae
5 changed files with 404 additions and 75 deletions
--- a/src/prof.c
+++ b/src/prof.c
@@ -137,10 +137,18 @@ rb_gen(static UNUSED, gctx_tree_, prof_gctx_tree_t, prof_gctx_t, dump_link,
 JEMALLOC_INLINE_C int
 prof_tdata_comp(const prof_tdata_t *a, const prof_tdata_t *b)
 {
+	int ret;
 	uint64_t a_uid = a->thr_uid;
 	uint64_t b_uid = b->thr_uid;

-	return ((a_uid > b_uid) - (a_uid < b_uid));
+	ret = ((a_uid > b_uid) - (a_uid < b_uid));
+	if (ret == 0) {
+		uint64_t a_discrim = a->thr_discrim;
+		uint64_t b_discrim = b->thr_discrim;
+
+		ret = ((a_discrim > b_discrim) - (a_discrim < b_discrim));
+	}
+	return (ret);
 }

 rb_gen(static UNUSED, tdata_tree_, prof_tdata_tree_t, prof_tdata_t, tdata_link,
@@ -504,7 +512,7 @@ prof_gctx_create(tsd_t *tsd, prof_bt_t *bt)
 	gctx->lock = prof_gctx_mutex_choose();
 	/*
 	 * Set nlimbo to 1, in order to avoid a race condition with
-	 * prof_tctx_destroy()/prof_gctx_maybe_destroy().
+	 * prof_tctx_destroy()/prof_gctx_try_destroy().
 	 */
 	gctx->nlimbo = 1;
 	tctx_tree_new(&gctx->tctxs);
@@ -516,7 +524,7 @@ prof_gctx_create(tsd_t *tsd, prof_bt_t *bt)
 }

 static void
-prof_gctx_maybe_destroy(tsd_t *tsd, prof_gctx_t *gctx, prof_tdata_t *tdata)
+prof_gctx_try_destroy(tsd_t *tsd, prof_gctx_t *gctx, prof_tdata_t *tdata)
 {

 	cassert(config_prof);
@@ -530,6 +538,7 @@ prof_gctx_maybe_destroy(tsd_t *tsd, prof_gctx_t *gctx, prof_tdata_t *tdata)
 	 */
 	prof_enter(tdata);
 	malloc_mutex_lock(gctx->lock);
+	assert(gctx->nlimbo != 0);
 	if (tctx_tree_empty(&gctx->tctxs) && gctx->nlimbo == 1) {
 		/* Remove gctx from bt2gctx. */
 		if (ckh_remove(tsd, &bt2gctx, &gctx->bt, NULL, NULL))
@@ -605,10 +614,10 @@ prof_tctx_destroy(tsd_t *tsd, prof_tctx_t *tctx)
 		 *
 		 * 1) Sample an allocation associated with gctx.
 		 * 2) Deallocate the sampled object.
-		 * 3) Successfully prof_gctx_maybe_destroy(gctx).
+		 * 3) Successfully prof_gctx_try_destroy(gctx).
 		 *
 		 * The result would be that gctx no longer exists by the time
-		 * this thread accesses it in prof_gctx_maybe_destroy().
+		 * this thread accesses it in prof_gctx_try_destroy().
 		 */
 		gctx->nlimbo++;
 		destroy_gctx = true;
@@ -616,7 +625,7 @@ prof_tctx_destroy(tsd_t *tsd, prof_tctx_t *tctx)
 		destroy_gctx = false;
 	malloc_mutex_unlock(gctx->lock);
 	if (destroy_gctx)
-		prof_gctx_maybe_destroy(tsd, gctx, tdata);
+		prof_gctx_try_destroy(tsd, gctx, tdata);

