Extent -> Ehooks: Move merge hook.

include/jemalloc/internal/ehooks.h

@@ -42,6 +42,9 @@ bool ehooks_default_purge_forced(extent_hooks_t *extent_hooks, void *addr,
 bool ehooks_default_split_impl();
 bool ehooks_default_split(extent_hooks_t *extent_hooks, void *addr, size_t size,
     size_t size_a, size_t size_b, bool committed, unsigned arena_ind);
+bool ehooks_default_merge_impl(void *addr_a, void *addr_b);
+bool ehooks_default_merge(extent_hooks_t *extent_hooks, void *addr_a, size_t size_a,
+    void *addr_b, size_t size_b, bool committed, unsigned arena_ind);
 
 static inline void
 ehooks_pre_reentrancy(tsdn_t *tsdn) {
@@ -238,14 +241,20 @@ ehooks_split(tsdn_t *tsdn, ehooks_t *ehooks, void *addr, size_t size,
 }
 
 static inline bool
-ehooks_merge(ehooks_t *ehooks, void *addr_a, size_t size_a, void *addr_b,
+ehooks_merge(tsdn_t *tsdn, ehooks_t *ehooks, void *addr_a, size_t size_a,
-    size_t size_b, bool committed, unsigned arena_ind) {
+    void *addr_b, size_t size_b, bool committed, unsigned arena_ind) {
 	extent_hooks_t *extent_hooks = ehooks_get_extent_hooks_ptr(ehooks);
-	if (extent_hooks->merge == NULL) {
+	if (extent_hooks == &extent_hooks_default) {
+		return ehooks_default_merge_impl(addr_a, addr_b);
+	} else if (extent_hooks->merge == NULL) {
 		return true;
+	} else {
+		ehooks_pre_reentrancy(tsdn);
+		bool err = extent_hooks->merge(extent_hooks, addr_a, size_a,
+		    addr_b, size_b, committed, arena_ind);
+		ehooks_post_reentrancy(tsdn);
+		return err;
 	}
-	return extent_hooks->merge(extent_hooks, addr_a, size_a, addr_b, size_b,
-	    committed, arena_ind);
 }
 
 #endif /* JEMALLOC_INTERNAL_EHOOKS_H */

include/jemalloc/internal/extent_externs.h

@@ -46,6 +46,7 @@ extent_t *extent_split_wrapper(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks,
     size_t size_b, szind_t szind_b, bool slab_b);
 bool extent_merge_wrapper(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks,
     extent_t *a, extent_t *b);
+bool extent_head_no_merge(extent_t *a, extent_t *b);
 
 bool extent_boot(void);
 

src/ehooks.c

@@ -182,3 +182,29 @@ ehooks_default_split(extent_hooks_t *extent_hooks, void *addr, size_t size,
     size_t size_a, size_t size_b, bool committed, unsigned arena_ind) {
 	return ehooks_default_split_impl();
 }
+
+bool
+ehooks_default_merge_impl(void *addr_a, void *addr_b) {
+	if (!maps_coalesce && !opt_retain) {
+		return true;
+	}
+	if (have_dss && !extent_dss_mergeable(addr_a, addr_b)) {
+		return true;
+	}
+
+	return false;
+}
+
+bool
+ehooks_default_merge(extent_hooks_t *extent_hooks, void *addr_a, size_t size_a,
+    void *addr_b, size_t size_b, bool committed, unsigned arena_ind) {
+	if (!maps_coalesce) {
+		tsdn_t *tsdn = tsdn_fetch();
+		extent_t *a = iealloc(tsdn, addr_a);
+		extent_t *b = iealloc(tsdn, addr_b);
+		if (extent_head_no_merge(a, b)) {
+			return true;
+		}
+	}
+	return ehooks_default_merge_impl(addr_a, addr_b);
+}

src/extent.c

@@ -31,9 +31,6 @@ static extent_t *extent_split_impl(tsdn_t *tsdn, arena_t *arena,
     ehooks_t *ehooks, extent_t *extent, size_t size_a, szind_t szind_a,
     bool slab_a, size_t size_b, szind_t szind_b, bool slab_b,
     bool growing_retained);
-static bool extent_merge_default(extent_hooks_t *extent_hooks, void *addr_a,
-    size_t size_a, void *addr_b, size_t size_b, bool committed,
-    unsigned arena_ind);
 static bool extent_merge_impl(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks,
     extent_t *a, extent_t *b, bool growing_retained);
 
@@ -54,7 +51,7 @@ const extent_hooks_t extent_hooks_default = {
 	NULL,
 #endif
 	ehooks_default_split,
-	extent_merge_default
+	ehooks_default_merge
 };
 
 /* Used exclusively for gdump triggering. */
@@ -1576,23 +1573,11 @@ extent_split_wrapper(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks,
 	    slab_a, size_b, szind_b, slab_b, false);
 }
 
-static bool
-extent_merge_default_impl(void *addr_a, void *addr_b) {
-	if (!maps_coalesce && !opt_retain) {
-		return true;
-	}
-	if (have_dss && !extent_dss_mergeable(addr_a, addr_b)) {
-		return true;
-	}
-
-	return false;
-}
-
 /*
  * Returns true if the given extents can't be merged because of their head bit
  * settings.  Assumes the second extent has the higher address.
  */
-static bool
+bool
 extent_head_no_merge(extent_t *a, extent_t *b) {
 	assert(extent_base_get(a) < extent_base_get(b));
 	/*
@@ -1620,20 +1605,6 @@ extent_head_no_merge(extent_t *a, extent_t *b) {
 	return false;
 }
 
-static bool
-extent_merge_default(extent_hooks_t *extent_hooks, void *addr_a, size_t size_a,
-    void *addr_b, size_t size_b, bool committed, unsigned arena_ind) {
-	if (!maps_coalesce) {
-		tsdn_t *tsdn = tsdn_fetch();
-		extent_t *a = iealloc(tsdn, addr_a);
-		extent_t *b = iealloc(tsdn, addr_b);
-		if (extent_head_no_merge(a, b)) {
-			return true;
-		}
-	}
-	return extent_merge_default_impl(addr_a, addr_b);
-}
-
 static bool
 extent_merge_impl(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks, extent_t *a,
     extent_t *b, bool growing_retained) {
@@ -1645,18 +1616,9 @@ extent_merge_impl(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks, extent_t *a,
 		return true;
 	}
 
-	bool err;
+	bool err = ehooks_merge(tsdn, ehooks, extent_base_get(a),
-	if (ehooks_are_default(ehooks)) {
-		/* Call directly to propagate tsdn. */
-		err = extent_merge_default_impl(extent_base_get(a),
-		    extent_base_get(b));
-	} else {
-		extent_hook_pre_reentrancy(tsdn, arena);
-		err = ehooks_merge(ehooks, extent_base_get(a),
 	    extent_size_get(a), extent_base_get(b), extent_size_get(b),
 	    extent_committed_get(a), arena_ind_get(arena));
-		extent_hook_post_reentrancy(tsdn);
-	}
 
 	if (err) {
 		return true;