diff options
author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-05-09 02:33:54 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 12:30:51 -0700 |
commit | 83c22520c51bf67529367e8237f95c03fe44e2da (patch) | |
tree | d9798e4f60551bdad0f7d8f1f1d5c69d7c4214c1 /kernel/workqueue.c | |
parent | edab2516a6c1752e8e5e3d55727cabf12346e5df (diff) | |
download | kernel_samsung_tuna-83c22520c51bf67529367e8237f95c03fe44e2da.zip kernel_samsung_tuna-83c22520c51bf67529367e8237f95c03fe44e2da.tar.gz kernel_samsung_tuna-83c22520c51bf67529367e8237f95c03fe44e2da.tar.bz2 |
flush_cpu_workqueue: don't flush an empty ->worklist
Now when we have ->current_work we can avoid adding a barrier and waiting
for its completition when cwq's queue is empty.
Note: this change is also useful if we change flush_workqueue() to also
check the dead CPUs.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Gautham Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r-- | kernel/workqueue.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 5176d51..5ecf498 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -404,12 +404,15 @@ static void wq_barrier_func(struct work_struct *work) complete(&barr->done); } -static inline void init_wq_barrier(struct wq_barrier *barr) +static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, + struct wq_barrier *barr, int tail) { INIT_WORK(&barr->work, wq_barrier_func); __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); init_completion(&barr->done); + + insert_work(cwq, &barr->work, tail); } static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) @@ -428,13 +431,20 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) preempt_disable(); } else { struct wq_barrier barr; + int active = 0; - init_wq_barrier(&barr); - __queue_work(cwq, &barr.work); + spin_lock_irq(&cwq->lock); + if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { + insert_wq_barrier(cwq, &barr, 1); + active = 1; + } + spin_unlock_irq(&cwq->lock); - preempt_enable(); /* Can no longer touch *cwq */ - wait_for_completion(&barr.done); - preempt_disable(); + if (active) { + preempt_enable(); + wait_for_completion(&barr.done); + preempt_disable(); + } } } @@ -475,8 +485,7 @@ static void wait_on_work(struct cpu_workqueue_struct *cwq, spin_lock_irq(&cwq->lock); if (unlikely(cwq->current_work == work)) { - init_wq_barrier(&barr); - insert_work(cwq, &barr.work, 0); + insert_wq_barrier(cwq, &barr, 0); running = 1; } spin_unlock_irq(&cwq->lock); |