When generating grpsym lists, avoid duplicates without searching the

already generated list. Speeds up startup on deeply nested dlopen binaries.
ok guenther@, tested by ckuethe@ and ajacoutot@

5 files changed, 61 insertions, 14 deletions

diff --git a/libexec/ld.so/dlfcn.c b/libexec/ld.so/dlfcn.c
index f09b8b5603e..f975f61603e 100644
--- a/libexec/ld.so/dlfcn.c
+++ b/libexec/ld.so/dlfcn.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dlfcn.c,v 1.81 2010/05/02 04:57:01 guenther Exp $ */
+/*	$OpenBSD: dlfcn.c,v 1.82 2010/07/01 19:25:44 drahn Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -85,7 +85,7 @@ dlopen(const char *libname, int flags)
 		/* if opened but grpsym_list has not been created */
 		if (OBJECT_DLREF_CNT(object) == 1) {
 			/* add first object manually */
-			_dl_link_grpsym(object);
+			_dl_link_grpsym(object, 1);
 			_dl_cache_grpsym_list(object);
 		}
 		goto loaded;
diff --git a/libexec/ld.so/library_subr.c b/libexec/ld.so/library_subr.c
index a1eb5fae752..852e5c12233 100644
--- a/libexec/ld.so/library_subr.c
+++ b/libexec/ld.so/library_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: library_subr.c,v 1.30 2010/05/09 09:53:28 matthieu Exp $ */
+/*	$OpenBSD: library_subr.c,v 1.31 2010/07/01 19:25:44 drahn Exp $ */
 
 /*
  * Copyright (c) 2002 Dale Rahn
@@ -448,13 +448,20 @@ _dl_link_child(elf_object_t *dep, elf_object_t *p)
 }
 
 void
-_dl_link_grpsym(elf_object_t *object)
+_dl_link_grpsym(elf_object_t *object, int checklist)
 {
 	struct dep_node *n;
 
-	TAILQ_FOREACH(n, &_dl_loading_object->grpsym_list, next_sib)
-		if (n->data == object)
+	if (checklist) {
+		TAILQ_FOREACH(n, &_dl_loading_object->grpsym_list, next_sib)
+			if (n->data == object)
+				return; /* found, dont bother adding */
+	} else {
+		if (object->lastlookup == _dl_searchnum) {
 			return; /* found, dont bother adding */
+		}
+	}
+	object->lastlookup = _dl_searchnum;
 
 	n = _dl_malloc(sizeof *n);
 	if (n == NULL)
@@ -464,6 +471,12 @@ _dl_link_grpsym(elf_object_t *object)
 }
 
 void
+_dl_cache_grpsym_list_setup(elf_object_t *object)
+{
+	_dl_newsymsearch();
+	_dl_cache_grpsym_list(object);
+}
+void
 _dl_cache_grpsym_list(elf_object_t *object)
 {
 	struct dep_node *n;
@@ -475,7 +488,7 @@ _dl_cache_grpsym_list(elf_object_t *object)
 	 */
 
 	TAILQ_FOREACH(n, &object->child_list, next_sib)
-		_dl_link_grpsym(n->data);
+		_dl_link_grpsym(n->data, 0);
 
 	TAILQ_FOREACH(n, &object->child_list, next_sib)
 		_dl_cache_grpsym_list(n->data);
diff --git a/libexec/ld.so/loader.c b/libexec/ld.so/loader.c
index 1b577effa47..2fa77a8804a 100644
--- a/libexec/ld.so/loader.c
+++ b/libexec/ld.so/loader.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: loader.c,v 1.118 2010/01/02 12:16:35 kettenis Exp $ */
+/*	$OpenBSD: loader.c,v 1.119 2010/07/01 19:25:44 drahn Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -337,8 +337,8 @@ _dl_load_dep_libs(elf_object_t *object, int flags, int booting)
 	}
 
 	/* add first object manually */
-	_dl_link_grpsym(object);
-	_dl_cache_grpsym_list(object);
+	_dl_link_grpsym(object, 1);
+	_dl_cache_grpsym_list_setup(object);
 
 	return(0);
 }
@@ -498,7 +498,7 @@ _dl_boot(const char **argv, char **envp, const long dyn_loff, long *dl_data)
 	_dl_add_object(dyn_obj);
 
 	dyn_obj->refcount++;
-	_dl_link_grpsym(dyn_obj);
+	_dl_link_grpsym(dyn_obj, 1);
 
 	dyn_obj->status |= STAT_RELOC_DONE;
 
diff --git a/libexec/ld.so/resolve.c b/libexec/ld.so/resolve.c
index 765a5b66c1c..ff516f6a3be 100644
--- a/libexec/ld.so/resolve.c
+++ b/libexec/ld.so/resolve.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: resolve.c,v 1.49 2008/05/05 02:29:02 kurt Exp $ */
+/*	$OpenBSD: resolve.c,v 1.50 2010/07/01 19:25:44 drahn Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -159,6 +159,7 @@ _dl_finalize_object(const char *objname, Elf_Dyn *dynp, Elf_Phdr *phdrp,
 	/* default dev, inode for dlopen-able objects. */
 	object->dev = 0;
 	object->inode = 0;
+	object->lastlookup = 0;
 	TAILQ_INIT(&object->grpsym_list);
 	TAILQ_INIT(&object->grpref_list);
 
