2007-05-29 Frank Ch. Eigler <fche@redhat.com>

	PR 2224
	* map.h (NEED_MAP_LOCKS): New config macro, defaults to 0.
	(MAP_GET_CPU, MAP_PUT_CPU): Wrappers, default to ~no-op.
	* map.c (_stp_pmap_clear,agg): Use them.
	* pmap-gen.c (_stp_pmap_new,set,add,get_cpu,get,del): Ditto.

4 files changed, 74 insertions, 11 deletions

diff --git a/runtime/ChangeLog b/runtime/ChangeLog
index d2cd0404..eb5f03bf 100644
--- a/runtime/ChangeLog
+++ b/runtime/ChangeLog
@@ -1,3 +1,11 @@
+2007-05-29  Frank Ch. Eigler  <fche@redhat.com>
+
+	PR 2224
+	* map.h (NEED_MAP_LOCKS): New config macro, defaults to 0.
+	(MAP_GET_CPU, MAP_PUT_CPU): Wrappers, default to ~no-op.
+	* map.c (_stp_pmap_clear,agg): Use them.
+	* pmap-gen.c (_stp_pmap_new,set,add,get_cpu,get,del): Ditto.
+	
 2007-05-15  Martin Hunt  <hunt@redhat.com>
 
 	* vsprintf.c: Add comment about %p.
@@ -35,6 +43,7 @@
 
 2007-03-21  Martin Hunt  <hunt@redhat.com>
 
+
 	* sym.h: Declare _stp_module_relocate.
 	* sym.c (_stp_module_relocate): Add comments, reformat, add
 	a way for "last" cached values to be cleared when modules
diff --git a/runtime/map.c b/runtime/map.c
index e4235901..2acf2fe2 100644
--- a/runtime/map.c
+++ b/runtime/map.c
@@ -369,9 +369,13 @@ void _stp_pmap_clear(PMAP pmap)
 
 	for_each_cpu(i) {
 		MAP m = per_cpu_ptr (pmap->map, i);
+#if NEED_MAP_LOCKS
 		spin_lock(&m->lock);
+#endif
 		_stp_map_clear(m);
+#if NEED_MAP_LOCKS
 		spin_unlock(&m->lock);
+#endif
 	}
 	_stp_map_clear(&pmap->agg);
 }
@@ -873,7 +877,9 @@ MAP _stp_pmap_agg (PMAP pmap)
 
 	for_each_cpu(i) {
 		m = per_cpu_ptr (pmap->map, i);
+#if NEED_MAP_LOCKS
 		spin_lock(&m->lock);
+#endif
 		/* walk the hash chains. */
 		for (hash = 0; hash < HASH_TABLE_SIZE; hash++) {
 			head = &m->hashes[hash];
@@ -892,13 +898,17 @@ MAP _stp_pmap_agg (PMAP pmap)
 					_stp_add_agg(aptr, ptr);
 				else {
 					if (!_stp_new_agg(agg, ahead, ptr)) {
+#if NEED_MAP_LOCKS
 						spin_unlock(&m->lock);
+#endif
 						return NULL;
 					}
 				}
 			}
 		}
+#if NEED_MAP_LOCKS
 		spin_unlock(&m->lock);
+#endif
 	}
 	return agg;
 }
diff --git a/runtime/map.h b/runtime/map.h
index 4bb8aee2..f89dc521 100644
--- a/runtime/map.h
+++ b/runtime/map.h
@@ -19,6 +19,23 @@
  * @{
  */
 
+
+/* Include map spinlocks only on demand.  Otherwise, assume that
+   caller does the right thing. */
+#ifndef NEED_MAP_LOCKS
+#define NEED_MAP_LOCKS 0
+#endif
+
+#if NEED_MAP_LOCKS
+#define MAP_GET_CPU() get_cpu()
+#define MAP_PUT_CPU() put_cpu()
+#else
+/* get/put_cpu wrappers.  Unnecessary if caller is already atomic. */
+#define MAP_GET_CPU() smp_processor_id()
+#define MAP_PUT_CPU() do {} while (0)
+#endif
+
+
 /* This sets the size of the hash table. */
 #ifndef HASH_TABLE_BITS
 #define HASH_TABLE_BITS 8
@@ -102,7 +119,9 @@ struct map_root {
 
 	int data_offset;
 