 	if (destroy_tdata)
 		prof_tdata_destroy(tsd, tdata);
@@ -657,7 +666,7 @@ prof_lookup_global(tsd_t *tsd, prof_bt_t *bt, prof_tdata_t *tdata,
 	} else {
 		/*
 		 * Increment nlimbo, in order to avoid a race condition with
-		 * prof_tctx_destroy()/prof_gctx_maybe_destroy().
+		 * prof_tctx_destroy()/prof_gctx_try_destroy().
 		 */
 		malloc_mutex_lock(gctx.p->lock);
 		gctx.p->nlimbo++;
@@ -710,7 +719,7 @@ prof_lookup(tsd_t *tsd, prof_bt_t *bt)
 		ret.v = imalloc(tsd, sizeof(prof_tctx_t));
 		if (ret.p == NULL) {
 			if (new_gctx)
-				prof_gctx_maybe_destroy(tsd, gctx, tdata);
+				prof_gctx_try_destroy(tsd, gctx, tdata);
 			return (NULL);
 		}
 		ret.p->tdata = tdata;
@@ -723,7 +732,7 @@ prof_lookup(tsd_t *tsd, prof_bt_t *bt)
 		malloc_mutex_unlock(tdata->lock);
 		if (error) {
 			if (new_gctx)
-				prof_gctx_maybe_destroy(tsd, gctx, tdata);
+				prof_gctx_try_destroy(tsd, gctx, tdata);
 			idalloc(tsd, ret.v);
 			return (NULL);
 		}
@@ -792,6 +801,31 @@ prof_sample_threshold_update(prof_tdata_t *tdata)
 #endif
 }

+#ifdef JEMALLOC_JET
+static prof_tdata_t *
+prof_tdata_count_iter(prof_tdata_tree_t *tdatas, prof_tdata_t *tdata, void *arg)
+{
+	size_t *tdata_count = (size_t *)arg;
+
+	(*tdata_count)++;
+
+	return (NULL);
+}
+
+size_t
+prof_tdata_count(void)
+{
+	size_t tdata_count = 0;
+
+	malloc_mutex_lock(&tdatas_mtx);
+	tdata_tree_iter(&tdatas, NULL, prof_tdata_count_iter,
+	    (void *)&tdata_count);
+	malloc_mutex_unlock(&tdatas_mtx);
+
+	return (tdata_count);
+}
+#endif
+
 #ifdef JEMALLOC_JET
 size_t
 prof_bt_count(void)
@@ -998,7 +1032,6 @@ static prof_tctx_t *
 prof_tctx_finish_iter(prof_tctx_tree_t *tctxs, prof_tctx_t *tctx, void *arg)
 {
 	prof_tctx_t *ret;
-	tsd_t *tsd = (tsd_t *)arg;

 	switch (tctx->state) {
 	case prof_tctx_state_nominal:
@@ -1008,9 +1041,7 @@ prof_tctx_finish_iter(prof_tctx_tree_t *tctxs, prof_tctx_t *tctx, void *arg)
 		tctx->state = prof_tctx_state_nominal;
 		break;
 	case prof_tctx_state_purgatory:
-		ret = tctx_tree_next(tctxs, tctx);
-		tctx_tree_remove(tctxs, tctx);
-		idalloc(tsd, tctx);
+		ret = tctx;
 		goto label_return;
 	default:
 		not_reached();
@@ -1056,27 +1087,47 @@ prof_gctx_merge_iter(prof_gctx_tree_t *gctxs, prof_gctx_t *gctx, void *arg)
 	return (NULL);
 }

-static prof_gctx_t *
-prof_gctx_finish_iter(prof_gctx_tree_t *gctxs, prof_gctx_t *gctx, void *arg)
+static void
+prof_gctx_finish(tsd_t *tsd, prof_gctx_tree_t *gctxs)
 {
-	tsd_t *tsd = (tsd_t *)arg;
 	prof_tdata_t *tdata = prof_tdata_get(tsd, false);
-	prof_tctx_t *next;
-	bool destroy_gctx;
+	prof_gctx_t *gctx;

