From 1265057fa02c7bed3b6d9ddc8a2048065a370364 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 8 Aug 2012 09:38:42 -0700 Subject: workqueue: fix CPU binding of flush_delayed_work[_sync]() delayed_work encodes the workqueue to use and the last CPU in delayed_work->work.data while it's on timer. The target CPU is implicitly recorded as the CPU the timer is queued on and delayed_work_timer_fn() queues delayed_work->work to the CPU it is running on. Unfortunately, this leaves flush_delayed_work[_sync]() no way to find out which CPU the delayed_work was queued for when they try to re-queue after killing the timer. Currently, it chooses the local CPU flush is running on. This can unexpectedly move a delayed_work queued on a specific CPU to another CPU and lead to subtle errors. There isn't much point in trying to save several bytes in struct delayed_work, which is already close to a hundred bytes on 64bit with all debug options turned off. This patch adds delayed_work->cpu to remember the CPU it's queued for. Note that if the timer is migrated during CPU down, the work item could be queued to the downed global_cwq after this change. As a detached global_cwq behaves like an unbound one, this doesn't change much for the delayed_work. Signed-off-by: Tejun Heo Cc: Linus Torvalds Cc: Ingo Molnar Cc: Andrew Morton --- include/linux/workqueue.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 20000305a8a6..b14d5d59af7c 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -102,6 +102,7 @@ struct work_struct { struct delayed_work { struct work_struct work; struct timer_list timer; + int cpu; }; static inline struct delayed_work *to_delayed_work(struct work_struct *work) -- cgit v1.2.3