+#ifdef NEED_MAP_LOCKS
 	spinlock_t lock;
+#endif
 
 	/* the hash table for this array */
 	struct hlist_head hashes[HASH_TABLE_SIZE];
diff --git a/runtime/pmap-gen.c b/runtime/pmap-gen.c
index 34bb9104..f84b9db7 100644
--- a/runtime/pmap-gen.c
+++ b/runtime/pmap-gen.c
@@ -1,6 +1,6 @@
 /* -*- linux-c -*- 
  * pmap API generator
- * Copyright (C) 2005 Red Hat Inc.
+ * Copyright (C) 2005-2007 Red Hat Inc.
  *
  * This file is part of systemtap, and is free software.  You can
  * redistribute it and/or modify it under the terms of the GNU General
@@ -411,7 +411,9 @@ PMAP KEYSYM(_stp_pmap_new) (unsigned max_entries)
 			m->get_key = KEYSYM(pmap_get_key);
 			m->copy = KEYSYM(pmap_copy_keys);
 			m->cmp = KEYSYM(pmap_key_cmp);
+#if NEED_MAP_LOCKS
 			m->lock = SPIN_LOCK_UNLOCKED;
+#endif
 		}
 		m = &pmap->agg;
 		m->get_key = KEYSYM(pmap_get_key);
@@ -469,7 +471,9 @@ PMAP KEYSYM(_stp_pmap_new) (unsigned max_entries, int htype, ...)
 			m->get_key = KEYSYM(pmap_get_key);
 			m->copy = KEYSYM(pmap_copy_keys);
 			m->cmp = KEYSYM(pmap_key_cmp);
+#if NEED_MAP_LOCKS
 			m->lock = SPIN_LOCK_UNLOCKED;
+#endif
 		}
 		m = &pmap->agg;
 		m->get_key = KEYSYM(pmap_get_key);
@@ -530,24 +534,32 @@ int KEYSYM(__stp_pmap_set) (MAP map, ALLKEYSD(key), VSTYPE val, int add)
 int KEYSYM(_stp_pmap_set) (PMAP pmap, ALLKEYSD(key), VSTYPE val)
 {
 	int res;
-	MAP m = per_cpu_ptr (pmap->map, get_cpu());
+	MAP m = per_cpu_ptr (pmap->map, MAP_GET_CPU ());
+#if NEED_MAP_LOCKS
 	if (!spin_trylock(&m->lock))
 		return -3;
+#endif
 	res = KEYSYM(__stp_pmap_set) (m, ALLKEYS(key), val, 0);
+#if NEED_MAP_LOCKS
 	spin_unlock(&m->lock);
-	put_cpu();
+#endif
+        MAP_PUT_CPU ();
 	return res;
 }
 
 int KEYSYM(_stp_pmap_add) (PMAP pmap, ALLKEYSD(key), VSTYPE val)
 {
 	int res;
-	MAP m = per_cpu_ptr (pmap->map, get_cpu());
+	MAP m = per_cpu_ptr (pmap->map, MAP_GET_CPU());
+#if NEED_MAP_LOCKS
 	if (!spin_trylock(&m->lock))
 		return -3;
+#endif
 	res = KEYSYM(__stp_pmap_set) (m, ALLKEYS(key), val, 1);
+#if NEED_MAP_LOCKS
 	spin_unlock(&m->lock);
-	put_cpu();
+#endif
+        MAP_PUT_CPU ();
 	return res;
 }
 
@@ -564,14 +576,15 @@ VALTYPE KEYSYM(_stp_pmap_get_cpu) (PMAP pmap, ALLKEYSD(key))
 	if (pmap == NULL)
 		return NULLRET;
 
-	map = per_cpu_ptr (pmap->map, get_cpu());
+	map = per_cpu_ptr (pmap->map, MAP_GET_CPU ());
 
 	hv = KEYSYM(phash) (ALLKEYS(key));
 	head = &map->hashes[hv];
 
+#if NEED_MAP_LOCKS
 	if (!spin_trylock(&map->lock))
 		return NULLRET;
-
+#endif
 	hlist_for_each(e, head) {
 		n = (struct KEYSYM(pmap_node) *)((long)e - sizeof(struct list_head));
 		if (KEY1_EQ_P(n->key1, key1)
@@ -589,14 +602,18 @@ VALTYPE KEYSYM(_stp_pmap_get_cpu) (PMAP pmap, ALLKEYSD(key))
 #endif
 			) {
 			res = MAP_GET_VAL((struct map_node *)n);
+#if NEED_MAP_LOCKS
 			spin_unlock(&map->lock);
-			put_cpu();
+#endif
+			MAP_PUT_CPU ();
 			return res;
 		}
 	}
 	/* key not found */
+#if NEED_MAP_LOCKS
 	spin_unlock(&map->lock);
-	put_cpu();
+#endif
+        MAP_PUT_CPU ();
 	return NULLRET;
 }
 
@@ -645,8 +662,10 @@ VALTYPE KEYSYM(_stp_pmap_get) (PMAP pmap, ALLKEYSD(key))
 		map = per_cpu_ptr (pmap->map, cpu);
 		head = &map->hashes[hv];
 
+#if NEED_MAP_LOCKS
 		if (!spin_trylock(&map->lock))
 			return NULLRET;
+#endif
 
 		hlist_for_each(e, head) {
 			n = (struct KEYSYM(pmap_node) *)((long)e - sizeof(struct list_head));
@@ -676,7 +695,9 @@ VALTYPE KEYSYM(_stp_pmap_get) (PMAP pmap, ALLKEYSD(key))
 				}
 			}
 		}
+#if NEED_MAP_LOCKS
 		spin_unlock(&map->lock);
+#endif
 	}
 	if (anode && !clear_agg) 
 		return MAP_GET_VAL(anode);
@@ -730,12 +751,16 @@ int KEYSYM(__stp_pmap_del) (MAP map, ALLKEYSD(key))
 int KEYSYM(_stp_pmap_del) (PMAP pmap, ALLKEYSD(key))
 {
 	int res;
-	MAP m = per_cpu_ptr (pmap->map, get_cpu());
+	MAP m = per_cpu_ptr (pmap->map, MAP_GET_CPU ());
+#if NEED_MAP_LOCKS
 	if (!spin_trylock(&m->lock))
 		return -1;
+#endif
 	res = KEYSYM(__stp_pmap_del) (m, ALLKEYS(key));
+#if NEED_MAP_LOCKS
 	spin_unlock(&m->lock);
-	put_cpu();
+#endif
+	MAP_PUT_CPU ();
 	return res;
 }