-	malloc_mutex_lock(gctx->lock);
-	next = NULL;
-	do {
-		next = tctx_tree_iter(&gctx->tctxs, next, prof_tctx_finish_iter,
-		    tsd);
-	} while (next != NULL);
-	gctx->nlimbo--;
-	destroy_gctx = prof_gctx_should_destroy(gctx);
-	malloc_mutex_unlock(gctx->lock);
-	if (destroy_gctx)
-		prof_gctx_maybe_destroy(tsd, gctx, tdata);
+	/*
+	 * Standard tree iteration won't work here, because as soon as we
+	 * decrement gctx->nlimbo and unlock gctx, another thread can
+	 * concurrently destroy it, which will corrupt the tree.  Therefore,
+	 * tear down the tree one node at a time during iteration.
+	 */
+	while ((gctx = gctx_tree_first(gctxs)) != NULL) {
+		gctx_tree_remove(gctxs, gctx);
+		malloc_mutex_lock(gctx->lock);
+		{
+			prof_tctx_t *next;

-	return (NULL);
+			next = NULL;
+			do {
+				prof_tctx_t *to_destroy =
+				    tctx_tree_iter(&gctx->tctxs, next,
+				    prof_tctx_finish_iter, NULL);
+				if (to_destroy != NULL) {
+					next = tctx_tree_next(&gctx->tctxs,
+					    to_destroy);
+					tctx_tree_remove(&gctx->tctxs,
+					    to_destroy);
+					idalloc(tsd, to_destroy);
+				} else
+					next = NULL;
+			} while (next != NULL);
+		}
+		gctx->nlimbo--;
+		if (prof_gctx_should_destroy(gctx)) {
+			gctx->nlimbo++;
+			malloc_mutex_unlock(gctx->lock);
+			prof_gctx_try_destroy(tsd, gctx, tdata);
+		} else
+			malloc_mutex_unlock(gctx->lock);
+	}
 }

 static prof_tdata_t *
@@ -1085,7 +1136,7 @@ prof_tdata_merge_iter(prof_tdata_tree_t *tdatas, prof_tdata_t *tdata, void *arg)
 	prof_cnt_t *cnt_all = (prof_cnt_t *)arg;

 	malloc_mutex_lock(tdata->lock);
-	if (tdata->state != prof_tdata_state_expired) {
+	if (!tdata->expired) {
 		size_t tabind;
 		union {
 			prof_tctx_t	*p;
@@ -1130,6 +1181,10 @@ prof_tdata_dump_iter(prof_tdata_tree_t *tdatas, prof_tdata_t *tdata, void *arg)
 	return (NULL);
 }

+#ifdef JEMALLOC_JET
+#undef prof_dump_header
+#define	prof_dump_header JEMALLOC_N(prof_dump_header_impl)
+#endif
 static bool
 prof_dump_header(bool propagate_err, const prof_cnt_t *cnt_all)
 {
@@ -1148,6 +1203,11 @@ prof_dump_header(bool propagate_err, const prof_cnt_t *cnt_all)
 	malloc_mutex_unlock(&tdatas_mtx);
 	return (ret);
 }
+#ifdef JEMALLOC_JET
+#undef prof_dump_header
+#define	prof_dump_header JEMALLOC_N(prof_dump_header)
+prof_dump_header_t *prof_dump_header = JEMALLOC_N(prof_dump_header_impl);
+#endif

 /* gctx->lock is held. */
 static bool
@@ -1277,7 +1337,7 @@ prof_gctx_dump_iter(prof_gctx_tree_t *gctxs, prof_gctx_t *gctx, void *arg)
 	malloc_mutex_lock(gctx->lock);

 	if (prof_dump_gctx(propagate_err, gctx, &gctx->bt, gctxs)) {
-		ret = gctx_tree_next(gctxs, gctx);
+		ret = gctx;
 		goto label_return;
 	}

