From: Oleg Nesterov Hello. This patch changes list_for_each_xxx iterators from: for (pos = (head)->next, prefetch(pos->next); pos != (head); pos = pos->next, prefetch(pos->next)) to: for (pos = (head)->next; prefetch(pos->next), pos != (head); pos = pos->next) Reduces my vmlinux .text size by 4401 bytes. Signed-off-by: Oleg Nesterov Signed-off-by: Andrew Morton --- 25-akpm/include/linux/list.h | 48 +++++++++++++++++-------------------------- 1 files changed, 20 insertions(+), 28 deletions(-) diff -puN include/linux/list.h~optimize-prefetch-usage-in-list_for_each_xxx include/linux/list.h --- 25/include/linux/list.h~optimize-prefetch-usage-in-list_for_each_xxx 2004-12-27 00:55:56.313135000 -0800 +++ 25-akpm/include/linux/list.h 2004-12-27 00:55:56.318134240 -0800 @@ -329,8 +329,8 @@ static inline void list_splice_init(stru * @head: the head for your list. */ #define list_for_each(pos, head) \ - for (pos = (head)->next, prefetch(pos->next); pos != (head); \ - pos = pos->next, prefetch(pos->next)) + for (pos = (head)->next; prefetch(pos->next), pos != (head); \ + pos = pos->next) /** * __list_for_each - iterate over a list @@ -351,8 +351,8 @@ static inline void list_splice_init(stru * @head: the head for your list. */ #define list_for_each_prev(pos, head) \ - for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \ - pos = pos->prev, prefetch(pos->prev)) + for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \ + pos = pos->prev) /** * list_for_each_safe - iterate over a list safe against removal of list entry @@ -371,11 +371,9 @@ static inline void list_splice_init(stru * @member: the name of the list_struct within the struct. */ #define list_for_each_entry(pos, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member), \ - prefetch(pos->member.next); \ - &pos->member != (head); \ - pos = list_entry(pos->member.next, typeof(*pos), member), \ - prefetch(pos->member.next)) + for (pos = list_entry((head)->next, typeof(*pos), member); \ + prefetch(pos->member.next), &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member)) /** * list_for_each_entry_reverse - iterate backwards over list of given type. @@ -384,11 +382,9 @@ static inline void list_splice_init(stru * @member: the name of the list_struct within the struct. */ #define list_for_each_entry_reverse(pos, head, member) \ - for (pos = list_entry((head)->prev, typeof(*pos), member), \ - prefetch(pos->member.prev); \ - &pos->member != (head); \ - pos = list_entry(pos->member.prev, typeof(*pos), member), \ - prefetch(pos->member.prev)) + for (pos = list_entry((head)->prev, typeof(*pos), member); \ + prefetch(pos->member.prev), &pos->member != (head); \ + pos = list_entry(pos->member.prev, typeof(*pos), member)) /** * list_prepare_entry - prepare a pos entry for use as a start point in @@ -408,11 +404,9 @@ static inline void list_splice_init(stru * @member: the name of the list_struct within the struct. */ #define list_for_each_entry_continue(pos, head, member) \ - for (pos = list_entry(pos->member.next, typeof(*pos), member), \ - prefetch(pos->member.next); \ - &pos->member != (head); \ - pos = list_entry(pos->member.next, typeof(*pos), member), \ - prefetch(pos->member.next)) + for (pos = list_entry(pos->member.next, typeof(*pos), member); \ + prefetch(pos->member.next), &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member)) /** * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry @@ -437,8 +431,8 @@ static inline void list_splice_init(stru * as long as the traversal is guarded by rcu_read_lock(). */ #define list_for_each_rcu(pos, head) \ - for (pos = (head)->next, prefetch(pos->next); pos != (head); \ - pos = rcu_dereference(pos->next), prefetch(pos->next)) + for (pos = (head)->next; prefetch(pos->next), pos != (head); \ + pos = rcu_dereference(pos->next)) #define __list_for_each_rcu(pos, head) \ for (pos = (head)->next; pos != (head); \ @@ -470,12 +464,10 @@ static inline void list_splice_init(stru * as long as the traversal is guarded by rcu_read_lock(). */ #define list_for_each_entry_rcu(pos, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member), \ - prefetch(pos->member.next); \ - &pos->member != (head); \ + for (pos = list_entry((head)->next, typeof(*pos), member); \ + prefetch(pos->member.next), &pos->member != (head); \ pos = rcu_dereference(list_entry(pos->member.next, \ - typeof(*pos), member)), \ - prefetch(pos->member.next)) + typeof(*pos), member))) /** @@ -489,8 +481,8 @@ static inline void list_splice_init(stru * as long as the traversal is guarded by rcu_read_lock(). */ #define list_for_each_continue_rcu(pos, head) \ - for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \ - (pos) = rcu_dereference((pos)->next), prefetch((pos)->next)) + for ((pos) = (pos)->next; prefetch((pos)->next), (pos) != (head); \ + (pos) = rcu_dereference((pos)->next)) /* * Double linked lists with a single pointer list head. _