@@ -302,6 +303,26 @@ _dl_find_symbol_bysym(elf_object_t *req_obj, unsigned int symidx,
 	return ret;
 }
 
+uint32_t _dl_searchnum = 0;
+void
+_dl_newsymsearch(void)
+{
+	_dl_searchnum += 1;
+
+	if (_dl_searchnum < 0) {
+		/* if the signed number roll over, reset
+		 * all counters so we dont get accidental collision
+		 */
+		elf_object_t *walkobj;
+		for (walkobj = _dl_objects;
+		    walkobj != NULL;
+		    walkobj = walkobj->next) {
+			walkobj->lastlookup = 0;
+		}
+		_dl_searchnum = 1;
+	}
+}
+
 Elf_Addr
 _dl_find_symbol(const char *name, const Elf_Sym **this,
     int flags, const Elf_Sym *ref_sym, elf_object_t *req_obj,
@@ -368,6 +389,8 @@ _dl_find_symbol(const char *name, const Elf_Sym **this,
 		if ((flags & SYM_SEARCH_SELF) || (flags & SYM_SEARCH_NEXT))
 			skip = 1;
 
+		_dl_newsymsearch();
+
 		/*
 		 * search dlopened objects: global or req_obj == dlopened_obj
 		 * and and it's children
@@ -377,6 +400,7 @@ _dl_find_symbol(const char *name, const Elf_Sym **this,
 			    (n->data != req_obj->load_object))
 				continue;
 
+			n->data->lastlookup_head = _dl_searchnum;
 			TAILQ_FOREACH(m, &n->data->grpsym_list, next_sib) {
 				if (skip == 1) {
 					if (m->data == req_obj) {
@@ -389,6 +413,7 @@ _dl_find_symbol(const char *name, const Elf_Sym **this,
 				if ((flags & SYM_SEARCH_OTHER) &&
 				    (m->data == req_obj))
 					continue;
+				m->data->lastlookup = _dl_searchnum;
 				if (_dl_find_symbol_obj(m->data, name, h, flags,
 				    this, &weak_sym, &weak_object)) {
 					object = m->data;
diff --git a/libexec/ld.so/resolve.h b/libexec/ld.so/resolve.h
index feb11d5a584..b259941c722 100644
--- a/libexec/ld.so/resolve.h
+++ b/libexec/ld.so/resolve.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: resolve.h,v 1.59 2010/05/02 04:57:01 guenther Exp $ */
+/*	$OpenBSD: resolve.h,v 1.60 2010/07/01 19:25:44 drahn Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -142,6 +142,10 @@ struct elf_object {
 	/* for object confirmation */
 	dev_t	dev;
 	ino_t inode;
+
+	/* last symbol lookup on this object, to avoid mutiple searches */
+	int lastlookup_head;
+	int lastlookup;
 };
 
 struct dep_node {
@@ -201,8 +205,9 @@ int _dl_load_dep_libs(elf_object_t *object, int flags, int booting);
 int _dl_rtld(elf_object_t *object);
 void _dl_call_init(elf_object_t *object);
 void _dl_link_child(elf_object_t *dep, elf_object_t *p);
-void _dl_link_grpsym(elf_object_t *object);
+void _dl_link_grpsym(elf_object_t *object, int checklist);
 void _dl_cache_grpsym_list(elf_object_t *object);
+void _dl_cache_grpsym_list_setup(elf_object_t *object);
 void _dl_link_grpref(elf_object_t *load_group, elf_object_t *load_object);
 void _dl_link_dlopen(elf_object_t *dep);
 void _dl_unlink_dlopen(elf_object_t *dep);
@@ -274,5 +279,9 @@ extern int _dl_symcachestat_lookups;
 TAILQ_HEAD(dlochld, dep_node);
 extern struct dlochld _dlopened_child_list;
 
+/* variables used to avoid duplicate node checking */
+uint32_t _dl_searchnum;
+uint32_t _dl_skipnum;
+void _dl_newsymsearch(void);
 
 #endif /* _RESOLVE_H_ */