@@ -1302,7 +1362,7 @@ prof_dump(tsd_t *tsd, bool propagate_err, const char *filename, bool leakcheck)

 	cassert(config_prof);

-	tdata = prof_tdata_get(tsd, false);
+	tdata = prof_tdata_get(tsd, true);
 	if (tdata == NULL)
 		return (true);

@@ -1352,7 +1412,7 @@ prof_dump(tsd_t *tsd, bool propagate_err, const char *filename, bool leakcheck)
 	if (prof_dump_close(propagate_err))
 		goto label_open_close_error;

-	gctx_tree_iter(&gctxs, NULL, prof_gctx_finish_iter, tsd);
+	prof_gctx_finish(tsd, &gctxs);
 	malloc_mutex_unlock(&prof_dump_mtx);

 	if (leakcheck)
@@ -1362,7 +1422,7 @@ prof_dump(tsd_t *tsd, bool propagate_err, const char *filename, bool leakcheck)
 label_write_error:
 	prof_dump_close(propagate_err);
 label_open_close_error:
-	gctx_tree_iter(&gctxs, NULL, prof_gctx_finish_iter, tsd);
+	prof_gctx_finish(tsd, &gctxs);
 	malloc_mutex_unlock(&prof_dump_mtx);
 	return (true);
 }
@@ -1533,7 +1593,7 @@ prof_thr_uid_alloc(void)
 }

 static prof_tdata_t *
-prof_tdata_init_impl(tsd_t *tsd, uint64_t thr_uid)
+prof_tdata_init_impl(tsd_t *tsd, uint64_t thr_uid, uint64_t thr_discrim)
 {
 	prof_tdata_t *tdata;

@@ -1546,8 +1606,10 @@ prof_tdata_init_impl(tsd_t *tsd, uint64_t thr_uid)

 	tdata->lock = prof_tdata_mutex_choose(thr_uid);
 	tdata->thr_uid = thr_uid;
+	tdata->thr_discrim = thr_discrim;
 	tdata->thread_name = NULL;
-	tdata->state = prof_tdata_state_attached;
+	tdata->attached = true;
+	tdata->expired = false;

 	if (ckh_new(tsd, &tdata->bt2tctx, PROF_CKH_MINITEMS,
 	    prof_bt_hash, prof_bt_keycomp)) {
@@ -1576,14 +1638,7 @@ prof_tdata_t *
 prof_tdata_init(tsd_t *tsd)
 {

-	return (prof_tdata_init_impl(tsd, prof_thr_uid_alloc()));
-}
-
-prof_tdata_t *
-prof_tdata_reinit(tsd_t *tsd, prof_tdata_t *tdata)
-{
-
-	return (prof_tdata_init_impl(tsd, tdata->thr_uid));
+	return (prof_tdata_init_impl(tsd, prof_thr_uid_alloc(), 0));
 }

 /* tdata->lock must be held. */
@@ -1591,22 +1646,21 @@ static bool
 prof_tdata_should_destroy(prof_tdata_t *tdata)
 {

-	if (tdata->state == prof_tdata_state_attached)
+	if (tdata->attached)
 		return (false);
 	if (ckh_count(&tdata->bt2tctx) != 0)
 		return (false);
 	return (true);
 }

+/* tdatas_mtx must be held. */
 static void
-prof_tdata_destroy(tsd_t *tsd, prof_tdata_t *tdata)
+prof_tdata_destroy_locked(tsd_t *tsd, prof_tdata_t *tdata)
 {

 	assert(prof_tdata_should_destroy(tdata));

