release GVL for most Ruby operations

Most of this code is independent of Ruby.  synchronize_rcu in
Mwrap#clear can take a while, and I would not rule out having a
version of this which works with Perl5 :>

1 files changed, 55 insertions, 43 deletions

diff --git a/ext/mwrap/mwrap.c b/ext/mwrap/mwrap.c
index 36eef05..fbba32b 100644
--- a/ext/mwrap/mwrap.c
+++ b/ext/mwrap/mwrap.c
@@ -292,30 +292,35 @@ struct dump_arg {
         size_t min;
 };
 
-static void dump_to_file(struct dump_arg *a)
+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) {
-                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->calls, (const char *)p);
-                        if (s) free(s);
+        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->calls, (const char *)p);
+                if (s) free(s);
         }
+out_unlock:
         rcu_read_unlock();
+        --locating;
+        return 0;
 }
 
 static VALUE mwrap_dump(int argc, VALUE * argv, VALUE mod)
@@ -335,9 +340,8 @@ static VALUE mwrap_dump(int argc, VALUE * argv, VALUE mod)
         GetOpenFile(io, fptr);
         a.fp = rb_io_stdio_file(fptr);
 
-        ++locating;
-        dump_to_file(&a);
-        --locating;
+        rb_thread_call_without_gvl(dump_to_file, &a, 0, 0);
+        RB_GC_GUARD(io);
         return Qnil;
 }
 
@@ -348,7 +352,7 @@ free_src_loc(struct rcu_head *head)
         free(l);
 }
 
-static VALUE mwrap_clear(VALUE mod)
+static void *totals_clear(void *ign)
 {
         struct cds_lfht *new, *old;
         struct cds_lfht_iter iter;
@@ -365,13 +369,17 @@ static VALUE mwrap_clear(VALUE mod)
         rcu_read_unlock();
 
         synchronize_rcu(); /* ensure totals points to new */
-
         cds_lfht_destroy(old, NULL);
+        return 0;
+}
 
+static VALUE mwrap_clear(VALUE mod)
+{
+        rb_thread_call_without_gvl(totals_clear, 0, 0, 0);
         return Qnil;
 }
 
-static VALUE mwrap_reset(VALUE mod)
+static void *totals_reset(void *ign)
 {
         struct cds_lfht *t;
         struct cds_lfht_iter iter;
@@ -384,7 +392,12 @@ static VALUE mwrap_reset(VALUE mod)
                 uatomic_set(&l->calls, 0);
         }
         rcu_read_unlock();
+        return 0;
+}
 
+static VALUE mwrap_reset(VALUE mod)
+{
+        rb_thread_call_without_gvl(totals_reset, 0, 0, 0);
         return Qnil;
 }
 
@@ -403,30 +416,29 @@ static VALUE dump_each_rcu(VALUE x)
         struct src_loc *l;
 
         t = rcu_dereference(totals);
-        if (t) {
-                cds_lfht_for_each_entry(t, &iter, l, hnode) {
-                        VALUE v[3];
-                        if (l->total <= a->min) continue;
-
-                        if (loc_is_addr(l)) {
-                                char **s = backtrace_symbols((void *)l->k, 1);
-                                v[1] = rb_str_new_cstr(s[0]);
-                                free(s);
-                        }
-                        else {
-                                v[1] = rb_str_new(l->k, l->capa - 1);
-                        }
-                        v[0] = rb_funcall(v[1], id_uminus, 0);
-
-                        if (!OBJ_FROZEN_RAW(v[1]))
-                                rb_str_resize(v[1], 0);
-
-                        v[1] = SIZET2NUM(l->total);
-                        v[2] = SIZET2NUM(l->calls);
-
-                        rb_yield_values2(3, v);
-                        assert(rcu_read_ongoing());
+        cds_lfht_for_each_entry(t, &iter, l, hnode) {
+                VALUE v[3];
+                if (l->total <= a->min) continue;
+
+                if (loc_is_addr(l)) {
+                        char **s = backtrace_symbols((void *)l->k, 1);
+                        v[1] = rb_str_new_cstr(s[0]);
+                        free(s);
+                }
+                else {
+                        v[1] = rb_str_new(l->k, l->capa - 1);
                 }
+
+                /* deduplicate and try to free up some memory */
+                v[0] = rb_funcall(v[1], id_uminus, 0);
+                if (!OBJ_FROZEN_RAW(v[1]))
+                        rb_str_resize(v[1], 0);
+
+                v[1] = SIZET2NUM(l->total);
+                v[2] = SIZET2NUM(l->calls);
+
+                rb_yield_values2(3, v);
+                assert(rcu_read_ongoing());
         }
         return Qnil;
 }