From: Oleg Nesterov list_splice_init(list, head) does unneeded job if it is known that list_empty(head) == 1. We can use list_replace_init() instead. Signed-off-by: Oleg Nesterov Acked-by: David S. Miller Signed-off-by: Andrew Morton --- arch/i386/mm/pageattr.c | 8 ++++---- block/ll_rw_blk.c | 5 ++--- fs/aio.c | 4 ++-- kernel/timer.c | 8 ++++---- kernel/workqueue.c | 4 ++-- net/core/dev.c | 6 +++--- net/core/link_watch.c | 5 ++--- 7 files changed, 19 insertions(+), 21 deletions(-) diff -puN arch/i386/mm/pageattr.c~list-use-list_replace_init-instead-of-list_splice_init arch/i386/mm/pageattr.c --- devel/arch/i386/mm/pageattr.c~list-use-list_replace_init-instead-of-list_splice_init 2006-05-18 01:28:27.000000000 -0700 +++ devel-akpm/arch/i386/mm/pageattr.c 2006-05-18 01:28:27.000000000 -0700 @@ -209,19 +209,19 @@ int change_page_attr(struct page *page, } void global_flush_tlb(void) -{ - LIST_HEAD(l); +{ + struct list_head l; struct page *pg, *next; BUG_ON(irqs_disabled()); spin_lock_irq(&cpa_lock); - list_splice_init(&df_list, &l); + list_replace_init(&df_list, &l); spin_unlock_irq(&cpa_lock); flush_map(); list_for_each_entry_safe(pg, next, &l, lru) __free_page(pg); -} +} #ifdef CONFIG_DEBUG_PAGEALLOC void kernel_map_pages(struct page *page, int numpages, int enable) diff -puN block/ll_rw_blk.c~list-use-list_replace_init-instead-of-list_splice_init block/ll_rw_blk.c --- devel/block/ll_rw_blk.c~list-use-list_replace_init-instead-of-list_splice_init 2006-05-18 01:28:27.000000000 -0700 +++ devel-akpm/block/ll_rw_blk.c 2006-05-18 01:28:27.000000000 -0700 @@ -3365,12 +3365,11 @@ EXPORT_SYMBOL(end_that_request_chunk); */ static void blk_done_softirq(struct softirq_action *h) { - struct list_head *cpu_list; - LIST_HEAD(local_list); + struct list_head *cpu_list, local_list; local_irq_disable(); cpu_list = &__get_cpu_var(blk_cpu_done); - list_splice_init(cpu_list, &local_list); + list_replace_init(cpu_list, &local_list); local_irq_enable(); while (!list_empty(&local_list)) { diff -puN fs/aio.c~list-use-list_replace_init-instead-of-list_splice_init fs/aio.c --- devel/fs/aio.c~list-use-list_replace_init-instead-of-list_splice_init 2006-05-18 01:28:27.000000000 -0700 +++ devel-akpm/fs/aio.c 2006-05-18 01:28:27.000000000 -0700 @@ -777,11 +777,11 @@ out: static int __aio_run_iocbs(struct kioctx *ctx) { struct kiocb *iocb; - LIST_HEAD(run_list); + struct list_head run_list; assert_spin_locked(&ctx->ctx_lock); - list_splice_init(&ctx->run_list, &run_list); + list_replace_init(&ctx->run_list, &run_list); while (!list_empty(&run_list)) { iocb = list_entry(run_list.next, struct kiocb, ki_run_list); diff -puN kernel/timer.c~list-use-list_replace_init-instead-of-list_splice_init kernel/timer.c --- devel/kernel/timer.c~list-use-list_replace_init-instead-of-list_splice_init 2006-05-18 01:28:27.000000000 -0700 +++ devel-akpm/kernel/timer.c 2006-05-18 01:28:27.000000000 -0700 @@ -419,10 +419,10 @@ static inline void __run_timers(tvec_bas spin_lock_irq(&base->lock); while (time_after_eq(jiffies, base->timer_jiffies)) { - struct list_head work_list = LIST_HEAD_INIT(work_list); + struct list_head work_list; struct list_head *head = &work_list; int index = base->timer_jiffies & TVR_MASK; - + /* * Cascade timers: */ @@ -431,8 +431,8 @@ static inline void __run_timers(tvec_bas (!cascade(base, &base->tv3, INDEX(1))) && !cascade(base, &base->tv4, INDEX(2))) cascade(base, &base->tv5, INDEX(3)); - ++base->timer_jiffies; - list_splice_init(base->tv1.vec + index, &work_list); + ++base->timer_jiffies; + list_replace_init(base->tv1.vec + index, &work_list); while (!list_empty(head)) { void (*fn)(unsigned long); unsigned long data; diff -puN kernel/workqueue.c~list-use-list_replace_init-instead-of-list_splice_init kernel/workqueue.c --- devel/kernel/workqueue.c~list-use-list_replace_init-instead-of-list_splice_init 2006-05-18 01:28:27.000000000 -0700 +++ devel-akpm/kernel/workqueue.c 2006-05-18 01:28:27.000000000 -0700 @@ -531,11 +531,11 @@ int current_is_keventd(void) static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) { struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); - LIST_HEAD(list); + struct list_head list; struct work_struct *work; spin_lock_irq(&cwq->lock); - list_splice_init(&cwq->worklist, &list); + list_replace_init(&cwq->worklist, &list); while (!list_empty(&list)) { printk("Taking work for %s\n", wq->name); diff -puN net/core/dev.c~list-use-list_replace_init-instead-of-list_splice_init net/core/dev.c --- devel/net/core/dev.c~list-use-list_replace_init-instead-of-list_splice_init 2006-05-18 01:28:27.000000000 -0700 +++ devel-akpm/net/core/dev.c 2006-05-18 01:28:27.000000000 -0700 @@ -3020,7 +3020,7 @@ static void netdev_wait_allrefs(struct n static DEFINE_MUTEX(net_todo_run_mutex); void netdev_run_todo(void) { - struct list_head list = LIST_HEAD_INIT(list); + struct list_head list; /* Need to guard against multiple cpu's getting out of order. */ mutex_lock(&net_todo_run_mutex); @@ -3035,9 +3035,9 @@ void netdev_run_todo(void) /* Snapshot list, allow later requests */ spin_lock(&net_todo_list_lock); - list_splice_init(&net_todo_list, &list); + list_replace_init(&net_todo_list, &list); spin_unlock(&net_todo_list_lock); - + while (!list_empty(&list)) { struct net_device *dev = list_entry(list.next, struct net_device, todo_list); diff -puN net/core/link_watch.c~list-use-list_replace_init-instead-of-list_splice_init net/core/link_watch.c --- devel/net/core/link_watch.c~list-use-list_replace_init-instead-of-list_splice_init 2006-05-18 01:28:27.000000000 -0700 +++ devel-akpm/net/core/link_watch.c 2006-05-18 01:28:27.000000000 -0700 @@ -91,11 +91,10 @@ static void rfc2863_policy(struct net_de /* Must be called with the rtnl semaphore held */ void linkwatch_run_queue(void) { - LIST_HEAD(head); - struct list_head *n, *next; + struct list_head head, *n, *next; spin_lock_irq(&lweventlist_lock); - list_splice_init(&lweventlist, &head); + list_replace_init(&lweventlist, &head); spin_unlock_irq(&lweventlist_lock); list_for_each_safe(n, next, &head) { _