-	malloc_mutex_lock(&tdatas_mtx);
 	tdata_tree_remove(&tdatas, tdata);
-	malloc_mutex_unlock(&tdatas_mtx);

 	if (tdata->thread_name != NULL)
 		idalloc(tsd, tdata->thread_name);
@@ -1615,14 +1669,22 @@ prof_tdata_destroy(tsd_t *tsd, prof_tdata_t *tdata)
 }

 static void
-prof_tdata_state_transition(tsd_t *tsd, prof_tdata_t *tdata,
-   prof_tdata_state_t state)
+prof_tdata_destroy(tsd_t *tsd, prof_tdata_t *tdata)
+{
+
+	malloc_mutex_lock(&tdatas_mtx);
+	prof_tdata_destroy_locked(tsd, tdata);
+	malloc_mutex_unlock(&tdatas_mtx);
+}
+
+static void
+prof_tdata_detach(tsd_t *tsd, prof_tdata_t *tdata)
 {
 	bool destroy_tdata;

 	malloc_mutex_lock(tdata->lock);
-	if (tdata->state != state) {
-		tdata->state = state;
+	if (tdata->attached) {
+		tdata->attached = false;
 		destroy_tdata = prof_tdata_should_destroy(tdata);
 	} else
 		destroy_tdata = false;
@@ -1631,32 +1693,44 @@ prof_tdata_state_transition(tsd_t *tsd, prof_tdata_t *tdata,
 		prof_tdata_destroy(tsd, tdata);
 }

-static void
-prof_tdata_detach(tsd_t *tsd, prof_tdata_t *tdata)
+prof_tdata_t *
+prof_tdata_reinit(tsd_t *tsd, prof_tdata_t *tdata)
 {
+	uint64_t thr_uid = tdata->thr_uid;
+	uint64_t thr_discrim = tdata->thr_discrim + 1;

-	prof_tdata_state_transition(tsd, tdata, prof_tdata_state_detached);
+	prof_tdata_detach(tsd, tdata);
+	return (prof_tdata_init_impl(tsd, thr_uid, thr_discrim));
 }

-static void
-prof_tdata_expire(tsd_t *tsd, prof_tdata_t *tdata)
+static bool
+prof_tdata_expire(prof_tdata_t *tdata)
 {
+	bool destroy_tdata;

-	prof_tdata_state_transition(tsd, tdata, prof_tdata_state_expired);
+	malloc_mutex_lock(tdata->lock);
+	if (!tdata->expired) {
+		tdata->expired = true;
+		destroy_tdata = tdata->attached ? false :
+		    prof_tdata_should_destroy(tdata);
+	} else
+		destroy_tdata = false;
+	malloc_mutex_unlock(tdata->lock);
+
+	return (destroy_tdata);
 }

 static prof_tdata_t *
 prof_tdata_reset_iter(prof_tdata_tree_t *tdatas, prof_tdata_t *tdata, void *arg)
 {
-	tsd_t *tsd = (tsd_t *)arg;

-	prof_tdata_expire(tsd, tdata);
-	return (NULL);
+	return (prof_tdata_expire(tdata) ? tdata : NULL);
 }

 void
 prof_reset(tsd_t *tsd, size_t lg_sample)
 {
+	prof_tdata_t *next;

 	assert(lg_sample < (sizeof(uint64_t) << 3));

@@ -1664,7 +1738,18 @@ prof_reset(tsd_t *tsd, size_t lg_sample)
 	malloc_mutex_lock(&tdatas_mtx);

 	lg_prof_sample = lg_sample;
-	tdata_tree_iter(&tdatas, NULL, prof_tdata_reset_iter, tsd);
+
+	next = NULL;
+	do {
+		prof_tdata_t *to_destroy = tdata_tree_iter(&tdatas, next,
+		    prof_tdata_reset_iter, NULL);
+		if (to_destroy != NULL) {
+			next = tdata_tree_next(&tdatas, to_destroy);
+			tdata_tree_remove(&tdatas, to_destroy);
+			prof_tdata_destroy(tsd, to_destroy);
+		} else
+			next = NULL;
+	} while (next != NULL);

 	malloc_mutex_unlock(&tdatas_mtx);
 	malloc_mutex_unlock(&prof_dump_mtx);